Voyager 2 and its twin launched in 1977, called Voyager 1, rely on a form of nuclear battery known as a radioisotope thermoelectric generator that uses the heat produced by the decay of plutonium. But the supply of plutonium on each probe drops at about four watts a year on each spacecraft.
To keep the probe running on this dwindling power supply, engineers recently reduced Voyager 2's power requirements by turning off a few non-science devices and using "lower-power alternatives" that are still effective enough to keep the spacecraft warm while it's so far from the sun, NASA officials said in a statement. "The spacecraft power margins have grown razor thin, requiring the team to conserve energy by shutting off non-essential devices and systems," NASA officials wrote of the mission, which is managed by the agency's Jet Propulsion Laboratory.
A signal to each spacecraft takes nearly 24 hours (or one light-day) to make a one-way journey, and officials noted Voyager 1 is further from Earth than its twin. (Voyager 2 is at about 142 astronomical units or sun-Earth distances, while Voyager 1 is nearing 171 AU.)
Next August Voyager 2 turns 50. They want to keep it going until then. Personally, I've always wondered if it would make it. Voyager 1 turns 50 in September.
ReplyDeleteThey're the farthest from Earth any objects have been. Their fuel will be gone in a couple of years. It took 48 years to get where they are. To make it to a nearest star will take thousands of years.
AU = Astronomical unit = the distance from the earth to the sun = 93 million miles more or less.
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