ISEE-3, one of America’s most dedicated space exploration vessels is on its way home. Unfortunately, when it gets here, no one will be talking to it. NASA decommissioned the equipment needed to communicate with the satellite nearly 15 years ago. [Emily Lakdawalla] at the planetary society has been following the long traveled probe for years. Her recent article on the topic includes the news that NASA essentially gave up the battle before it even started.
Originally named International Sun/Earth Explorer 3 (ISEE-3), the spacecraft was launched atop a Delta rocket on August 12, 1978. Its mission was to study interaction between the Earth’s magnetic field and solar wind. As part of this mission ISEE-3 became the first spacecraft to enter halo orbit. It did this by positioning itself at Lagrangian point L1, directly between the sun and the Earth. In 1982, scientists on earth were preparing for the 1986 flyby of Halley’s Comet. ISEE-3 was repurposed as a comet hunter, and renamed International Cometary Explorer (ICE). The craft flew back to Earth and entered lunar orbit, coming within 120km of the moon’s surface. It used this momentum to achieve a heliocentric orbit, on track for two comet encounters. ICE/ISEE-3 encountered Comet Giacobini-Zinner on September 11, 1985, collecting data and becoming the first spacecraft to fly through a comet’s plasma tail. While not considered part of the Halley Armada, ICE/ISEE-3 took measurements as it passed within 28 million km of Comet Halley’s nucleus. Since then, ICE/ISEE-3 has continued on its 355 day heliocentric orbit. It studied coronal mass ejections in the early 90’s, before being shut down in May of 1997. Follow us past the break to learn ICE/ISEE-3’s fate.
In 1999, NASA contacted the probe to verify it was still functioning. All systems were determined to be operating fine. On September 18, 2008, NASA attempted to receive the probe’s carrier signal. To the space agency’s surprise, they found that the probe was never shut down after the 1999 status check. It was still transmitting data, and amazingly, 12 of its 13 science instruments were still operational.
This brings us to 2014. ICE/ISEE-3 is on its way home. It will return for a close Earth pass in August. NASA has determined that the equipment needed to contact ICE/ISEE-3 was decommissioned from the Deep Space Network (DSN) in 1999. Due to budget limitations, rebuilding the equipment is not possible. If NASA won’t reach out to ICE/ISEE-3, perhaps Makers, Hackers, and Ham radio operators could. ICE/ISEE-3 includes two 5 watt S-Band transponders. Receiving the signal may not be a major problem. Transmitting however, will be. Without the gain of the large DSN dishes, contact will be difficult. This effort is further stymied by operating within the rules of governing bodies such as the FCC in the USA. It would seem to be an impossible task, however we can’t help but wrack our brains and scour the web for a solution. We’re not the only ones, [Mike Kenny] has put together a summary of the ICE/ISEE-3 communications systems (pdf link). Readers of ICE/ISEE’s facebook page are also suggesting plans. Maybe we’re a bit romantic, but wouldn’t it be great if private citizens of Earth accomplished what a major government organization couldn’t – contacting an all but forgotten space probe.
[Images Courtesy of NASA]