On maneuvers with the Voyagers.
Imagine a sub-zero winter morning. You are worried your car might not start. You turn the ignition key and wait, and wait, and wait. For a total of 19 hours, 35 minutes, you wait to learn that your car has started.
That’s the very scenario NASA scientists faced recently with the first U.S. spacecraft to leave our solar system. They needed to reorient the 40-year-old Voyager 1 so its antenna would point toward Earth, 13 billion miles away. But the “attitude control thrusters,” the first option to make the spacecraft turn in space, have worn out.
So NASA searched for a Plan B, eventually deciding to try using four “trajectory correction maneuver” (TCM) thrusters, located on the back side of Voyager 1. But those thrusters had not been used in 37 years, so NASA wasn’t sure they’d work.
After engineers sent the signal to fire up the thrusters they waited eagerly to find out whether the plan was successful. It took an agonizing 19 hours and 35 minutes to get their answer, the time it took for the results to travel the 13 billion miles back to Earth. The set of four thrusters worked perfectly turning the spacecraft to face home and continue to communicate. It was yet another stunning engineering marvel for officials at NASA.
Because the thrusters were still functional after 37 years, NASA will be able to extend the life of the Voyager 1 spacecraft by two to three years, and gives hope for extending the life of Voyager 2 as well.
The Voyagers story is a remarkable one. In 1977 (significantly, the year the box office smash hit Star Wars was released), the twin spaceships Voyager 1 and 2 were launched, 16 days apart. In September 2013, NASA’s Voyager 1 spacecraft became the first human-made object to leave the solar system, entering interstellar space.
Voyager 2 lags behind, but according to NASA, the spacecraft is following the lead of the first Voyager and is on course to enter interstellar space in the coming years. The pair are still exploring the outer solar system and continue to communicate with Earth daily.
The Voyager missions made milestone discoveries in space exploration: the first active volcanoes beyond Earth, at Jupiter’s moon Io, and hints of a subsurface ocean on Jupiter’s moon Europa; they explored Saturn’s largest moon, Titan, where data showed a thick Earth-like atmosphere; found the icy moon Miranda of Uranus; and spotted icy-cold geysers on Neptune’s moon Triton.
Because of the success in the attempt to test Voyager 1‘s TCM thrusters, NASA plans to test the thrusters on Voyager 2. The need to use them is not as immediate, however, because the primary thrusters of Voyager 2 have not significantly degraded.
Like proverbial “Energizer Bunnies” the Voyagers will keep on going and going, probing into the deep reaches of our universe.
It is projected that in the year 40,272, Voyager 1 will come within 1.7 light years of an obscure star in the constellation Ursa Minor (the Little Bear or Little Dipper) and in about 40,000 years, Voyager 2 will come within about 1.7 light years of a star called Ross 248, a small star in the constellation of Andromeda.
What wonders of modern science and engineering excellence those two little, nearly forgotten spacecraft are… stunning examples of American exceptionalism.