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ESA’s Clean Space Industry Days (2021 CSID) have become the central forum for European industry working on designing and building sustainable missions.
The 2021 edition will be entirely online.
This year, the CSID will cover the following topics:
Ecodesign for space: embedding environmental sustainability within space mission design
Managing the end of life: Developing technologies to prevent the creation of future debris, including Design for removal
The Clean Space initiative started almost 10 years ago when an ESA team was asked to investigate the environmental impact of a launcher. This led to the adaptation of existing environmental LCA (Life Cycle Assessment) tools to space activities and the development of the Space System Life Cycle Assessment guidelines. Applying LCA to a space mission is still today far more challenging than in many other industrial sectors.
Once you have the results of your LCA study and have identified the most polluting elements of your activity, you must carry on with reducing its environmental impacts. This topic is addressed by the ‘EcoDesign for space missions’ branch of Clean Space. EcoDesign for space missions means to design missions taking into account their environmental impact and fostering the use of green materials and manufacturing processes – and that will be compliant with European environmental legislation such as REACH.
It is no surprise that both environmental LCA and eco-design for space missions are of high interest to European space actors. We indeed live in a region where tackling environmental issues is considered a priority.
ESA intends to minimise the production of space debris and support European space industry to comply with existing and future space debris mitigation rules, guidelines, policies and laws.
Design for Demise will be a prominent topic during this year’s CSID. A lot is happening in Europe regarding the development of new technologies that will demise during re-entry. These investigations and developments will be discussed during sessions focusing on several technologies.
Other topics will be covered such as post-mission disposal, passivation and managing the end-of-life of small satellites and cubesats.
Satellites are also being prepared to be removed in the future. You will get an update on technology developments designed for satellites that will be launched in future that will simplify the rendezvous and capture process in the event a satellite is unable to perform its disposal / end-of-life manoeuvres. Therefore, a specific session on Design for Removal will cover:
In 2019, ESA challenged European space industry to come up with a service to remove one or more ESA object(s) whilst also demonstrating in-orbit functionalities required for future on-orbit services that industry foresees based on market needs. By acting as pioneers in the first debris-removal service, European industry will gain first-mover advantage on the global stage and kick-start a new market for on-orbit servicing.
Such a mission is technically demanding, and as such ESA has been carrying out a number of studies to develop and mature the necessary technologies both for debris removal and in-orbit servicing. The Clean Space Industrial Days will be an opportunity to gain up-to-date information on the latest technology developments in the areas of:
The event will also open the floor to system-level presentations about in-orbit servicing missions.
Activities carried out to develop technologies for approaching, grasping and manipulating spacecraft on orbit helped identified knowledge gaps of major importance for rendezvous and capture.
These gaps mean that there is a particular lack of technical requirements and verification methods for ensuring that rendezvous and proximity operations are conducted in a sustainable manner.
A workshop on ‘Close Proximity Operations’ aims at triggering discussions with European space actors to define requirements and guidelines to ensure safe rendezvous and capture operations.
For decades we assumed that in-orbit assembly, manufacturing and recycling was a future, scifi concept. Today, ESA decided to take these subjects seriously. Indeed, they could change the way space systems will be designed and operated in the future.
Thus, our last session will cover system aspects and technology developments needed for future services (in Earth orbit) such as manufacturing, refurbishing, assembling, recycling and refuelling. This is going to be addressed in the sessions covering On-orbit manufacturing, assembly and recycle (OMAR)
Enabling the first active debris-removal mission as the cornerstone for a vital new European business providing in-orbit servicing such as repairing, refuelling or even recycling. This encompasses also Close-proximity operations and On-orbit manufacturing, assembly and recycling (OMAR)
The project ADR-LEOCOM (Active Debris Recovery System for LEO Communications Missions) was a project in the frame of the ARTES program. The objective of this activity was to identify different business model architectures for debris removal systems together with the associated high-level Concept of Operations where applicable. After finding a valid business model, then an initial design of the associated chaser was made, including verification of the initial cost estimates of the service assumed in the business cases.
Nowadays, less than 9,000 objects have been launched to space. Around 5,000 are still in orbit, although only about 2,000 are operational. Besides these satellites, collisions and explosions have generated several thousands of debris pieces. To put a number, on average, two satellite failures per year in LEO result in a total loss of the satellite.
Moreover, recently there has been a cheapening on the access to space (led by the CubeSats paradigm). On the wake of this movement, new space concepts have appeared, like the mega-constellations being implemented for Telecommunications and Earth Observations purposes, which comprise hundreds and thousands of satellites in LEO.
Several studies indicate that to keep the debris population under control, the success ratio for disposal should be of 90% or 99% (higher than the current ratios). In order to keep the debris problem under control, new solutions have to be considered, as for instance the Active Removal of failed satellites, to avoid possible future collisions.
The objective of the ADR-LEOCOM project wass:
• to identify different business models for debris removal systems
• if a valid business model is identified, initial design of the debris
removal satellite
The presentation will go on the main points of the study, presenting the concept developed for the servicing.
There is little doubt that we are witnessing a rapid expansion of space activities, both in Earth orbits and outside Earth's sphere of influence. This is mostly driven by commercial activities: new and existing companies that are exploiting the "Resource Space" to deliver innovative product and services while making profits.
In order to use space efficiently, an infrastructure of logistics services will be necessary, in the same way it is on Earth. This would first of all ensure a safe and clean access to space, while supporting the long-term sustainability and profitability of commercial space activities.
D-Orbit has identified Deorbit Kits as an important building block for such a servicing and logistics infrastructure. Those kits can be installed potentially on any space asset, including debris, to move it from one orbit to another, increasing reusability, sustainability and reconfigurability of space resources. Kits are designed to be modular, so that can be adaptable to different mission scenarios, and can be transported to the target by a mothership. They can deliver services such as debris removal, end-of-life management, relocation, transportation, life extension.
embedding environmental sustainability within space mission design
Developing technologies to prevent the creation of future debris, including Design for removal
Following the extensive work done in the last years to develope solution to ease the compliance with SDM requirements, OHB, Airbus, Thalès and ESA will discuss the current challenges and future solutions in LEO and GEO during this session
Enabling the first active debris-removal mission as the cornerstone for a vital new European business providing in-orbit servicing such as repairing, refuelling or even recycling. This encompasses also Close-proximity operations and On-orbit manufacturing, assembly and recycling (OMAR)
Airbus has developed many concepts in the field of In-Orbit Servicing, and built unique experience and competencies across:
• Rendezvous and proximity operations: as prime for the ATV programme, leading the world first full automated rendezvous; this success was the result of an intense effort involving design and validation of whole GNC functional chain (incl. Visual Based Navigation sensors and image processing), FDIR means, and operations procedures definition;
• Capture: effective management of the docking between the ATV and the ISS, which remains the only in-flight experience in Europe;
• Key roles were held for the RemoveDebris mission, with in-orbit experiments of net and harpoon capture: overall system engineering lead for the mission (on behalf of SSTL as prime), and responsibility for net system design and development;
• Prime for the various projects in the field of debris removal: ESA-funded e.Deorbit up to phase B1 consolidation as single team (covering all aspects of the system definition for the Envisat removal mission), DLR-funded DEOS up to PDR, phase A study for the removal of mega-constellations in the frame of SUNRISE ESA-OW PPP, etc;
• Various technology development studies, supported by ESA or space national agencies, related to in-space manufacturing and assembly, at both system and technology level;
• Internal Space Tug project, with the O.CUBED initiative, addressing in-orbit servicing for GEO satellites (lifetime extension, refuelling, etc), has also been enabling development of key skills for managing such missions and services.
We need new missions to be smarter and innovative in order to counteract and better manage the future in space to tackle the growing population of satellites. We have to do On-Orbit Servicing: it’s a way of directly managing satellites while they are operating in space. In order to better enable these new advanced operations in space like refuelling or upgrading, this requires satellites, from now on, to be prepared with specific interfaces and grapples fixtures. Thales Alenia Space is working towards developing the next generation of servicing vehicle to perform these robotic operations.
In-Orbit Servicing means performing activities through robotics technology onto a spacecraft or, more generically, a “space object” in space, right when it is in orbit. Today Satellite Operators deal with unserviceable satellites in orbit that might need to be repaired, refurbished, refueled, reconfigured, or placed in orbits where they can last for many more years, or deorbited (either closer to Earth where they get burned to dust by our planet’s atmosphere or into “cemetery orbits” where their presence does not interfere with active space objects safe operation).
Moreover, as the small satellite demand will experience fast pace growth over the next 10 years, we are left with the urgent task of designing solutions for sustainability and reduction of orbital debris in space.
IOS are therefore defined as the emerging concepts of products or services that can meet those market needs.
How does Avio imagine to address such market, as well as Space Debris issue?
Vega Family of Launchers are, by their very nature, designed to deliver payloads into orbits where space debris proliferate. Question we’ve asked ourselves is the following: what if, potentially for each Vega mission, some payloads are delivered in LEO and, at the same time, a robotic solution could be deployed to counter space junk and to operate different types of services?
Answer is that, by defition, such solution can result as one of the most promising and surely cost-effective, as a significant proportion of the overall costs for a single IOS mission (related to the access to space) will be partially borne by the Vega Launcher passengers of satellite deployment.
Such concept relies on the assumption, based on historical data observation and future launches projection, that not all the flights occur at unitary filling factor, thus leaving enough "room" for a low-weight solution to take part of a standard Vega mission, thus enabling new services at marginal cost.
We do believe that conceiving IOS as an end-to-end mission, integrated with launch service, can be a game changer for this emerging market: the Launch Service Provider executes at the same time the injection in the reference orbit of a payload (bearing as usual the launch service expenses) and In-Orbit Services, with the latter being provided by the – properly configured - upper stage of the launch vehicle itself. This results in a unique end-to-end solution for satellite operators and, by definition, the cheapest possible solution for any customer interested in the specific service.
The overall technical solution conceived by Avio should be ideally be fitted-for integration, as auxiliary payload, onto Ariane family of launchers, in order to address the market abiding in more energetic orbits (MEO and GEO).
The sustainability of the servicing mission stands only in the case the servicer can reliably perform different services.
Celestial mechanics have an impact on the servicer spacecraft design. The needed versatility of the servicer cannot withstand with frequent changes of the orbital planes; therefore, the servicer shall target a specific orbit.
embedding environmental sustainability within space mission design
This session will present the work conducted by Deloitte for ESA regarding the requirements of the disclosure
of non-financial data for the launcher industry.
