The AeroThermoDynamics and Design for Demise (ATD3) Workshop managed by ESA and CNES took place in Bordeaux from 27 to 28 October 2022. HyFAR-ARA was locally in charge of the Workshop organisation.

The workshop gathered over 50 participants from more than 10 countries during the two days. HyFAR-ARA is pleased and honored to have contributed to this event.

Group photo at the end of workshop


The workshop is free of charge for participants (registration is nevertheless mandatory). This has been made possible thanks to the sponsoring of the Hyfar-ARA association, Von Karman Institute and Frazer Nash Consultancy





Since the launch of the first Sputnik in 1957, more than 6,000 rockets have put into orbit nearly 13 000 satellites, of which about 8000 are still present (active or inert).

A galore of debris adds up to these objects [1]: more than 600 destroyed satellites (explosions, collisions…), launcher stages and various debris (launcher elements, tools…). A total of approximately 36,000 objects larger than 10 cm, representing nearly 10,000 tons, are circulating today in Earth’s orbits.

The creation of satellite constellations worth thousands of objects (Starlink…) has made these numbers soar (see figure), with the risk of a rapid saturation of useful orbits as well as an increase in the risks of collisions and debris production.

This ESA video  presents the various situations encountered when accounting for a sustainable space exploitation, and the different strategies that are applied in each case.

In brief, the different cases presented in the video are the following :

1.       Interstellar spacecraft such as pioneer 10 do not raise any concern regarding space debris or orbits congestions

2.       Exploration probes to the farther planets of the solar system (Saturn, Jupiter), at about 600 000 000 km from Earth, could be a contamination hazard by terrestrial forms of life. To avoid it, they are safely disposed off

3.      Most of the satellites that have been launched since the beginning of space exploration were assigned to the rocky planets of the solar system : Mercury, Venus, Earth and Mars. A great majority of them are used in Earth orbits. Mars comes in second (80 000 000  km).

Active probes orbiting Mars can be tracked, but the positions of their now inactive predecessors are poorly known and pose a possible risk to others.

3D interactive satellites tracking

4.       The most critical satellites and debris, because they are the most numerous and they orbit in a limited space, are those in Earth orbits. Starting from the most distant orbits to the closest, the strategies adopted by ESA are the following:

      • ·         The satellites located at the Lagrange points of the Earth-Sun system (distance to Earth of about 1 200 000 km) do not raise particular difficulties, although they are in an area of Space whose demand increases: at the end of their life they can free this area by moving to a solar orbit from which the risk of return to Earth is almost null (see slides).
      • Satellites in very eccentric orbits (up to more than 100 000 km of apogee): orbit maneuvers are applied to make end-of-life satellites re-enter the atmosphere at safe latitudes about two decades later
      • Closer to Earth (36 000 km), geostationary satellites are located in very congested orbits. The maneuvers to make these satellites re-enter in Earth’s atmosphere at the end of their life would be too costly. They are therefore moved to “parking” orbits to free up space and avoid the risk of collisions with active satellites. The same strategy is applied to the upper stages of launchers. The sustainability of this strategy raises however questions quite similar to those that arise on low orbits (see next)
      • Satellite constellations for terrestrial navigation (about 20 000 km – 25 000 km) are at altitudes that make it very difficult to move them towards parking orbits. Fortunately, to date (2011) no incident (collision or explosion) has ever disturbed the use of this category of orbits
      • Low Earth orbits (1000 km to a few thousands km) are those in which both the congestion of satellites in circulation and the accumulation of debris and launch vehicle fragments are most critical: they concentrate two thirds of the objects launched into space from Earth. The situation is even worse since it is in these orbits that mega constellations of satellites such as Starlink have recently been accumulating.

To ensure the sustainability of the operations at these low orbits, the control of debris and/or inactive satellites is of utmost importance.

Various actions are possible :

  1. When satellites are active, monitor their environment and perform the necessary maneuvers to avoid collisions with drifting debris or other satellites
  2. Passivation of launchers stages: depleting residual fuel, venting pressure tanks and discharging batteries
  3. Reduction of the number of inactive satellites to avoid cascading collisions that could hinder the use of these orbits. To this end, a duration of less than 25 years in orbit after the end of the mission is recommended

At these altitudes, the most effective solution to reduce the number of inactive satellites is to move them towards lower orbits where the increase in the density of the atmosphere will slow them down progressively, and drag them into an atmospheric re-entry during which they will be destroyed

This last phase is critical because most of the time the moment and the position of the beginning of re-entry are not controlled. It is then necessary to master sufficiently well the physical phenomena of re-entry, and the mechanisms of destruction of the satellites and their components, in order to guarantee  the absence of risk for the populations with an extremely high probability.

The ATD3 Workshop focuses on the issues that need to be addressed to provide this guarantee:

  • mastering the space environment in which the objects in orbit evolve,
  • physical and numerical modeling of the atmospheric re-entry of space objects (satellites, launchers…),
  • design of satellites allowing to control the destruction process during re-entry.


