Summary
NASA says a September power-saving change will let Voyager 1’s remaining science instruments operate longer than previously anticipated. The spacecraft’s signal also returned after a brief communications loss in October.
NASA’s Voyager team completed a power-saving change on Voyager 1 in September, replacing three devices with lower-power alternatives. NASA’s Jet Propulsion Laboratory says the work will allow the probe’s remaining science instruments to operate longer than previously anticipated. The team also restored communication after a brief signal loss in October, while engineers continue investigating what triggered it.
A coordinated swap to conserve power
The change, nicknamed the “Big Bang,” followed the same device swap on Voyager 2 by about six weeks. On Voyager 1, engineers turned off three devices and substituted three alternatives that use less power. The devices help keep the spacecraft warm. The changes had to be made together so the team could reduce power use while maintaining an appropriate distribution of heat across the spacecraft.
Voyager 1 and Voyager 2 generate electricity with radioisotope thermoelectric generators, which convert heat from decaying plutonium. As the plutonium supply declines, each probe loses about 4 watts of power per year. With the spacecraft’s power margins narrowing, engineers have been shutting down nonessential systems to preserve operations.
The mission launched in 1977 with 10 science instruments. Some were turned off after the probes’ planetary encounters, and two instruments on Voyager 1 have been shut down in recent years as power dwindled. NASA says that without the Big Bang, the team would have needed to turn off another Voyager 1 instrument as early as summer 2027.
The Voyagers are now beyond the heliosphere—the vast bubble of particles and magnetic fields created by the Sun—and travelling through interstellar space. NASA says they are the only spacecraft to have studied this region directly. Keeping the remaining instruments running extends that direct exploration.
Signal returns as Voyager nears a one-light-day distance
NASA’s Deep Space Network could not detect Voyager 1’s radio signal during two scheduled communications attempts, on Oct. 18 and 19. The probe’s signal reappeared on Oct. 20, and the team has maintained contact since. At the time, Voyager 1 was about 16 billion miles (24 billion kilometres) from Earth.
Engineers found that one group of thrusters had gone offline and its backups had switched on. Voyager’s fault-protection system is programmed to make that change if its computers detect a problem with the active thrusters. The system puts the spacecraft into a stable configuration and pauses normal operations so engineers can diagnose the issue. NASA said the investigation into what caused the incident was continuing.
JPL reported that Voyager 1 was travelling at 38,000 mph (61,155 kph) toward a distance milestone. On Nov. 18, it was projected to be 16.09 billion miles (25.89 billion kilometres) from Earth—about one light-day. At that distance, a radio signal takes 24 hours to reach the spacecraft, and its reply takes another 24 hours to return. The milestone will not change conditions aboard Voyager 1; its significance is the communications delay and the distance the spacecraft has travelled.