“ISEE-3 was the first spacecraft to be placed in a halo orbit at one of Earth-Sun Lagrangian points (L1). Renamed ICE, it became the first spacecraft to visit a comet, passing through the tail of Comet Giacobini-Zinner within about 7,800 km of the nucleus, and later flew through the tail of Halley’s comet.
The purposes of the mission were:
to investigate solar-terrestrial relationships at the outermost boundaries of the Earth’s magnetosphere;
to examine in detail the structure of the solar wind near the Earth and the shock wave that forms the interface between the solar wind and Earth’s magnetosphere;
to investigate motions of and mechanisms operating in the plasma sheets; and,
to continue the investigation of cosmic rays and solar flare emissions in the interplanetary region near 1 AU.
and investigations of coronal mass ejections
On September 18, 2008, NASA, with the help of KinetX, located ICE using the Deep Space Network after discovering that it had not been powered off after the 1999 contact. A status check revealed that all but one of its 13 experiments were still functioning, and it still has enough propellant for 150 m/s of Δv.
So, what’s next? Perhaps change it’s orbit to take it close to another comet.