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Description
Note:
The presentations will become available as part of the proceedings only. Therefore no presentations can be accessed from this web site.
The proceedings are available at: https://exchange.esa.int/thermal-workshop/
Final update
Tue 6 - Thu 8 October our workshop takes place.
To participate please register, for free, via the "Registration" link in the grey menu on the left. The confirmation that you will receive contains the link to connect. Information about the tool used for this event is included as well and can also be found at the bottom of this page.
Do not hesitate to contact me or my colleagues in TEC-MT, if you have any questions or suggestions. Do not hesitate to get in touch with us for any aspects related to our space thermal engineering activities. More detailed contact information can be found here
Below you will find the usual text for the workshop for information. It has not been fully modified to take all changes into account. If something is not clear then please do not hesitate to contact me.
INTRODUCTION
The European Space Thermal Engineering Workshop, organised by the ESA/ESTEC Thermal Division, will be held on:
Tuesday 6 to Thursday 8 October 2020
at ESA/ESTEC, Noordwijk, the Netherlands.
Aim and scope
The aim of the workshop is:
- to provide a forum for the exchange of views, experiences, best practices and lessons learned for thermal engineers involved in space missions
- to promote and facilitate contacts between thermal engineers and thermal technologies and tool developers
- to present recent developments on all aspects of the thermal engineering domain and to solicit feedback
- to present new approaches and methodologies e.g. for thermal design, analysis and verification
Topics covered include in particular
- thermal design (for platforms, instruments etc.)
- thermal analysis and software tools
- thermal testing
- thermal control technologies
- two-phase heat transport technology
- thermal technologies and methodologies related to small satellites and CubeSats
- mapping of thermal results to mechanical models and guidelines for thermo-elastic (for thermal part)
Organisation
The workshop will consist of presentations only. The working language will be English.
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Opening and ESA updateConvener: Dr Harrie Rooijackers (ATG-Europe)
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1
OpeningSpeaker: Dr Harrie Rooijackers (ATG-Europe)
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2
ESA Missions and Thermal Technology Development UpdateSpeaker: Stephane Lapensee (ESA/ESTEC)
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1
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10:00
Break
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Thermal Control and DesignConvener: Romain PEYROU-LAUGA (ESA)
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3
Correlating Intense Solar Loads for the Solar Orbiter SPICE Instrument
The Spectral Imaging of the Coronal Environment (SPICE) instrument is one of ten instruments comprising the science payload of ESA’s Solar Orbiter mission. Launched in February 2020, and successfully commissioned by July, SPICE was built at the STFC Rutherford Appleton Laboratory and is a high resolution imaging spectrometer operating at extreme ultraviolet wavelengths.
With Solar Orbiter ultimately reaching a perihelion of 0.28 AU (corresponding to a solar flux of approximately 17 kW per square metre or 13 solar constants), the thermal performance of SPICE under extreme solar loading is a crucial element of the instrument’s design. The instrument’s primary mirror is of particular importance for managing this solar load; it is designed to reflect ultra-violet wavelengths that are of scientific value whilst being transmissive to visible and infrared wavelengths. This allows a significant portion of the solar energy to pass through the instrument and back into deep space. During thermal balance testing, an intense UV lamp was the best approximation available to provide data for correlating the solar properties of the instrument. The correlation process therefore had to also account for the spectral differences between the UV lamp and the true solar spectrum.
This talk will discuss the real world challenges in such a correlation and compare the outcome of the original correlated model with flight data recently acquired at 0.88 AU and 0.54 AU during the commissioning phase of Solar Orbiter. In particular, the insight gained on designing and modelling instruments for such extreme thermal conditions in deep space will be explored.
Speaker: Samuel Tustain (UKRI STFC RAL Space) -
4
Thermal control of a light-weight rover system in the permanently shadowed regions of the lunar south pole
The exploration of the Earth’s Moon has become a topic of great interest in recent years to both private and governmental entities. ispace is aiming to be the enabler for private industry to access new business opportunities on the Moon by capitalizing on lunar resources and expanding our presence in space. The Polar Ice Explorer (PIE) is an in-situ resource utilization (ISRU) exploration mission that aims to find and characterise potential water ice deposits in the lunar polar regions. In the scope of this project, the rover thermal control system development will be discussed. PIE leverages on ispace developed and flight qualified Team HAKUTO’s SORATO rover. The paper explores findings from three key areas: operations in the permanently shadowed regions (PSR) of lunar poles, thermal control design of the rover system and modelling of lunar environment. Thermal modelling of the lunar polar region was conducted with a particular attention towards identification of surface properties, lunar regolith characteristics and modelling of environmental fluxes. Operational mission constraints, such as cooling rates and heater power requirements, were investigated. Thermal design philosophy aimed to maximise passive control means through decoupling of the rover from the ground, reduction of heat losses and conductive path management. Mechanical issues induced by larger temperature swings were investigated. Active control means were considered for elements with tighter operational ranges, such as batteries, motors and externally mounted elements. The rover thermal design challenges and preliminary findings enabling operations in the PSR were outlined.
