NASA has shut off one of Voyager 2’s scientific instruments to preserve its remaining power as it journeys through interstellar space. The spacecraft, launched on 20 August 1977, is currently positioned 12.8 billion miles from Earth and is exploring beyond the solar system. Since leaving the heliosphere on 5 November 2018, Voyager 2 has been studying the interstellar environment using four active science instruments. However, as the probe’s power supply gradually declines, NASA has had to make the tough decision of deactivating another instrument.

Managing diminishing power supplies

Voyager 2, along with its counterpart Voyager 1, is powered by decaying plutonium, which diminishes its available energy by around 4 watts each year. To extend its operational life, NASA has progressively turned off non-essential systems and some instruments. As of now, six of the spacecraft’s ten original instruments have been deactivated. On September 26, 2024, the decision was made to switch off the plasma science instrument, which had played a pivotal role in confirming the probe’s exit from the heliosphere by detecting the drop in solar particles.

Key data from the plasma science instrument

The plasma science instrument featured four “cups” to measure charged particles, three of which were pointed towards the Sun and monitored solar winds while inside the heliosphere. After the spacecraft moved beyond the heliosphere, these cups stopped collecting data, leaving only one operational. This remaining cup provided useful data at intervals when Voyager 2 performed its periodic 360-degree rotation.

Voyager 2’s future

NASA’s Jet Propulsion Laboratory confirmed that the plasma instrument was turned off without any complications, and the spacecraft continues to operate normally. As the remaining instruments collect valuable data, engineers will continue to monitor the probe’s energy reserves to determine when further shutdowns will be necessary, allowing the mission to continue for as long as possible.