PARIS (CNES PR) — SpaceBlower, in French “space blower”. The purpose of this light suborbital launcher is to eject its plume at large unmaneuverable space debris. By avoiding collision with one another and their fragmentation into several thousand others, the aim is to preserve the safety of orbits and satellites. SpaceBlower is a preliminary project initiated and funded by CNES, with the support and co-funding of Bertin Technologies (now CT France). Christophe Bonnal, senior expert at the CNES launchers department, discusses it with us.
Here is a possible scenario ten years from now: a disabled satellite and the upper stage of a launcher are on a collision course. Neither is maneuverable, so you have to intervene to avoid serious consequences. In just a few hours, SpaceBlower is launched by a plane and rises to an altitude of 1000 km. The 3rd stage goes on a trajectory of intercepting the debris, and ejects a cloud of particles in front of it towards the debris. This artificial atmosphere could create a slowdown of only 10 cm/s and yet sufficient. By being launched 12 hours in advance, SpaceBlower could create a safety distance of 13 kilometers: the collision would be avoided.
Christophe Bonnal initiated this project as a space debris expert at CNES.
“With CT France, we have done a lot of work on the shape of the plume,” explains Christophe Bonnal. “Very wide but not dense, with gases or particles. The ideal is to have rather small particles of 5 microns in diameter, for example copper. SpaceBlower would be on a suborbital path, with a bell curve. So all the particles would come down with it, it wouldn’t generate any new debris which is important of course.”
In addition to the air launch which provides initial speed to the launcher and allows it to be much less sensitive to weather conditions, SpaceBlower could even benefit from the current development of the reusability of launchers, to reduce costs.
“We would like the first 2 stages to be reusable. The 3rd stage can also be reused, by carrying a parachute and a buoy. But it weighs heavily, and the impact on performance can be significant. So we would do the first missions without reuse to check how the quantity of copper on board is sufficient. And after 4-5 or 6 launches, we could decrease the payload and go to full reusability. The cost would be around 2 to 3 million euros, around 10 times less than other active withdrawal solutions.”
International Cooperation for an International Space
SpaceBlower would be fired by plane from half a dozen partner airports. They should all be located close to the equator to optimize the trajectory, which must be in phase with that of the debris. Then, the take-off site would be chosen based on the geometry of the collision, and the lightest debris would be preferred.
“The idea is to offer SpaceBlower at the international level,” continues Christophe Bonnal. “It would take one plane per airport, and 2-3 rockets available. We could thus avoid major collisions which occur approximately every 5 years. And complete transparency is absolutely necessary to prevent it from being an anti-satellite weapon.”
The law on space operations initiated by CNES has regulated and limited since 2010 the production of space debris. The best solution is to act preventively before they have dispersed into thousands of fragments.
“Debris that pre-existed decades before the law of space operations continues to be a problem. They hit other debris and worse, active satellites, which happens about ten times a year. This exponential multiplication of debris is the Kessler syndrome illustrated in the film Gravity. To avoid getting there there are 2 solutions. Mitigation, which consists of either limiting the rapid duration of new debris to less than 25 years. And if this is not respected, remediation with active withdrawal or intervention like SpaceBlower to avoid the collision.”
Last Minute Space Intervention
SpaceBlower is one of the three tracks explored by Christophe Bonnal and CT France to avoid collisions between debris at the last minute. This is the more general principle of the JCA for “Just-in-time Collision Avoidance”: just-in-time collision avoidance.
“We started from the principle that a small pulse is enough to avoid a collision of several kilometers. 3-4 techniques were studied, such as small CubeSats to hang on the debris to make them maneuverable. Even from the ground, the laser-matter interaction is enough to sublimate the surface of the debris. With pulses of only 10 picoseconds, the degassing would act as a propulsion and would be enough to deflect it sufficiently.”
This laser sublimation technique is the same used to analyze rocks on Mars thanks to ChemCam aboard the Curiosity rover, and soon by the Perseverance rover with SuperCam after its arrival in February 2021.