Launched on 24 June 1999, I'm the Hubble Space Telescope's poor cousin. We both send our results to the same place, and we're both related in a lot of other ways too.
Unlike Hubble, which has cameras and multiple instruments, I'm a single purpose workhorse. I'm basically a big flying spectroscope, able to study far ultraviolet light way down to about 800 Angstroms wavelength.
As satellites go, I'm getting a little old. I'm already past my design lifetime, and unlike my famous cousin I don't get servicing visits. I've been pretty lucky to have some really smart people in my flight team back at Johns Hopkins, who came up with some slick tricks to make my pointing and guidance system a lot smarter. That compensated for the loss of two of my four reaction wheels, which had caused me some pretty serious problems.