Speakers: Mr Dmitri Ivanov (ispace inc.), Mr Domingos Fernandes (ispace inc)
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3
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11:15
Break
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Cube SatsConvener: Philipp Hager (ESA)
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5
Development of a 3D-printed heat pipe for thermal management of a high-power CubeSat thruster
Recently FOTEC started the development of 3D-printed heat pipes as a prospective thermal management solution for a high-power CubeSat thruster. The use of 3D printing could improve design flexibility and adaptability in geometrically confined situations, while enabling the heat pipe to be manufactured in one process, minimizing the number of thermal interfaces.
This contribution presents the development process leading to the ability to print tailored metallic porous structures using Additive Layer Manufacturing (ALM), the design and fabrication of a number of ALM heat pipe breadboards, and the results of a test campaign comparing the achieved performance with a copper-water heat pipe, a k-Core encapsulated graphite coupon and a flexible k-Core thermal strap.
The work is part of a research project concerned with the further development of a flight-proven CubeSat thruster with a size of 1 U. The thruster Power Processing Unit was redesigned to approximately double the system power, which also increased the thermal dissipation to 15 W, while keeping the size constant, reflecting the industry trend of steadily increasing power densities.Speaker: Dr Christoph Buchner (FOTEC Forschungs- und Technologietransfer GmbH) -
6
Mini Mechanically Pumped Loop Modelling and Design for standardized cubesat thermal control
With the miniaturization of space-borne sensors, more powerful payloads are anticipated to be used in small satellites. Therefore, new thermal concepts are required to cope with the increasing thermal dissipation and the negative effects. This paper presents a new thermal control concept to thermally standardize small satellites with power dissipation problems and making them thermally independent of their orbits.
This new thermal design concept is a small Mechanically Pumped Loop (MPL). The heart of the system is the multi-parallel micro-pump (MPMP) as developed by the Netherlands Aerospace Centre (NLR). This pump concept provides a low mass MPL solution with high reliability.
Subsequently, the article describes the concept of the loop and the pump in detail. The Mini-MPL is modelled in Matlab with the objective to support MPL system design trade-offs. The model is described and modelling results are presented. Further micro-pump test results are presented and the first results of the mini-pumped loop test results.
The design of the MPL takes into account the requirements imposed by CubeSats and their subsystems, thereby ensuring its compatibility with small satellites and a variety of missions.
Finally, the advantages and drawbacks of the system are elucidated by comparison with conventional thermal design options. The paper concludes with an outlook on further development and mini-MPL applications.Speaker: Dr Ramon van den Berg (Senior Engineer)
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5
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12:30
Lunch Break
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Thermal Control and DesignConvener: Thierry Tirolien
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7
Thermal cryogenic cavity modelling: Vulcain Aft Bay on Ariane 6
In the scope of Ariane 6 development, thermal analyses are performed on the cryogenic cavities of the launcher 1st and 2nd stages. The Vulcan Aft Bay (VuAB), or cavity near the Vulcan 2.1 engine, experiences extreme heat differences between the engine exhaust, booster plumes, aerothermal fluxes, and its bottom liquid hydrogen tank and associated lines. Furthermore the thermal environment on ground has a specific chronology and associated natural and conditioning fluxes.
All these constraints lead to a specific modelling of the cavity and associated sizing cases. This enables the thermal justification of the launcher at system level, as well as thermal specifications to partners. Furthermore the thermal control of equipment items, as well as icing risk inside and outside this cavity, are discussed.
For the European Space Thermal Engineering Workshop, ArianeGroup will present the sizing constraints, and associated modelling involved with the VuAB cryogenic cavity, as well as anticipated results expected in the frame of Ariane 6 test campaign.
Speakers: Thibault de Bras de Fer (ArianeGroup), Vincent Le Goff (ArianeGroup) -
8
Recuperator for 40 K Reverse Turbo-Brayton Cooler and Remote Cooling Applications
Compact efficient Counter Flow Heat EXchangers (CFHEX) or recuperators are crucial components of recuperative coolers, such as Joule-Thomson and Turbo-Brayton coolers. Also in cryogenic systems that apply a convective cooling loop, in which a working fluid is circulated by a warm pump and cooled by a cryocooler, high-effectiveness recuperators are essential. In a collaboration project of ESA, University of Twente and CERN, a new innovative mesh-based recuperator design covering the 4.5-290 K temperature and 1-10 bar pressure operation ranges is developed and presented. A system level analysis of a convective cooling loop circuit with helium as the working fluid has been accomplished defining the performance characteristics of the CFHEXs, while matching the available cooling powers of a two-stage cryocooler. A discretized numerical model including the flow and material parameters, based on experimental and theoretical data, was developed to size the first recuperator prototype, which was tested between 40 K and 290 K. The schematic test stand is presented for measuring the effectiveness and the pressure drop of both fluid streams at variable mass flow and pressure levels. An average effectiveness of ≈ 94.8 % with a pressure drop of ≈ 30 mbar was achieved in the first design iteration. The numerical model was correlated with the experimental results showing good agreement for the set mass flow and inlet pressure dependencies. The deviations from the model were investigated and design improvements are proposed for a recuperator construction for Reverse Turbo-Brayton cooler application.
