[X] My Assistant

[Rakhir]

This information from Emily is amazing.
http://www.planetary.org/blog/article/00001673/

ICE is alive and may perhaps be assigned to a new mission.

[dvandorn]

OK -- there are a few reasons why, at the end of a spacecraft's mission, you would want to shut it down and turn off its systems, including its radio transmitter/receiver.

It's true that funding only really pays for the ground support of a mission. Extended missions are funded to pay for the DSN time it takes to communicate with the spacecraft, and to pay the people tending the spacecraft, both in an engineering and in a scientific sense.

Turning off the spacecraft may just be a formality on a vehicle that is nearly out of RCS fuel, for example, or a vehicle that is about to go into a power-negative state for longer than it can ever be expected to recover from. Each of these things happens with fair frequency.

Another reason to turn off a spacecraft is to shut down any further requests for an extended mission. On a political level, someone in management somewhere may be sick to death of seeing extension after extension to a given mission drain funds off from projects that manager is more interested (or invested) in. A final directive to a final mission extension is often "shut down the spacecraft in such a way that it cannot be revived," or words to that effect. It's a way of stating with certainty that *no* further extensions will be allowed.

And, if you have no further interest in using the spacecraft, there is a legal principle that suggests you want to deny that resource to anyone who might want to use it for purposes of which our country may not approve. Now, I grant you, there is very little one could do with a 30-year-old probe that would violate America's interests... but, as with a lot of legal principles, it looks at low-likelihood events with very large consequences and decides what actual preventive measures are warranted. In some cases, you want to shut down your spacecraft at the end of their missions just to make sure no one else tries to use them.

-the other Doug