France is spending $42 million to upgrade its special radar used to track objects in LEO (low earth orbit, under 1,000 kilometers out). The upgraded Graves (“Gravity”) System will be more reliable and capable. Graves entered service in 2005 but was quickly overtaken in capabilities by similar American and Russian radars. Graves will eventually be able to track satellites as small as 150 kg and lots of space debris. This would enable France to share intel on LEO satellites with the U.S., which agreed to this 2015 once France had equivalent capabilities.
LEO is where most of the espionage satellites are and tracking them has always been important because this lets you know what these birds are looking at. Graves has impressed the United States because the French system spotted over 30 “stealthy” American and Chinese spy satellites that occasionally orbit over France and are generally undetected by anyone else. Proof is being able to tell the Americans when the mystery bird was spotted and what its apparent orbit was. The U.S. was also impressed that Graves had up time of over 88 percent and was also making a major contribution to the international effort to track orbital space debris. France began developing Graves in 1990 and got it into service remarkably quickly and economically.
Knowing whose spy satellites are overhead is becoming more valuable for more nations. At the same time there has been little work done to create more stealthy satellites. Cold War era weapons, designed to fight a foe (the Soviet Union), that no longer exists, have been getting killed off with increasing regularity since the 1990s. Many others have been threatened, including some that are supposed to be top secret. A prime example are effort to develop ever stealthier spy satellites. Back when there was a Soviet Union, there was a need for spy satellites that were difficult to track from the ground. You can see spy satellites from the ground. They often have orbits that bring them within a few hundred kilometers of the ground, making them even easier to track. Spy satellites can be detected by radar, and seen (if you know where to look) with telescopes.
Spy satellites can change their orbits (via small rockets, and a supply of fuel), thus you have to keep an eye on them if you want to know what the birds will be watching. This is exactly what the Soviet Union did. They had thousands of people, and billions of dollars’ worth of equipment dedicated to tracking foreign spy satellites. By doing this, the Russians knew when the foreign (usually American) photo satellites would be overhead. The Russians made sure they did not do anything that they wanted to keep secret, when those American spy birds were watching. American intelligence already knew, from spies and defectors, that Russia was able to keep many projects secret because of their satellite tracking system. Thus the desire to develop a spy satellite that would be difficult to track, and would be out of (Russian) sight often enough to get a look at some of the hidden Russian projects.
With the Cold War over, the Soviet Union is gone, the Russians have much less money for secret projects. Besides, Russia is pretty wide open now, compared to the old Soviet days. Much more difficult to hide stuff. So why is it so important for more nations to know what is up there? Much of it has to do with fear that China is becoming a major presence in LEO and as the French now know, and the Americans have long known, the Chinese are getting better at hiding what they have in orbit. Thus the more nations pointing specialized radars and telescopes at LEO the less likely that Chinese stealth spy sats will become a major problem.