Attempt to Move NASA Probe ISEE-3 spacecraft Hits Snag

This artist's rendition shows the International Sun-Earth Explorer-3 (ISEE-3) spacecraft, the which later became Interplanetary Cometary Explorer. 

A private team, called the SEE-3 Reboot Project, is hoping to restart the 36-year-old spacecraft's engines for a new science mission.

Credit: NASA

The quest to rescue a 36-year-old NASA spacecraft will go on for at least another day, as a private group controlling the probe achieved only partial success with an engine firing Tuesday (July 8).

The private team operating NASA's International Sun-Earth Explorer 3 spacecraft (ISEE-3) aimed to fire its engine numerous times to change the probe's trajectory and put it in a more stable position for communicating with Earth but things did not go exactly as planned.

"The first segment was full duration but only partially successful," Keith Cowing, co-leader of the SEE-3 Reboot Project, wrote in a blog post Wednesday (July 9).

"The second and third attempts failed. Possible causes (under investigation) include valve malfunction and fuel supply issues."

Controllers in California, who are beaming commands to ISEE-3 via the Arecibo Observatory in Puerto Rico, tried the burns several times.

After resetting the spacecraft and sending more commands, they stopped work for the day when their "window" of communication closed.

They noted that ISEE-3's thruster valve was opening and closing as expected, but the spacecraft wasn't accelerating.

"Either we are low on fuel in System A, or latch valve A is not working," the group said via Twitter, adding that the sun guidance sensor and accelerometers were not showing thrust.

"The ISEE-3 team is working [on] a strategy for tomorrow's pass. More to follow," the team concluded late Tuesday night.



The private group took control of the spacecraft several weeks ago after raising more than $150,000 via crowdfunding and obtaining permission from NASA, which retired the spacecraft in 1997.

ISEE-3 launched in 1978 and worked as a comet chaser and sun probe, among other roles.

The team has not yet determined what to do next with ISEE-3, focusing first on making sure the spacecraft can consistently communicate with Earth.

The clock is ticking for the SEE-3 Reboot Project to change ISEE-3's trajectory; Cowing has said that fuel consumption will become an issue by late July.

NASA - Solar-Electric ION Engine Burns Blue

This image shows a cutting-edge solar-electric propulsion thruster in development at NASA's Jet Propulsion Laboratory, Pasadena, Calif., that uses xenon ions for propulsion. 

An earlier version of this solar-electric propulsion engine has been flying on NASA's Dawn mission to the asteroid belt.

This engine is being considered as part of the Asteroid Initiative, a proposal to robotically capture a small near-Earth asteroid and redirect it safely to a stable orbit in the Earth-moon system where astronauts can visit and explore it. 

This image was taken through a porthole in a vacuum chamber at JPL where the ion engine is being tested.

Image credit: NASA/JPL-Caltech

SpaceX Optimistic about Launch Despite Thruster Outage

SpaceX said it was "optimistic" Friday after a thruster outage delayed the latest resupply mission of its unmanned Dragon capsule en route to the International Space Station.

SpaceX and NASA officials said the cargo resupply mission was still on track, but the technical mishap could fuel concerns about the US agency's ambitious plans to cut costs by privatizing elements of the space program.

SpaceX's billionaire founder Elon Musk said the failure of three out of four thruster pods to fire up was a "little frightening" but that two pods were back online within a few hours and the others should be working again shortly.

"I'm optimistic that we will be able to turn all four thruster pods on and restore full control," he told reporters.
Musk later tweeted: "Thruster pods one through four are now operating nominally. Preparing to raise orbit. All systems green."

SpaceX and NASA officials said once the pods are back online, they would carry out a number of checks before clearing the vessel to dock at the space station in the coming days, perhaps as early as Sunday.

The original rendezvous had been planned for 1130 GMT Saturday, but Mike Suffredini, NASA program manager for the International Space Station, said there was "quite a bit of flexibility" in the berthing date.