Now Leaving Your Solar System; Welcome to Interstellar Space
The Voyager 1 spacecraft is getting awfully close to the outer edge of our solar system. For the first time ever by a human-made object, NASA expects to reach the frontier of interstellar space within the next three years.
Launched in 1977, Voyager 1 and Voyager 2 were intended to explore the outer solar system — a task they competed in 1989. Voyager 1 crossed into the outermost layer of the heliosphere, called the “heliosheath,” in 2004. (The heliosheath is marked by slower solar winds, due to the proximity of interstellar gas.)
Today, Voyager 1 may be only a few hundred million to a billion miles away from the edge of the solar system. It now travels one billion miles every three years, and is currently 11 billion miles away from the sun.
You can get the backstory and more detail from a great NPR “Morning Edition” interview with NASA’s Ed Stone, who has been Voyager’s lead scientist since 1972.
Stone notes that Voyager’s onboard computers have only 8,000 words of memory, with a 23-watt transmitter, much less than modern devices have. With such old and basic equipment, it’s the battery life that’s impressive — based on the decay of Plutonium-238, there will be enough power for some of the scientific instruments on board until 2025.
(Image courtesy of NASA/JPL-Caltech)