"German satellite hurtling towards Earth"

ROSAT, a German satellite is indeed "hurtling towards Earth", as the Guardian and many other news outlets have been telling us in recent days. Well, "hurtling" isn't quite accurate, but it'll reach us sometime in the next few days as its orbit gradually decays (in fact, since I typed this it looks as though it's come down).

I was slightly surprised to learn it hadn't come down a long time ago. It was a pioneering X-ray astronomy space mission of the early 1990s. When the first X-ray detectors were thrown briefly up above the atmosphere on rockets, there were no great expectations. This was in 1962 and imaginations stretched only to a faint glow from the Sun's million-degree outer atmosphere, or possibly from the Moon's surface as energetic particles in the solar wind smashed into it. As the world knows, the results were much more exciting: bright, point sources of X-rays beyond the solar system, among the stars of the Milky Way; a cosmic "background", X-rays coming from all directions on the sky; X-radiation from the Crab Nebula. A new window had opened on the high-energy universe of black holes and neutron stars; nobody thought much about X-rays from the Moon for a long time.

ROSAT closed this particular historical circle by detecting, for the first time, X-rays from the Moon. The ROSAT image of the Moon, illuminated only on its sunward side, looks so familiar that you might need to look twice and think about it to realise just how amazing it is. It is lit up only on the sunward side because the Moon's surface is reflecting X-rays from the Sun (strictly, scattering those X-rays, and apparently also fluorescing).

ROSAT was used to make many important advances in X-ray astronomy; a brief list is here. I always had a soft spot for it because it closed the lunar loose end. None of this prevented its fiery doom, however, which no doubt is as it should be. None of us escapes his doom, watery, fiery or otherwise, no matter what sort of songs we've sung in the meantime.

None of the news reports let us forget it was a German space mission, rather than, say an "X-ray telescope", "orbiting X-ray laboratory" or some such border-less phrase. I wonder why? If it had actually fallen on somebody's head, would the German nation have been held to account? Would we have seen invoked the ghost of Wernher van Braun? I'm really not sure what's behind this.