Speaker: Ms Aleksandra Onufrena (CERN/UTwente/ESA)
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7
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14:30
Break
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Thermal AnalysisConvener: Gunnar Sieber
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9
PASTA – AIRBUS parametric workflow manager for thermal analysis
Thermal analyses are performed throughout the entire life cycle of a space project, from the first rough architecture trade-offs to the last in-orbit simulations.
In general, they consist in building a more or less complex thermal model, running different sizing cases and post-treating them. These activities are conducted by “thermal analysts” who are specialized in the different pre-post and solver tools, while “thermal architects” are responsible of the thermal design itself.
Although this organization has proven its value, its limitations arouse in the past years. Indeed, more and more complex and coupled designs are now necessary to overcome the future space products challenges such as high thermo-elastic stability in scientific programs, variable environments in constellations, or high power telecoms.
To address these new challenges, Airbus Defence and Space has developed a new tool called PASTA: Parametric Process Automation Software for Thermal Analysis.
PASTA is an in-house workflow manager which provides a “black-box” interface, enabling any user to launch any kind of thermal study, once settled by a thermal analyst. It is for instance possible to any project engineer to test a change of coating with no knowledge in the thermal tools. PASTA also enables an easier share of workload among analysts, because it is not necessary for them to understand the inner construction of the model when new studies are necessary. Finally, PASTA provides all usual design exploration tools to help find the best design solution or assess its robustness.
The presentation will describe the main PASTA features:
• GUI interface to capture:
o the workflow chain (model modification, solving, post-treatment)
o the parameters configuration (files, allowables, description)
o the user values to be applied (coatings and materials definition, study definition)
• Different studies can be defined:
o Custom (for sizing cases for instance)
o Sensitivity analyses
o Design of Experiments (Full factorial, Latin HyperCube)
o Optimisations
o Surrogate Models
o Robustness analysis (RSS, Monte Carlo)
• Compatible with Systema, Thermisol, NX but also any usual python or shell script
• Can be chained with other discipline post-treatments, for instance mechanical and optical for thermo-elastic end-to-end assessmentsSpeaker: Mr marco scardino -
10
Development of a new software tool for thermal analysis of satellite harnesses
“Development of a new software tool for thermal analysis of satellite harnesses”
• Ewin Bloem (Royal Netherland Aerospace Centre), edwin.bloem@nlr.nl
• Roel van Benthem (Royal Netherland Aerospace Centre), roel.van.benthem@nlr.nlThe harness sizing for space applications is defined by derating rules that are specified in international standards such as the ECSS-Q-ST-30-11C Rev 1 (ESA, 2011) , “Space Product Assurance, Derating EEE Components”. ESA recently conducted a study led by Airbus DS SAS together with the Royal Netherlands Aerospace Centre NLR to update the ECSS ruleset for wires and bundles in free vacuum. The new ruleset, currently under evaluation in Revision 2, is based on tests done by NLR on single wires and representative bundles, as well as on thermal simulations performed by Airbus DS. The update of the ECSS-Q-ST-30-11C Rev 2 (19 may 2020) significantly reduces uncertainty margins and explicitly allows for the use of thermal simulations. As confirmed by Airbus DS, a reduction of mass and volume of satellite harnesses is already demonstrated in the design process. To optimize spacecraft harness design under the conditions as provided in ECSS-Q-ST-30-11C Rev 2, space companies will be allowed to perform thermal simulations with dedicated space harness evaluation tools. The presentation will focus on the development of a new Satellite HARness Evaluator (SHARE) tool, enabling thermal optimizations for space harness designs. SHARE is based on an existing tool, the Thermal Design Module (TDM), developed by NLR for the thermal analysis of aircraft harnesses. While under vacuum conditions in space, convective analysis is suppressed in SHARE. The validation of SHARE is based on the same ESA study that led to the update of ECSS-Q-ST-30-11 Rev 2. In a future update, convective analysis may be relatively easily included in SHARE, for instance for optimization of rover harnesses designs in a low pressure Co2 atmosphere on Mars.
Speaker: Mr Edwin Bloem (Royal Netherlands Aerospace Centre NLR)
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9
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15:45
Break
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Thermal AnalysisConvener: James Etchells
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11
ESATAN Thermal Modelling Suite—Product Developments
ESATAN-TMS provides an advanced thermal modelling environment for the thermal analysis of spacecrafts and launch vehicles. The suite is continually being enhanced to meet current and future requirements of space projects, and to support the specific needs of thermal engineers.
