An attempt to rescue a 36-year old explorer spacecraft, ISEE-3, by veteran space engineers has failed after the spacecraft’s thruster system was found to be faulty.
NASA’s venerable International Sun-Earth Explorer 3 (ISEE-3 aka ISEE 03) spacecraft has had a long and illustrious history. ISEE-3 was originally launched in August 1978 to the L1 position 930,000 miles from the Earth to monitor the solar wind. ISEE-3 was diverted back towards the Earth in late 1982 so that it could be directed into a series of swing-bys to throw it towards the first ever spacecraft encounter with a comet – Giacobini-Zinner – on 11th September 1985. The spacecraft then had a course change to direct it to more famous Halley’s Comet which it encountered albeit at a long distance in March 1986. The ISEE-3 spacecraft was then retired before being used from 1990 for solar wind research until 1997. when it was again retired as it wended its way around the sun.
However, a group of space enthusiasts and ex-space engineers led by former NASA scientist and space blogger Keith Cowing, realising that the craft was heading back towards Earth, wondered whether it could be recovered to the Lagrangian L1 position. Using crowd funded software and hardware, along with time given on the Arecibo radio telescope, in May this group of veteran NASA engineers successfully recontacted the ISEE-3 spacecraft via its Transponder A before its lunar swingby in July 2014.
After slowly powering up the spacecraft, on 3 July 2014, ISEE-3 was successfully commanded to make a thruster firing to increase its spin to 19.76 revolutions per minute the 19.16 revolutions per minute. This rate of spin was needed for the next manoeuvre. However, the attempt to change the course direction of the spacecraft on 8 May failed when the thruster made only 63 of a planned 400 pulse thrusts to change course direction. It was suspected that thruster/valve had a fault.
A second attempt to make a course correction on 9 July failed. At that point the team ran out of time and the attempt at rescuing the spacecraft to L1 is now abandoned. The spacecraft will now make an Earth flyby before moving away again on a heliocentric flight path.
Comment by David Todd: It was a nice try lads. Well done for trying.
