NASA felt it had gotten its money’s worth out of the International Sun-Earth Explorer-3 mission back in the 1980s. Its last scientific mission ended in 1997, and contact was suspended in 1998. But time and a fortuitous orbit mean that ISEE-3 is now catching up with Earth and will make a close pass this summer. When we first noted this story last year, some enthusiasts were suggesting that the probe should be revived and returned to scientific duty, but the perpetually tight budgets at NASA made that outcome unlikely.
Yesterday, NASA announced that it found a solution: it would hand the keys to the probe over to those enthusiasts.
Launched in 1978, the hardware was initially sent to the L1 Lagrange point between the Earth and Sun and was used to study the solar wind. With that mission complete, the International Sun-Earth Explorer-3 was renamed the International Cometary Explorer and was sent into orbit around the Sun, where it passed through the tails of two comets before its mission ended in 1997.