With the new French space policy to be announced in a few months, and likely including a heavy Space Situational Awareness (SSA) emphasis, a few companies were presenting their solutions at the 2019 Paris Airshow:
Sodern is working with cubesat builder Hemeria and electronics expert CS on Hirondelles, a constellation of cubesats to do satellite-to-satellite imaging. There would be 4 satellites in slightly elliptical 400x500km, 500x600km, 600x700km and 700x800km, using a sensor derived from Sodern’s Auriga star tracker to get resolved images of foreign observation satellites and other suspicious objects. Satellite-to-satellite imaging is not new in France, with the Pléiades HR satellites having taken pictures of the Envisat satellites back in 2012, and of the ISS.
The true benefit of using cubesats is probably that they can use non-circular orbits to have many conjunctions with the targets: dedicated observation satellites are often on tightly controlled circular, sun-synchronous orbits, so the conjunctions with another SSO satellite operating at the same altitude happen either every orbit or not at all. On the contrary, Sodern advertises that 94% of objects of interest could be imaged within 7 years, with 40 pictures per object on average.
Sodern is also advertising putting its cameras aboard military satellites to detect close approaches by suspicious objects. The next-generation French Syracuse 4 communication satellites will have this kind of capability.
Arianegroup was showcasing its Geotracker network of telescopes, which can track satellites in GEO, MEO and LEO, and also image LEO objects using lucky imaging. It is considering a 2nd generation of telescopes with laser ranging capabilities, and foresees a huge growth of SSA activities due to the launch of megaconstellations. Arianegroup has its own telescopes, and sometimes asks for time on larger scientific telescopes for special cases.
French aerospace lab Onera was showing its radar and optics expertise, with some pictures of Envisat taken using adaptative optics. Onera recently announced it blinded a Spot observation satellite using a laser using the same adaptative optics technology.
It was also explaining its plans for the Graves LEO SSA search radar: first, an upgrade to replace obsolete component and make it work until 2030, then a new-generation radar in the HF band, to be able to track cubesats, and have a range of 2000km. The system would have an emitter looking like a scaled-down version of the Graves emitter, and a completely new receiver located a few kilometers away from the emitter. Graves is in the VHF band, cannot detect small satellites, has a range of 1000km and has a receiver located 400km away from the emitter.
The French Ministry of the Armed Forces also had an exhibit illustrating what space operations could be like in a few years: in their scenario, a foreign country declared a space exclusion zone in the GEO belt. It then sent a satellite very close to a French comsat that was in this zone. The comsat was escorted by a notional “bodyguard” small satellite, tasked with observing the space around it and taking pictures of any interference attempts.