Voyager 1 and 2 have surpassed all expectations on mission longevity, constantly proving the exceptional engineering and mission support put into their projects. Their continued operation in the most extreme conditions have led to several moments where they seemed lost and unrecoverable, before returning to scientific operations to the surprise of us all.
To continue further scientific operation with reduced available power, both Voyager 1 and 2, now operating outside of the heliosphere, have had to reduce the number of science instruments powered-up. In continued reduction of power draw, the Cosmic Ray Subsystem was powered-down on Voyager 2 and the Low-Energy Charged Particle Instrument in Voyager 2 will be switched off shortly.
The instrument contains two subsystems: the low-energy particle telescope for broader energy measurements, and the low-energy magnetospheric particle analyzer for more focused magnetospheric studies.
Both of the systems utilise a rotating platform powered by a stepper motor designed for 360 degree field of view. The motor units were tested to 500,000 steps (to guarantee continuous operation through the mission's
encounters with Saturn in 1980) will have completed more than 8.5 million steps by the time it's powered-down on Voyager 2.
The Voyager mission engineers have taken steps to avoid powering-down science instrumentation for as long as possible as they are collecting unique data in environments we have never encountered before. The decision to switch these instruments off will allow the craft to operate for around another year before the team needs to power-down another instrument on both of the probes.
Losing around 4W of power each year since launch 47 years ago, it is incredible to see the Voyager craft now 19.5 and 23 hours radio distance from Earth, still discovering and relaying findings back to us.
It is believed that the two Voyager probes could have enough energy reserve to continue operation with at least one instrument into the 2030's as long as unforseen challenges in deep space do not shorten the timescale.
More information on Voyager missions can be found on the NASA Voyager Mission site.
Keywords: Space Satellite Voyager Power Deep Space NASA