I just saw on CNN that they are terminating the Galileo mission after one last hurrah. The craft is due to smack Jupiter in 2003. Some insturments are no longer working, but a lot are.
So my question is this. Why not keep it flying until there is no use to fly it anymore? Or is there another reason that wasn’t mentioned, like it running out of propelant or something?
They don’t want it to accidentally crash into Europa, the single most promising location for extraterrestial life. If Galileo were to crash into Europa at some point in the future then there is a non-zero risk that any bacteria that hitched a ride on Galileo and has remained dormant for the past fifteen years could be revived and contaminant the virgin Europan biosphere. I don’t believe Galileo was sanitized as carefully as our Mars landers were because no one really thought that far ahead at the time.
No one expected Galileo to last this long. I hope that NASA’s final big money mission, Cassini, is as successful.
To take the questions in reverse order (because the answers make more sense that way):[list=1]
[li]Galileo will probably be crashed into Jupiter (other “disposal” options are being considered) to avoid its ever crashing into and potentially contaminating Europa, where primitive life may exist. Galileo wasn’t sterilized before leaving earth, and, whilst probably nothing has survived, anything that has will be pretty hardy.[/li][li]The key items on Galileo (that I know of) are the comm link to Earth and the manuevering engines. If either of those fails, Galileo cannot be disposed of. The scientists at NASA are hoping that the planned flyby of Amalthea will not cause them to fail; the conservative position advocated is to crash Galileo now, whilst we know that they still work.[/li][li]Hi, Opal![/li][/list=1]
One more “reason” (more of a rationalization) is that the spacecraft has avoided getting too close to Jupiter, because the closer you get, the nastier the radiation environment is. By flying into the planet in the bitter end, they can get some close-in data on Jupiter’s ionosphere, magnetic field and gravitational field. No images, though–they take too long to downlink.
It is about the money! The space-craft completed its’ mission and its’ budget. By extending the project life, they are in effect keeping the people on the ground around and employed. After the project is over, no funding, no people to steer the craft and listen for its’ signal.
By crashing it into Jupiter, NASA is being the good celestial neighbor and getting rid of its’ trash before heading on to bigger and better things.
All these worlds are yours to discover
except Europa
attempt no landings there.
Explore them together
Explore them in peace. Dave Bowman, USS Discovery
[hijack]
[/hijack]
Though, of course, Mars is already possibly contaminated due to the lack of sterilization of the early probes (e.g., the Viking landers), so any primitive life found there must be closely scrutinized to ensure that it is not of earthly origin.
-b
Uh, Viking was looking for life on Mars, so it was meticulously sterilized. Do you have some information that demonstartes that the sterilation failed?
Also, it has been demonstarted through computer models that Earth and Mars have been trading rocks in the form of meteorites for four billion years.
Oh, for the love of Mike. I misspelled “demonstrate” twice? At least it’s not a grammar thread.