A major focus of ESATAN-TMS development this year has been on providing facilities within Workbench to further streamline the thermal process. This presentation will outline all the developments going into ESATAN-TMS 2021.Speaker: Henri Brouquet -
12
Leveraging ECAD Data for PCA Thermal Simulation
During this presentation, we will compare and evaluate the different workflows available in Simcenter 3D PCB Exchange and Simcenter 3D Space System Thermal for printed circuit board assembly analysis in the context of spacecraft thermal design. Component reliability is heavily dependent on temperature and so PCA thermal design and simulation is an important aspect of spacecraft development. The first aspect of PCA thermal analysis is the choice of data exchange format between ECAD (Electrical Computer Aided Design) and MCAD (Mechanical Computer Aided Design) software. Many data exchange formats are available for use in PCB exchange : IDF, Zuken, Gencad, ODB++ and IDX, each one shall be described and compared. We will also compare the various ways the Printed Circuit Board are thermally modelled in Simcenter 3D Space System Thermal, using average conductivity values or detailed conductivity fields that account for the copper content distribution in the various layers of the PCB. We will conclude this presentation by looking at the “assembly fem” concept in Simcenter 3D that enables the efficient re-use of these PCB board level models for the full spacecraft models.
Speaker: Mr Jean-Frederic Ruel (Maya HTT) -
13
Physics driven geometrical model reduction (GMM)
There are current necessities of real-time simulation and satellites model exchanges with launchers. We are developping a geometrical model reduction (currently manualy done in the industry) complementary with a TMM reduction module (done by tools such as TMRT). A budget of faces for GMM is almost always imposed (Launcher or DSS constraints). The presented model reduction tool is physics unaware but physics driven. Here the focus is made on the thermal simulation. The first approach relies on the following assumptions :
• limited to radiative couplings, external fluxes (solar and albedo) will be considered next
• no conductive couplings in the resolution of the heat equation (focus on the radiative part for a steady state)
• Isothermo-optical properties (identical alpha, tau, rho for all mesh elements) so node couplings are accurate to view factors
First approach : geometric reduction of each physical node individually (Lindstrom-Turk edge collapse, preserving volume and shape boundaries of the surface mesh), then the assembled reduced model is given to an oracle (black box) returning the physical validity of the model (distorsion). If the new model is validated, the reduction step is repeated until the distorsion is too high.
An animation illustrating the progressive approximation of the geometry faithful to temperatures will be shown in this presentation.
As future works, we plan to achieve the following landmarks :
- Compare different geometric reduction metrics (volume preserving, normal orientations preserving, memoryaware reduction etc)
- Introduce external fluxes (solar and albedo) so the reduction process is receptive to shadows and masking (geometric algorithm only slightly affected since reduction process is physics unaware)
- Sensitivity of the algorithm for different thermo-optical properties (again should not imply many changes)
- Sensitivity to power injections
- Add the conductive part (implying bigger geometrical reduction since tolerance is higher)
- Results analysis to favor the use of AI (better reduction targeting, adaptive version)
External models to do more tests are welcome!Speaker: Vincent Vadez (DOREA)
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11
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Thermal AnalysisConvener: James Etchells
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14
Thermal-hydraulic design and analysis of the PLATO thermal-vacuum optical calibration experiment
The thermal-hydraulic design and analysis of the PLATO focal plane assembly (FPA) and normal-front end electronics (N-FEE) thermal-vacuum calibration experiment is presented. Optical calibration of the instrument, which consists of a 300mm diameter Ti-6Al-4V FPA with 4xCCDs, connecting via flex-cables to the 15W N-FEE, requires two separate thermal control loops with temperature ranges of 150K – 210K and 220K – 308K, respectively. The FPA connects to the PLATO telescope at four different points, and operates with time-varying power dissipations at each point. The N-FEE conductive interface consists of three mounting points that are thermally and geometrically asymmetrical. Both instruments expect a temperature variation of less than 1K across their respective interfaces. A network of gold electro-plated copper straps connected to a static liquid nitrogen vessel, is used to deliver thermal control for the FPA. This temperature control system has been custom designed using ESATAN. A bespoke phase change subroutine has also been developed to capture the physics of time-dependent pool-boiling and evaporation of liquid nitrogen during the experiment, which allowed the investigation of several normal control and potential failure scenarios. This subroutine interacts with the geometric model via a non-geometric node. Heat absorption, heat transfer coefficients and the development of temperature gradients across the vessel and wider system are predicted. Cooling of the N-FEE is delivered using two custom designed closed-loop pipe networks connected to a heat pump circulating Galden heat transfer fluid across the system. This has been developed using a purpose-written thermal-hydraulic program developed on Matlab. The program predicts flow rates, pressure drops, heat flows and temperature gradients of the working fluid throughout the system, and has been used to specify compressor flowrates and pipe sizes for the full working range. The design objective is to achieve a temperature variation of less than 1K across both pipe loops without the use of supplementary PID controllers. In this presentation, we discuss the thermal development and design of both purpose-made systems and their supplementary mathematical tools and we provide comparisons to currently available experimental data.
