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Messenger's Mercury Trip Ends With a Bang, and Silence
mpicpp writes with an expected followup: Nasa's Messenger mission to Mercury has reached its explosive conclusion, after 10 years in space and four in orbit. Now fully out of fuel, the spacecraft smashed into a region near Mercury's north pole, out of sight from Earth, at about 20:00 GMT on Thursday. Mission scientists confirmed the impact minutes later, when the craft's next possible communication pass was silent. Messenger reached Mercury in 2011 and far exceeded its primary mission plan of one year in orbit. That mission ended with an inevitable collision: Messenger slammed into our Solar System's hottest planet at 8,750mph (14,000km/h) — 12 times quicker than the speed of sound. The impact will have completely obliterated this history-making craft. And it only happened because Mercury has no thick atmosphere to burn up incoming objects — the same reason its surface is so pock-marked by impact craters. According to calculations, the 513kg, three-metre craft will have blasted a brand new crater the size of a tennis court. But that lasting monument is far too small to be visible from Earth.
greenhouse effect
The sun's gravitational attraction caused the orbit to decay. It ran out of maneuvering fuel and could not raise its orbit anymore. This was expected - the mission fulfilled all of its primary objectives and some. A lot of good science was had from that probe.
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There wasn't enough fuel to sustain orbit. The team responsible for this went to heroic lengths to keep it in orbit --- including at one point venting the spacecraft's helium to give it a final boost. This was all done so the probe could keep sending back data, which it did happily. In the end we got approximately four times the expected data we wanted from the probe.
Not bad for government contractors.
Finding God in a Dog
The question is sort of answered in the article if you read between the lines:
Despite being able to look back with pride, Dr Raines said this was still a sad day for Messenger scientists.
"Pretty much all the instruments are still doing great, so that makes it a little harder," he told BBC News. But the mission was always going to be limited by the fuel needed to maintain its difficult orbit.
"To be honest, I've seen this day coming for a long time and it's just one of these things that I've not been looking forward to. I'm really going to be sad to see it go."
So, the fuel was needed to keep the orbit stable, and without that, it degraded and impacted the planet. It's likely they didn't have enough fuel to even break away from orbit, and if they did, it would have shortened the mission duration. And to what end? It's not like it harms anything. It's just another crater on the planet.
Irony: Agile development has too much intertia to be abandoned now.
This *was* the bitter end. It used up all of its fuel. It had to periodically lift its orbit ever since it arrived in 2011. It finally just ran out of fuel. It has been in orbit around Mercury for nearly four years (initially planned to survive only one year, due to the intense solar radiation).
Left MS Windows for Linux Mint and never looked back!
Vote for Bernie in 2016!
Seen by who? If you can't get a good look at the crater it made now, then what did you expect to see at the time of impact?
Yes it's an anecdote! Were you expecting original research in a Slashdot comment?