WASHINGTON — A volunteer effort to revive a moribund 1970s-vintage NASA spacecraft succeeded the week of May 26, even as the possibility of bringing the satellite back into Earth orbit remains murky, according to the leaders of the International Sun-Earth Explorer (ISEE-3) Reboot Project.

Using a custom-designed transmitter from Dirk Fischer Elektronik of Germany, the ISEE-3 Reboot Project led by blogger Keith Cowing and businessman Dennis Wingo has established two-way communications with the old heliophysics observatory, Wingo wrote in an online post May 29. 

The good news is that the spacecraft, launched in 1978, is now in engineering telemetry mode, meaning controllers on Earth can assess the health of the satellite and its instruments. A three-person team awakened the dormant ISEE-3, which is in its heliocentric orbit, using the Arecibo radio telescope in Puerto Rico, to which the German-made transmitter was affixed. 

The bad news is that ISEE-3 might crash into the Moon. ISEE-3 Reboot Project team members in Puerto Rico figured that out when they pinged the spacecraft May 20 in a preliminary test of their transmitter and discovered that “the ISEE-3 spacecraft is not exactly where [NASA’s Jet Propulsion Laboratory’s] database said it would be,” Wingo wrote in a May 24 post on the project’s crowdfunding page at RocketHub.com. 

In fact, the satellite is about 250,000 kilometers from where Wingo expected to find it, raising the possibility that the craft, which the project team believed was on track for a low lunar flyby, “could hit the Moon.”

Based on JPL’s latest data on ISEE-3, which NASA shut down in 1997, Wingo and Cowing figured they had until mid-July to fire the spacecraft’s engines and divert it from its current comet-chasing orbit, where it has been in since 1984, to an Earth orbit suitable for resuming its original heliophysics mission.

The engines have to be turned on “rather soon,” Wingo wrote on the crowdfunding page. 

Just how soon is unclear. “We don’t know yet,” Wingo wrote in a May 30 email. “Our orbital dynamics team is evaluating that now.”

A NASA Space Act Agreement signed May 21 with Wingo’s company Skycorp Inc., Los Gatos, California, clears the ISEE-3 Reboot Project to take command of the venerable satellite, and to use a decommissioned McDonald’s restaurant at NASA’s Ames Research Center in Mountain View, California, as a base of operations. Wingo and Cowing, who have used the building before, call it McMoons.

If ISEE-3 can be saved, its primary communications link to Earth will be the so-called Big Dish at Morehead State University in Morehead, Kentucky. 

The dish would be fitted with a $200,000 receiver donated to the ISEE-3 Reboot Project by AR Research of Souderton, Pennsylvania.

The ISEE-3 Reboot project is covering its operational expenses with more than $150,000 raised on RocketHub.com. The total is about $25,000 more than Wingo and Cowing set out to raise when they began soliciting contributions online in April.

Follow Peter on Twitter: @Leone_SN

Dan Leone is the NASA reporter for SpaceNews, where he also covers other civilian-run U.S. government space programs and a growing number of entrepreneurial space companies. He joined SpaceNews in 2011.Dan earned a bachelor's degree in public communications...