Voyager 2 can continue to send science back from interstellar space for a little longer.
NASA’s long-running Voyager 2 mission will push back an instrument shutdown by three years to 2026, thanks to a feat of engineering. The change will allow the mission launched in 1977 to collect valuable science in space.
“We’re definitely interested in keeping as many scientific instruments operational for as long as possible,” Linda Spilker, Voyager’s project scientist at NASA’s Jet Propulsion Laboratory in Southern California, said in a statement on the decision (opens in new tab) Wednesday (04/26)
Voyager 2 and its twin, Voyager 1, will therefore continue to collect valuable data deeper in space than any spacecraft before them. Investigations ongoing, NASA says (opens in new tab)include the study of the Sun’s magnetic field, the energy of the solar wind emanating from our Sun, and radio emissions in interstellar space.
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The Voyagers both run on nuclear power, as the sun’s rays are too weak for solar power so far out in space. The radioisotope thermoelectric generators (RTG) they use decay over time, meaning the plutonium produces slightly less electricity each year.
Engineers have already turned off heaters, among other non-essential systems, to prioritize science for the robust spacecraft. But performance is so low now that tough decisions have had to be made for Voyager 2’s five science instruments this year. (Voyager 1 only runs four times early in its life due to a bug with an instrument, leaving it with enough power for everyone by 2024.)
Solving Voyager 2’s power problems came down to removing a protection that is usually in place to prevent power surges from damaging the spacecraft’s instruments. This protection is called a voltage regulator. This regulator triggers a backup circuit that draws additional power from the RTG as over-voltage protection in the event of problems.
“Instead of reserving this power, the mission will now use it to keep the science instruments operational,” NASA officials wrote in the statement. This decision will loosen the spacecraft’s voltage regulation, but both Voyagers have experienced “relatively stable” power levels, “minimizing the need for a safety net.”
Related: Voyager turns 45: What the legendary mission taught us and what’s next
Engineers will monitor the success of this strategy on Voyager 2. If everything works, Voyager 1 will use the same technique as it runs out of power next year, NASA officials said. They found that everything on Voyager 2 has been working well for a few weeks with the new process.
“Variable voltages pose a risk to the instruments, but we found that the risk is small, and the alternative offers a large reward because the scientific instruments can stay on longer,” says Suzanne Dodd, Voyager project manager at JPL. said in the same statement.
Both Voyagers were expected to stay in space for just four years, accumulating solar system science on Jupiter and Saturn. A mission extension in 1981 eventually allowed Voyager 2 to fly past Uranus and Neptune, making it the only spacecraft to date to have done so. Voyager 1 was high above the plane of the Solar System after Saturn’s flyby, but the spacecraft collected valuable solar data from its trajectory due to its expansion.
Another mission expansion in 1990 aimed to take Voyager into interstellar space. Voyager 1 crossed this region in 2012, while the slower Voyager 2 reached the milestone in 2018.
Elizabeth Howell is co-author of “why am i taller (opens in new tab)?” (ECW Press, 2022; starring Canadian astronaut Dave Williams), a book on space medicine. Follow her on Twitter @howellspace (opens in new tab). Follow us on Twitter @spacedotcom (opens in new tab) or Facebook (opens in new tab).
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