At the end of their lifespan, uncontrolled spacecraft eventually re-enter Earth’s atmosphere and demise, totally or partially, due to their interaction with the surrounding flow. The growing population of junk in Earth’s orbits induced space agencies to tackle the space debris issue by imposing increasingly stringent requirements over the years. The recently published standard ESA Space Debris...
The French Space Operation Act (LOS) adopted in 2008 has established a national regime of authorization and supervision for space activities. CNES, the French Space Agency, is in charge of ensuring the right application of this Space Operation Act. In this context, to predict the debris survivability of a space vehicle and its associated fragments during their atmospheric re-entry, and assess...
At enGits, we have developed an in-house CFD code for compressible flow. From the start, this code has been designed with massively parallel hardware in mind. As a result the code is able to run very large simulations on simple PCs or similar hardware. For example, we are able to run a buffeting simulation with 100 million cells overnight on a single PC. We believe that this is interesting...
Atmospheric re-entry tools and their predictions are increasingly utilized in the satellite design process due to the demand for safe satellite disposal to minimize the rising debris population in orbit. Accurate predictions of re-entry, particularly in aerothermodynamics, are crucial to evaluate the probability of demise and casualty risk associated with re-entering vehicles. Destructive...
As the number of objects in LEO increases, Design for Demise (D4D) becomes an ever-more important philosophy for space engineering which relies upon robust modelling of re-entry processes. Uncertainty Quantification (UQ) is a vital part of ensuring this robustness but is limited by the significant computational costs associated with high-fidelity re-entry simulation and as such most UQ...
DRAMA (Debris Risk Assessment and Mitigation Analysis) is a comprehensive tool for the compliance analysis of a space mission with space debris mitigation standards. As part of the suite DRAMA allows modelling of the re-entry of a spacecraft into the Earth’s atmosphere along with an assessment of ground casualty risk.
Presented herein is an overview of two tools, Event Simulator and...
Dynamic fragmentation is a process during which a material or structure subjected to intense loads fails catastrophically through the initiation, propagation and coalescence of a multitude of cracks. It is a key topic in many fields of engineering, as for instance in aerospace industry, where the outcome of destructive re-entry is of great concern. Robust numerical models are direly needed to...
In recent times, satellite systems boasting thousands of satellites have been launched into orbit. The relatively short lifespan of these satellites, typically lasting only 3-5 years, has lead to increasing chances of in-orbit collisions and overall space cluttering. As the number of space debris experiencing post-mission uncontrolled re-entry rapidly increases, there is growing concern for...
Direct numerical simulations (DNS) are performed by our in-house flow solver INCA (www.inca-cfd.com)(Başkaya et al., Computers & Fluids, 2024) over a 15 degree compression ramp undergoing ablation at Mach 8. The setup is validated against experiments and simulations that considered the laminar flow over an inert ramp. Streamwise vortices, which generate heating-cooling streaks through the...
One of the peculiarities of some space debris materials compared to thermal protection systems is that the ablation of the critical parts of such objects might involve melting and the presence of three phases (gas, liquid, solid). This is the case for glassy and metallic materials. Given the huge properties differences that exist between the gas and the condensed phases and the complex...
Highly Eccentric Orbits (HEO; eccentricities above 0.8 and perigee above the drag regime) are favourable for scientific and observations missions since the satellite is outside of the Earth’s radiation belt for most of the orbital period, avoiding noise and radiation effects which can interfere with Earth and Universe observations. Over the years, more than 30 missions have been operating in...
The historic re-entry of a Delta-II upper stage in 1997 has been re-assessed using a simplified model in DRAMA v3.1 and SAMj. The analysis considers five scenarios covering both object-oriented and component-centric models of the spacecraft, as well as the impact of improvements in material representation since the case was originally executed in 2012.
The trajectories predicted by DRAMA...
SCARAB Numerical rebuilding Delta II Second Stage re-entry - ATD3 Test Campaign
As the number of small satellites in Low Earth Orbit grows, understanding their re-entry demise becomes increasingly crucial for ensuring the sustainability of space utilization. This includes risks associated with ground impacts from incompletely demised components and the release of aerosols and gases into the upper atmosphere. The SOURCE PWK project, funded by the German Aerospace Center...