[1] , issue of 4 April 2022


Design for Demise

ATD3 workshop is dedicated to “design for demise” issues

A multi-fidelity simulation framework  for atmospheric re-entering bodies
Morgado, F., Peddakotla, S., Fossati, M.
02.12.2021  – ATD3 2021 Workshop

For those satellites reentering in the Earth atmosphere, the objective to comply with the requirement of extremely low casualty risks on ground raises the following questions:

  • mastering the space environment in which the objects in orbit evolve,
  • physical and numerical modeling of the atmospheric re-entry of satellites and other objects in orbit (launchers…),
  • design of satellites allowing to control the destruction process during re-entry.

The last item above is referred to as design for demise which is the core subject of the ATD3 workshop.

Design spacecraft for demise means

  1. develop design features and methods that account for the requirement of a low risk on ground after reentry
  2. develop the tools (either experiments or numerical simulations) to demonstrate the effectiveness of the design.

The main steps toward this goal [3] :

  • identify those elements of a satellite that are critical from a re-entry point of view
  • identify design for-demise techniques applicable to those critical elements
  • validate the proposed techniques in representative mission scenarios
  • for the most promising techniques, identify a dedicated technology roadmap to ensure a proper and timely development

There are a number of properties of a spacecraft component which make it more likely to survive to the ground :

  • Being made of a material which is particularly difficult to demise, such as materials with high heat capacities, high melting temperatures, or high heats of melting
  • Being large and heavy
  • Being protected by other parts of the spacecraft (delayed exposure to heat fluxes)
  • Being thermally thin, i.e. reaching very quickly a radiative equilibrium which preserves the component to heat up beyond melting temperature

Design for demise addresses the features of a spacecraft that minimize those effects. The representativity and validity of the simulation tools that provide either proof of effectiveness or design requirements are at the heart of the methodology.


[3] Design for demise techniques to reduce the re-entry casualty risks
David Riley, Irene Pontijas Fuentes, Cristina Parigini, Jan-Christian Meyer, Pénélope Leyland, Gwenael Hannema, Enrique Guzman, Christian Kanesan
66  International Astronautical Congress, Jerusalem, Israel. – 2015

[4] ESA – Design For Demise – A First Look

The workshop in a nutshell

Workshop overview

The workshop is organized by the Working Group “ATD3” managed by ESA and CNES through the ESA Technology Directorate and the CNES Research and Technology Directorate.

The ATD3 working group is a regular forum at European level to facilitate the discussions (at technical and scientific level), collect and disseminate information, propose new topics/activities and plan (roadmap definition and coordination).

The 2022 edition is the first in person workshop since the 2018 edition in Germany (2 videoconferences took place since then :  16 September 2020 and 2 December 2021, this last one registering over 150 participants)

The main objectives of the working group are:

  • Setting of a framework for verification, validation and comparison of numerical methods for space object reentry simulation tools.
  • Disseminating recent results within the ATD3 community. Members include academics ( in particular PhD students) and experts from industry
  • Coordinating and discussing future activities. The objective is to get expert opinion from the academic and industry sector regarding future activity in the domain of aerothermodynamics and design for demise.

The format is a sequential list of presentations of about 20 minutes each, with 5 minutes brief Q&A session per presentation


Unsteady MISTRAL simulation

The workshops addresses the issues that are raised by the knowledge of satellites breakup and debris transformations as they enter the Earth atmosphere, the ultimate goal being to predict their survival or total demise before reaching the ground.

The other issue is to determine how fast and how big the remaining debris (if any) will be upon arrival at ground, in order to assess the hazard for populations.

In case the outcome would be an unacceptable risk to the public, the experimental and numerical evidences shall help to improve the design of the spacecraft being assessed.

The workshop is a focus on the experimental data, experimental techniques, ground test characterizations, numerical simulations and physical models that are used in this process.

Some examples of the topics that are addressed in the workshop :

  • Wind tunnel and arc jet diagnostics
  • Development and experimental assessment of new ground tests facilities
  • Study and development of fuse systems to initiate spacecraft demise
  • Rebuilding of actual spacecraft reentry and comparison to observations
  • Benchmarking of simulation tools
  • Arc jet tests experiments on spacecraft components (reaction wheels, optics, structures…)
  • Development of physical models and their numerical implementation, tests against experimental results : aerothermodynamics, flight mechanics, structural mechanics, thermal behavior, etc…
  • Materials databases
  • Demise experiments on ground
  • Numerical tools for spacecraft demise modeling


Provisional Schedule


This schedule is only a tentative one. It will be updated as presentation proposals  will be submitted (last update :31  May 2022).

For the most up to date timetable, follow this link :
ESA timetable

Practical information


The HyFAR-ARA association and the Workshop sponsors take in charge most of the expenses.

What is left on participants budget is :

  • Travel from and to their premises
  • Lunches: a suggested list of places for lunches will be published here before Workshop starts
  • 27th October dinner at Café Maritime for those interested (40€ : to apply see dedicated section in this page)
  • Accommodation (see this other section in this page)


The workshop will take place in the « Ellul » aula  which is located in the building of the University of Bordeaux Law School.

The building is erected on Place Pey-Berland which is in the heart of Bordeaux, close to two of the town’s most important monuments : the  Cathédrale Saint André (Saint Andrew Cathedral) and the City Hall.

