Voyager 2: NASA switches off measuring instrument to save power

NASA has switched off a measuring instrument on the Voyager 2 space probe in order to save power. In future, the space probe, which was launched in 1977, will no longer collect data with the plasma probe from interstellar space, which it travels through at a distance of around 20.5 billion kilometers from Earth. NASA sent out the signal for the shutdown on September 26, 2024; it arrived at Voyager 2 19 hours later.

The mission team tried to delay the shutdown of the plasma science instrument for as long as possible, according to a statement from NASA's Jet Propulsion Laboratory. The probe has enough power to continue exploring the region outside the heliosphere with at least one scientific instrument until the 2030s.

A total of eleven measuring instruments are on board, four of which are still working. The electricity comes from radioisotope generators in which plutonium 238 decays. These lose 4 watts of power every year.

The end of the heliosphere

As with its sister probe Voyager 1, several measuring instruments that were not needed for the exploration of interstellar space were switched off after the main mission – of exploring the gas planets –. In addition, NASA engineers switched off all onboard systems that were not necessary for the operation of the probes, including some radiators.

The instrument that NASA has now turned off was able to measure the amount of plasma and the direction in which it was flowing. Because of the probe's orientation to the plasma stream, the instrument had only been able to collect limited data in recent years. In 2018, the instrument was crucial in determining that Voyager 2 had left the heliosphere. At that time, the plasma flow measured by three of the four cups pointing towards the sun rapidly decreased. Voyager 1's plasma measurement instrument had not been providing sufficient data since 1980 and was switched off in 2007.

Voyager 2 was launched on August 20, 1977 and passed Jupiter in 1979, Saturn in 1981, Uranus in 1986 and Neptune in 1989. Of these, it was accelerated less than its sister probe Voyager 1, which was launched 16 days later, during its flybys. This is why it is now further away and traveling faster.

(anw)