An emotional farewell for a distant friend
By Marsha Walton
WASHINGTON (CNN) -- Like any human child, he had a troubled adolescence, didn't follow orders from authority figures and didn't behave as expected.
But after a lot of give and take, he found his way, even opened up a new and unorthodox form of communication. And then he started delivering some dazzling insights, enough to thrill even those who thought he was a lost cause.
"He," of course, is the spacecraft Galileo, snake-bitten for years with launch delays, a useless main antenna, a temperamental tape recorder and critics who wrote it off as a pricey failure. But the $1.4 billion mission to Jupiter eventually turned into a NASA success story. It captured images of the Jupiter system and made unexpected discoveries that changed some long-held beliefs about the solar system and even the origins of life.
"It's almost like having a troubled child that ends up graduating from law school," said Claudia Alexander, Galileo Project Manager at NASA's Jet Propulsion Laboratory in Pasadena, California.
"You're so happy that it was able to overcome the difficulties, and it gave us a fabulous return," she said.
Hundreds of contributors to the Galileo project will gather Sunday, September 21, to share the final minutes of the spacecraft's mission. It's programmed for a deliberate death dive into the gaseous planet, because it's nearly out of fuel and when it runs out scientists would no longer be able to control it.
There may be some weeping Sunday at the JPL auditorium, near Mission Control that will be monitoring the final transmission from the craft that was launched from the space shuttle Atlantis on October 18, 1989.
Scientists shed tears too
"I will be crying because I'm sentimental," said Alexander at NASA headquarters in Washington this week. "But don't tell anyone I said that!" she laughed.
And she's not likely to be the only one, said Ed Weiler, Associate Administrator for NASA's Office of Space Science.
"You do anthropomorphize your spacecraft and your science when you've spent your entire career on it," said Weiler. "By the time Galileo goes into Jupiter's atmosphere, that will be 14 years after the launch and about 10 more years in the development time frame and probably another 10 years in the planning. So you can't help but feel pain," he said.
Colleen Hartman, director of the solar system exploration division at NASA Headquarters, said the Galileo spacecraft has given tantalizing clues to help address the question, "Are we alone?"
She too looks back on the mission with pride.
"Robotic explorers ... are not going on their own," she said. "It's the human side of the story that makes it possible. And I think that's both fascinating, and from a scientific point of view, extraordinary."
It's because of one of Galileo's discoveries that scientists designed the "death drop" scenario to end the mission. Observations from Jupiter's moon Europa indicate it has an ocean. On Earth, water indicates life, so to find water outside the Earth's atmosphere suggests it's possible elsewhere, according to scientists.
When the spacecraft runs out of propellant, it could go out of control and crash into Europa. While unlikely, microbes from Earth that may have survived the 14-year odyssey could contaminate that moon.
"Disposing" of the flight hardware is the right thing to do, says Alexander, because that sensitive Europa environment will almost certainly be studied more intensely in the future.
Counting years and children
Donald Williams was principal investigator for Galileo's heavy ion counter, studying the magnetic fields of the planet and its satellites. He spent 27 years on the project, beginning as one of the writers of the mission's first development proposal. He knows longevity:
"When we started I had not yet celebrated my 25th wedding anniversary and none of my children were married. This year I celebrated my 50th wedding anniversary and I have 7 grandchildren, four of them in college," he said.
The technical problems and the dramatic re-structuring of the mission as it progressed sometimes took a toll on the researchers.
"It does cause tension in the family when you have to make choices between having Thanksgiving with your family and going off to solve a problem on the spacecraft," former project manager Jim Erickson said.
Like others on the project, Erickson said there were elements of a parent-child relationship.
"You tend to think of it as something you have to take care of, but at the same time you're trying to get it smarter and develop new capabilities and at the same time make it do a job. And part of that is to expose it to risk. It does take a toll on your emotions," he said.
It won't be just NASA veterans who may be touched with sadness this weekend. Hundreds of scientists around the world worked on Galileo's experiments over its long life.
Barbecue to mark the end
Robert Pappalardo of the University of Colorado helped plan the limited number of pictures Galileo would take after researchers learned the main high gain antenna would not operate. The planning paid off.
"When the first piece of the first image came back, it was spectacular," said Pappalardo, an assistant professor in the department of astrophysical and planetary sciences.
His students are planning a farewell barbecue to mark Galileo's final plunge.
"It is a sad occasion. It's like losing a friend you've had for decades," said Pappalardo, who is writing a book, "The Moons of Jupiter."
Pappalardo and many other scientists are already at work on the next project headed to Jupiter, the Jupiter Icy Moons Orbiter, known as JIMO. NASA is now developing a new fuel system for that spacecraft, a type of nuclear propulsion.
While launch isn't expected for another decade or so, scientists are already itching for the secrets it might reveal about Jupiter's four largest satellites.
"It will be able to drop into orbit around all these moons. And not spend a few minutes or a few hours but a few months" orbiting each, Weiler said.