On Thursday a group of space enthusiasts announced that they had established two-way communication with the International Sun-Earth Explorer 3 (ISEE-3), a satellite launched in 1978 and used throughout the 80’s to study solar winds.
After the satellite had completed its mission, NASA used the Moon’s gravity to fling it into an orbit leading Earth around the Sun. Contact with the ISEE-3 was officially suspended in 1998. Many years later, the ISEE-3 is about to catch up with Earth from behind, an occasion which led the space enthusiasts at the ISEE-3 Reboot Project to try to make contact with the dormant spacecraft.
With NASA funds perpetually low, using resources to make contact through the space agency was an impossibility. But last week, NASA handed the keys to the satellite over to the ISEE-3 Reboot Project, which is backed by a company called Skycorp, Inc.
The project wrote today on its blog:
"The ISEE-3 Reboot Project is pleased to announce that our team has established two-way communication with the ISEE-3 spacecraft and has begun commanding it to perform specific functions. Over the coming days and weeks our team will make an assessment of the spacecraft's overall health and refine the techniques required to fire its engines and bring it back to an orbit near Earth.”
The group first made contact at the Arecibo Radio Observatory in Puerto Rico. As it describes in more detail:
We have successfully commanded both of ISEE-3's data multiplexers into engineering telemetry mode. The current bitrate is 512 bits/sec. We have been able to verify modulated data through ground stations in Germany, Morehead State in Kentucky, and the SETI Allen Array in California. We will not be transmitting over the next few days after this success but concentrating on telemetry. When we are confident of the state of the spacecraft, we will be placing the bird in engineering telemetry mode as soon as possible. We will keep everyone updated on this. We are setting up, with the cooperation of Arecibo, a means to remotely command the spacecraft.
Although the news is good for ISEE-3 lovers, it’s still uncertain whether the ISEE-3 reboot project will be able to fire its engines after such a long time out of contact. If the engines can’t be fired, the satellite will swing out of reach, perhaps for two centuries or more.