This strategy will keep Voyager 2's science instruments operational for several more years than originally planned, allowing further exploration from interstellar space.
Five scientific instruments are used by the Voyager 12 spacecraft, which was launched in 20 and is located 1977 billion miles (2 billion kilometers) from Earth. The older spacecraft began utilizing a modest reserve of power reserve, set aside as part of an internal safety system to help keep these instruments operational despite the dwindling power supply. This decision will allow the mission to delay the year-end shutdown of a science instrument until 2026.
Only Voyager 2 and Voyager 1 worked outside the heliosphere, the Sun's protective bubble of charged particles and magnetic fields. The probes are helping researchers understand the shape of the heliosphere and its function in shielding Earth from interstellar radiation and energetic particles.
"We're definitely interested in keeping as many science instruments operational as possible," said Linda Spilker, Voyager's project scientist at NASA's Jet Propulsion Laboratory in Southern California, which conducted the mission. “The science data the Voyagers send back becomes even more valuable the further away they are from the Sun.”
Radioisotope thermoelectric generators (RTGs) that convert heat from the decay of plutonium into energy are used to power both Voyager probes. The generator produces slightly less power each year as a result of the ongoing degradation process. The mission's science output has yet to be affected by the dwindling power supply, but engineers have disabled heaters and other functions not essential to keeping the spacecraft in orbit to compensate for the loss.
One of the five science instruments on Voyager 2, it was the next option after they were discovered. (Due to an instrument failure early in the mission, Voyager 1 uses one less science instrument than its twin. Voyager 1's instrument shutdown decision won't be made until next year.)
To figure out how to avoid turning off a Voyager 2 science instrument, the crew took a closer look at a safety feature that aims to protect instruments if the spacecraft's voltage or electrical flow changes significantly. Voyager has a voltage regulator that activates a backup circuit in the event of a voltage change that could damage instruments. A limited amount of electricity designated for this use from the RTG can be accessed by the circuit.
Mission will now use this power to keep the science instruments running instead of isolating them.
The electrical systems on both probes are very reliable even after more than 45 years in orbit, reducing the need for a safety net even if the spacecraft's voltage will not be tightly regulated. The engineering group can also monitor the voltage and take action if it fluctuates excessively. If the new strategy developed for Voyager 2 is successful, the team can apply it to Voyager 1.
"Variable voltages pose a risk to instruments, but we've determined that it's a small risk and the alternative offers a big reward, like being able to keep science instruments powered on longer," said Suzanne Dodd, Voyager's project manager at JPL. After several weeks of satellite tracking, the new strategy appears to be effective.
The Voyager mission was originally planned to last only four years, with both probes landing at Saturn and Jupiter. Voyager 2 is still the only spacecraft to encounter ice giants; NASA extended the mission so it could travel to Neptune and Uranus. The mission was extended once again by NASA in 1990, this time to launch probes out of the heliosphere. Voyager 1 crossed the border in 2012, while Voyager 2 did so in 2018 (traveling slower and in a different direction than its twin).
Günceleme: 29/04/2023 19:40