A group of citizen scientists has commandeered a NASA spacecraft that was launched in 1978 and had gone unused since 1997.

Today the group made first contact with the International Sun-Earth Explorer-3 (ISEE-3) when the spacecraft acknowledged receiving a signal from the Arecibo radio telescope in Puerto Rico, says Keith Cowing, co-director of the ISEE-3 Reboot Project, a group of about 20 volunteer space buffs. “We knew we could do this—it’s a vindication,” he says. “It’s sort of like reaching back in time to grab something that otherwise would have been lost.”

Cowing says that the group is now getting telemetry data from the spacecraft. Over the coming days, they will try to understand the health of the spacecraft and its 13 scientific instruments. The spacecraft was launched to study space weather and is due to make a close pass around the moon.

Next month, they plan to instigate a burn with the remaining fuel and move the spacecraft into a new orbit. Also in June, they plan to start communicating with ISEE-3 from a second radio telescope, a 21-meter dish at Morehead State University in Kentucky. This dish is more movable than the massive Arecibo telescope and can better track the spacecraft as it gets closer to Earth, Cowing says.

The ISEE-3 Reboot Project raised more than $150,000 in crowd-funding to support its volunteer efforts.