Citizen scientists revived NASA’s long-retired ISEE-3 probe in 2014 and fired its thrusters for the first time in 27 years

Citizen scientists revived NASA’s long-retired ISEE-3 probe in 2014 and fired its thrusters for the first time in 27 years, restoring its spin—but the larger burn meant to return it to an Earth–Sun observation point failed because the nitrogen needed to pressurize its fuel system had apparently run out.

In 2014, a spacecraft launched before the first Space Shuttle flight was approaching Earth for the first time in decades. NASA had ended support for ISEE-3 in 1997. The specialised ground equipment once used to command it had been discarded, and no funded agency mission was waiting to take control.

A publicly financed group of independent engineers, scientists, programmers and radio specialists decided to rebuild that capability. The ISEE-3 Reboot Project secured NASA’s permission, assembled a modern command system around software-defined radio hardware and reached the spacecraft through some of the world’s largest radio telescopes.

On 2 July 2014, the probe fired its hydrazine thrusters for the first time since 1987. Eleven short pulses returned its spin almost exactly to the original operating range. Six days later, the team attempted the much larger manoeuvre needed to reshape its path through the Earth-Moon system. That burn quickly faded.

The failure was probably not an empty hydrazine tank. Telemetry indicated that the spacecraft had lost the nitrogen gas used to pressurise the propulsion system. Fuel could remain aboard, but without pressure to push it through the plumbing, it could not reach the thrusters.

Read more – Space Daily: https://bit.ly/4rBVOrF