‘The Farthest’ is a real trip
Forty years ago this Sunday, Voyager 2 took off from Cape Canaveral, beginning the astounding story of the first exploration of our solar system and beyond — one that continues today.
“It’s the fact there are still discoveries that keep me interested, not the fact it’s 40 years old,” says 81-year-old Ed Stone, Voyager’s chief scientist for 45 years. “I hope someday other things will follow on behind and will take advantage of what Voyager will have laid the groundwork for.”
“The Farthest: Voyager in Space,” a documentary airing Wednesday on PBS, illustrates dazzlingly how the Voyager mission opened our eyes to the wonders of the universe. The film also gives us a look into the ingenuity of the scientists who created the space probes and kept them going.
Early on in the documentary, Rich Terrile, an imaging scientist at the Jet Propulsion Laboratory, notes that the technology used for the Voyager mission was comparable to what we have in our pockets today. “And I’m not talking about a cell phone. I’m actually talking about a key fob,” he says pulling one out of his pocket.
A cell phone has “240,000 times” more memory than Voyager, explains Stone.
Yet since they were launched in 1977 — Voyager 2 was first but on a slower trajectory — the pair of probes have boldly gone “where no one has gone before.” Oh, that’s “Star Trek,” but that was the spirit that was behind the mission.
“I think both they spring from the same source, and it’s that human longing to know,” says Carolyn Porco, a Voyager imaging scientist. “Scientists just let it go hog wild within us, but we all want to know.”
In 1979, Voyager 1 reached Jupiter first — relaying pictures of the planet never seen before. In fact, every stop was a first and gave us new and often mind-boggling discoveries. In 1980, it approached Saturn and its moon Titan, nearly a billion miles from Earth.
In 1986, Voyager 2 reached Uranus, and three years later Neptune.
In 2012, Voyager 1 became the first man-made object to exit our solar system and enter interstellar space, and it continues to send signals. It is nearly 13 billion miles from Earth. At more than 10.6 million miles Voyager 2 is en route and still sending signals.
“Voyager really gave us a new view of the solar system, revealed things that we couldn’t have imagined,” says Stone, professor of physics at California Institute of Technology, and former director of the NASA Jet Propulsion Laboratory, where the spacecraft were conceived, built and guided.
“All the same physical processes that we’re familiar with here on Earth came out in much different forms,” he adds. “It told us that our terracentric view of planets was really much too limited.”
Among the Voyagers’ discoveries were: Jupiter’s turbulent atmosphere; an indication of an ocean beneath the cracked icy crust of Jupiter’s moon Europa; Neptune’s Great Dark Spot and 1,600 kilometer-per-hour winds; and geysers erupting from the polar cap of Neptune’s moon Triton.
In “The Farthest,” the scientists still marvel at their finds. “I found the first evidence of active volcanism beyond Earth,” recalls Linda Morabito, a navigation engineer who spotted gas plumes on Jupiter’s moon Io.
While there have been many triumphs during the four decades of the Voyagers’ missions, it also brought reminders of our humanity.
In 1986, on the day when JPL was excitedly about to reveal findings from Uranus, the Space Shuttle Challenger blew up on takeoff. It was a sad day, but President Ronald Reagan’s response to the public was, “The future doesn’t belong to the faint-hearted. It belongs to the brave.”
That encapsulated the attitude of the JPL scientists. Financially, the government only OK’d a four-year mission to Jupiter and Saturn, but scientists devised a plan to include Uranus and Neptune in the trip.
“There was a little bit of subversiveness in that,” notes Porco.
Still, even if Voyager 1 reached Neptune after 12 years, there was no way to get images back to Earth. That technology was invented after the launch. So, talk about faith.
The mission, which was five years in the making, left in 1977 because the alignment of the planets, which happens about once every 176 years, made the trip some 20 years shorter.
JPL scientists tried to imagine everything that could go wrong. At the last minute, they wrapped parts of the spacecraft in aluminum foil bought off grocery stores’ shelves because of concerns over the magnetic fields of Jupiter.
“It was done stage by stage, and I think that made it possible to design a simpler system,” says Stone. “Yet we have one which lasted not only 12 years, but, it turns out, now 40 years.”
The mission ended its historic “grand tour” of the solar system in 1989 after Voyager 1 flew past Neptune, but NASA at the urging of physicist Carl Sagan did something that had “absolutely zero science in it,” notes Brad Smith, an imaging specialist on the Voyager.
On Valentine’s Day 1990, Voyager 2 turned its camera back to where it had been and took some family snaps.
In a scene in “The Farthest,” Sagan shows the photos at a 1994 lecture. Hesitating, he peers closer at one for dramatic effect. Then announces, “The Earth in a sunbeam.”
“This is where you live — on a pale blue dot,” he observes. “I think this perspective underscores our responsibility to preserve and cherish that pale blue dot, the only home we have.”
Almost more famous than Voyager itself — and also with no real scientific value — was the “Golden Record” on each of the spacecraft. The discs carry music, images and greetings from the people of Earth to any intelligent beings that may one day encounter Voyager.
The amount of information that could be conveyed was limited. A stylus was included and with instructions on how to play it. Cosmic directions to Earth — using a pulsar map — are stamped onto the cover of the Golden Records.
Music included a Pygmy chant, an Indian raga, Azerbaijani folk music, a blues song by Blind Willie Johnson, a Navaho chant, and plenty of classical music — Bach, Mozart, Beethoven, Stravinsky.
“Once you can play it, of course, there are all sorts of questions about what kind of time scale do you live on? What range do you hear in, if at all?” says Timothy Ferris, the science writer and producer of the “Golden Record.” “And for that reason, we paid particular attention to the internal mathematics of music, particularly in the relationships between Bach, Beethoven. So that even if sound wasn’t involved at all, you could still learn a lot from the content of the record.”
It is worth noting that we are likely to lose contact with the Voyager spacecraft in about a decade — the plutonium-powered batteries will be too weak by then to send back signals, which now take more than 17 hours to reach Earth.
But our interstellar message in a bottle will continue until some ETs pick up the spacecraft. Even if it takes a billion years, they will still be carrying a record of humanity’s existence — whether we exist or not then.
If you’re wondering why we haven’t been contacted yet, remember Earth has only been sending signals into space for less than a century.
The Voyager scientists remain optimistic about the future, though. Porco is on a project to search for life beyond Earth involving a mission to the Saturnian moon Enceladus.
There is still plenty to be learned, says Stone. “The surprise will be something we aren’t smart enough to know that’s out there waiting for us to discover.”