EPT
ICE/ISEE-3 Returning to Earth in Silence
![[image loading]](https://upload.wikimedia.org/wikipedia/commons/3/37/ISEE3-ICE.jpg)
Photo Credit: Wikipedia
The International Cometary Explorer (ICE) was originally the International Sun/Earth Explorer 3 (ISEE-3). NASA launched it in 1978. As the ISEE-3 it operated near the Langrangian point between the sun and the earth and recorded information about solar wind, plasma sheets, and cosmic rays. In 1982 after finishing its original mission, it was repurposed as the International Cometary Explorer. It orbited the moon several times, then began an orbit around the Sun, passing by Comets Giacobini-Zinner and Halley. In 1991 it was repurposed to investigate coronal mass ejections and study cosmic rays.
Finally, in 1997, NASA shut the probe down. It still has a carrier signal but that's it. In 1999, NASA verified the carrier signal, and then dismantled the equipment necessary to communicate with and control ICE/ISEE-3.
ICE/ISEE-3 will be passing close to earth in 2014. We've reacquired contact with it, but it's been so long that we've lost the ability to talk with it. (link)
Communication involves speaking, listening and understanding what we hear. One of the main technical challenges the ISEE-3/ICE project has faced is determining whether we can speak, listen, and understand the spacecraft and whether the spacecraft can do the same for us. Several months of digging through old technical documents has led a group of NASA engineers to believe they will indeed be able to understand the stream of data coming from the spacecraft. NASA's Deep Space Network (DSN) can listen to the spacecraft, a test in 2008 proved that it was possible to pick up the transmitter carrier signal, but can we speak to the spacecraft? Can we tell the spacecraft to turn back on its thrusters and science instruments after decades of silence and perform the intricate ballet needed to send it back to where it can again monitor the Sun? The answer to that question appears to be no.
The transmitters of the Deep Space Network, the hardware to send signals out to the fleet of NASA spacecraft in deep space, no longer includes the equipment needed to talk to ISEE-3. These old-fashioned transmitters were removed in 1999. Could new transmitters be built? Yes, but it would be at a price no one is willing to spend. And we need to use the DSN because no other network of antennas in the US has the sensitivity to detect and transmit signals to the spacecraft at such a distance.
This effort has always been risky with a low probability of success and a near-zero budget. It is thanks to a small and dedicated group of scientists and engineers that we were able to get as far as we have. Thank you all very much.
The transmitters of the Deep Space Network, the hardware to send signals out to the fleet of NASA spacecraft in deep space, no longer includes the equipment needed to talk to ISEE-3. These old-fashioned transmitters were removed in 1999. Could new transmitters be built? Yes, but it would be at a price no one is willing to spend. And we need to use the DSN because no other network of antennas in the US has the sensitivity to detect and transmit signals to the spacecraft at such a distance.
This effort has always been risky with a low probability of success and a near-zero budget. It is thanks to a small and dedicated group of scientists and engineers that we were able to get as far as we have. Thank you all very much.
I admire the ingenuity and resourcefulness of the scientists, engineers, and administrators who kept on adding new purposes to this probe's mission. After a 30-year journey around the sun, it would be fascinating to see what ICE/ISEE-3 has to tell us. Last we checked, 15 years ago, 12 of its 13 instruments were operational. I wonder, if we could speak to it now, what would this probe have to tell us about the last decade and a half it spend going around the sun?
