Galileo: Breaking Up's Hard to Do

By Suneel Ratan

Story location: http://www.wired.com/news/technology/0,1282,60520,00.html

02:00 AM Sep. 20, 2003 PT

When the Galileo spacecraft slams into Jupiter on Sunday, one of the
longest-running dramas in the history of space exploration will come to an
end.

For the 800 or so people who have worked on the mission since its inception
in the mid-1970s, the occasion will be bittersweet.
                  
Many of them will be among 1,500 people expected to congregate at the Jet
Propulsion Laboratory in Pasadena, California, for what amounts to a funeral
for a much-loved, soon to be long-lost friend.

Dr. Claudia Alexander recalls beginning her career in 1986 at the age of 26
as an instrument specialist for Galileo. Now 44, she is the last of
Galileo's
project managers -- NASA-ese for head honcho.

"Sometimes it's like an old car that's giving you everything it can give
you, and other times I think of it like your troubled kid that ended up
getting graduated from Harvard," Alexander said.

On Friday, as Galileo's end neared, mission team members expressed a broad
range of emotions.

Systems engineer Nagin Cox fought off tears. But Kathy Schimmels, 32, one of
the youngest Galileans, conveyed an exuberant sense of celebration of the
craft's long and storied life.

"I'm excited for the final hurrah," said Schimmels, who joined the team in
1996, fresh out of a master's program at the University of Colorado,
Boulder. "I'm going to miss working on it, but we've got to celebrate the
life it had."

Sunday's reunion of team members will include reminiscing about a mission
that at times seemed cursed, but in the end went beyond NASA's expectations
that it would be the first to explore the complex environment of the solar
system's biggest planet.

The mission was designed to head straight to Jupiter after being lofted from
a space shuttle flight in 1986. However, the Challenger shuttle disaster
earlythat year scuttled that plan.

The flight path was redesigned as a six-year odyssey with two flybys of
Earth and one of Venus in order to use the gravity of those planets as
slingshots toward the outer solar system.

Galileo launched in 1989 from aboard the shuttle Atlantis. But as it neared
Jupiter, disaster struck. The craft's high-gain antenna got stuck, likely
because of the years it spent in storage. The remaining antenna could only
transmit data home at the rate of 10 bits per second.

Faced with a crippled mission, engineers and scientists embarked on the
risky course of rewriting Galileo's software so it could run on faster
data-compression algorithms.

"Now it's standard practice to do post-launch updates of flight software,"
said engineer Cox, who is working on the upcoming Mars Exploration Rover
mission. "We take for granted something that Galileo pioneered."

With that near-death experience behind it, Galileo arrived at Jupiter and
began sending back images and data that made scientists' jaws drop. The show
began en route, as Galileo passed two asteroids and watched as comet
Shoemaker-Levy smashed into Jupiter.

Galileo carried a probe that dove into Jupiter itself, giving scientists a
better sense of the gas giant's weather patterns and upper atmosphere. The
craft staged flybys of big moons like Europa, Ganymede and Callisto, and
cast its eyes on the volcanoes of Io.

The mission was designed to last two years, but NASA extended it three
times.

The mission had a staff of 367 people when Galileo entered Jupiter's orbit
in 1995, Alexander said. That was cut back to about 60 in the late 1990s. It
had dwindled to half a dozen or so by November, when Galileo performed its
last major observation of the Jovian moonlet, Amalthea.

With its propellant expended and its scientific usefulness exhausted,
Galileo might have died a natural death, drifting around the system until
gravity pulled it into Jupiter or one of its moons.

But NASA decided to kill the craft before it had launched, Alexander said.
At that point, scientists believed Europa was clad in a planetary ocean that
could harbor life. Now, after its 14 years in deep space, they are carrying
out plans to destroy Galileo since it might be carrying microbes from Earth
that could contaminate those oceans.

Galileo's handlers do not need to program any sequences or push any buttons.
The craft was set on its fatal collision course last fall.

Engineer Bruce McLaughlin will arrive at the Jet Propulsion Laboratory on
Saturday afternoon to check on the craft. If everything appears all right,
he'll go home and come back early Sunday morning, when 11 or so others will
join him for the probe's final hours.

The probe is expected to break up at 11:57 a.m. PDT. Traveling at the speed
of light, its telemetry will arrive on Earth about 52 minutes later.

"Monday morning will be interesting," McLaughlin said. "We'll come into work
and there'll be nothing more to do on Galileo except put away
documentation that we no longer need."


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