The International Sun-Earth Explorer (ISEE-3) launched toward the first leg of its journey on 12 August 1978. The craft was designed to measure the effect of the Earth's magnetosphere on solar wind, a stream of charged particles constantly emanating from our companion star.
This original mission involved the use of a mother-daughter pair of vehicles, ISEE-1 and ISEE-2, each of which was placed into an orbit around the Earth and Moon. The first two vehicles, launched together and each entered the atmosphere of the Earth during September 1987, four years after ISEE-3 was flung into orbit around the Sun following a close encounter with the Moon, launching the next phase of its mission.
As the International Cometary Explorer (ICE), the vehicle traveled through the tail of Comet Giacobini-Zinner on 11 September 1985. The spacecraft continued communication with the ground continued until 5 May 1997, when operations were ended by mission planners.
NASA recently discovered the spacecraft is still transmitting data, but the space agency was unable to provide a budget to monitor the craft. In the first action of its kind, NASA announced they were willing to turn control of a spacecraft to citizens.
A group of private space enthusiasts started a crowdfunding campaign to raise money needed to manage the vehicle on an extended version of its original mission, examining the solar wind.
"Dennis Wingo and Keith Cowing formed the ISEE-3 Reboot Project... for the benefit of citizen science... In May 2014, they began successfully communicating with the spacecraft" mission planners wrote on the Spacecraft for All Web site.
During this new phase of the life of the spacecraft, the vehicle will race past the Moon, making the closest encounter it has had with Earth in decades. Thrusters aboard the ISEE-3 spacecraft have not functioned since the Reboot team took control of the vehicle. Four instruments aboard the craft are still fully-functional.
A Spacecraft for All is a Google experiment designed to allow amateur scientists a chance to see information live as it is streaming in from the interplanetary observatory.
The new highly-interactive Web site for A Spacecraft for All combines 3D graphics with video, giving users a chance to follow the mission from launch to the current day. The Web site is naturally optimized for Chrome, which does a far better job than IE or Firefox at displaying the project site.
Closest approach of ISEE-3 and the Moon will take place on 10 August, when the revived vehicle will pass just 7,500 miles away from our planetary companion.
The Spacecraft for all project can be accessed at the experiment's web site.