Hugh Pickens DOT Com (2995471)
writes "Randall Munroe's XKCD cartoon on the ICE/ISEE-3 spacecraft inspired me to do a little research on why Nasa can no long communicate with the International Cometary Explorer. Launched in 1978 ISEE-3 was the first spacecraft to be placed in a halo orbit at one of Earth-Sun Lagrangian points (L1). It was later (as ICE) sent to visit Comet Giacobini-Zinner and became the first spacecraft to do so by flying through a comet's tail passing the nucleus at a distance of approximately 7800 km. ICE has been in a heliocentric orbit since then, traveling just slightly faster than Earth and it's finally catching up to us from behind, and will return to Earth in August. According to Emily Lakdawalla, it's still functioning, broadcasting a carrier signal that the Deep Space Network successfully detected in 2008 and twelve of its 13 instruments were working when we last checked on its condition, sometime prior to 1999. 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? Unfortunately 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. "So ISEE-3 will pass by us, ready to talk with us, but in the 30 years since it departed Earth we've lost the ability to speak its language," concludes Lakdawalla. "I wonder if ham radio operators will be able to pick up its carrier signal — it's meaningless, I guess, but it feels like an honorable thing to do, a kind of salute to the venerable ship as it passes by.""