The presentation will begin with the definition of the key concepts of the disclosure of environmental
information. Then, Deloitte will present the analysis of the environmental-related information disclosure
aspects of Directive 2014/95/EU (disclosure of non-financial and diversity information). We will finally go over
its transposition in the national legislation of selected ESA Member States together with key aspects of
international guidelines and frameworks.
To conclude the presentation, two series of suggestions will be detailed:
• Towards the European space transportation industry for a more efficient and transparent
environmental-related reporting
• Towards the Agency to support industry in its efforts to improve the disclosure of such information
Developing technologies to prevent the creation of future debris, including Design for removal
The status and novelties of the ESA Space Debris Mitigation and Re-entry Safety framework is shown in this presentation.
The ESA policy on Space Debris Mitigation makes applicable the requirements in the standard ECSS-U-AS-10C, Rev. 1 / ISO 24113:2019.
The latest update of the ECSS/ISO Space Debris Mitigation requirements was published in 2019. Furthermore, the work on the next updates of these standards is also progressing.
The ESA re-entry safety requirements are collected in the standard “ESSB-ST-U-004 since 2015.
The ESA handbook “ESSB-HB-U-002 - ESA Space Debris Mitigation Compliance Verification Guidelines” explains how ESA requests Projects to implement and verify the Space Debris Mitigation. The first issue of ESSB-HB-U-002 was published in 2015.
An update of the “ESSB-HB-U-002 - ESA Space Debris Mitigation Compliance Verification Guidelines” is expected in 2021 to reflects the updates in ECSS-U-AS-10C, Rev.1 / ISO 24113:2019.
Enabling the first active debris-removal mission as the cornerstone for a vital new European business providing in-orbit servicing such as repairing, refuelling or even recycling. This encompasses also Close-proximity operations and On-orbit manufacturing, assembly and recycling (OMAR)
The PERIOD Consortium, -bringing together the competencies of Airbus Defence and Space, DFKI, EASN-TIS, GMV, GMV-SKY, ISISPACE, SENER Aeroespacial and Space Application Services, is proposing a very ambitious demonstration scenario for an orbital Factory concept. A satellite will be manufactured, assembled in the Factory and injected in LEO for being operated. The manufacturing includes the fabrication of an antenna, the assembly of the satellite components and its reconfiguration and inspection in the Factory. The demonstrator will be upgraded to extend the level of capability validation from assembly and manufacturing of structures to refueling experiments. The objectives of the PERIOD project (PERASPERA In-Orbit Demonstration) are therefore focusing on the main levers to generate the core in-orbit Services, Manufacturing and Assembly (ISMA) capabilities. In PERIOD which is currently running a phase A/B1 the in-orbit demonstration is planned to be implemented as early as 2026 and the space robotics technologies are being matured to TRL5. The SRC building blocks ESROCOS, ERGO and InFuse are being further developed after an alignment of their perimeter to the demonstration objectives. The Standard Interconnects (SI), at TRL5 at project start, will be tested in a benchmark for evaluating their performance. In addition, these SRC building blocks will be integrated in a breadboard at Airbus for supporting the system definition work. The new ISMA capabilities will generate on-orbit services improving the orbital infrastructure, creating in turn a very promising business opportunity with sizeable market. The PERIOD demonstration will cover the short and mid-to-long term ISMA business cases and will support the transition to in-space services, assembly and manufacturing paradigm. The PERIOD project has received funding from the European Union’s Horizon 2020 research and innovation programs under grant agreement No 101004151.
The presentation will give insite of the outputs gained at the end of phase A for the e.Inspector 12U cubesat mission.
Rationale for the proposed baseline together with the opportunities the mission offers to play as on orbit demonstrator for technologies to cope with interesting challenges the close proximity operations ask to face will be presented as well.
A glimpse on the MBSE approach adopted to effectively go through this cubesat lifecycle will also shown.
To make in-orbit servicing a tangible and viable reality, a set of foundational technologies must be matured and verified accordingly. Such technologies act as cornerstones or columns from where in-orbit activities such as debris removal, refueling and inspection can stand upon. ReOrbit is embarked on demonstrating such foundational technologies with a tech maturation mission called Ukko which consists of two smallsats equipped with the capabilities to perform a set of scenarios:
• Distributed and decentralized software-defined architectures, where both smallsats can interchange roles as leader and follower, showcasing the possibilitty of reconfigurable missions.
• Autonomous RPO (Rendezvous and Prox Operations) where both smallsats can keep in a relative fixed geometry without any intervention from ground operations, including a fully autonomous docking simulation scenario.
• Autonomous on-board self-diagnostics and failure detection, isolation and recovery (FDIR).
The presentation will consist in showing how ReOrbit is progressing with Ukko and what partnerships and technologies are key for achieving this pioneering mission's goal.
Blackswan Technologies is building autonomy in space. While developing autonomous navigation and space robotics technologies, we have realized that all the currently available tools for training and testing autonomous space missions are lacking. Thus, our team has started developing the Mission Design Simulator (MDS) to enable rapid prototyping without the need to use multiple software packages as well as generate synthetic data for training DL models, CV algorithms, and provide a standardized framework for autonomous mission design and testing.
In this talk we will present an in-orbit servicing scenario that was built with MDS and discuss how the software can help other teams developing their IOS and debris removal missions in their early phases and beyond.
Satellite owners, operators, space agencies and commercial players owning the mega-constellations (e.g. Starlink, Amazon Kuiper, OneWeb, etc.) will need to find economically viable ways to inspect, refuel, augment, extend and manage the lifetime of their satellites. Satellite owners are bound to face the challenge to choose the most reliable and profitable on-orbit satellite servicing solution for extending the capabilities of their satellites and in an effort to keep customers on board.
Satellite owners will need to develop trade-off scenarios in order to choose from the rich spectrum of on orbit satellite services or the launch of a new satellite. Some of the emerging trends taking place in the space industry are on orbit satellite servicing, active debris removal services and end-of life services. With the technology demonstrations on orbit of MEV-1, MEV-2 and ELSA-d missions.
The presentation proposes an initial user-driven framework presenting the elements that could be taken into account when developing trade-off scenarios for on-orbit satellite services, active debris removal services and recycling of satellite components. For example space agencies should consider collision risks, technology innovations and costs for active debris removal services when choosing services, while satellite operators ought to look at satellite profitability, continuation of the customer base, cost-savings, time to market, launch and insurance costs.
It is important to understand the factors influencing the end-user choice for on-orbit servicing or active debris removal services because that will help satellite owners and operators develop their trade-off scenarios. Service provider companies will also be able to develop optimistic, realistic and pessimistic market scenarios for their business models, which will facilitate their process of attracting private investors and offering competitive prices during the different market development phases of their on-orbit satellite servicing activities.
embedding environmental sustainability within space mission design
The “LCA Ground Segment” project (ESA Contract No. 4000123991/18/NL/GLC/as) aimed to assess the environmental performances and the applicability of eco-design principles to Ground Segment through the elaboration of a specific methodology, the involvement of ground segment experts and the in-depth evaluation of the most promising options.
The Life Cycle Assessment (LCA) is a standardized methodology, which assesses environmental impacts associated with all the stages of a product/service life cycle, from raw material extraction and materials processing to manufacture, distribution, use, repair and maintenance and disposal or recycling.
The Ground Segment’s main functions are the management of the communications between the in-orbit satellite and the mission control centre as well as the archiving and processing of the mission-specific scientific data collected.
The study (started in June 2018, ended in February 2020), managed by RINA with the support of Spanish Space Company Deimos Space and French Consulting Company CT Ingenierie, has reached the following objectives:
• Identification and define of the main constituting blocks of Ground Segment representatives for Telecommunication (TC), Navigation (NAV), Scientific, Earth Observation (EO), CubeSat missions and related to Ground Station, Mission Operation Centre, Data & Science Centres.
• Performing of LCA for the Maintenance and Operation Phases of the Ground Segment, Ground System Development Phase, Overall Ground Segment Facilities, Space Missions (Functional Unit: The Fulfilment of requirements of Ground Segment for the entire mission, along its lifetime). The analysis ended with the identification of main hotspots: Electricity consumption in Facilities, Stainless-Steel manufacturing for Antennas, Printed Wiring Board manufacturing in Electronic components.
• Definition of methodological guidelines about LCA methodology applied to Ground Segment in order to update/ the ESA LCA Handbook.
• Creation of more than 70 LCA datasets, covering more than 160 equipment of ESTRACK Database, in order to provide a database for future LCAs in Ground Segment.
• Investigate 18 innovative eco-design options (technical solutions, spin-ins and/or new technologies, innovative processes, etc.) by also considering non-technical aspects (cost and risks, TRL, implementation roadmap, etc.) which can be applied to the various Ground Segment family’s infrastructures and operations in order to reduce their environmental impact. Three options have been deeply studied: 1) Install innovative cooling systems in server rooms; 2) Different design solutions for overall lighter design in Ground Segment Facilities; 3) Use alternative material in Ground Segment.
The project is part of the ESA Clean Space Initiative, which promotes an eco-friendly approach to space activities.
This session will present the methodology and the results of the Life Cycle Assessments conducted on two
ground stations of the ESTRACK network: Kiruna (antenna KIR-1) and Cebreros.
Due to the high complexity of the systems, the project team developed a specific methodology for this LCA,
which will be summarized during the presentation. Indeed, a significant challenge lied in the fact that thousands
of items are used in a ground station to catch the signal from the satellites, process it and transmit it to ESOC
(and vice-versa). We will also detail the nature of the environmental impacts of the ground stations and the
sources of these environmental hotspots.
Based on the learnings of the two case studies, two simplified methodologies were proposed to derive the
environmental impacts of other ground stations, both stations from ESTRACK and outside the network. These
methodologies will be presented.
The final aspect of the activity that will be introduced during the meeting is the approach for the reduction of
the impacts developed throughout the project.
We will finally conclude with the main learnings and takeaways from this study.
Developing technologies to prevent the creation of future debris, including Design for removal
ESA will host a session on passivation for managing the spacecraft's end-of-life where ESA, Airbus, Thalès, RUAG, ArianeGroup, Arquimea and CNES will present their perspectives for passivation. The discussion will focus on what technologies are still needed to achieve full passivation in-orbit.
embedding environmental sustainability within space mission design
Atmospheric Re-entry Assessment is an ESA study dedicated to the investigation of the potential impacts on the atmosphere and on climate, caused by gases and particles released during the re-entry of spacecrafts and rocket upper stages. The activity had been carried out by combining very diverse heritages and capabilities, such as re-entry analyses, by-products evaluations and different types of atmospheric and climate simulations.