Speaker: Ashraf Al-Bahlawan -
15
Thermal modelling of an in-orbit refuelling process of a xenon tank with ESATAN-TMS Fluid
The Lunar Orbital Platform-Gateway (LOP-G) space station is one key element of the NASA Artemis Program, which has the goal to bring humans back to the moon by 2024 and to provide a sustainable infrastructure for future missions. One of the LOP-G modules is the European System Providing Refuelling, Infrastructure and Telecommunications (ESPRIT) module, which contains, among others, the xenon refuelling supplies for the LOP-G Power and Propulsion Element (PPE). While electric propulsion and the associated on-board xenon storage is already commonly used on today’s space crafts, a relatively new field of studies is the in-orbit refuelling.
This presentation investigates the thermal behaviour of a xenon tank during a refuelling process in microgravity and its numerical representation. Furthermore, the physical assumptions and discretisations, which were carried out to obtain the final thermal model, are presented. For a flexible use of the refuelling model and an easy integration into already established thermal models on system level, ESATAN-TMS Fluid was used. Therefore the construction of the thermal model in ESATAN-TMS, the choice of a specialised fluid solution routine and the implementation of a Xenon fluid library including a supercritical phase are part of the presentation. Additionally, also the problems faced during the simulation runs with ESATAN-TMS Fluid and closer information about the attempts to fix those problems are presented, which was successful at the end.Speaker: Dr Frank Bodendieck (OHB System AG)
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14
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10:00
Break
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Thermal Control and DesignConvener: Dr Harrie Rooijackers (ATG-Europe)
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16
Testing of a Propylene Loop Heat Pipe at Low Power under AccelerationSpeaker: Stephane Lapensee (ESA/ESTEC)
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17
White Kapton evaluation for space applications
A new white colored Kapton has been developed by DuPont. It is available in two versions: Kapton WS (White Shinny) and Kapton MW (Matte White). An evaluation of this material, with different surface depositions, for its use on space applications as thermal control foil has been successfully carried out by Airbus DS in Madrid, in cooperation with DuPont and Astral Technology Unlimited (ATU). This evaluation consists in the measurement of the main relevant properties before and after the submission of different samples to a simulated space environment, including exposure to high vacuum, large temperature excursions, UV radiation, charged particles radiation, and atomic oxygen.
Speaker: Mr Ignacio Melendo (Airbus DS Madrid)
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16
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11:15
Break
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Thermal Control and DesignConvener: Philipp Hager (ESA)
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18
TARANIS Micro satellite thermal control system design and verification
TARANIS Micro Satellite with 8 Scientific Instruments: Thermal Control System Design and Verification
Christophe Daniel, Maxime Andre
CNES (French Space Agency), Toulouse, 31400, FranceTARANIS (Tools for the Analysis of RAdiation from lightNIngs and Sprites) is a microsatellite of the CNES Myriade family (≈200 kg and ≈180 W). TARANIS is on a quasi-polar sun-synchronous orbit at an altitude of 670 km. The launch is planned in November 2020 on a VEGA launcher.
The aim of the TARANIS mission is the study of the phenomena associated with atmospheric storms and the coupling between magnetosphere-ionosphere-atmosphere. In particular, the scientific observations concern the transient optical phenomena called Transient Luminous Events (TLEs) occurring above storm systems at an altitude of between 20 and 100 km, the gamma-ray and X-ray flashes probably associated to the TLEs called Terrestrial Gamma Flashes (TGFs) and the transient precipitations and accelerations of energy electrons. TARANIS is the first space mission with the capability to identify simultaneously the optical, X-Gamma, electron-beam, and electromagnetic signatures associated to TLEs and TGFs.
To meet these objectives, the TARANIS payload includes 8 scientific instruments with a total of 13 sensors managed by 2 electronic boxes. Each scientific sensor type has various particular needs that induce strong constraints on the accommodation of the payload and require so many local and separate Thermal Control System (TCS).This paper gives an overview of the TARANIS TCS design with a focus on the mechanical and thermal interfaces, internal to the payload, that are necessary to meet the needs and constraints of each scientific instrument. Then, it presents the TCS verification logic. A specific focus emphasizes the early validation of the design of the payload Multi Layer Insulation (MLI) blankets. Finally, it discusses the specificities and results of the thermal balance/thermal vacuum (TB/TV) tests performed early 2019 and the TCS performances expected in flight.
Speaker: Maxime ANDRE
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18
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12:30
Lunch Break
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Thermal Control and DesignConvener: Victor Cleren (ESA)
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19
7 Years of Radiator Ageing on Alphasat (GEO)
Radiator degradation in orbit is of interest as it is one of the main drivers for the radiator sizing. Information from ground testing and LEO flight samples are abundantly available but not for GEO S/C. With 7 years of telemetry data from a radiator dedicated to the Laser Communication Terminal at the GEO satellite Alphasat insights into solar absorptivity increase of the radiator’s surface are available.
