NASA: Voyager 1 probe has left the solar system
Voyager I has become the Little Spacecraft That Could as scientists said it had become the first man-made object to exit the solar system, an achievement that NASA could only fantasize about when the probe was launched in 1977, the same year “Star Wars” was released.
The New York Times
PASADENA, Calif. — The spacecraft’s technology was laughable by today’s standards: It carried an 8-track tape recorder and computers with 240,000 times less memory than a low-end iPhone. When it left Earth 36 years ago, it was designed as a four-year mission to Saturn, and everything after that was gravy.
But Voyager I has become — unexpectedly — the Little Spacecraft That Could. On Thursday, scientists said it had become the first man-made object to exit the solar system, an achievement that NASA could only fantasize about when the probe was launched in 1977, the same year “Star Wars” was released.
“I don’t know if it’s in the same league as landing on the moon, but it’s right up there — ‘Star Trek’ stuff, for sure,” said Donald Gurnett, a professor of physics at the University of Iowa and co-author of a paper about Voyager’s feat published Thursday in the journal Science. “I mean, consider the distance. It’s hard even for scientists to comprehend.”
Even among planetary scientists, who tend to dream large, the idea that something they built could travel so far for so long and pierce the sun’s reach is an impressive one. Plenty of telescopes gaze at the far parts of the Milky Way, but Voyager 1 can now touch and feel the unexplored region and send back detailed dispatches. Given the distance, it takes about 17 hours for Voyager’s signals to reach NASA’s Jet Propulsion Laboratory in Pasadena.
“This is historic stuff, a bit like the first exploration of Earth, and we had to look at the data very, very carefully,” said Edward Stone, 77, NASA’s top Voyager expert, who has been working on the project since 1972.
Ever the stoic scientist, he does get excited about what comes next. “It’s now the start of a whole new mission,” he said.
The lonely probe, which is 11.7 billion miles from Earth and hurtling away at 38,000 mph, has long been on the verge of bursting through the heliosphere, a vast, bullet-shape bubble of particles blown out by the sun.
Just in case Voyager encounters intelligent life out there, it is carrying a gold-plated, 1970s-era phonograph record with multicultural greetings from Earth, photos and songs, including Chuck Berry’s “Johnny B. Goode,” along with Beethoven, Bach, Mozart and Louis Armstrong.
The record, devised by astronomer Carl Sagan, also holds 116 images of science and art, speeches in 55 languages, the sounds of birds and whales, and human brain waves designed to describe what life on Earth is like.
Voyager’s passage into interstellar space apparently occurred in August 2012, said NASA scientists.
In addition to the Science article, NASA announced the feat at a news conference in Washington that began with the “Star Trek” theme playing in the background.
Voyager 1, which is about the size of a small car, made its exit more than a year ago, scientists said.
But since there’s no “Welcome to Interstellar Space” sign out there, scientists spent this year debating whether the probe had done so, interpreting the data Voyager sent back in different ways.
But now it is official that Voyager 1 passed into the cold, dark and unknown vastness of interstellar space, a place full of dust, plasma and other matter from exploded stars. The article in Science pinpointed a date: Aug. 25, 2012.
“This is the moment we’ve all been waiting for,” Jia-Rui Cook, the media liaison at NASA’s Jet Propulsion Laboratory, said in an email. “I can’t even sleep it’s so exciting!”
Coincidentally, the same month that Voyager 1 left the solar system, Curiosity, NASA’s state-of-the-art rover, landed on Mars and started sending home gorgeous snapshots. Soon afterward, Curiosity’s exploration team, some 400 strong, dazzled the world by driving the $2.5 billion robot across a patch of Martian terrain, a feat that turned the engineers and scientists of Building 264 of the Jet Propulsion Laboratory campus into rock stars.
A spoof video, “We’re NASA and We Know It,” recorded to the beat of the song “Sexy And I Know It,” generated 2.8 million views on YouTube.
Voyager, meanwhile, stopped sending home pictures in 1990, to conserve energy. In its heyday, it pumped out never-before-seen images of Jupiter and Saturn, but lately there has not been much to see.
As the mission lost its sizzle, its 12-person staff was booted from the laboratory’s campus and sent to cramped quarters down the street next to a McDonald’s.
Suzanne Dodd, the Voyager project manager, said that when she has attended meetings in Building 264, she has kept a low profile in deference to the Mars team.
“I try to stay out of the elevator and take the stairs,” Dodd said. “They’re doing important work there, and I’ll only slow them down.”
Now she and her team seem poised to be back in the spotlight.
Stone, vice provost for special projects at the California Institute of Technology and former director of the Jet Propulsion Laboratory, expects Voyager 1 to keep sending back data — with a 23-watt transmitter, about the equivalent of a refrigerator light bulb — until roughly 2025.
Not that the aging spacecraft has made things easy. An instrument that measures the energy of particles in plasma stopped working in 1980. But scientists still have access to a related sensor, a spindly antenna that records electron oscillations in plasma. The catch is that these oscillations don’t occur all the time; they typically happen when stirred up by a solar eruption.
Voyager 1’s plasma-wave antenna picked up audible vibrations in April and May that allowed Gurnett and his colleagues to calculate the density of the plasma around the spacecraft, which would help them determine whether the craft was still in the solar system. “It was exactly what we expected for interstellar plasma,” Gurnett said.
Moreover, by combing through older oscillation data collected by Voyager 1, the team discovered that the edge of the solar system — the threshold that was crossed in late summer 2012 — was roughly where Gurnett predicted it would be back in 1993 by using different solar-storm calculations.
“Am I bragging here? No,” he said. “All right. I admit it. It’s bragging a little.”
Meanwhile, Voyager 1’s twin, Voyager 2, also launched in 1977, trails behind at 9½ billion miles from the sun. It may take three more years before Voyager 2 joins its twin on the other side.
Material from The Associated Press and San Francisco Chronicle is included in this report.