In the context of the Eco-design/Clean Space initiative, ESA has been developing tools to quantify the environmental impacts of the space industry. It has adopted a standard approach, Life Cycle Analysis (LCA), which evaluates inputs, outputs, and potential environmental impacts throughout the entire life cycle of products. LCA can deal successfully with most phases of space activities (R&D, infrastructure, production, assembly, in-orbit operations,...) because they are common to other industries. In contrast, like the launch, the re-entry phase is specific to the space industry with highly specialized problems. Therefore assessing the environmental impacts of re-entry is more challenging.
When an object re-enters the Earth’s atmosphere, it is generally subject to quasi-complete demise releasing gases and particles in the atmosphere that can impact the environment. We will describe the methodology used in an ESA-funded project (ATISPADE / ATmospheric Impact of SPAcecraft Demise, led by Varuna-UK) in assessing atmospheric impacts of re-entry demise emissions. We will present key findings on global environmental issues (e.g. ozone depletion, climate change) and highlight outstanding issues.
embedding environmental sustainability within space mission design
Over the last few years, ESA has established a life cycle assessment (LCA) database and collected data from use of this database in several contracts. Recently, efforts were made to integrate all datasets into one harmonized database for materials, manufacturing processes, system components, propellants and support functions, with the intention to support ecodesign. In this presentation we summarize the development process and host a guided tour to the insides of the the current ESA LCA database.
Due to its uniqueness, the space sector needs more specific methodology definitions besides the ISO 14040 and 14044 standards on LCA, in order to apply LCA studies to space applications. Therefore, to enhance and strengthen the LCA approach in space industry, ESA developed a new methodological LCA framework, taking into consideration the specificities of space sector. Additionally, a consolidated LCA oriented database for the space sector was developed as part of this methodological approach..
Since 2012, ESA have conducted several projects on space LCA. Collectively, these are an important step toward the realisation of the LCA as a viable approach for scientifically quantifying environmental impacts in Space Sector, both for internal activities (using datasets with confidential information and industry proprietary information) but also promoting it with external stakeholders (containing non-confidential information). During past ESA contracts around 1000 relevant, unique datasets have been included and harmonized into the ESA LCA Database (internal and external), using SimaPro software with ecoinvent database.
The objective of the ESA Environmental LCA Database project is to further build, consolidate and maintain a fully operational and up-to-date environmental LCA database to be used by ESA and European stakeholders from ESA member states. As such, this presentation details the current ESA LCA Database structure and features, and follows the foreseen improvements during the contract.
Developing technologies to prevent the creation of future debris, including Design for removal
In the frame of the French Space Operation Act (LOS) signed on 3rd June 2008, CNES and R.Tech are particularly interested by re-entries of space debris. CNES is indeed in charge of ensuring the right application of the law, for every mission launched or operated from the French territory. To predict the debris survivability during their re-entries and assess the prospective risk on ground, the development of complete multidisciplinary tools is required.
With this in mind, CNES and R.Tech develops together their own spacecraft-oriented tool named PAMPERO since 2013. PAMPERO aims to simulate the complete atmospheric reentry of an entire satellite, launcher or the associated fragments due to the breakup process. These characteristics are the following:
- Six degrees-of-freedom flight dynamics,
- Aerodynamics and aerothermodynamics analysis : aerodynamics coefficients & parietal thermal heat fluxes computation,
- Heat transfers modeling by a 3D thermal conduction module,
- Mechanical stress analysis from the aerodynamic and thermal loads,
- Estimate of the destruction phenomena: ablation & fragmentation.
The purpose of this communication is to highlight the latest developments in the PAMPERO code, such as:
- New mesh generation strategy by merging of simple meshes
- Efficiency of the new thermal solver compared to other codes
- Comparison of the degradation model to experiments
- Coupling with the ASTER code, for mechanical stress analysis,
- Rigorous validation of each module of the code performed automatically with a comparison to analytical results, experiments and data of other simulations
Ability of PAMPERO to model complex industrial test cases easily will be presented as well as upcoming developments.
During re-entry into the Earth's atmosphere a spacecraft encounters strong thermal and mechanical loads. The thermal loads result in heating and eventually thermal failure (e.g. melting, combustion) of some of the spacecraft parts. The mechanical loads can result in bending and eventually breaking of parts. Both effects are considered in state-of-the-art re-entry simulation tools separately, or if combined, in a heuristic manner by trigger events or tailored for specific cases (e.g. for predefined cut planes). The presentation will summarize the outcome of a study on the combined effect of thermal and mechanical loads, which has been investigated numerically and experimentally.
embedding environmental sustainability within space mission design
ESA has started to include mandatory requirements into some its projects to perform an assessment of the environmental impacts. While the LCA approach might be relatively new for the space sector some valuable experience has already been gathered by primes in implementing LCA in ESA projects. LCA requirements are indeed been followed at different phases of a mission. In this session the primes will share their experience by giving feedback on the most challenging aspects of LCA and eco-design implementation. The current and future challenges of the implementation of LCA in projects and the steps to be taken will be afterwards discussed in a round table.
Developing technologies to prevent the creation of future debris, including Design for removal
The on-ground casualty risk of any re-entry (controlled or uncontrolled) shall be below 1 in 10,000. One way of reducing the risk for the system is to focus on the equipment on-board.
For equipment which does not demise, the casualty risk can be reduced by design-for-demise (D4D), this is achieved by reducing the number, size, and kinetic energy of the surviving fragments associated with the equipment. To assess improvement in demisability one can use spacecraft-oriented re-entry tools (e.g. SCARAB). By studying the equipment in detail with numerical re-entry simulations and experiments using high-enthalpy wind tunnels one can ensure that the equipment will demise upon re-entry.
The current status and evolution of the equipment-level based analysis within HTG will be presented.
The shift within Europe to destructive re-entry models which are grounded in test data has provided significant steps in the understanding of key phenomena, and capturing of critical effects such as length-scale dependent heating and fragmentation through joint failure. This has led to more careful modelling, both of critical parts within a wider range of components, and of fragmentation processes. In turn, this has resulted in the prediction of larger numbers of smaller objects reaching the ground, and an increase in the predicted casualty risks.
This pattern was particularly evident in the outputs from the PADRE activity, where a probabilistic framework for destructive re-entry calculations was developed. This framework is tool agnostic, and has been used to execute large scale comparative simulation capaigns of identical vehicles in both SAMj and DRAMA. To manage the associated complexity, a common input spreadsheet-based vehicle definition format has been implemented. Allied to a new SAMj viewer, this greatly simplifies the construction of component-based models for both tools. The uncertainty models developed in PADRE are now used by default in SAMj simulation campaigns. This is important because, although significant progress has been made in the last five years, fragmentation and demise processes in destructive re-entry are still not well understood, and the modelling of these processes continues to have high levels of uncertainty.
In order to refine estimates of casualty risk, a number of other small enhancements have been made to SAMj. The failure of aluminium has been shown in testing to be driven by the tearing of the oxide layer once the material inside has sufficiently melted that it can move. This occurs once a significant proportion of the material has melted, and is represented by the use of a mass loss fraction model in SAMj. This model can be applied to release of nested objects as well as fragmentation, and has also been applied to other materials. Testing shows that the material failure occurs at higher mass loss fractions for aluminium than for other metals examined. The Heat Balance Integral model used in SAMj for insulating materials such as glasses and composites has been simplified, leading to improved robustness and performance. This is expected to be exercised in upcoming work in ongoing activities. Another recent upgrade considers complex shapes reaching the ground where the affected area is not well represented by the projection of the shape as it contains large holes or gaps. A convex hull algorithm has been added so that SAMj will not underpredict the casualty area in these circumstances.
There are a number of remaining gaps in state-of-the-art destructive re-entry tool capabilities, some of which will be addressed in upcoming activities. These include improvements in the representation of aerothermodynamic heating to complex, and particularly concave shapes, fragmentation of bolted joints and uneven heating effects.
Usually heat flux measurements in ground test facilities as well as simulations in the hypersonic flow regime are performed at static conditions with non-moving objects. But objects performing an uncontrolled re-entry are quite likely to rotate and/or tumble. This is true for meteorites, satellites and empty stages of launch vehicles.
Previous experiments were conducted with free flying objects in the hypersonic test section H2K of the Department of Supersonic and Hypersonic Technologies at the German Aerospace Centre DLR in Cologne, which focused on the forces acting on rotating and tumbling objects. However, these experiments were not suited to perform heat flux measurements. Therefore, a new set-up with forced spinning objects have been tested. This activity is complementary to demise experiments with spinning objects in the arc heated facility L2K at DLR in Cologne. We present the concept of the experiments, the challenges and first experimental results of spinning cylinders.
There are many limitations in ground testing in the laboratory, that prohibit fully realistic simulation of the destructive entry-flight. Some of these limitations could be overcome by technical solutions, others are determined by the physics (e.g. gravitational forces acting on the test hardware). The impact of the limitations varies and have been discussed in the community for years. One of the major limitations that could be solved technically, is the testing of satellite components in a static setup. Static testing does not reproduce the dynamic re-entry environment with its changing heat flux distribution and the inertial forces.
The Department of Supersonic and Hypersonic Technologies of the German Aerospace Centre DLR constantly works on improving the test facilities, setups and instrumentation and has now developed a solution that allows dynamic demise simulation in the arc heated facility L2K. This development is complementary to the implementation realised in H2K wind tunnel for measurement of the heat flux distribution on spinning samples. We present the spinning device and wind tunnel setup and show results of the first component tests in L2K.
Fluid Gravity Engineering FGE have been active in destructive entry modelling for ground safety and planetary protection applications for well over a decade. Modelling approaches have evolved significantly during the past eight years and particular attention has been focused on: (i) methods to verify component level demise and (ii) methods to assist in Design for Demise (D4D) assessment. Balancing model fidelity with required run time; the ability to develop a stochastic model; the physical data available to modellers and; the relative accuracy of the various physical models is a challenge that all D4D modelling activities have to be prescient of. How to make best use of experimental data to support this approach is also an important question which has to be developed alongside modelling capability.
This paper describes how we have approached this balancing act during the past eight years and how this has been incorporated into the development of the Spacecraft Aero thermal Model (SAMj) jointly with Belstead Research Ltd (BRL).