To quickly spot the location of the Place Pey-Berland, please refer to the figure below. Additional directions are provided in the slide show next to this text, together with more photographs of the venue and its surroundings.

The accommodations that are proposed in the next section have  been picked to be within reasonable distance to the venue and with a large span of prices.

The organizing committee recommends the  hotels on accommodations list. Pey Berland is mentioned as this is the location of the venue.

Cap Science is a permanent place of scientific exhibitions close to the Café Maritime where a common dinner at the end of day 1 is proposed (see dedicated section on same page).

All of the addresses are within easy access to the center of Bordeaux. We recommend as early booking as possible.

Should you prefer to book an other hotel, we recommend to choose one that would be not more than 15 to 20 minutes away from the « Pey Berland » station.

For additional information on public transportation and touristic spots see dedicated section on same page

October 27 dinner @ Café Maritime

For those who may be interested, a pre-reservation has been made at Café Maritime restaurant.

The fee for the dinner is 40€ per person. If you are interested, please be kind enough to apply early (all information in this section of the present page). This will make the organization committee confirmations to the Café Maritime easier.

Important notice : the deadline for the registration to the dinner is set to September 30th.The registration is closed

How to get there ?

From Place Pey Berland, the best way is to use the tram (direct journey to Café Maritime restaurant).

At Pey Berland, board the tram Line A towards Berges de la Garonne.

Exit at Cité du Vin station.

The Café Maritime is at 5 minutes walk (see figures in slideshow next left)

Touristic spots & public transportation

Tramway plan with touristic spots

Hover the mouse above the circles to open a bullet with information on the touristic spots. Right click to zoom the map in To get full map download here (773k) Link to Bordeaux public transportation website

1 : Grand Théâtre


Grand-Théâtre (crédit Steve Le Clech Photos)


2 : Miroir d’eau


Miroir d’eau (Crédit Christophe Bouthé (2)-Vent d’Antan)


3 : Place des Quinconces

hotspot-03-Place des Quinconces

03-Place des Quinconces : monument aux Girondins (crédit-Vincent Bengold)


4 : Jardin public

hotspot-04 : jardin public

04- Jardin public (©Cyril Cosson – Droniryc)


5 : Porte Cailhau

hotspot-05 : Porte Cailhau

05-Porte-Cailhau (© Deepix)


6 : Cathédrale St André et Tour Pey Berland

hotspot-06: Cathédrale St André et tour Pey Berland

06-Cathédrale Saint-André (Crédit : Teddy Verneuil – @lezbroz)


7 : Place de la Victoire

07- Place de la Victoire

07- Place de la Victoire (©Nicolas-Duffaure)


8 : Basilique Saint Michel

08-Basilique Saint Michel

08-Basilique Saint Michel (©Cyril Cosson-Droniryc)


9 : Les Hangars – Quai des Marques

09 – Les Hangars – Quai des Marques

09- Quai des Marques (crédit Bordeaux Metropole – Didier Doustin)


10 : Place Stalingrad – Le Lion bleu de Veilhan

Place Stalingrad – Le lion bleu de Veilhan

10- Place Stalingrad – Le lion bleu de Veilhan


11 : Jardin botanique

11- Jardin Botanique

11-Jardin Botanique-(Crédit Sophie Duboscq)


12 : La Grosse Cloche

12 – La Grosse Cloche

12-La Grosse Cloche (©picsol)


13 : CAPC (Musée d’art contemporain)

13-CAPC (musée d’art contemporain)

13- CAPC (Musée d’art contemporain)


14 : Musée des Beaux Arts

14- Musée des Beaux Arts

14- Musée des Beaux Arts (crédit musba)


15 : Musée des Arts Décoratifs

15- Musée des Arts Décoratifs

15-Musée des Arts Décoratifs (©madd-bordeaux – I. Gaspar Ibeas)


16 : Espace Darwin

16- Espace Darwin

16- Darwin Caserne Niel (crédit Nicolas-Duffaure)


17 : Cap Sciences (Hangar 20)

17- Cap Sciences

17-Cap-Sciences (© Cap Sciences, expo Odyssee-2015)


18 : Musée national des douanes

18- Musée National des Douanes

18- Musée National des Douanes


19 : Musée du vin et du négoce

19- Musée du Vin et du Négoce

19- Musée du Vin et du Négoce (© C.Pamelard)


20 : Musée d’Aquitaine

20- Musée d’Aquitaine

20- Musée d’Aquitaine (crédit Mélanie Tammeveski)


21 : Cité du Vin

21- Cité du Vin


21- Cité du Vin (© Cyril Cosson-Droniryc ; XTU architects)


22 : Map ressources

Contacts and Registration


Registration to the workshop

Link to the ESA registration page : ESA /CNES ATD3 2022 Workshop

Registration to the 27th October 2022 dinner

If you want to participate to the 27th October 2022 dinner, click on the button bellow (deadline extended to September 30th 2022 )

Contacts with local organization team

If you need to contact the organization team, please use the form below. We will answer as soon as possible.

2 + 5 = ?