A dozen years. Time enough for a toddler to become a teen-ager, for a fledgling scientist to become a veteran, for arcane technologies to become everyday. Time enough for an 1,800-pound package of primitive electronics to skate more than 4 billion miles toward the stars.
And time enough for the 300 people who remain part of the Voyager 2 team to take stock of memories built up over years of planning, engineering and executing their grand tour of four planets. Especially for the estimated 10 to 20 scientists and engineers who have been around since the very beginning, the tour's finale at Neptune this week is a time of bittersweet recollection.
Stewart (Andy) Collins, 42, is one of those whose careers was built on Voyager; in 1970 he came to the Jet Propulsion Laboratory as a 23-year-old, straight out of college, and then joined the Voyager planning team shortly after the program began in 1972. He has since moved on to supervise JPL's development of light detection equipment for other space missions.
Collins remembers that his son, Brian, now 12, said one of his first words in 1979 when Voyager flew by the solar system's largest planet: "Jupiper."
"He's our launch boy," Collins said, explaining that Brian was born a few months before Voyager's launch in August, 1977. "And our daughter, we think of her as Encounter plus 20 days, because she was born 20 days after the second Jupiter flyby. And our latest is Encounter minus 17 days."
Marie Collins was born Aug. 7, as the laboratory in Pasadena geared up for Voyager 2's pass by Neptune. That close encounter will come at 8:56 p.m. tonight, when Voyager will fly just 3,000 miles from Neptune's swirling clouds.
Although the Neptune mission will not be considered finished until Oct. 2, the close approach marks the beginning of the end of a program that has changed not just astronomy textbooks but also the lives of those who have been dedicated to it. Their days, they say, will always carry reminders of Voyager.
"Voyager has spoiled me for anything else," Collins said. "I'm reconciled to the fact that whatever comes next probably won't be nearly as satisfying."
The Voyager experience has also shaped the life of Christopher P. Jones, section manager for guidance and control systems at JPL. He joined Voyager in 1973, one year after the program officially began.
All the years of planning for every conceivable disaster in Voyager's clunky computers--something he now does for all JPL missions--changed his personality, Jones said with a grin.
"I always have contingency plans. I'm always thinking ahead, and never optimistically," Jones said. He checks to see if there is air in the spare tire. He builds time into his schedule so he will not be late. He knows which route he will take if the freeway off-ramp is closed.
"It comes across as a pessimistic view of life, but in fact it's more insurance than anything else," he said.
Jones and his colleagues had to imagine every improbable glitch along the 4.4-billion-mile journey to Neptune, equipping Voyager's six computers both for frontier science and to correct problems as they developed. But they only had 28,000 bytes of computer memory to do it with--35 times less than the memory of Jones' desktop computer of today.
Indeed, now that scientists can stop worrying about nursing the aging spacecraft past another planet, they can sit back and laugh affectionately at its outdated technology.
When Voyager 1 and 2 flew by Jupiter in 1979, the days before George Lucas-style supercomputer graphics, the Voyager team used laborious techniques to make a motion picture of the rotating gases and famous red spot, Collins recalled.
Several dozen images taken in sequence were processed individually at JPL, with extra care taken so they would all be in the same scale. The images were given to a film recorder to be converted into large transparencies. These then were trundled off to a Hollywood animation house, where they were sequenced onto film--"like Disney would do," Collins said.
"VCRs weren't what they are today. Back then, if you didn't have 16-millimeter film, nobody would know how to show it," Collins said. "Today, you'd do the processing, record the images right onto a videodisc and play them onto videotape." Instant movie.
Voyager's television cameras, called vidicons, also find it hard to get respect. Although they were the state of the art in the late 1960s, their light sensitivity is many times less than that of the silicon-chip-based cameras that have since become standard fare of home videotapers, noted Bradford A. Smith of the University of Arizona, leader of the imaging team since 1972.
"You just couldn't even compare the two," Smith said. "Vidicons are just the last thing in the world that anyone would want to fly."
For Linda Horn, infrared experiment specialist for Voyager, the mission opened up a magical world that she had dreamed about since childhood.
"I had a little telescope when I was a girl, and I used to look at the planets and the stars," said Horn, who joined the Voyager team shortly before the 1977 launch. "To actually come to JPL, get on a space mission and then go to the launch--talk about enthusiastic."
She and others involved with Voyager emphasize the team nature of the project, the kind of effort that makes lifelong friends.
Said Collins: "It was always staffed with just enough people. By that I mean everyone had to do his job well, because there wasn't a second person there to do it for them. So you develop a lot of good relationships with your co-workers."
This sense of the end of something unique and wondrous is common among these interplanetary pioneers.
"We're not going to go back to Neptune in our lifetimes," Jones said. "To be able to participate in an enterprise like Voyager is a special, one-time chance. It's like being around when Columbus discovered America."
Smith said he remains convinced that Voyager is scientifically the most productive, most exciting space mission ever.
"Just look at Neptune," Smith said. "The whole system is so photogenic and so exciting. You've got the atmosphere which is much more active than what we had ever expected it to be. There are dynamics there that we don't understand.
"That's what makes missions exciting. If you immediately understand what you're looking at, that's no fun. It's when you see things that just leave you lying awake at night thinking about them, and then you eventually figure out what it's all about--that's the fun part of it."
Charley Kohlhase, mission design manager and a primary mover in Voyager since the early days, is spending this week careening from scientific meeting to press briefing to official reception, trying not to look too rumpled for the TV cameras.
One morning early in the week, he paused briefly to talk about both the excitement and the sadness he is feeling.
"It's just exhilarating now. The problem will come next Monday or Tuesday," Kohlhase said. "The press will pick up and leave, all the trailers will go. We'll look at Neptune and it'll be shrinking smaller and smaller in the pictures, and even only barely be seen as a small crescent. And we'll know that the last big picture show is ended."
His comfort comes not from looking forward to other space missions, but from turning homeward.
"I have a grandson only a year and a half old, and I love to go hiking in the Sierra," he said. "Ten or 12 years from now I'll be hiking, and some night after the sun's down and the stars are up and I'm telling him stories, I'm going to look up and see Sirius."
Voyager will be headed toward Sirius, the brightest star in the heavens, after it leaves our solar system. "And I'll reflect back and tell him stories that he can share and pass on to the generations," Kohlhase said, "and I guess amaze him a little bit."
SHOW-STOPPING MOON--An obscure moon threatened to steal Neptune's thunder as Voyager raced toward the distant planet. Page 37