Enabling the first active debris-removal mission as the cornerstone for a vital new European business providing in-orbit servicing such as repairing, refuelling or even recycling. This encompasses also Close-proximity operations and On-orbit manufacturing, assembly and recycling (OMAR)
Enabling the first active debris-removal mission as the cornerstone for a vital new European business providing in-orbit servicing such as repairing, refuelling or even recycling. This encompasses also Close-proximity operations and On-orbit manufacturing, assembly and recycling (OMAR)
Space debris removal needs a complex strategy of mitigation and remediation where technological innovations may open new routes and possibilities. At present, the use of cleaning satellites for debris capture and de-orbiting seems to be very promising. Nevertheless, traditional solutions are mainly investigated, from the net to robotized arms. It is evident that the grabbing device technology should be selected on the basis of the debris size to remove, and its orbiting characteristics as well as the different cleaning mission goals. In this scenario, shape memory polymer composite (SMPC) devices may play a very important role for small debris removal with undefined shape, mainly in the optic of in-space manufacturing of cleaning satellites. SMPC can freeze a non-equilibrium shape (open) and recover the equilibrium shape (closed) by heating. Heaters and sensors are integrated in the SMPC structure during manufacturing. The ESA project e-SpaDeS (Space Debris Suppression) has the goal to design SMPC devices for space debris grabbing. SMPC devices apply low grabbing forces and high damping during debris capture approach, thus minimizing possible fragmentation and issues due to debris spin. Moreover, SMPC devices are light structures with manufacturing procedures compatible with the additive logic, therefore in the line of the concepts for in-space manufacturing. The project aims to define, for the first time, the optimal SMPC geometry for debris capture. Present status of the results will be shown with the focus on the expected device requirements and new laboratory findings.
On-orbit manufacturing, assembly and recycling (OMAR) servicing entails many challenges with one of the most complex tasks being that of cooperative capture. Such challenges are related to rendezvous proximity operations, close range navigation, capture and manipulation of payloads or client spacecraft.
Robotic arms are key enablers of OMAR, providing capabilities for soft capture and berthing of cooperative and uncooperative spacecraft, including assets that have not been specifically design to be captured or serviced. Indeed robotic arms are key and critical enabler for OMAR as they increase the range of operations of on-orbit missions by providing capabilities such as:
● capture for cooperative and noncooperative objects,
● inspection and repair,
● on orbit assembly,
● spacecraft maintenance,
● refueling assistance,
● replacement of modular unit on spacecraft, rover, or payload,
● sample collection,
● payload management,
In 2016 Luxembourg put in place the SpaceResources.lu initiative aiming at positioning the country as a pioneer in the exploration and in situ resources utilisation (ISRU), pushing for strong incentives for increasingly seeking involvement of the private sector in all aspects of space.
In this context, Luxembourg-based Redwire Space Europe set the goal to develop its line of STAARK inexpensive robotic arms to address both the on-orbit servicing market and ISRU market. The STAARK robotic arms are built from a suite of modular elements enable mission engineers to optimize performance, dexterity, reach, and stowage using an interchangeable selection of joints, links, end effectors and software packages. The STAARK arms are designed to support space missions in LEO, MEO, and GEO orbits as a low cost and low lead time robotic manipulation technology.
The STAARK arm will fly on Momentus DEMO-II mission in late 2022.
This paper addresses the innovation and use cases of the STAARK robotic arm for on-orbit servicing missions.
Nowadays two tendencies makes that the number of in orbit objects are increasing exponentially. The launch of smallsats constellations, and the fact that the old satellites remains in orbit which also increase the risk to generate colliding debris. Considering these trends, the aim of the CRUSSADER (Capture system for servicing and debris removal) project is to develop a gripping system up to TRL6 with its associated GSE and control algorithm able to perform the capture of medium to large size spacecraft equipped with a common standardised interface. The final objective is to deorbit them to radically reduce the risk of collision and free up orbits for the placement of new satellites.
Based on previous design studied in the frame of ESA project (RETURN, PRINCE and MICE), the gripping system concept is composed of a clamp system and a robotic hexapod. The anchoring point on the targeted satellite is standardised interface defined during the projects PRINCE (Passive Mechanical and Rendezvous Interface for Capture After End-of-life) and its continuity MICE (Mechanical Interface for Capture at End-of-life). Both common standardised interface and gripping system are fixed at the centre of the LAR of respectively the spacecraft and the servicer module which are used as hard docking during launch and end of capture phase as defined in RETURN concept of mission.
The main challenges are the development of the interface fine sensing system, the design of the End-Effector to be able to support the high loads induced during the hard capture especially during the deceleration phase and the design of the hexapod to allow the highest possible range in terms of translation and rotation.
With the dramatic increase in the use of drones, protecting people and assets against from uncontrolled or hostile drones is a priority for public and private organizations responsible for safety and security. Drone Catcher is a net-based drone capture system that allows the capture and retrieve of the drone safely without it falling to the ground, though the action of a tether pulled by an electric motor.
embedding environmental sustainability within space mission design
ArianeWorks, an innovation platform initiated by CNES and ArianeGroup, is currently developing Themis, a demonstrator of a low cost and reusable rocket stage paving the way for the 2030 European launch fleet. In consistency with an eco-design vision shared with its partners, ArianeWorks wants Themis to be a pathfinder for eco-friendly rocketry. In this regard, an ongoing internship aims at performing a Life Cycle Assessment (LCA) of a launch service based on a launcher derived from Themis, and at exploring eco-design solutions to prepare the future. The presentation will first describe the framework that was built to account for the reusability of the launch vehicle, which requires the use of an adapted functional unit and the introduction of new phases in the lifecycle. Preliminary results of the LCA will be subsequently presented and discussed. Then, this study having the particularity to be carried out during the early stages of the design of a launch system, a return on experience on associated difficulties and opportunities will be proposed.
Developing technologies to prevent the creation of future debris, including Design for removal
Design-for-demise looks at technical solutions to reduce the casualty risk on ground of re-entering satellites and their components by promoting demise during atmospheric re-entry. Earlier studies have shown that the early release of the satellite structure will also help to improve the overall demise of the satellite. A broad range of current joining samples were tested under a range of conditions in order to broaden the current understanding. A wide range of phenomena was exhibited by the samples and a number of different failure scenarios were seen to be dependent upon technologies tested, heat flux profiles, and the mechanical loads, among other influencing factors.
Based on the improved understanding, design concepts which would result in earlier joint demise were identified for potential further investigation. This showed a considerable preference towards leveraging the introduced heat and enabling clear and decisive separation. Based on an elaborated trade-off system, four joining concepts have been selected for subsequent tests in a plasma wind tunnel and re-entry chamber. Testing compared the demiseability to the state-of-the-art technology and assessed their demise performance. Based on the results, the appropriate utilisation of demise technology can improve the demise of any given spacecraft and by association, reduce the casualty risk on the ground.
A dedicatedly designed demisable insert has achieved the best overall results, especially in terms of system impact, performance and costs. Potentially, this design concept can be used as replacement to standard inserts for early opening of any LEO spacecraft. Some work is still required for improving the scalability and flight qualification for attaining large-scale implementation.
To ensure that near-Earth space remains commercially and scientifically viable in the future, it is of great importance to reduce the amount of space debris in orbit and minimise the generation of new debris. Major space actors such as ESA and NASA have issued guidelines for reducing space debris. An important part of this is the removal of discarded rocket stages and satellites from orbit. One of the cheapest and easiest methods of removal is uncontrolled re-entry into the Earth’s atmosphere with the aim of burning up the hardware. To ensure that the risk of such re-entring debris endangering humans on Earth is minimised, the design philosophy "Design for Demise (D4D)" seeks to reduce the amount of debris reaching the ground as much as possible.
This work explored how additive manufacturing can be used for D4D, primarily through its freedom of form, but also by influencing material behaviour. The overall aim was to use additive manufacturing to create demisable designs for joining primary structures, where it breaks apart on re-entry at higher altitudes than it would normally do. Previous research has shown that the longer high enthalpy flow exposure of subsystems that can be achieved in this way can significantly reduce the amount of debris that reaches the Earth’s surface.
Two concepts were investigated in this study; a patch concept and an insert concept. First, a preliminary investigation was carried out, in which the re-entry conditions were examined, a suitable design material was selected and preliminary satellite designs were proposed based on an existing satellite mission. Subsequently, the selected material CF30-PEEK was subjected to a mechanical and thermal characterisation in order to have suitable material parameters available for the subsequent simulations and to investigate how additive manufacturing may affect them. In the next step, the designs were examined by Finite Element Analysis for their stability, iteratively adjusted, optimised and finalised in order for the structure of the satellite to be able to bear the loads occurring during launch. Finally, re-entry simulations were performed with ESA DRAMA for the finalised designs to determine the altitude at which the primary structure of the satellite is expected to fail and break apart. In the process the satellite models were scaled up to give break-up estimates for satellites of different sizes when implementing the proposed designs. It was shown that a failure of the primary structure occurred above 97 km for all designs and satellite sizes up to a maximum investigated satellite mass of 4000 kg, and even a maximum break-up altitude of 107 km was reached. The targeted exploitation of the freedom of form of additive manufacturing played a decisive role in the development of the designs.
In light of the increasing importance of Design for Demise (D4D), the Demisable SADM activity was initiated to better understand the breakup phenomenology of Solar Array Drive Mechanisms, as these components are recurrent units on satellites.
The first phase of the activity made use of the high fidelity reentry simulator SCARAB to recreate a detailed model of KARMA-4 TG, a commercial baseline from Kongsberg Defence & Aerospace for LEO missions. Using recommended conditions for the parent spacecraft, simulations for a baseline scenario were conducted and suggested that KARMA-4 TG is demisable with a 5% significance level when released from the spacecraft at an altitude of 76 km or above.
The second phase of the activity consisted of a plasma wind tunnel test campaign carried out on a simplified model of KARMA-4 TG in an effort to verify the fragmentation phenomenology observed in SCARAB.
Using the output of the test campaign, a numerical rebuild was performed in SCARAB which gave a good agreement between simulation and physical test. Both the test campaign and simulations indicate a demisable unit. However, it is important to note there are significant discrepancies between the test unit and the real flight hardware, which may affect results in either direction by making the unit either more demisable or less demisable. Combined with the inherent uncertainties of the D4D field, this only allows to provide a tentative demisability statement.
