A crowdfunded group of citizen scientists will attempt to reboot and take control of a 36-year-old space probe that is flying back past Earth long after the end of its original mission to study comets and the solar wind.
Launched in 1978, the International Sun/Earth Explorer-3 (ISEE-3) spacecraft studied how the stream of charged particles flowing from the sun, the so-called solar wind, interacts with Earth's magnetic field.
After completing its primary mission the probe was given a new name, the International Comet Explorer, and new targets to study, including the famed comet Halley as it passed by Earth in March 1986.
A third assignment to investigate powerful solar storms, known as coronal mass ejections, followed until 1997, when Nasa deactivated the spacecraft. But the probe's radio transmitters were left switched on, apparently by mistake, and it has continued to send a carrier signal.
In August the dormant probe's orbit around the sun will bring it back past Earth, an event that caught the eye of the ad hoc group of citizen scientists. In April the team undertook a successful crowdfunding project to raise $125,000 to reboot the probe under the banner of the ISEE-3 Reboot Project.
The group has successfully picked up the probe's carrier signal and is assembling equipment to communicate with it from Earth – necessary because Nasa scrapped its own 1970s equipment long ago.
A Nasa animation shows the ISEE-3 probe catching up with Earth over several years.On Wednesday the project received Nasa's blessings and access to technical data to help engineers make contact.
"We have a chance to engage a new generation of citizen scientists through this creative effort to recapture the ISEE-3 spacecraft as it zips by the Earth this summer," said John Grunsfeld, Nasa's associate administrator for science.
The Nasa agreement gives Skycorp Inc, a California company working with the ISEE-3 Reboot Project, permission to attempt to contact and possibly command and control the satellite, which is believed to still have fuel and working scientific instruments.
"Our plan is simple: we intend to contact the ISEE-3 spacecraft, command it to fire its engines and enter an orbit near Earth, and then resume its original mission," said Keith Cowing, a former Nasa engineer who runs the Nasa Watch website.
"If we are successful it may also still be able to chase yet another comet," Cowing said.
If the effort proved unsuccessful the ISEE-3 would swing by the moon and continue to circle the sun, he said.
Nasa has never before signed an agreement to turn over a decommissioned spacecraft for private use. "New data resulting from the project will be shared with the science community and the public, providing a unique tool for teaching students and the public about spacecraft operations and data-gathering," Nasa said in a press release.
The ISEE-3 must be contacted within a month or so and change its orbit no later than mid-June if it is to have a shot a new mission, according to Skycorp.
The manoeuvres may include a flyby of the moon at an altitude of less than 31 miles (50km), Cowing said.
Reuters contributed to this report