By Elizabeth Howell
Attempts to move a vintage NASA spacecraft into a new orbit 36 years after the probe’s launch are in flux, with controllers fearing the spacecraft may have run out of fuel while performing maneuvers on Tuesday (July 9).
The vintage International Sun-Earth Explorer 3 (ISEE-3) spacecraft, now under the control of a private group, was expected to fire its engines several times Tuesday to move into a more advantageous position to communicate with Earth. The first burn went off without a hitch, but the second engine burn halted for reasons that are still being investigated.
“Our troubleshooting today eliminated some suspected causes of propulsion system problems. We do not think any of the valves are malfunctioning,” Keith Cowing with the ISEE-3 Reboot Project wrote in a statement Wednesday (July 9). “Right now we think there is a chance that the nitrogen used as a pressurant for the monopropellant hydrazine propulsion system may have been depleted. That said, we still have a number of troubleshooting options yet to be explored.”
If the spacecraft is not redirected soon, it will loop around the moon and be in an orbit that is less advantageous for communicating with Earth. But even if that scenario happens, the group plans to use it “for science in other location within the inner solar system” as at least some of the instruments are functioning, Cowing added.
The group has been diligently communicating with the spacecraft in recent weeks after receiving authorization from NASA to proceed and also raising more than $150,000 during a crowdfunding effort.