The purpose of the study is to identify and validate containment techniques that can be broadly applied to spacecraft critical elements to reduce the casualty area of the spacecraft re-entry event. In this activity, the methods to contain critical elements shall be investigated, assessed, traded-off and prototypes of the containment method(s) will be developed and tested.
Demisable Joint is a technical solution to allow an early break up of satellites structure and payload separation in order to reduce the risk posed by re-entering satellites, improving their demise. The ESA study “ITI – Innovation Triangle Initiative - Demisable Joint” aims at identifying the environment conditions, an then design, manufacturing and testing dedicated breadboards to verify this solution.
Enabling the first active debris-removal mission as the cornerstone for a vital new European business providing in-orbit servicing such as repairing, refuelling or even recycling. This encompasses also Close-proximity operations and On-orbit manufacturing, assembly and recycling (OMAR)
To properly reconstruct shape and dynamics of a target a chaser has to interact with is a crucial skill that servicing spacecraft shall ensure in performing on-orbit servicing missions. Imaging based sensor suite on board the chaser is the baseline for target data acquisition and drives the proper fly-around guidance synthesis in the mission design phase.
That scheme, however, lacks flexibility and timeliness, highly desirable whenever approaching partially unknown target. A promising solution, here discussed, stays in planning fly-around paths via deep reinforcement learning fed by the set of images acquired during the close proximity operations. To get robustness, fundamental for this application, a vast database of scenarios is adopted for the training phase, together with an artificial neural network settling for the agent policy and the state-value formulation. The core algorithm exploits the recurrent neural networks technique and designs the time history of the maneuvers in order to get the controlled chaser trajectory. The relative guidance is then output learnt to maximize the imaging sequence needed for the mission, taking into account light and background constraints, which might drastically affect the imaging quality and the burden of the data post-processing.
One of the focuses of TIRVOA (ESA Contract No. 4000132353/20/NL/CRS/hh) project is to collect, evaluate and compare open-air with vacuum conditions through tests, simulation, and image rendering data in the thermal infrared band. The gathered information can help to improve the application of thermal infrared cameras in vision-based navigation for active debris removal.
Tests have been implemented in a closed and temperature-controlled experiment container, containing a small satellite mock-up that was equipped with representative material, like solar panel elements, external MLI, etc.) The temperature evolution of the mock-up was continuously recorded by several thermocouples during illumination and eclipse phases, which were implemented using a quartz reflector. A series of thermal infrared images were also taken. Vacuum conditions are planned to be set up through simulation. The geometric math model together with the thermal math models of the mock-ups after certain conversion steps can be used for thermal IR image rendering with the help of PANGU software (high-res real-time image rendering toolset).
A multi-spectral system has been developed by an European consortium, led by cosine Remote Sensing (NL), including Spanish GMV Aerospace and Defence (ES), for a visual based navigation approach, based on the complementary use of imagery acquired in the Visible Near Infrared (VNIR) and the Thermal Infrared (TIR) spectral ranges. VNIR images exhibit high spatial resolution, but favourable illumination conditions are required to ensure high image quality. Instead, TIR images exhibit a moderate spatial resolution, but they provide target detection irrespective of the illumination condition. Therefore, their use can drastically increase the robustness of the navigation solution (estimation of the relative position and attitude for instance of a chaser spacecraft with respect to a target one in space debris applications).
A dual channel Camera Optical Unit (COU), based on cosine’s heritage in optical instrumentation for robotic and navigation applications has been developed. It integrates two (VNIR and TIR) camera heads in the same mechanical housing. The VNIR camera head consists of a monochromatic 4 Mpx sensor, responsive in the visible and near infrared ranges (400 – 1000 nm). It is equipped with a 21 mm lens, resulting in a 30 x 30 deg field of view. The TIR camera head is equipped with an uncooled, amorphous Silicon 0.3 Mpx microbolometer, sensitive to wavelengths between 8 μm – 14 μm. The two camera heads are interfaced to an integrated image acquisition and processing unit, equipped with a FPGA and a CPU unit. This subsystem exploits cosine’s heritage in CubeSat and nanosatellite applications and performs image grabbing and preprocessing (background subtraction and distortion correction), and handles the communication and data transfer with the IPB.
Two image processing algorithms have been considered by GMV and implemented for real-time applications running on GR740 (LEON4 processor): image centroiding for far range operation (5 km – 100 m) and Model Based Tracking (MBT) for short range operation (100 m – 2 m) potentially used with other sensors. MBT performs a pose estimation (position + attitude) based on the realignment of projected model edges with respect to the observed ones on the target. The use of MBT allows a complete target pose estimation, including an accurate range estimation.
The complementary use of VNIR and TIR images allows to obtain an accurate pose estimation, irrespective of the target illumination and thermal conditions as tested in the Hardware in the Loop campaign, performed at the platform-art© facility, located at GMV premises in Madrid. This included a representative satellite mock-up with active thermal control which allows to replicate evolution of conditions in orbit with results in open-air experiments that can be correlated with those in the vacuum of space.
The proposed navigation system reached a Technology Readiness Level of 5. A roadmap for the flight model has been identified with a compact optical head based on mirrors for a shared optical path (VNIR and TIR), as an evolution of the cosine HyperScout-2 instrument, already successfully employed in Low Earth Orbit operations.
One of the most important technical challenges for future on-orbit servicing missions is represented by the autonomous relative navigation in the proximity of a potentially uncooperative target. Current relative navigation techniques mostly rely on visible band (VIS) images. However, the acquisition of such images imposes several constraints on the spacecraft trajectory and operations, since it is necessary to guarantee both Sun avoidance in the sensor field of view and a sufficient target illumination to obtain useful measurements. To mitigate the inherent lighting condition problems, Polimi started investigating an imaging system working in the Thermal Infrared spectrum. The effects of the exploitation of multispectral imaging sensors to improve spacecraft relative navigation and target mapping are promising as shown through a case study discussion. Specifically, the VESPA has been selected as debris target to generate synthetic images in the VIS and LWIR bands for a Simultaneous Localization And Mapping algorithm to prove the expected benefits of the multispectral data exploitation in close proximity operations. The approach is proposed to be adopted in the framework of the future e.Inspector ESA mission for debris close prospecting.
embedding environmental sustainability within space mission design
In 2016, ESA published the first worldwide guidelines on how to perform Life Cycle Assessment (LCA) of space
systems. This first publication of the guidelines was based on previous ESA LCA studies and on the European
guidelines at the time. Since then, ESA and different European stakeholders have had the opportunity to use
the Handbook on different ESA projects and technologies. In order to keep ESA's leading position in this field,
the project aims to keep the Handbook up to date. Therefore, this activity aims at performing an expert review
of the ESA LCA Handbook to ensure coherence with other guidelines and new environmental recommendations
/ methods and identify possible updates.
The objectives of this session are twofold:
1. Present the context and the methodology of the ongoing activities around the update of ESA LCA
Guidelines.
2. Benefit from the panel expertise to interact on the subject and identify priority actions and
approaches
Besides, ESA would also like to provide guidance to industry on possible ways to deploy ecodesign approaches
for space systems. The project team has analysed several ecodesign methodologies for other sector that could
be applicable to space activities. The main preliminary outcomes of this benchmark will be presented during
the session.
Finally, an interactive discussion will take place to gather the views and opinions of the participants.
Developing technologies to prevent the creation of future debris, including Design for removal
As the challenge of orbital debris is set to grow, the Space Sustainability Rating (SSR) was conceived to provide a new, innovative way of addressing the orbital challenge by encouraging responsible behaviour in space through increasing the transparency of organisations’ debris mitigation efforts.
The SSR will provide a score representing a mission’s sustainability as it relates to different aspects of debris mitigation and to the alignment with international guidelines. Organisations will provide mission data through a questionnaire, which will be evaluated in combination with other external data through a mathematical model that establishes a rating for the mission. By voluntarily taking part in the rating, spacecraft operators will share a single point of reference externally describing their mission’s level of sustainability.
The presentation will provide an overview of the design phase of the rating, by describing its formulation and the outcomes of the alpha and beta testing, and give an update on the on-going transition towards its operational phase
Enabling the first active debris-removal mission as the cornerstone for a vital new European business providing in-orbit servicing such as repairing, refuelling or even recycling. This encompasses also Close-proximity operations and On-orbit manufacturing, assembly and recycling (OMAR)
Successful in orbit servicing missions rely on a variety of sensors, which provide crucial GNC information. These sensors include navigation cameras and LiDAR sensors. They are the foundation to detect, track, approach and finally enable close proximity operations such as berthing, docking or other operations on the client. Jena-Optronik’s sensors enabled the successful approach and docking in the frame of the two MEV (Mission Extension Vehicle) missions to prolong the lifetime of geostationary communication satellites for the first time. In this presentation, an overview of the performance of the Navigation Cameras and the docking LiDAR is given. Further, Jena-Optronik gives an outlook on GNC sensors, which will augment the existing product portfolio in the next years.
Operating spacecraft equipped with robotic manipulators for Servicing and Assembly and Active Debris Removal missions poses significant challenges to autonomy and GNC-driven design.
GMV has actively participated in ESA’s steps towards development of technological responses to their most critical aspects.
The state-of-the art and lessons learnt from GMV's recent experience in the topic are summarized and framed as stepstones to future missions.
The outcomes and conclusions of the dedicated activities in ESA’s AITAG, COMRADE, RACE, DETUMBLING , COBRA, D4R are critically and analytically summarized and complemented with conclusions of commercial operation of GMV’s PLATFORM-ART robotic testbench, spun-in technologies from adjacent topics like MPC-based Bearings-Only Navigation for Rendez Vous (GUIBEAR) and the Formation Flying of Proba 3, and GMV’s contributions to e.Deorbit which was ESA’s flagship activity to deorbit Envisat in the last decade.
RACE focused on CubeSats for in-orbit demonstration, AITAG on the challenge of running on-board Artificial Intelligence Techniques for vision-based proximity operations, COMRADE investigated and matured the complex couplings between the different control systems for autonomous capture, derived required algorithms and performed HW-in-the-loop end-to-end demonstration . MSRN investigated usage of the non-visible spectrum to tackle challenges like eclipses and early detection. DETUMBLING addressed de-tumbling strategies, particularly robust control for robotic arm capture but also contactless detumbling, which was the main subject of COBRA. D4R investigates technologies to facilitate the removal in targets to be launched.
Topics covered: Collision-free guidance, Contacteless detumbling, Advanced Control Techniques, Visual servo and Compliant/Coupled Control, model based design and development process - and the role of Software qualification in hardware-in-the-loop Robotic Facilities.
