HETE-2

HETE-2 was a small international observatory built to catch gamma-ray bursts and pin down their positions within seconds, then beam the coordinates straight to ground telescopes so they could swing onto the fading afterglow while it was still bright. That rapid-alert role made it a key node in the early-2000s effort to understand where bursts come from. It was air-launched by a Pegasus over the Pacific near Kwajalein.