It's aliiiiiiiiiiiiiiiiiiiiiive

[Josh]

Meant to post this a couple days ago when it broke

An old NASA spacecraft under the control of a private team fired its thrusters yesterday (July 2) for the first time in a generation.

NASA's International Sun-Earth Explorer 3 probe (ISEE-3), which the agency retired in 1997, performed the maneuver in preparation for a larger trajectory correction next week. The spacecraft hadn't fired its engines since 1987, ISEE-3 Reboot Project team members said.

It took several attempts and days to perform the roll maneuver because ISEE-3 was not responding to test commands. But this time, controllers got in touch. They increased the roll rate from 19.16 revolutions per minute to 19.76 RPM, putting it within mission specifications for trajectory corrections.

"All in all, a very good day," co-leader Keith Cowing wrote in a blog post on the ISEE-3 Reboot Project's website.

Cowing and his group are now gathering data from the spacecraft to get ready for its next contact with the Deep Space Network, a collection of NASA dishes the team is renting to get precise information on ISEE-3's location.

The next step will be to change the spacecraft's trajectory, which will likely happen next week, Cowing added. That might happen on Tuesday (July 7), the group said in a Twitter post.

With the help of over $150,000 raised via crowdfunding, the team reactivated the hibernating spacecraft a few weeks ago. ISEE-3 ceased operations in 1997 following a 19-year career that saw it perform a variety of missions, such as observing the sun and chasing comets.

The recent maneuvers were commanded using the Arecibo Observatory in Puerto Rico, through a command center in California. While the group is made up heavily of former NASA employees, the ISEE-3 Reboot Project pointed out that isn't true of all of its team.

"Some of our team members were not even born yet the last time the engines fired," the team said via Twitter, giving that date as Feb. 2, 1987.

ISEE-3 needs to be moved to put it in an advantageous position to communicate with Earth. In past interviews with Space.com, Cowing has said the group will focus on what to use the spacecraft for after rescuing it. Another priority will be seeing how well its 13 scientific instruments function.

At least one instrument, the magnetometer, is working well enough to do science. "Recent magnetometer data shows recent solar event," the team said via Twitter on Wednesday (July 1).

[Batman]

NASA sure built them to last.

[Josh]

Siiiiigh

A 36-year-old NASA spacecraft, still largely in working condition, will zip through Earth’s neighborhood on Sunday for the first time in decades before receding again into the solar system.

The craft — the International Sun-Earth Explorer-3, or ISEE-3, better known as the zombie spaceship that was revived by a scrappy band of space enthusiasts — will pass about 9,700 miles from the surface of the moon at 2:16 p.m. Eastern time.

The enthusiasts had hoped to nudge it much closer to the moon, just 30 miles from its surface; the moon’s gravity would then have swung the spacecraft into orbit around Earth, from which it could have been catapulted on a new mission.

But when they tried the course change on July 8, the thrusters sputtered. The craft’s nitrogen tanks, needed to pressurize the propulsion system, had somehow emptied.

Although ISEE-3 and many of its scientific instruments are still working, there is now no way to steer the spacecraft.

“Obviously, we were very, very disappointed,” said Dennis Wingo, an engineer and entrepreneur who is a leader of the ISEE-3 Reboot Project.

But the enthusiasts did not give up. They have commanded the craft to continue collecting scientific measurements and sending them back to Earth, an interplanetary exercise in “citizen science” that they hope will show NASA how to tap into the expertise of people outside the space agency.

A website started on Friday with help from Google, space

craftforall.com, offers an interactive history of the mission and an archive of the science data, including of the magnetic fields in space and the number of protons from the sun streaming by. The team will hold a live video chat on Sunday afternoon from its mission control, a former McDonald’s at an old Navy airfield north of San Jose, Calif., that is now part of a research park run by NASA Ames Research Center.

Mr. Wingo said his team had turned on eight of the spacecraft’s 14 experiments and recruited the help of some of the original mission scientists.

They include Michael Coplan, a physicist at the University of Maryland who, along with his students, helped build the ion composition instrument, which counted different types of charged atoms. Dr. Coplan had largely forgotten about the experiment after they received the last data in the late 1980s. This year, to clear space in a laboratory he would be sharing with another scientist, he threw out his ISEE-3 data notebooks.

Then, in June, one of his former students heard about the reboot project and told Dr. Coplan, who went to the waste bin and found the notebooks. “That sat around for a while, fortunately,” he said.

Mr. Wingo said scientists were already comparing ISEE-3’s data with observations from newer spacecraft. “We’re already in touch with the larger scientific community,” he said.

He said his team should be able to send commands to the craft for four more months before it is too far away, and moderate-size radio telescopes will be able to hear the spacecraft’s signals for at least the next year or two.

“There is still much we need to learn about the sun, and ISEE-3 will continue to contribute to gathering science data,” Mr. Wingo said.

Still a mystery is what happened to the nitrogen, especially as the first firing of the thrusters, on July 2, worked perfectly. Firings on July 8 also initially seemed to work, but then stopped. Two weeks of troubleshooting indicated that everything was working properly and the spacecraft had plenty of fuel.

But the nitrogen tanks were empty. “All of the options are equally unlikely, but one of them has to be the case,” Mr. Wingo said.

The propulsion failure was a disappointment to Robert W. Farquhar, the flight director for ISEE-3 when it was launched in 1978. When he last fired the thrusters, in 1987, he deliberately set the spacecraft on a course to fly by Earth on Aug. 10, 2014.

“I’m going to wave goodbye to the spacecraft,” said Dr. Farquhar, who will be at the mission control at the former McDonald’s on Sunday.

The craft’s looping orbit around the sun will again put it in the vicinity of Earth 17 years from now. Might he plot something for it then?

“Hah,” said Dr. Farquhar, now 81. “No.”

Good try, good thinking boys and girls. And who knows, it may find something awesome while it's still rolling.

[LadyTevar]

I wonder if a micro-meteor hit the tank?

[Josh]

That's probably one of their highly improbable scenarios. We'll likely never know. But still, my hat's off to them for the effort. I wonder what other hibernating probes could be reactivated like this?