An audacious quest to reconnect with a vintage NASA spacecraft has suffered a serious setback and is now pretty much over.
The satellite launched in 1978 and has been in a long, looping orbit around the sun for about three decades. Earlier this year, NPR told you about an effort to get in touch with this venerable piece of NASA hardware and send it on one more adventure.
But there are no guarantees when you try to recapture the past.
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.
"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.
"At this point we're sort of scratching our heads," Cowing says. "We may take one last run at the spacecraft, but this may be it for an attempt to bring it back to Earth."
Bob Farquhar, a former NASA mission designer who has always felt a close connection to the spacecraft, told NPR things don't look good. "I don't know what's the matter, but it sounds like it's pretty serious," he says.
Without the thrusters, Farquhar says, there's no way to keep ISEE-3 around. Once it's far enough away that we can't really communicate with it, he says, "they should probably turn off all the transmitters this time and not have anything left on like they did before. I think we should let it have a good death."
Farquhar, who is 81, has long felt his own fate was connected to this spacecraft's. Now, he says, he hopes they're not that connected. "But I am getting pretty old also," he says. "If you measure a spacecraft's life, he's probably about the same age I am."
He says his friend should pass close to Earth on Aug. 10. That's when Farquhar plans to wave goodbye.
STEVE INSKEEP, HOST:
Scientists may be nearing the end of a passionate quest to reconnect with a vintage NASA spacecraft. For decades, that satellite has followed a long, looping orbit around the sun. The scientists wanted to recover control of it, but it's not been easy to rekindle an old flame. NPR's Nell Greenfieldboyce reports.
NELL GREENFIELDBOYCE, BYLINE: When a spacecraft called ISEE-3 blasted off in 1978, Jimmy Carter was president and this was the top Billboard hit.
(SOUNDBITE OF SONG, "THREE TIMES A LADY")
LIONEL RICHIE: (Singing) You're once, twice, three times a lady.
GREENFIELDBOYCE: The original plan was for ISEE-3 to hang out between the Earth and the sun to study space weather. But in the 1980s, a NASA mission designer, named Bob Farquhar, figured out a creative way to send it off on a bold, new adventure. It became the first probe to ever visit a commet. Farquhar says some scientists were not amused.
BOB FARQUHAR: They thought - oh, it was in the newspapers, even that we stole their spacecraft. We didn't steal it. We just borrowed it for a while. That's what I tried to tell them.
GREENFIELDBOYCE: It's new flight path would return it to Earth in the far-off year of 2014 and Farquhar has been waiting for the chance to reconnect and put it back to work.
FARQUHAR: It's my baby, yeah.
GREENFIELDBOYCE: But as the date of the rendezvous approached, NASA officials didn't seem that interested. Talking to this agent machine would be a major effort. That's because space communication has changed radically in the last 25 years. So a volunteer group of intrepid space geeks said, let us try. Keith Cowing is one of the group's leaders. He says they had experienced. They'd previously worked with old data tapes to recover moon images taken by orbiters in the 1960s.
KEITH COWING: We'd already done a crazy project with hardware that's not supposed to work with people who were supposed to be dead. And so our common sense had already pretty much disappeared.
GREENFIELDBOYCE: To revive ISEE-3, they solicited donations online and got about $150,000. They unearthed forgotten hardware manuals and found a way to use computer software to speak ISEE-3's obsolete language.
COWING: Our spacecraft does not have a computer. I mean, it's truly accurate to say your toaster is smarter.
GREENFIELDBOYCE: When they finally said hello, the faithful spacecraft answered. And last week, things got even more exciting. They successfully fired its thrusters for the first time since 1986. It really seemed like they're be able to take control of its flight path and send it off to a spot where it could do some useful science. Cowing says this week they sent commands to fire its engines again and again.
COWING: In our first series of burns, we thought went OK. And when we went to the second set, but pretty much nothing happened. And we tried it again and nothing happened.
GREENFIELDBOYCE: The team now thinks that nitrogen tanks needed to pressurize the fuel either aren't working or are empty.
COWING: So in essence, we can't really find engines anymore.
GREENFIELDBOYCE: They may keep trying, but it looks like it's game over. Even Bob Farquhar sees that.
FARQUHAR: I don't know what's the matter but it sounds like it's pretty serious.
GREENFIELDBOYCE: He says without the thrusters there's no way to keep it around. Once it's far enough away that we can't really communicate with it...
FARQUHAR: They should probably turn off all the transmitters this time and not have anything left on like they did before. I think, we should let it have a good death.
GREENFIELDBOYCE: He's always felt his own fate was connected to the spacecraft. Now he says he hopes they're not that connected.
FARQUHAR: But I am getting pretty old also. If you measure the spacecraft's life, it's probably about the same age I am.
GREENFIELDBOYCE: He says his friend should pass close to Earth on August 10. That's when he plans to wave goodbye. Nell Greenfieldboyce, NPR news.
INSKEEP: This is NPR News. Transcript provided by NPR, Copyright NPR.