25 billion kilometers from Earth, the iconic Voyager 1 is once again operating normally after NASA’s JPL laboratory temporarily lost communications with the probe.
The context. In mid-October, the Voyager 1 space probe automatically turned off its main radio transmitter. The failsafe system had detected excessive power consumption after NASA sent a command to the spacecraft to turn on one of its heaters.
After activating safe mode, Voyager 1 stopped communicating with Earth through its main X-band transmitter. The probe then began using an S-band transmitter that had not been used for more than 40 years.
The explanation. Voyagers are programmed to automatically shut down their non-essential systems, maintaining minimum flow to critical subsystems if failover protection detects low available power.
However, the probes have already turned off all their non-essential systems except four scientific instruments. Voyager 1’s failsafe system had no choice but to turn off its X-band transmitter and turn on the less power-consuming S-band one.
The rescue. The switch to a much weaker radio transmitter prevented the mission team from receiving scientific and status data from the probe until early November. Voyager 1 is the spacecraft that has reached the furthest from our planet, and NASA was not even sure that it could capture its frequencies with the Deep Space Network antennas.
Despite the difficulties, the team managed to contact the ship and restart the system that synchronizes its three onboard computers, recovering the sending of scientific data and the four instruments still operational.
Old technology. The twin probes Voyager 1 and Voyager 2 have been traveling in space for more than 47 years, and are the only spacecraft operating in interstellar space. His advanced age has posed new challenges for the mission team, which not only works with ancient technology, but also with extremely small energy margins.
Powered by the heat of decaying plutonium from their thermoelectric generators, these twin probes lose about 4 watts of power each year. About five years ago, NASA began shutting down all systems not critical to keeping them in flight, including heaters on some scientific instruments.
To the team’s surprise, four of these instruments continue to function on each of the probes, despite reaching temperatures lower than what they were designed to withstand. They are scientific instruments that study the particles, plasma and magnetic fields of interstellar space, the region between stars where the solar wind loses its influence.
Image | NASA/JPL-Caltech
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