Engineers at NASA's Jet Propulsion Laboratory in Southern California sent commands on April 17 to shut down the Low-energy Charged Particles experiment, known as the LECP, aboard Voyager 1. The move was driven by the nuclear-powered spacecraft's dwindling power supply, with mission managers concluding that disabling the LECP offered the best path toward keeping the probe operational into the future.

The LECP had been running almost continuously since Voyager 1 lifted off in 1977, a stretch of nearly 49 years. The instrument measured low-energy charged particles, encompassing ions, electrons, and cosmic rays generated within the solar system and across the broader galaxy.

Over the decades it provided critical data on the structure of the interstellar medium, detecting pressure fronts and regions of varying particle density in the space that lies beyond the heliosphere. The twin Voyager spacecraft remain the only probes positioned far enough from Earth to gather that class of measurement.

The decision over which instrument to power down was not made hastily. Science and engineering teams at JPL had previously worked through a prioritized shutdown sequence, agreeing well in advance on the order in which components would be switched off while preserving the mission's capacity to conduct scientifically unique observations.

Of the 10 identical instrument sets carried by each spacecraft, seven had already been deactivated before the latest action. The LECP was identified as the next in line for Voyager 1. An equivalent step was carried out on Voyager 2 in March 2025, when that spacecraft's LECP was also turned off.

Voyager 1 holds the distinction of being the most distant spacecraft ever built, having crossed into interstellar space and continuing to travel farther from the Sun with each passing year. Additional details on the mission's status are available through the Voyager blog hosted at science.nasa.gov.