'Sad day' for astronomers as Nasa telescope set to crash back to Earth

An Otago based astronomer says it's a sad day as a half-a-billion-dollar satellite looks set to crash back to Earth.At some point on Wednesday Nasa's Swift Observatory is expected to burn up somewhere over the Pacific Ocean after an attempt to save it failed.It was launched in 2004 to study black holes and exploding stars.But ever since then its orbit has been slowly dropping, and in 2025 a last-ditch rescue to push it back up didn't work.Otago Museum director and astronomer Ian Griffin says the satellite's work was remarkable.RNZ / Tess BruntonOtago Museum director and astronomer Ian Griffin told Morning Report the satellite was one of the best tools they had."It was a remarkable space telescope," he said."It's helped us understand the biggest explosions in the universe, and it even saw the death of a star more than 13 billion years ago."Griffin said most of the satellite would burn up in re-entry.It raised questions about how we dispose of satellites, he said."We, in recent years, put enormous numbers of satellites up into the low earth orbit and they're now re-entering at a rate of about two a day."Griffin said when the satellites burn up, their material goes into the atmosphere."We're sort of changing the chemistry of our atmosphere in a great experiment at the moment, we really don't know where it's going to end up."That could considerably change the chemistry of the Earth's atmosphere over the next few years, Griffin said.