The use of pyrotechnic formulations to assist spacecraft demise during re-entry has been investigated in the frame of the SPADEXO ESA-TRP project. The approach selected during this activity consisted in the direct integration of thermite powder in the structural voids of robust components, which could be passively ignited by the aerothermal heat experienced by the spacecraft during the...
During the atmospheric entry, the decommissioned satellite is strongly affected by aerodynamic heating due to dissipation of a huge amount of kinetic energy into thermal energy. In these conditions, the vehicle usually breaks-up into several parts which are, in turn, degraded by the high enthalpy flow. However, Carbon Fiber Reinforced Polymers (CFRP) materials behave similarly to thermal...
An end-of-life scenario for the demise of a LEO satellite might start with deceleration from drag in the LEO environment, followed by heating, ablation, and breakup as the satellite descends into the dense atmosphere. Some key physical and chemical processes would be gas-surface energy transfer, ablation reactions on high-temperature surfaces, and pyrolysis of polymeric materials. Molecular...
Operating satellites in very low earth orbit (VLEO), approximately between 100-300km altitude, has numerous advantages. One advantage is close proximity to earth, which can enable accurate sensing with significantly lower SWaP+C (size, weight, and power + cost). Another advantage is that VLEO is effectively a “self-cleaning-orbit” where unpowered spacecraft will quickly re-enter the atmosphere...
The aerodynamic forces and aerothermal loads experienced by spacecraft components during a fragmenting reentry likely influence their trajectories, demisability, and, as a consequence, the resulting ground casualty probability. Due to the complexity of this phenomenon, Design for Demise tools often simplify the dispersion of the fragments and the interactions between the components,...
The PRODUCERS project, funded by ESA and led by Fluid Gravity Engineering, Ltd., aimed to experimentally investigate and computationally predict radiative markers associated with the destructive re-entry of spacecraft at the end of their life. The purpose of the research activity is to improve the analysis of spectroscopic and visual data obtained through dedicated remote observation campaigns...
Setting up a clean scenario for space management, where space debris are effectively removed from orbit following a design-to-demise strategy presents a formidable challenge. This involves employing design tools commonly developed and used for Thermal Protection System (TPS) of reentry vehicles. However, designing for space debris demise introduces a higher level of complexity, requiring...
To assess the effectiveness of tools designed for hypersonic material testing and space debris analysis, it is essential to replicate specific environmental conditions such as pressure, temperature, and shear stress in ground-based testing facilities. As part of the latest developments in space debris material research, the Plasmatron facility at the von Karman Institute now provides a unique...
This study aims at describing the physio-chemical alterations in standard layered materials, analogous to those utilized in spacecraft construction, under the influence of reactive atomic oxygen (ATOX). ATOX conditions similar to those found in Low Earth Orbit (LEO) were simulated to assess, quantitatively and qualitatively, the impact of ATOX exposure [1] in mass loss, structural and chemical...
With the recent awareness of the space sector on the fragile near-Earth space region and the forecast of the booming number of satellited objects, various mitigation approaches are currently evaluated and start to be implemented to limit the impact of space activities and achieve a safe and sustainable space environment.
The re-entry of spacecraft into the Earth’s atmosphere can contain...
The Kentucky Re-entry Universal Payload System (KRUPS) provides a quick-turnaround, low-cost plat- form to conduct atmospheric entry experiments. KRUPS is designed to test multiple types of thermal protection systems (TPS) and scientific instrumentation. Five KRUPS capsules were sent to the International Space Station (ISS) via the NG-20 Cygnus resupply vehicle. After the completion of the...
Spent upper stages of launch vehicles are a very large and dangerous class of space debris since they are prone to spontaneous explosions producing many small objects. This makes old upper stages one of the primary targets for future active space debris removal missions. If the initial attitude motion of the target stage is known, e.g., from in-situ measurements exploiting CubeSats, it is...
