"We have received confirmation from NASA that we have been confirmed for time on the DSN (Deep Space Network) for two-way Doppler and ranging activities with the ISEE-3 spacecraft. This is being done so as to determine the location of ISEE-3 with great precision for navigation purposes. Based on this data we will conduct our course correction engine firing. We have moved that original firing date from 17 June to a window that currently covers 30 June and 2 July."
Calling Back a Zombie Ship From the Graveyard of Space, New York Times (front page story)
"After 36 years in space, the craft, the International Sun-Earth Explorer-3, appears to be in good working order. The main challenge, the engineers say, is figuring out how to command it. No one has the full operating manual anymore, and the fragments are sometimes contradictory."
"NASA has given us approval to fire the spin thrusters on ISEE-3 to increase its spin from 19.16 rpm up to the mission specification of 19.75 +/- 0.2 rpm."