Future science and exploration missions will implement innovative mission concepts to embark on daring endeavors exploiting cooperating intelligent systems. Two future applications are the Orbit Debris Removal and the On-Orbit Servicing. The approach to an uncooperative object is challenging but it can enable the achievement of important mission objectives, such as restoring, refueling, repairing or removing a malfunctioning satellite. All these features are achieved at the cost of a significant increase in the on-board autonomy. Due to the relative distances involved, the agent composing the system needs to be able to rapidly and autonomously react to unforeseen events, such as collisions. To this end, it is critical that the chaser spacecraft is capable of planning, navigating and controlling itself in unknown or partially-known environment around a partially known uncooperative object, without ground-intervention. The research work presented here focuses on the development and testing of a full Guidance, Navigation & Control system aided by Artificial Intelligence techniques. The enhancement provided by Artificial Intelligence techniques allow the system to fly around objects whose dynamics is not fully determined, such as uncooperative debris, by incrementally learning its mathematical modeling. The AI-reconstructed dynamics is capable of detecting a non-nominal thrust or torque, which is not predictable beforehand. A number of methods are explored to recover the underlying dynamics by simply measuring relative state and processing it with an Artificial Neural Network. This dynamics is then used to plan control action and enhance the navigation and control synthesis. In particular, three methods for dynamics reconstruction are developed, together with their mathematical foundation. The three approaches integrate the Artificial Neural Network at different levels: from fully integrated, where the dynamics is completely encapsulated into an Artificial Neural Network, to partially integrated in which the network learns either the unknown dynamical accelerations or reconstructs the unknown parameters of the analytical expression. Such reconstruction scheme is used in two different planning and control algorithms: Neural-Artificial Potential Field method and Model-Based Reinforcement Learning. The former is a fast and light algorithm that easily handles collision avoidance but lacks of planning; the latter is able to generate plans and control the spacecraft based on the learnt dynamics. In order to reconstruct future plans of the inspected spacecraft, it is necessary to develop an AI-based routine coupling Long-Short Term Memory and Inverse Reinforcement Learning to predict the behavior of the external agent, being either in free-motion or controlled-motion. The algorithms, when compared to classical methods, showed superior performance and constant increase in relevant Guidance, Navigation & control metrics (navigation accuracy, maneuvers Δv, etc.). Finally, in order to increase the Technology Readiness Level of the algorithms, the work presents the Processor-In-the-Loop testing campaign executed with relevant hardware: a micro-controller unit and a single-board computer with similar computational power with respect to flight-hardware. An end-to-end autocoding procedure has been developed to transition from Model-In-the-Loop simulations to Processor-In-the-Loop validation. The tests were deemed successful by evaluating the execution times, resource utilization and achieved accuracy. The outcome of the Thesis is a complete framework to integrate different AI-based techniques to enhance existing, well-established, algorithms. The methodology described here can easily be extended to other mission scenarios, where the flexibility and adaptivity of the system is critical.
IOSHEXA is a spacecraft developed to have highly cost-effective access to space to perform a wide variety of operations. Thanks to SAB’s heritage in the development of adapters for Rideshare and PiggyBack missions, IOSHEXA takes advantage of the launcher structure in a way that the launch capacity for such structure is included in the baseline services already being provided by the Launcher Provider.
Moreover, IOSHEXA design is highly modular and can be adapted to many different mission scenarios, granting the capability to perform a broad assortment of in-orbit services which are becoming increasingly popular in the new space market, while having the possibility to deploy smallsat passengers on custom orbits selected by the customers.
A particular focus Is devoted to active debris removal. Accommodating space debris removal systems on IOSHEXA allows it to take measures now and in the future to conserve a space debris environment within tolerable risk levels, particularly in Low Earth Orbit regions.
The demonstration mission is focused on active debris removal of a dead satellite in the sun-synchronous orbit at 800 km altitude, with the additional task of deploying Cubesats at customers selected orbits along its way to the debris.
Space Debris Removal applications will require precise navigation and orbital manoeuvres so may include a variety of onboard sensors to support different types of autonomous guidance systems. Vision and LiDAR-based Guidance Navigation and Control (GNC) systems are well-established for space applications including planetary landers, small-body approach and landing, hazard detection for precise landing, orbital cannister capture and spacecraft docking manoeuvres. Cameras that sense radiation in the infrared frequency ranges, are now a viable additional sensor that can be considered for use in future space applications because they can provide additional information to vision-based systems and could be particularly useful for autonomous GNC in space debris capture missions.
Autonomous GNC systems require extensive testing with realistic images. Modern artificial intelligence systems, based on machine-learning algorithms, require extensive data sets for training, testing and validation. Software test platforms that can provide sufficiently realistic simulated sensor data have been shown to be useful for testing, developing and benchmarking GNC algorithms for training testing systems in real-time [1], but currently focus on simulating vision and LiDAR-based sensors. There are also well-established and validated thermal simulation tools (e.g., ESATAN [2]) that model heat transfer and thermal profiles of orbiting spacecraft to enable thermal engineers to manage the thermal control of spacecraft. These thermal solvers work on simplified geometric models to simulate heat flow but current limitations on model resolution and analysis processing time make them unsuitable for generating realistic thermal emission images at the resolution of thermal sensors in real-time.
PANGU (Planet and Asteroid Natural Scene Generation Utility) is a long-established, validated software package for generating realistic simulated images of onboard vision and LiDAR sensors of high-resolution planetary surfaces, asteroids, surface rovers and spacecraft, all in real-time at framerates expected of navigation cameras in a variety of tests systems such as off-line, open loop, closed-loop and hardware-in-the-loop type tests [3]. PANGU includes support for surface and spacecraft modelling, a custom high-speed renderer that can handle very large model files, CAD file import and export and an integrated GPU-based real-time camera module. Recent PANGU development has focused on designing and implementing functionality to generate representative, simulated thermal images of high-resolution models in near real-time for simulating planetary surfaces, orbiting spacecraft and other objects which could include space debris, and a stateless, equation-based approach for spacecraft.
We use a stateless thermal model based on thermal equilibrium equations [4] to generate representative thermal images from polygon models in real-time, applying the equation-based model at the pixel level which allows us to generate high-resolution images of complex geometrical models in near real-time (i.e. >=10Hz). The equation-based model sums the different thermal contributions and has been designed to be extendable in future enhancements. The individual sources currently included in our model are:
• background heat from space or a laboratory,
• direct solar considering cosine foreshortening, and dynamic shadows,
• reflected solar from a neighbouring planet or large Moon,
• emission from a neighbouring planet or moon, and
• internal heat absorption and dissipation.
PANGU uses these thermal contributions to calculate temperatures at the pixel level and can generate both false-colour temperature images and thermal radiance images, using Planck’s law to convert temperatures to radiance image pixel intensities. There is currently a limited set of real thermal images of orbiting spacecraft, so the equation-based spacecraft thermal model has initially been evaluated by comparing the temperate ranges obtained to low-resolution equivalent simulations run on a validated heat-transfer analysis tool, running finite-difference and finite-element analysis in equivalent orbital scenarios.
We will present the equation-based thermal simulation model, show the validation images and temperature comparisons where we compare simplified PANGU models with equivalent ESATAN simulations to validate the temperature calculations, and show equation-based thermal images of asteroid Ryugu and the International Space Station where we can compare our simulated images with real thermal camera images.
References
[1] M. Dunstan and K. Hornbostel, “Image processing chip for relative navigation for lunar landing”, in 9th International ESA Conference on Guidance, Navigation, and Control Systems (GNC 2014), 2014.
[2] ESATAN, https://www.esatan-tms.com/.
[3] I. Martin, S. Parkes, M. Dunstan, M. Sanchez Gestido, G. Ortega, “Simulating planetary approach and landing to test and verify autonomous navigation and guidance systems”, ESA GNC 2017, Salzburg, May 29th–June 2nd, 2017.
[4] C. J. Savage, “Spacecraft Systems Engineering (3rd Ed)”, chapter 11 “Thermal control of spacecraft”, Wiley.
embedding environmental sustainability within space mission design
Germanium is the semiconductor of choice for the production of high-efficient multi-junction space solar cells. Solar cells technology is, by nature, a large surface area semiconductor application and therefore Germanium is the most important semiconductor material, in weight, of all Space missions. Ge has been identified as one of the important environmental hotspots of space missions. This presentation will outline the ambitions of Umicore Electro Optic Materials to reduce the environmental impact of germanium.
The presentation will cover the entire scope of our approach from LCA study to sustainable supply of Ge to recycling of Ge in internal and external processes and increasing the efficiency of Ge use in the substrate and solar cell manufacturing processes. We will cover a description of the current status and a visionary outlook for the years to come.
Germanium is a high-value material of limited availability and with a high CO2-footprint. Today, solar cells with the highest efficiency are produced on germanium substrates. For space applications, only high efficiency photovoltaic modules are used due to the restrictions in weight. Therefore, the consumption of germanium has to be reduced and the waste produced during the manufacturing of germanium-based solar cells should be recovered. Fraunhofer ISE and Fraunhofer CSP develop processes to extract germanium even from very diluted process water streams (as low as 100 ppm) and accumulate and recover the germanium. Our recycling process can handle high volumes of process water flows. The germanium is then fed back into the value cycle.
The Green-eSpace activity aims at providing a Life Cycle Assessment (LCA) of improvements in space electronics technology, design, manufacturing and verification & validation (V&V), that reduce the environmental impact of the different levels of electronics used in any type of spacecraft. This presentation will provide an overview of the ongoing and planned work to bring green electronics for space applications to a higher level.
Developing technologies to prevent the creation of future debris, including Design for removal
The ADEO-N subsystem is the smallest of a scalable drag augmentation device family ADEO that uses the residual Earth atmosphere present in Low Earth Orbit (LEO) to passively de-orbit small satellites. For the de-orbit manoeuvre a large surface is deployed which multiplies the drag effective surface of the satellite significantly. Thereby the drag force is increased, causing accelerated decay in orbit altitude. An advantage of a drag augmentation device compared to other de-orbit methods is, that it does not require any active steering and can be designed for passive attitude stabilization thereby making it applicable for non-operational, non-stabilized spacecrafts as well. The ADEO-N subsystem consists of four deployable booms that span a sail in a planar shaped configuration. While the sail is made of an aluminium coated polyimide foil, its coating thickness was chosen such that it provides sufficient protection from the LEO space environment. ADEO-N was qualified in the first half of 2021 and was launched in a 3.6m² drag sail configuration on 30th of June 2021 on D-Orbit’s “Dauntless David” ION Satellite Carrier for its “In Orbit Demonstration” (IOD). The deployment of the ADEO-N drag sail in orbit is planed between the end of 2021 and before the end of the second quarter of 2022, to demonstrate its capabilities to accelerate the orbit degradation of the ION Satellite Carrier in the following months.
