NASA’s Voyager 1 spacecraft has cleared a crucial power‑draw test performed at the end of July, moving the aging probe one step closer to a power‑saving maneuver that could keep its remaining science instruments operational for at least another year. The test, overseen by Voyager project manager Kareem Badaruddin at the Jet Propulsion Laboratory, examined whether a planned hardware swap would consume more electricity than anticipated.
Current instrument status
Launched in 1977, Voyager 1 originally carried ten scientific instruments designed for flybys of the outer planets. Over the past five decades the spacecraft has systematically turned off devices as its dwindling plutonium‑based power source eroded. Today only two instruments remain active: a magnetometer that measures magnetic fields and a plasma wave subsystem that detects plasma oscillations. By contrast, its twin, Voyager 2, still operates three instruments.
The most recent instrument loss on Voyager 1 occurred in April when engineers permanently shut down the Low‑energy Charged Particles (LECP) experiment. The LECP had recorded ions, electrons and cosmic rays continuously since launch, but an unexpected power dip during a roll manoeuvre on 27 February pushed the probe close to its automatic undervoltage fault protection. To avoid an uncontrolled shutdown, the team elected to retire the experiment, leaving a small motor inside the instrument running at half a watt so the hardware could be re‑energized if power conditions improved.
The “Big Bang” power‑saving swap
The procedure being tested on Voyager 1 is nicknamed the “Big Bang” within the mission. Rather than disabling low‑priority loads one at a time, engineers simultaneously turn off several aging devices—such as tape recorders and heaters that have drawn power for decades—and replace them with lower‑power alternatives. The swap is timed to keep the spacecraft’s electronics above the temperature at which they would fail permanently.
A similar swap was executed on Voyager 2 in July. That operation liberated roughly ten watts per year, enough to sustain Voyager 2’s three remaining instruments for at least another year. Although both probes share an identical original design, Badaruddin notes that after 49 years of separate flight the two spacecraft exhibit real differences. Those differences mean the success of the “Big Bang” on Voyager 2 does not guarantee identical behaviour on Voyager 1.
Voyager 1 is now more than 25 billion kilometres from Earth, compared with Voyager 2’s roughly 21 billion kilometres. The increased distance translates to a round‑trip command delay of about one day, adding complexity to any engineering maneuver.
Upcoming tests and timeline
The power‑draw test completed in July confirmed that the swap would not exceed the probe’s electrical budget. The next milestone is a thermal test scheduled for the end of August. That test will verify that the spacecraft’s temperature remains within safe limits after the power‑saving devices are turned off, because a component that becomes too cold in interstellar space may not recover.
If the thermal test succeeds, NASA will issue the command to implement the swap on Voyager 1, following the same cautious, day‑long command cadence used throughout the mission. A hopeful outcome of the maneuver is the possible re‑activation of the LECP experiment. NASA has indicated that, should sufficient power be freed, the same physical instrument could be turned back on, restoring measurements that have been absent since April. The agency has not promised this result, but it remains a realistic possibility.
Two dates loom on the mission’s calendar. The thermal test is due by the end of August, and Voyager 1 is expected to cross the one‑light‑day distance from Earth in mid‑November—a point at which a signal takes a full day to travel each way. While the two events are independent, together they illustrate that, nearly half a century after launch, the probe is still capable of engineering surprises, continues to increase its distance from Earth every second, and remains under the careful stewardship of engineers who can neither see nor touch it directly.
Steve Lopez is the Editorial Page Editor for News Raise. He covers Health. He has won more than a dozen national journalism awards for his reporting and column writing at seven newspapers and four news magazines.
