ISEE-3 originally operated in a halo orbit about the L1 Sun-Earth Lagrangian point, 235 Earth radii above the surface (about 1.5 million km, or 924,000 miles). It was the first artificial object placed at a so-called “libration point”, proving that such a suspension between gravitational fields was possible. It rotates at 20 rpm about an axis perpendicular to the ecliptic, to keep it oriented for its experiments, to generate solar power and to communicate with Earth.

http://en.wikipedia.org/wiki/International_Cometary_Explorer

It appears to have run out of compressed N2 to force fuel and oxidizer to the engines.

On May 29, 2014, two-way communication with the spacecraft was reestablished by the ISEE-3 Reboot Project, an unofficial group[4] with support from the Skycorp company.[5][6][7] On July 2, 2014, they successfully fired the thrusters for the first time since 1987. However, later firings of the thrusters, on July 8, 2014, failed, apparently due to a depleted supply of nitrogen, essential in pushing the hydrazine fuel to the thrusters. According to the project team, an alternative plan in the use of the spacecraft is to “collect scientific data and send it back to Earth.”[8]

Too bad, recycling these old birds and giving them new missions they weren’t even originally designed for is engineering at its finest.

None of those may be high power items, but they do add up.

Would batteries have survived all the radiation over the years? I don’t know.

Or was it a plutonium generator at the end of one of those rods sticking out of the side? Might have been, would it be operational. Beats the hell out of me. Maybe Wikipedia would be revealing.

electrically powered gyroscopes for attitude control,

And solar panels to operate on-board systems. In theory, the machine could remain dormant forever until it was given the right radio commands, as long as the sun was shining. In practice, things degrade in the space environment, lubricants, insulators, plastics, even metals.

7-9-2014 | Dan Leone, NASA reporter for SpaceNews

WASHINGTON — NASA’s International Earth/Sun Explorer (ISEE)-3 will not be resuming its original mission after all, now that citizen scientists and engineers striving to rescue it discovered July 9 that the old heliophysics observatory’s propulsion system is not working.

“There was no burn and we detected no acceleration and nothing was coming out of the engines,” NASAWatch.com editor Keith Cowing, who spearheaded the ISEE-3 Reboot Project along with entrepreneur Dennis Wingo, said in a July 9 phone interview.

“We really can’t do anything,” Cowing said.

The widely read blogger spoke to SpaceNews after a failed attempt to complete the remaining engine burns that project officials thought would be required to send the spacecraft, currently in a heliocentric orbit, back toward the gravitationally stable Earth-Sun Lagrange Point 1. From that position, the 1970s-vintage spacecraft was expected to be able to resume observations of solar winds breaking against Earth’s magnetosphere.

Freefall…

Woody time-travels to the distant future, and meets

an old friend.