A hardy little spacecraft is about to come home after an incredibly long journey and an unexpected mission it had not been built for. As it flies by Earth next month, scientists will have a brief window to attempt to communicate with the vintage NASA craft and put it back to work on its original mission.
Because of a tight budget, NASA couldn't muster the resources to make this revival happen. So, a group of citizen scientists stepped forward to take on the challenge. Yesterday, NASA officially endorsed the group, known as the the ISEE-3 Reboot Project, and signed a space act agreement giving it the go ahead to try to bring back to life a mission that started during the Carter Administration.
The International Sun-Earth Explorer 3 (ISEE-3) satellite launched in 1978 to monitor the solar wind, a constant stream of radiation and charged particles coming from the sun. It joined two sister spacecraft—ISEE-1 and ISEE-2—that launched a year earlier. But in 1982, ISEE-3 was pulled away from its mission and repurposed to join a mini international race to make the first encounter with Halley's comet. The satellite, renamed the International Cometary Explorer (ICE), won that race, zipping close enough to inspect another comet in 1985 and Halley's comet in 1986, ahead of Russian, European and Japanese spacecraft.
The triumphant ICE spacecraft then embarked on a 30-year victory lap of sorts that eventually would bring it back within reach of Earth, and potentially return to monitoring the solar wind as if nothing ever happened. Unfortunately, by 1997 NASA was no longer interested or able to keep monitoring the little probe. Yet people knew it was returning and several folks suggested making attempts to contact ISEE-3 again
In March, amateur radio astronomers were able to track the spacecraft and determine its trajectory, raising hopes that the mission could be brought back to life.
With NASA hobbled by lack of funds, the ISEE-3 Reboot Project stepped in and appealed to the public for help. Within a month, the project crowdfunded more than $125,000 and learned as much as it could about the probe, relying on information from engineers who worked on the project in the 1980s.
But the mission's original communication hardware no longer exists, so commanding the spacecraft to do anything will require programmers to recreate virtual software versions of the original hardware. If they can do this, the project will use the Arecibo radio telescope in Puerto Rico to beam new instructions to ISEE-3.
Though they now have official NASA blessing, the ISEE-3 Reboot Project must work fast. Their goal is to get the probe into a gravitationally stable point between the Earth and sun known as L1. For that to happen, the spacecraft must be told to fire its engines by mid-June, which means the virtual communication hardware must be up and running by then.
If the attempt works, ISEE-3 will be given a new trajectory, taking it within 30 miles of the moon's surface in August before reaching L1. There, it could continue monitoring the solar wind and studying space weather, though the exact goals of this new mission have yet to be decided. The project's crowdfunding efforts continue.
If the team fails to reach the spacecraft in time, it will fly past Earth and into space, not to return for another 30 or 40 years.
