NASA’s Voyager Probes Power Down Instruments in Interstellar Space

NASA’s twin Voyager probes, launched 47 years ago, are now shutting off some of their scientific instruments to conserve power and extend their remarkable missions. Voyager 1 and Voyager 2 are currently navigating uncharted territories in interstellar space, far beyond the influence of our solar system.

Conserving Power for Longevity

Engineers at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California, recently commanded Voyager 1 to deactivate its cosmic ray subsystem experiment on February 25. In a similar move, Voyager 2’s low-energy charged particle instrument is set to power down on March 24. This decision leaves each probe with three operational scientific instruments, a necessary step as their power supplies continue to dwindle.

The Voyager spacecraft rely on electricity generated from the heat of decaying plutonium, and both probes are losing approximately 4 watts of power each year. “The Voyagers have been deep space rock stars since launch, and we want to keep it that way as long as possible,” stated Suzanne Dodd, Voyager project manager at JPL. “But electrical power is running low. If we don’t turn off an instrument on each Voyager now, they would probably have only a few more months of power before we would need to declare end of mission.”

Voyager’s Distance from Earth

As of now, Voyager 1 is more than 15 billion miles (25 billion kilometers) away from Earth, while Voyager 2 is over 13 billion miles (21 billion kilometers) distant. Both probes are the only spacecraft to operate beyond the heliosphere, which is the sun’s bubble of magnetic fields and particles extending well beyond Pluto’s orbit. This unique position allows them to gather invaluable data about interstellar space.

Instruments and Their Missions

Initially, instruments necessary for collecting data during the planetary flybys in the 1970s and 1980s were turned off after the probes completed their primary objectives. However, the Voyager mission team decided to keep some instruments operational to gather data about the heliosphere and interstellar space. Voyager 1 crossed into interstellar space in 2012, followed by Voyager 2 in 2018, each taking different trajectories. Voyager 1 is moving upward away from the plane that includes all the planets orbiting the sun, while Voyager 2 is traveling beneath this plane.

Over the years, the Voyager team has systematically shut down instruments to ensure the probes can continue their historic journeys. In October, NASA powered down Voyager 2’s instrument designed to measure the number of electrically charged atoms in space. This decision was made due to the instrument returning limited data in recent years because of its orientation. Voyager 1’s identical instrument has been inactive for years due to performance degradation.

Cosmic Ray Subsystem and Its Importance

The cosmic ray subsystem that was recently shut off on Voyager 1 included a trio of telescopes that studied and measured cosmic rays—highly energetic particles released from the sun and the Milky Way galaxy. Data from this instrument was crucial in determining the exact moment and location when Voyager 1 exited the heliosphere and entered interstellar space.

As the Voyager probes continue their journey into the unknown, the scientific community eagerly anticipates the data they will continue to provide. The low-energy charged particle instrument on Voyager 2, which will be powered off later this month, measures particles that contribute to our understanding of the cosmic environment.

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