The Deorbit Kit is intended as a modular end-of-life platform for a automated, mission budget friendly controlled re-entry of satellites. The system is planned to be highly scalable for multiple missions in the future. The targets for the Deorbit Kit will be Low Earth Orbit (LEO) spacecraft in the size range of 50 to 300 kg mass.
The system consists of electric power system, sensor packages, communications, guidance, navigation and control unit as well as the propulsion system. The exact physical size of the module can be tailored according to the spacecraft to be deorbited, but will strive for a very modest and economic form factor.
The deorbit capability configuration will follow the modular design paradigm; the main driver for deorbiting will be the plasma brake. The plasma brake is a propellantless micro tether deorbiting device, that utilizes the Coulomb drag force to generate thrust in LEO to deorbit a satellite. However, the system incorporates the possibility of a traditional chemical propulsion unit, to be utilized in situations where the plasma brake is not an optimal choice. The system can be installed either as a completely autonomous unit, or as an integrated part of the satellite. This allows the proposed concept to cover both cases of uncontrolled deorbiting of a Designed for Demise (D4D) by the plasma brake module and the more demanding controlled deorbiting of a non-D4D satellite by utilizing both the plasma brake as well as a chemical thruster.
The proposal is in early concept stages having undergone preliminary design for the entire system. The plasma brake system has been extensively studied for over a decade, and several attemps have been made to deploy the system in-orbit. Here we present the overall system concept, the applicable areas for it's utilization, the preliminary system architecture as well as preliminary performance characteristics.
The Aerothermodynamics Design for Demise Workshop (ATD3) is back and it will take place in the second half of November.
As in the previous editions, the main objectives of this workshop are:
Setting up a forum for the dissemination of recent results within the ATD3 community for re-entry missions, experiments, and simulation tools and models.
Creating a framework for verification, validation and comparison of numerical methods for space object re-entries.
Coordinating and discussing future activities via expert opinions from National Agencies, Industry, and Academia.
More details about the Agenda and the main topics we are going to to tackle and discuss, during the upcoming 2021 edition, will be presented during this time slot.
embedding environmental sustainability within space mission design
Polyurethanes (PUs) are versatile materials applicable across many industries for their excellent resilience and applicability in different forms: flexible and rigid; monolith and foam. In space industry they find utilization for instance in spacecraft as coating and potting materials for protection of electronic compounds, and further in launchers as rigid foams for thermal insulation of cryogenic tanks for liquid propellants.
Results of our screening study (1) are confirming great potential of green PUs to replace conventional PUs in the selected space applications by the newly developed eco-friendly hybrid non-isocyanate polyurethane materials (HNIPU). The HNIPU materials are formulated with the aim to minimize health and ecological issues related to the use of toxic isocyanates that are main starting compounds in the production of conventional PUs. Sustainability aspect is achieved using renewable resources, such as vegetable oils and/or their derivatives.
The recent research confirmed the possibility to prepare non-isocyanate conformal coating and potting systems with bio-sourced mass content exceeding 50 wt. % and the content of non-isocyanate based hydroxy urethane bonds mass per total bond mass up to 100 %. Processing, thermo-mechanical and electrical properties are adjustable according to requirements of industrial applications.
The currently developed HNIPU foam has been compared to the reference PU system CRE210VS (provided by Latvian State Institute of Wood Chemistry). It displays ca. 3.5 times higher density (0.163 g/cm3), about 10 times higher compression strength at 10% deformation (1.85 MPa @ 25 °C), and almost 2 times higher conductivity (0.042 W/m∙K @20 °C). Enhanced mechanical properties and increased thermal conductivity result from higher density of the developed foam.
Scale-up of the HNIPU foam production by industrial PU spraying equipment as the next step of the study is feasible by optimization of foaming parameters with the aim to reach requirements of industrial process, as well as more fine and closed cell structure.
The developed HNIPU materials give a promise for further development of non-isocyanate based conformal coating, potting, and thermo-insulation polyurethane foam materials applicable in space industry.
(1) ESA Contract No. 4000119685/17/NL/KML: „Development of „Green“ Polyurethane Materials for Use in Spacecraft and Launcher Applications“.
European Space Agency (ESA) has previously established life cycle data for life stages up to launch. In this work we extend the previous ESA LCA data and present complete life cycle assessment of several current propellants, including propellant chemical production, loading and launch stage emissions with impacts to climate change and ozone depletion. CEARUN was used to estimate launch stage emissions. The life cycle performance of RP-1/LOx, LH2/LOx, CH4/LOx, UDMH/NTO and solid ammonium perchlorate composite propellant (APCP) is benchmarked per specific impulse. Results clearly show the importance of including emissions both before and during launch, e.g., production stage emissions dominate for climate change emissions from hydrogen and UDMH, and launch emissions from APCP overrule any other contribution to ozone depletion. Some of the propellants carry climate cooling effects through emissions of reflective particulates, while others contribute to increased radiative forcing by emission of black carbon. We make emission forecasts from global launch rates towards 2050, to project climate change emissions (GWP100) and ozone depletion, and findings from these underline the importance of the ongoing shift towards certain propellants. We conclude that, under some conditions, hydrogen and methane appear good candidates for the future. Results have been submitted to a relevant journal.
While designing satellites, trade-offs are often made between different architectures, designs, materials,...
In most cases, these trade-offs do not consider the environmental performance of the various alternatives.
In the frame of this study, AirbusDS chose to focus on 2 alternative materials being used for optical payload structural parts: SiC and AlSi. The objective was to evaluate the environmental impacts of each material and their manufacturing processes and compare their respective environmental performance.
Developing technologies to prevent the creation of future debris, including Design for removal
This presentation concerns an overview of development of propulsion system consisting of Solid Rocket Motor and Thrust Vector Control designed at the Lukasiewicz Research Network – Institute of Aviation in Warsaw, Poland (L-IoA).
The protection of Earth’s orbit environment has become one of the main interest at the L-IoA. After successful pre-qualification of a solid propellant, which shall be compliant with the solid particles generation restrictions proposed by ESA, preparation for the rocket motor development with dedicated thrust vectoring system has been started. One of the greatest challenge introduced by deorbitation purpose for a solid motor is extremely long burn time due to acceleration limits, imposed by fragile, deployable appendages. That requirement results in necessity to pay special attention to various design features, i.a. material selection, thermal protection strategy. The unique propellant and its exhaust gases decomposition can be also challenging in terms of design, especially for the thrust vectoring system based on outside flap concept. The mechanism introduces a system of movable deflectors which are built around outer nozzle of the motor. When needed, a flap slides into the exhaust gases producing perpendicular (to the axial thrust) force, resulting in a moment with regards to the vehicle centre of gravity, which in the end results in a turn.
Currently separated two projects (first concerning SRM and second TVC) are ran closely together in order to ensure full mechanical, thermal and electronic fit and compatibility for the whole propulsion system.
In the wider context of Active Debris Removal (ADR) missions, the de-orbiting kit’s plug-in solution is special in its potential to become a self sustaining product. While the aim of the initial activity addressed within Cleanspace is to deorbit a passive launch adaptor (such as a VESPA upper part) as an in-orbit demonstration, the ultimate goal is to develop a modular and scalable concept that would allow the deorbit kit to be accommodated on other hosts (other launch adaptors and satellites).
This constraint is fully integrated into the mechanical and electrical architecture of the deorbiting kit. Firstly, the kit is designed as a short disc to ease the integration within the payload adapters on existing spacecraft. Secondly, the kit is connected to the spacecraft through the inclusion of a watchdog-dedicated board in the on-board computer that listens in on a MIl-STD-1553 bus, and can be customised for each application without affecting the rest of the de-orbiting kit design to adapt to different requirements or bus architectures.
This standardisation effort is essential to the success of the deorbiting kit as a viable ADR solution in the coming years.
Enabling the first active debris-removal mission as the cornerstone for a vital new European business providing in-orbit servicing such as repairing, refuelling or even recycling. This encompasses also Close-proximity operations and On-orbit manufacturing, assembly and recycling (OMAR)
The concept of On-orbit manufacturing and recycling has received increasing attention in the past years and a number of isolated technology developments have been initiated. The production and reuse of spacecraft in orbit provides the potential to turn problems into valuable assets. This requires the understanding of the implications at mission and system level as well as a clear view of the use cases benefiting from this approach. To address this complex issue,ESA introduced the OMAR (On-orbit Manufacture, Assembly & Recycle) initiative.
Within this activity the OMAR Mission Architecture Study was led by OHB System. Multiple mission architectures are possible for the implementation of services in orbit. The main objective of the OMAR Mission Architecture study was to identify and trade-off different mission architectures, to provide different services in LEO, MEO and GEO. For the investigated scenarios, a system functional analysis and trade-off of different architectures and concepts of operations was performed. The results of study led to three mission architectures including a LEO satellite manufacturing and assembly station as well as LEO and MEO satellite refurbishment architectures.
Through its Clean Space (CS) initiative, ESA has been devoting an increasing amount of attention to the environmental impact of its activities, including its own operations as well as operations performed by European industry in the frame of ESA programmes. On-orbit manufacturing and recycling is a concept that has been gaining momentum in the past years. A number of isolated technology developments have taken place recently. The reuse of space debris in orbit would turn a problem into a valuable asset.
The On-orbit Servicing Satellite design study falls under the industrial studies, part of the overall OMAR initiative. As such, it addresses the main system segments based on established architectures (i.e. paradigm change on satellites design, on-orbit manufacturing/recycling plant, and logistics segment including servicing vehicles).
Seven scenarios were compared, from which two scenarios were downselected for further investigation (Scenario A: OSS for LEO constellation manufacturing and servicing, and Scenario H: versatile OSS for Geo S/C, from telecommunication GeoHub to Cloud S/C), and Scenario H was finally chosen for preliminary mission design.
A specific use case was selected for this design, based on the choice of items to manufacture in orbit: a large telecommunication satellite is launched with most of its solar arrays, radiators and reflectors missing, taking advantage of the mass saving to increase the payload power and capability. The missing items are
manufactured in near-geostationary orbit by the Main Station from raw materials delivered by a Resupply S/C.