Speaker: Mr Jan Klement (Tesat-Spacecom GmbH & Co. KG) -
20
JUICE thermal performance and verification
JUICE (Jupiter Icy Moon Explorer) spacecraft will provide a thorough investigation of the Jupiter system in all its complexity with emphasis on the three potentially ocean-bearing Galilean satellites, Ganymede, Europa and Callisto, and their potential habitability.
The JUICE spacecraft will carry the most powerful remote sensing, geophysical, and in situ payload complement ever flown to the outer Solar System. The payload consists of 10 state-of-the-art instruments.
The main design drivers of JUICE mission are the very harsh radiation in Jupiter environment, leading to shield individually or collectively all the sensitive components, the stringent Electro-Magnetic Compatibility (EMC) requirements to fulfil the magnetic and electrical fields’ measurement objectives and the low solar illumination received at Jupiter. This latter parameter drives both the size and technology of the solar arrays, and the thermal control, that is designed to cope with hot and cold environments. JUICE spacecraft thermal control has to cope with a large variation of external environment during the mission (Sun flux from 3323 W/m² in the inner Solar System down to 46 W/m² in Jovian environment) and long eclipses of up to 4.8 hours.
The JUICE thermal control is designed with the objective to minimize the impact of the external environment on the spacecraft through high efficiency Multi-Layer Insulation. Minimizing heating power demand especially during science and communication phases and minimizing hardware mass is a constant concern and solutions are found to build to a maximum extent a robust and passive design supplemented by heaters.
The verification of the Spacecraft thermal control included the test of a scale 1:1 Thermal Development Model in cold and hot environment, including the use of a Solar Simulator in May 2018. The presentation will also present the preparation of the Flight Model thermal vacuum test, foreseen beginning of 2021.Speaker: Mr Romain Peyrou-Lauga (ESA)
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19
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14:30
Break
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Thermal AnalysisConvener: Matthew Vaughan (ESA)
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21
Systema-Thermica
In the past year, two Systema versions have been issued. First Systema 483P2 has been released last May 2020 to address some issues signalled by users.
Then the version of Systema-Thermica V4.9.0 was released and available to users in fall 2020. This new version embeds features presented during the last edition of ESTEW, such as the Orekit library for enhanced accuracy of in-orbit computations, as well as the new tools in the modeller for better user experience, such as the Gizmo tool.
Moreover some features of the STEP-TAS protocol have been implemented in this latest version. Systema embeds the validation dataset provided by the last STEP-TAS SDK. Some Systema shapes that were not accounted for in the STEP-TAS protocol are now compatibles.
The kinematic and trajectory of Systema have also been updated as aforementioned with the Orekit library, and some accesses for working with python scripts have been enhanced. The possibility to work more interactively with Albedo maps has been required by users and the projection of albedo map on planet skins is now available, as well as maps of the actual computation step which can be generated and displayed.
The new version of Thermicalc, the thermal excel access to Thermisol for predesign is now available. The major upgrades target the accessibility and ergonomy of the product, for a more pleasant and intuitive use.Speaker: Mathieu Lepilliez (Airbus Defence & Space) -
22
Systema-Thermica – User new possibilities
The Long-Term Support version of Systema-Thermica V4.8.3 was released last year. As day-to-day users, we conducted an extensive validation campaign based on various realistic use cases including both Telecom and Observation satellites/instruments.
First, the presentation will focus on this validation campaign implementation including the definition of the use cases, the validation criterion and the results obtained.
This new version offers a various new range of possibilities. These new possibilities make thermal modelling easier for numerous applications including projects such as MSR-ERO. The presentation will feature a part of these improvements and how they can help the user in his task.Speaker: Lilian Govone (ADS Toulouse)
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21
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15:45
Break
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Thermo-ElasticConvener: Benoit Laine (ESA)
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23
Thermo mechanical analysis of LISA instrument support structure
The presentation will cover the thermo-mechanical design and analysis of a concept for the LISA instrument support structure.
A brief introduction will be given to the LISA mission and to the main design drivers and requirements. The concept to be presented is a "thermally compensated" structure, where the different coefficients of thermal expansion (CTE ) of titanium and aluminium are used to create a very thermally stable assembly. The thermal analysis approach will be presented as well as the mapping of temperatures to the mechanical model for static cases and also in the frequency domain.
Results and conclusions of the analysis campaign will be presented and finally some perspectives and lessons learned concerning the tools and methods will be presented.
Speaker: James Etchells -
24
Further developments in the correlation of a Thermal Model for Thermo-Elastic Predictions
TBD
Speaker: Kimberly Rutherford -
25
Thermo-Elastic Response Analysis Methods
Thermo-elastic analysis has been performed for the SXI instrument to check the compatibility with allowable alignment errors resulting from thermal cycling in orbit near to cryogenic temperatures. The presentation focuses on the napping of temperature results between ESATAN thermal and NASTRAN FEM mechanical. Various interpolation methods were investigated and their accuracy compared.The resulting best method was then applied to the instrument model.
