The Little Spacecraft That Couldn't

A team of space enthusiasts recently got permission from NASA to reconnect with the old spacecraft as it approached Earth. The idea was to put it on a new course so that it wouldn't just fly past. Instead, it would be commanded to go to a new orbit and join younger satellites in monitoring space weather. On Tuesday, and then again Wednesday, the volunteer group sent commands to fire ISEE-3's engines again and again. "And our first series of burns, we thought went OK," says Keith Cowing, a former NASA guy who is one of the leaders of the volunteer group — the ISEE-3 Reboot Project. "And then when we went to the second set, pretty much nothing happened. And we tried it again, and nothing happened." Their troubleshooting suggests that nitrogen tanks that are needed to pressurize the fuel either aren't working or are empty, Cowing says. "So, in essence, we can't really fire the engines anymore." The earlier engine firings may merely have burned fuel that was already in the fuel lines, says Cowing. If the nitrogen tanks won't work, then the team can't get more fuel into those lines. That means they won't be able to do a course correction that would let the spacecraft be recaptured into an orbit that would enable it, once again, to do useful science.