The study concludes with an investigation into technology gaps and a proposed development plan, identifying additive manufacturing of metals and liquid glues as key technologies to progress.
Space Sustainability has become an important topic over the last two decades fueled by the debris issue and an increasing number of space infrastructure elements. Besides servicing and debris removal partly sharing technologies, new system solutions are proposed to broaden the scope of space mission, to improve their economics and to make space sustainable in the long-term, also regarding technology, systems, missions, operations and business alike.
The upswing of innovative and commercial NewSpace ventures and general space industry trends suggest a move toward higher lot sizes of systems, subsystems and components, thus, series production. At large, these developments and concepts will benefit from cooperative design and plug-and-play (PnP) principles, which in turn are centered around standardized interfaces per se – as well as modularity as enabling system philosophy. With On-Orbit Assembly (OOA), On-Orbit Servicing (OOS) including refurbishing and re-fueling, On-Orbit Manufacturing (OOM), Active Debris Removal (ADR) and In-Space Recycling (ISR) or other supporting services. Space missions and business span over manifold themes beyond Earth orbits and across the solar system, involving robotics, habitats, manufacturing, resource exploitation and more. Large space structures, logistics and warehousing will become common space infrastructure elements.
In this context especially modular concepts and standardization of space infrastructure elements have been investigated for decades and are now gradually becoming a reality as the CubeSat revolution has shown in a first step. Standard interfaces are considered instrumental enablers for new dimensions of flexibility and entirely new space systems, operations and business. New standards are intended to provide the foundation for a new commercial repertoire of robust space-based capabilities and a future in-space economy. Besides Safety, cost and flexibility will become key to allow for adjustments and repurposing, staged approaches, etc. and economy of scale effects as routine operations suggest. And, NewSpace will drive this with new space approaches.
This paper elaborates on the iSSI® Modular Coupling Kit by iBOSS, yet the most advanced and mature multi-functional and multi-purpose potential future space system interface standard. Core is the patented iSSI® (intelligent Space System Interface), the fastest (coupling), the most compact (dimensions) and the lightest (mass) solution of its kind with an industry series-manufacturing process solution to date. The iSSI® technology, its specialties and specs will be presented, followed by selected applications and use cases and associated benefits. Finally, enhancing capabilities and effects regarding flexibility, design, architecture and operations will be sketched in the context of OMAR (On-Orbit Manufacturing, Assembly and Recycling).
The authors and partners involved have longstanding experiences, background and visibility in the global commercial space arena with involvement in multiple innovative new business endeavors comprising dedicated expertise in space commercialization and innovation, new business creation and finance, international partnerships, commercial prototyping and series manufacturing.
Enabling the first active debris-removal mission as the cornerstone for a vital new European business providing in-orbit servicing such as repairing, refuelling or even recycling. This encompasses also Close-proximity operations and On-orbit manufacturing, assembly and recycling (OMAR)
Large format, on-orbit additive manufacturing (AM) and assembly is actively being considered as a modular solution that facilitates resource efficient manufacturing, operations, and servicing in space. Customizable structures that can be manufactured in space bring a myriad of benefits that can significantly contribute towards sustainable space missions. To realize this, a novel AM approach to freeform fabricate large, functional structures in space has been developed. Combining the reach of a free-flying CubeSat with a collaborative robotic arm and a 3D printing head, large support-free structures can be manufactured, with dimensions vastly exceeding the printing setup itself. The feasibility of this fabrication approach was established through experiments conducted via the Experimental Lab for Proximity Operations and Space Situational Awareness (ELISSA). Large, support-free, truss structures were 3D printed using a modified Fused Filament Fabrication (FFF) setup in conjunction with a free-flying satellite mock-up. Using a continuous navigation path incorporating an infinite fabrication loop, meter-scale, support-free trusses were produced to demonstrate the potential of the proposed method in scalable, boundless direct printing of complex structures, independent of gravity or printing orientation. The proposed approach offers great flexibility due to the unconstrained build volume of the setup along with the flexibility afforded, not just in the structures that could be printed, but also the manufacturing processes and the feedstock used.
The opportunity for in-space manufacturing is significant. The potential for in-space manufacturing to create new materials, composites, and alloys by leveraging the conditions of the space environment is high. As is, the ability to use in-space manufacturing technologies for future exploration and In-Situ Resource Utilisation (ISRU) needs.
However, in-space manufacturing is limited due to the lack of available infrastructure to experiment and scale activities, with only the International Space Station routinely available. At the same time, retrieving experiments and products from space can be a time consuming, and often difficult, procedure.
In order to address the limits in current space infrastructure, Space Forge is developing the ForgeStar platform. The ForgeStar is a remotely operated small-scale returnable vehicle for microgravity experimentation and in-space manufacturing activities. Underpinning this technology is a novel return from space methodology that does not use an ablative heat capsule. The ForgeStar's re-entry mechanisms enable a significantly more gentle return from orbit, enabling full platform recovery and reuse. This return technology can be adapted for in-space manufacturing missions for return to Earth, landing on other planetary bodies, and other ISRU applications. Moreover, opposed to 'design for demise' applications to end of life disposal, Space Forge's re-entry approach can be deployed for debris mitigation, enabling sustainable debris removal without dispersion in Earth's atmosphere.
The ForgeStar platform offers researchers the opportunity to capitalise on the space environment in manners not compatible with the ISS for both experimentation and quality of space environment achieved. It also offers commercial space companies the ability to scale in-space manufacturing activities for applications useful on Earth, such as ZBLAN fibre optic cable and pharmaceutical research.
The development of the ForgeStar is supported by ESA GSTP and other elements.
Through its Clean Space (CS) initiative and to fully benefit from the removal of constraints linked to on-ground manufacturing and launcher requirements, ESA has set up the OMAR (On-orbit Manufacture, Assembly & Recycle) initiative. It is a system approach aiming to give an overview of the most interesting applications, to map the state-of-the-art and to derive a roadmap for the critical technologies development. The On-orbit Manufactured Large Antenna Reflector Preliminary Design study is part of it, alongside On-orbit Servicing Satellite design study, Mission Architectures and On-orbit Manufactured Spacecraft. These studies aim at understanding the possible strategies, system level impacts and potential benefits, while exploring the trade-space.
The starting point is a state-of-the-art looking at antenna designs focused on assessing the currently used technologies against the specific requirements for on-orbit manufacturing. Despite the enormous range of design variation for an antenna reflector, there are some key features of the key components of the antenna which are consistently the design drivers. In parallel, main requirements are surface accuracy (as-built, thermo-elastic, dynamic), pointing stability, mass, and stiffness.
Many of the current on ground manufacturing processes and reflector designs are not compatible with an on-orbit manufacturing. Different conceptual designs have been proposed with different manufacturing and assembly philosophy including parts size and proportions of manufacturing occurring on-orbit. The conceptual have been ranked on the following criteria:
• Maturity/Risks
• Robotical Needs
• Mechanical Performance
• Radiofrequency Performance
• Versatility
• Pollution
• Lead Time
• Stowability
Similarly, a wide range of materials, manufacturing and joining processes have been studied and ranked according to relevant criteria such as:
• Mechanical Performance
• Resistance to space environment
• Cleanliness
• Reliability
Taking into account all these criteria, the combination of conceptual design, materials and process converge on designs for the two use cases identified.
Further than reflector conceptual design itself, the “Space Factory” that will perform on-orbit manufacturing, testing and integration steps of large antenna reflector has also been preliminary designed. Preliminary mass, power and time budget have been estimated.
Finally, a technology roadmap has been achieved highlighting a clear distinction between:
• On-orbit manufacturing technologies (materials, processes, operations) which are still in their infancy.
• Client satellite that will require large evolutions to manage such very large reflectors.
The high cost of the overall development corresponding to the standard conservative space approach suggests the need to consider a new space approach to reduce the cost and make competitive products in terms of price and performances.
Enabling the first active debris-removal mission as the cornerstone for a vital new European business providing in-orbit servicing such as repairing, refuelling or even recycling. This encompasses also Close-proximity operations and On-orbit manufacturing, assembly and recycling (OMAR)
In terms of design for removal, passive technologies installed on the target satellite may potentially ease identification, tracking and pose estimation of the target. From far to close rendezvous, planar distributed 2D markers can be used for such purpose, while for the last moments of the rendezvous, up to capture, a single 3D marker is required to perform pose estimation. Installing LRRs on 2D markers helps to determine the spin-rate of tumbling objects such as defunct satellites.
Both types of markers are already being developed in an on-going activity with Admatis (HU)
with the purpose of designing them and selecting materials to fulfil the marker’s functional
requirements, by performing environmental tests at sample and hardware/assembly level.
Several thermal films and paints are being considered to address visibility of the markers in
both the visual and thermal-infrared spectrum. Qualification of these coatings and markers development is an ongoing activity in the frame of MSN (Markers Supporting Navigation) project, while application of LRRs on 2D marker assembly is performed in MSN-FD (Markers Supporting Navigation-Further Developments).
In the last years many space agencies and national entities have raised the problematic of introducing and/or already introduced Space Debris Mitigation (SDM) requirements within the design and development of the next generation of space missions, LEO scenarios/platforms in particular. The introduction those SDM requirements has a not negligible impact both at system and sub-system level on platforms’ design. Those technologies shall guarantee compliance with acting regulation not only under nominal conditions but also in case of failures bringing to an unexpected EoL event that would turn to the need of performing an ADR. Following the failure of a S/C, and at the scope of performing ADR, one of the critical aspects to be guaranteed is the feasibility of capturing, stabilizing and de-orbiting the failed/uncontrolled S/C. This need clearly asks for navigation and mechanical solutions/devices to be carried on-board new generation of EO S/C (target passive interface with integrated navigation aids) and to be taken into account by any future SSV vehicle targeting the active ADR role.
MICE is a follow-up of previous PRINCE activity, concerning the design, manufacturing and test of the passive mechanical interface to be installed on future EO satellites for its capture and later de-orbiting after End of Life. With this heritage, a review of the interface concept and iteration on the design has been performed. In addition to analyses of the different aspects concerned a testing campaign was carried out in order to demonstrate fulfilment of all requirements up to TRL6 and show feasibility of the capture of the failed satellite under the operational environment defined.
Ultimately, MICE objective is to become a standard element to be implemented in next future European missions. It is critical to guide the design of MICE towards a definitive and optimal solution of passive interface, linked to an active capture concept that cannot be separated from the passive side specification.