NASA has shut off one of Voyager 1's scientific instruments in a bid to conserve power and keep the aging spacecraft operational, the agency announced. The decision reflects the ongoing challenge of managing a probe now nearly 25 billion kilometres from Earth, running on a nuclear power source that loses roughly four watts of power each year.
NASA engineers have deactivated one of the remaining scientific instruments aboard Voyager 1, the most distant human-made object ever built, as part of a careful power management strategy designed to extend the spacecraft's operational life as long as possible.
Voyager 1, launched in September 1977, crossed into interstellar space in 2012 and continues to transmit data back to Earth. However, its radioisotope thermoelectric generators (RTGs), which convert heat from decaying plutonium-238 into electricity, produce progressively less power over time. Engineers must now make difficult trade-offs about which instruments remain active.
The spacecraft currently carries several science instruments, and NASA has periodically shut down heaters and non-essential systems over the years to redirect power to the most scientifically valuable equipment. The latest instrument shutdown follows that same pattern of incremental sacrifice to preserve the mission's core capabilities.
Communicating with Voyager 1 presents its own unique challenges. A one-way signal travelling at the speed of light takes approximately 22.5 hours to reach the spacecraft, meaning any command sent from the Jet Propulsion Laboratory in Pasadena, California, receives a response nearly two days later. This communication delay makes troubleshooting and adjustments a slow, deliberate process.
The mission has not been without recent drama. In late 2023 and into 2024, Voyager 1 experienced a significant anomaly in which it began transmitting garbled data, leaving mission controllers uncertain whether the spacecraft could be saved. Engineers eventually traced the problem to a faulty memory chip in one of the spacecraft's flight data computers and developed a creative software workaround — an impressive feat given that the original team members who designed the system are largely no longer available, and documentation from the 1970s must be carefully studied.
NASA's Voyager project team, based at the Jet Propulsion Laboratory, has described the work of keeping both Voyager 1 and its twin, Voyager 2, alive as increasingly akin to archaeology — piecing together the intentions of engineers from a half-century ago using tools and programming languages that are largely obsolete today.
Despite the constraints, Voyager 1 continues to provide unique scientific data about conditions in interstellar space — the region beyond the heliopause where the Sun's solar wind no longer dominates. No other spacecraft has ever operated in this environment, making every transmission from Voyager 1 scientifically irreplaceable.
NASA has not specified a firm end date for the Voyager missions, but engineers estimate the spacecraft will no longer be able to power any science instruments sometime in the latter half of the 2020s, after which only limited engineering data may be recoverable before contact is lost entirely.
Analysis
Why This Matters
- Voyager 1 is humanity's only active scientific observer in interstellar space; each instrument shutdown permanently reduces our window into a region no other probe has reached.
- The mission demonstrates both the longevity possible in spacecraft engineering and the hard limits of physics — declining power budgets will eventually silence one of humanity's greatest exploratory achievements.
- Decisions made now about which instruments to keep active will shape what science can still be extracted from the final years of the mission.
Background
Voyager 1 and Voyager 2 were launched in 1977 to take advantage of a rare planetary alignment that allowed gravity-assist flybys of the outer planets. Voyager 1 conducted close encounters with Jupiter in 1979 and Saturn in 1980, before being slung onto a trajectory out of the solar system. In August 2012, NASA confirmed it had crossed the heliopause — the boundary where the Sun's influence gives way to interstellar space — becoming the first human-made object to do so.
The spacecraft's power source, a radioisotope thermoelectric generator, began the mission producing about 470 watts. By the mid-2020s, that output has fallen to roughly 40% of the original capacity. NASA has managed this decline by progressively turning off heaters and instruments over the decades: the plasma science instrument was shut down in 1980, the steerable antenna platform disabled in 1990, and various heaters and subsystems decommissioned since.
A near-catastrophic anomaly in November 2023 saw Voyager 1 transmitting meaningless data for several months. Engineers eventually identified a corrupted memory chip in the flight data system computer and, in a remarkable feat of remote engineering across 24 billion kilometres, restructured the spacecraft's code to work around the damaged hardware — restoring science data returns by mid-2024.
Key Perspectives
NASA / Jet Propulsion Laboratory: Mission engineers view each power management decision as a careful optimisation to maximise total scientific return over the remaining mission life. They have expressed confidence in their ability to keep at least some instruments active for several more years.
Space science community: Researchers studying the heliosphere and interstellar medium regard Voyager 1's continued operation as uniquely valuable. No follow-on mission designed to reach interstellar space has been funded, meaning there is no replacement instrument suite on the horizon.
Critics / mission realists: Some space policy analysts note that the resources dedicated to maintaining the ageing Voyager missions — specialist engineers, deep space network antenna time — involve real opportunity costs. Others point out that the remaining science may be limited, though this view is contested by heliophysics researchers who argue the data remains irreplaceable.
What to Watch
- Which instrument was deactivated and what data it was collecting — NASA's formal announcement should clarify the scientific trade-offs involved.
- Power output projections: engineers will continue to publish updated estimates of when the last instrument must be shut down, currently expected sometime in the late 2020s.
- Any future software or hardware anomalies: given the spacecraft's age and the 2023 memory chip crisis, additional faults are possible, and each one tests the limits of remote engineering at interstellar distances.