Speaker: nicholas eaton (Space Acoustics GmbH)
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23
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Thermal AnalysisConvener: Matthew Vaughan (ESA)
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26
Leveraging Hardware Accelerated Ray Tracing For Fast View Factor Determination
To prevent thermal induced breakdown, thermal modelling is a crucial task during each design phase of a new space mission. Monte Carlo ray tracing, while computationally demanding, is usually the go-to method to simulate thermal energy transfer. State of the art thermal modelling suites, such as ESATAN-TMS, usually rely on a CPU-based implementation of Monte Carlo ray tracing.
Due to the relatively long simulation times, only the mission points with the highest thermal loads, which have to be determined in advance, can be evaluated.In 2018 NVIDIA announced their RTX GPUs, which feature dedicated ray tracing cores. This, together with their powerful OptiX ray tracing API allows for the
development of performant and highly optimized programs, where the developer
can solely focus on the ray behaviour.
The potential of these technologies for thermal modelling was investigated as part of an ESA project.In the scope of this project, Fraunhofer EMI developed RayNer, a command-line-based technology demonstrator capable of determining black body view factors. The algorithm was verified against simple analytically solvable scenarios. Complex geometries can be built using the open source modelling software blender and
imported to RayNer in the GLTF format. Using realistic test geometries and similar sampling routines, RayNer determines the view factors up to 100 times faster than the ESATAN-TMS reference. The obtained view factors deviate only by ${\sim}10^{-3}$.
The complete pipeline and technology of RayNer will be discussed. Obtained results will be presented and compared to ESATAN-TMS.As our results suggests, existing solutions, such as ESATAN-TMS, might experience a drastic speed increase when switching from CPU- to GPU-based ray tracing. RayNer could be developed further into a thermal ray tracing API, or into a slimmed down stand-alone tool for quick first thermal assessments.
Currently the implementation of environmental fluxes and a physically accurate
reflection model is being investigated.Speaker: Mr Martin Henriquez Wehr (Fraunhofer EMI, University of Stuttgart) -
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INTA Thermal testing and Model Correlation of Cryostat Thermal Straps
INTA Thermal testing and Model Correlation of Cryostat Thermal Straps
M. Fernandez-Sanchez1, J. Azcue1, M. Reina1, L. Bastide2, A. García-Llases2, J. Gómez-Elvira1, A. Balado1
1 INTA, Ctra. Torrejón-Ajalvir Km.4 28850-Torrejón de Ardoz, Spain
2 ISDEFE Consultant at INTA, Ctra. Torrejón-Ajalvir Km.4 28850-Torrejón de Ardoz, SpainABSTRACT
Scientific missions to study the Hot Universe, the effect of Active Galactic Nuclei (AGN) in the intra-cluster medium (ICM) and by obtaining the distribution and properties of the warm/hot baryonic filaments in the intergalactic medium, does use of X-ray spectrometry, which detectors are transition-edge sensor (TES) superconductor detectors operating at millikelvin. That goal could be reached with a cryostat refrigerated by means of cryocoolers up to 2 K, while the subKelvin refrigeration is part of the Focal Plane Assembly, where the TES are.
DCS (Detector Cooling System) is a demonstrator of such cryostats, designed to test the performance and the functionality of a cryogen free coolers chain. The DCS is composed by two main assemblies: Focal Plane Assembly (FPA) and a Dewar (the pressure vessel structure and radiative shields cooled by Pulse tube and Joule-Thompson coolers), which creates a 2K environment for the FPA, where an ADR cools the detectors. The radiation is managed by the intermediate cooled shields, while the conduction goes through two “radial” paths: mechanical straps and harness. In both cases, there are a number of thermal anchors with the internal cooled shields. Thus, gradually, its temperatures are decreased and heat fluxes removed by the coolers.
Each mechanical strap is formed by four links of composite materials (GFRP and CFRP) manufactured by INTA Composites Area. The materials of the links was selected according to structural and thermal requirements, first Eigen frequencies above 60Hz, and a heat load on 2K enclosure lower than 20mW. Thus, the material distribution is GFRP for high temperature stages (300K to 30K) and CFRP in low temperature stages (30K to 2K).
To verify the design, a dedicated thermo-mechanical test was performed, submitting the straps to temperature gradients and mechanical stress similar to the expected. A dedicated set-up was designed and two straps were tested at their temperature range, with the hot end of the strap at 300K, while the cold end was at 30K due to the facility constrains. Straps under a tension of 6.000N applied at room temperature, according the DCS design. Active thermal control, insulating shields and ancillary elements, were used to create the thermal environment, and Silicon-Diode thermal sensors used to measure the strategic spots. Moreover, strain gauge was used before the cool down to measure the deformation due to the tension, which were checked before and after the test to discard any loss of tension due to temperature changes.
