True, the Kuiper Airborne Observatory (KAO) was retired in 1995 to free up funding for SOFIA. Work on SOFIA started in the 90s and it made its first flight with the telescope installed last year. SOFIA is a similar idea to KAO, but on a much larger scale (the telescope is 2.5 m in diameter, compared to 91.5 cm for the KAO) and representing a significantly larger engineering challenge.
But yeah, I don't know why this is news now. Science flights aren't supposed to start taking place until next year.
Interestingly, it won't really be ready for science flights next year, but every ten years the US National Research Council does its decadal surveys
of all the science programs it's supporting and decides which ones to continue funding on. SOFIA's been so delayed that if it doesn't have any science results by mid-2009 (when the 2010 decadal survey will be taking its data), it runs a real risk of having its US government funding cut. If this happens, DLR (German Aerospace Center
), another one of the big funders, will be likely to cut funding as well, resulting in a bleak future for the SOFIA program.
(I worked on SOFIA as an intern at NASA last year.)