Life Has Changed For Voyager’s Builders
PASADENA, Calif. (AP) _ Twelve years ago Sunday, an unlovely collection of human engineering named Voyager 2 broke free of the Earth’s gravity and started a long tour of the solar system.
The spacecraft has cruised the rings of Saturn, observed Jupiter’s Great Red Spot, watched volcanos erupt on its moon Io and discovered clandestine moons circling Neptune.
And in that blink of cosmic time there have been changes for Voyager’s creators and handlers, those who built it and shepherded it across space, marking its 4 billion-mile course in human milestones.
″There’s people who remember their children’s birthdays in terms of where the spacecraft was. We’ve had people get married and people who died during the mission,″ said Charles Kohlhase, the mission design manager for Voyager. ″There are going to be a lot of people who have been loyal to this project who are going to be sad when it’s over.″
The sad day is coming. After a close encounter with Neptune this week that promises another set of spectacular pictures from a distant planet, Voyager 2 will continue on its way out of the solar system at 37,000 miles an hour, becoming the man-made object that has traveled the farthest from Mother Earth.
Voyager 2 was launched on Aug. 20, 1977. Its sister ship, Voyager 1, launched Sept. 5, 1977, has been cruising through an empty part of the solar system following a 1981 flyby of Saturn.
Only a skeleton crew of technicians will monitor the Voyagers as they continue to sniff deep space for information, looking for the heliopause, the zone where the sun’s influence on the solar system ends.
With enough plutonium to keep their electronics running another 28 years, the gangly 1,700-pound creations resembling failed Erector sets will likely outlive the humans who built them and whose signatures, and the names of their families, are etched on thin sheets of titanium bolted into the spacecrafts’ side.
″Everybody in my family feels connected to what’s happened with Voyager,″ said Ray Heacock, the deputy assistant director at the Jet Propulsion Laboratory who oversaw development of Voyager. ″I’ve worked on a lot of other projects, but this is my baby.″
And others’ baby as well. Thousands of people in dozens of companies and universities across the country helped design and build the sturdy spacecrafts.
″It was tremendously exciting and satisfying to be involved in the project,″ said James McAnally, who led the Denver-based Martin Marietta’s efforts to develop Voyager’s guidance system and planetary radio receiver.
At JPL, there are constant reminders of Voyager. Hallways and offices are adorned with its pictures from Jupiter and Saturn like the artwork of a favorite child. The facility’s closed-circuit television system offers updates about the progress of the mission.
Yet Voyager is a success story that almost wasn’t.
Originally envisioned as an ambitious and expensive ″grand tour″ of the outer solar system by four spacecraft, the plan was scrubbed in 1972 as the nation, sated with moon flights, turned its attention away from the space program.
Instead, NASA dropped the idea of visiting Uranus and Neptue with a new spacecraft and built two souped up versions of the proven Mariner design for a mission to only Jupiter and Saturn.
But scientists hoped it still might be possible to send one of the spacecraft on to Uranus and Neptune by using gravitational fields of the giant planets to bend Voyager’s trajectory like a billiard ball in a cushion shot.
When it became apparent Voyager 2 could make the Grand Tour, scientists had to improvise with its aging technology. While the spacecraft has 5 million electronic parts - the equivalent of 2,000 color TV sets - it has only a quarter the computing power of today’s personal computers.
So Voyager 2′s onboard computers were reprogrammed from across space to compress its bursts of data. A new tracking system was devised for its cameras to ensure clear, detailed pictures despite the increasing transmission distance to Earth and the feebler light at the end of the solar system.
More tracking dishes were added in the deserts of California and New Mexico and in Australia, Spain and Japan to capture Voyagers’ weak radio signals that have spread and diffused over the billions of miles.
″We’ve done things with it that we haven’t done with any other system,″ said Heacock.
This technological creativity would have gone wanting if the spacecrafts’ key equipment broke down. There have been what Heacock calls ″cliffhangers″: one radio that received Earth communications blew a fuse, another became deaf to some frequencies. Voyager 2′s computer lost some memory and a platform that scans the planets gets stuck if it moves too fast.
Yet everything else has continued to work, despite a dozen years of the absolute heat and cold of space and bursts of radiation from Jupiter 1,000 times the lethal dose for a human.
Even though the Voyagers have ″total redundancy″ - basically two of everything - the odds of making it this far were considered slim.
The scientists had data on the reliability of the spacecrafts’ components, and said Heacock, ″None of those numbers that we used had us operating at this point.″
Kohlhase credited the human factor. ″I hate to sound trite, but the people involved with the design of the spacecraft were motivated, talented, creative people,″ he said. ″The reliability is the result of those creative energies.″
Heacock and Kohlhase say they don’t think of the Voyagers as living beings. And yet, said Kohlhase, ″We all feel affection for them.
″It’s sort of like we’re connected to these machines. They are not human, but they are extensions of our human qualities.″
Kohlhase bears a strong resemblance to Star Trek’s Mr. Spock, and has gone to costume parties dressed as the science fiction character. Now 53, he was 39 when he began working on Voyager. In the time of Voyager he survived major surgery for cancer of the thyroid.
″I was able to schedule it between the two Saturn encounters,″ he said, laughing.
Also in the time of Voyager he saw his two daughters grow from teen-agers into lives of their own. He now has a grandson whose picture shares a spot on the office wall with images from space.
″I look forward to the time when I’m an old man telling my grandchildren my name is on a spacecraft escaping from the solar system to travel in the core of the Milky Way,″ he said.