This paper describes the test set-up and thermal model done to correlate the DCS Mechanical Strap performances under the foreseen environment, and the results of such correlation.Speakers: Miguel Fernández (INTA), Mrs Almudena García Llases (ISDEFE), Mr Laurent Bastide (ISDEFE)
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10:00
Break
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Thermal TestingConvener: Elena Checa
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Thermal tests monitoring and Analysis in Airbus Defence & Space Toulouse
Dynaworks has been defined as the CORE tool to manage the whole process from test operators to design analysts :
- DynaThermaNeo as been designed for Test operators to manage all the flows of information during the TVAC test
- DynaWorks is used by test operators and design analystS for monitoring the test
- DySCo is used by design analysts to monitor the test within the DMU and compare test and simulations.Speaker: Mr Guillaume PELISSIER -
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Thermal and functionality testing of a locomotion system for Phobos
The Mars Moon eXploration (MMX) mission of the Japan Aerospace Exploration Agency (JAXA) will launch in 2024 and explore Phobos. The Deutsches Zentrum für Luft- und Raumfahrt (DLR) and Centre National D'Etudes Spatiales (CNES) jointly develop a 29 kg rover that will land on Phobos and explore its surface. This presentation focuses specifically on the locomotion subsystem of the MMX rover, which is developed by the Robotics and Mechatronic (RMC) and System Dynamics and Control (SR) institutes at DLR. This subsystem is a highly dynamic and critical part of the rover. Therefore, thermal modelling, analysis and testing is performed to validate the thermal behaviour, functionality, and power consumption. In order to validate system requirements regarding power consumption, an extensive characterisation is performed inside extreme thermal environments. With Matlab Simulink, a thermal network was made to estimate the system’s temperature range. According to this range, a test setup was designed and built. Since many tests are done in different thermal scenarios, an efficient and rapid test setup is needed. A fully integrated testing setup is presented, which logs all the temperature and power data, and controls the locomotion system. All measurement devices are interlinked via a LAN interface which enables low-latency and high bandwidth logging. To avoid extraneous manual work in post-processing, data streams are synchronised and saved in one easily accessible data file. Strong temperature dependence of power consumption is found and quantified.
Speaker: Mr Harald Luiks (DLR / TU Delft)
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11:15
Break
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Thermal AnalysisConvener: Dr Harrie Rooijackers (ATG-Europe)
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Characterisation of the Venus thermal environment for the VenSpec-H instrument on Envision
EnVision is one of the three candidates for ESA's next medium class mission with the aim to explore the link between geological activity and the Venusian atmosphere. The mission consists of a suite of instruments to probe various layers of the Venus atmosphere, surface and sub-surface.
The topic of this presentation is a preliminary thermal study for the VenSpec-H instrument developed by the Royal Belgian Institute for Space Aeronomy (BIRA). The instrument is a spectrometer which is tasked with mapping the near surface atmosphere with the aim to identify water and sulphur dioxide compounds related to volcanic activity. The instrument consists of a warm section which houses a detector-cooler assembly and a cold section consisting of the optics with a challenging temperature requirement of -60 °C and stability of +/-1 °C.
It became apparently early on that the instrument would have operational constraints whilst trying to achieve a purely passive thermal control design due to the harsh Venus thermal environment. A scan of the mission profile including multiple attitudes was performed to assess the spacecraft sink temperatures and to trade-off the location of a cold and warm section radiator on the spacecraft. There was a requirement on the thermal analyses to go beyond the standard hot/cold case definition in order to demonstrate the instrument feasibility during the Venus year. This was made possible due to some in-house post-processing workflows of the thermal analysis results.
A number of radiator designs were investigated to try to minimise the influence of Venus Albedo and IR planet fluxes, with tilted cavity radiators showing the best performance. This concept was developed to produce a simplified coupled model of the instrument and spacecraft in order to identify any constraints on operation.
Finally, recommendations were given to instrument team which highlighted the critical design parameters to enable the planning of early characterisation tests to reduce the uncertainties. In addition, a recommendation of bi-annual spacecraft flip over manoeuvre to maintain a cold face was adopted by the system team. The study is ongoing with the next milestone being MSR in early 2021.
Speaker: Mr Matthew Vaughan (ESA) -
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STEP-TAS Updates
The presentation will give a short overview of the ongoing work on in the area of thermal analysis data exchange and specifically STEP-TAS.
The ongoing work with tool vendors to provide more robust and feature complete STEP-TAS interfaces will be presented, as well as some perspectives for the verification of STEP-TAS models. The latest converters for Thermal Desktop models will also be presented.
The presentation will also provide an opportunity to recall the key contact points and locations for downloads etc.
Speaker: James Etchells
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ClosureConvener: Dr Harrie Rooijackers (ATG-Europe)
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ClosureSpeaker: Dr Harrie Rooijackers (ATG-Europe)
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