NASA engineers have turned off one of the vital scientific instruments on the Voyager 2 spacecraft to extend its lifespan as power resources dwindle.
Voyager 2 was launched into space on August 20, 1977, and left the Solar System on November 5, 2018. Currently, the spacecraft is located 20.5 billion kilometers from Earth and operates four scientific instruments to study the space beyond the heliosphere, the bubble of charged particles and magnetic fields surrounding the Solar System. NASA believes that Voyager 2 has enough power to maintain one scientific instrument’s operations into the 2030s, but this requires shutting down other instruments.
Simulation of Voyager 2 entering interstellar space.
The mission team is exploring ways to delay shutting down instruments because Voyager 1 and Voyager 2 are the only two spacecraft currently operating in interstellar space, making any data they collect extremely valuable. To date, six of the original ten instruments on the spacecraft have ceased operations. Currently, the shutdown of the seventh instrument is unavoidable, and this time it is the plasma science instrument. On September 26, engineers sent the command to turn off the instrument.
The plasma science instrument includes four cups that gather information about the amount of plasma and charged particle flows moving through Voyager 2 and their directions. Three cups are angled towards the Sun, monitoring charged particles in the solar wind while within the heliosphere. The fourth cup faces the opposite direction, observing plasma in the planetary magnetic field and interstellar space. This instrument played a crucial role in detecting the decline of charged particles from the Sun, indicating that Voyager 2 crossed the boundary between the heliosphere and interstellar space in 2018.
“The engineers working on the mission are always carefully monitoring changes in the operations of the 47-year-old spacecraft to ensure they do not cause any unintended side effects,” a representative from NASA’s Jet Propulsion Laboratory shared. “The entire team confirms that the shutdown command was executed without incident and the probe is functioning normally.”
The usefulness of the plasma science instrument is limited because the three cups facing the Sun stopped collecting plasma after leaving the heliosphere and moving beyond the influence of the solar wind. Additionally, due to Voyager 2’s trajectory, the data collected in recent years has also been more limited. One operational cup only provides useful data every three months, when the spacecraft rotates 360 degrees around its axis. This led to the decision to turn off the plasma instrument to conserve power instead of shutting down other instruments.
Both Voyager 1 and Voyager 2 operate on decaying plutonium, losing about 4 watts of power each year. In the 1980s, some of their instruments were turned off after the two spacecraft completed their explorations of the giant planets in the system. This helped increase power for the duo of probes, extending their lifespans. A few years ago, both spacecraft also shut down all non-essential instruments. The plasma instrument on Voyager 1 ceased operations in 1980 and was turned off in 2007.
NASA engineers are closely monitoring Voyager 2’s power supply to decide which scientific instrument to shut down next, ensuring the interstellar probe can continue to provide scientific data for as long as possible.
