Plans to return the rebooted "zombie" spacecraft, ISEE-3, to Earth's orbit has met an anticlimactic end this week after a team of experts and students determined that key resources in the forgotten satellite's propulsion system may have been depleted.
According to an update from the crowd-funded ISEE-3 Reboot Project team, troubleshooting has revealed that main valves on the craft are not damaged or malfunctioning, easing initial concerns.
However, "now we think there is a chance that the Nitrogen used as a pressuring for the monopropellant Hydrazine propulsion system may have been depleted," the team writes.
They first discovered problems with the propulsion system last week when performing a spin-up burn. Initially things were going smoothly - with the team succeeding in making a small test alteration in the craft's orbit around the Sun - but then the engines stopped firing entirely.
"There's only so much you can do before you have to say, 'It's dead, Jim,'" Keith Cowing, a former NASA astrobiologist and a spokesman for the ISEE-3 Reboot Project, told the LA Times.
According to Bob Farquahar, a retired NASA engineer, there was always a real chance that the 35-year-old spacecraft could have exhausted important resources after not only completing its primary mission, but a secondary comet-chasing mission as well.
"I'll know where it is in the sky and at what time, and I'm just going to look up and wave goodbye to my old friend," Farquhar said.
However, the Reboot Project team hasn't given up entirely. Without a shot at bringing the craft into Earth's orbit, as was originally intended, they will now put their efforts towards learning as much form the forgotten craft as possible.
"We still have a number of troubleshooting options yet to be explored... Even if the L-1 halo orbit is no longer an option, we do have plans to use ISEE-3 for science in other locations within the inner solar system after the lunar flyby on 10 August," the team reported.
This depressing news come after the private team excitedly made first contact and reprogrammed the spacecraft this past May.