| Getting to Jupiter would
be no easy matter, even in the best of conditions -- so
when we set our schedule, we aimed at having our Galileo
spacecraft ready in time to take advantage of a window
of opportunity in early 1982, when celestial conditions
would favor our mission. We were assigned a berth on the
25th Shuttle mission, scheduled for February of '82 --
the first time the Shuttle would be used for a planetary
The trouble was that the shuttle was still under development
when that schedule was set. As time went on, the Shuttle
had problems with its high-pressure turbines, thermal
protection tiles, engines, and more. The early launch
dates had to be scrapped. NASA Headquarters told us,
"We're going to delay your launch two years to allow
more time for the Shuttle development to take place.
You can slow your development accordingly."
Right off the bat, we looked into the celestial mechanics
and how they would affect us. The difficulty in launching
a spacecraft to Jupiter changes on a year-to-year basis,
in a cyclical pattern that repeats about every ten or
twelve years. In order to achieve the velocity needed
to get from low earth orbit to Jupiter, an upper stage
is required in the Shuttle. For the 1982 launch the
upper stage was adequate, but it could not provide the
velocity we would need in 1984. This meant we would
have to separate the Galileo probe from the Galileo
orbiter before launch and put each of them on separate
Shuttles with separate upper stages.
When we told the folks at Headquarters this, they
told us, "Okay we'll give you two Shuttle launches."
We adjust our plans
Separating the probe from the orbiter wasn't the real
challenge. We needed to do that as the spacecraft approached
Jupiter, anyway. What we needed was a probe carrier,
a spacecraft to service the probe on the way to Jupiter.
This required an entirely new development. We could
do that, if necessary, but I worried that we couldn't
get the design completed in time and within our budget.
When I told them this at Headquarters, they said,
"Well, maybe you ought to cancel this mission." I told
them that we would find a way.
We got every one lined up and working on the new development
for more than a year -- when someone said, "If the Centaur
[an upper stage used on the Titan] could be adapted
for use on the Shuttle, then we could put these two
spacecraft back together." The Centaur upper stage uses
liquid hydrogen and liquid oxygen, which is much more
powerful than the Inertial Upper Stage (IUS) that we
were going to use. So, we started working that idea
through. Some people didn't think it would work, some
thought it would take too long, and we all worried about
the cost of the thing -- but we kept
working the problem as we explored all our options.
Finally, in early 1986 we were set to launch a large liquid
oxygen/liquid hydrogen upper stage in a rocket inside
the Shuttle with our spacecraft on top of it. We put everything
together, and brought our spacecraft to Kennedy Space
Center for the launch. Then came the Challenger accident.
The Shuttle was grounded. On top of that, upper management
came back to us and said that we had to be more conservative
when we got back to flight. "We've decided that the Centaur
upper stage is too risky; you can't use it. You can use
the IUS," they told me. But it was the same story as in
1984:The old one wouldn't get us there unless we split
Galileo apart. By this time we already had the spacecraft
built -- so splitting it apart was out of the
question. Those were the darkest days for me on this project,
but I never gave up hope.
the darkest days for me on this project, but I never
gave up hope.
Selling the project
I knew my team would eventually find a way to get Galileo
launched, and I knew what the spacecraft could deliver
-- but it wasn't an easy sell. When I went in front
of senior NASA management, I made an opportunity cost
argument to them. I pointed out that for the increment
of funding we still needed, they could, in essence,
buy an entire mission. The sunk cost didn't count because
they couldn't recover that -- it was water under the
bridge. So, what was the opportunity cost of that additional
increment that we would need to finish? Could they buy
something of more value for that same amount of money?
We were in the middle of the Cold War then, so I also
used the argument that what we were doing would make a
powerful statement to the Soviets. "We're going to go
to Jupiter, 500 million miles away, and we can deliver
the spacecraft with an accuracy of plus or minus fifteen
miles. That speaks volumes of our capabilities." I also
told them that we would get data back at higher rates
than previously thought possible. In all, we could demonstrate
an enormous engineering capability to the rest of the
world in a non-threatening way. For if we could send something
like this to Jupiter, think of what we could do on Earth.
spacecraft Galileo for flight.
I described how compelling the mission was in terms
of the science return we could expect. I reminded them
that we knew without a doubt that that our target was
rich because Voyager had told us that. We knew
that we had the capability to go into orbit around Jupiter
and stay there for several years and do multiple flybys,
close flybys -- the equivalent of ten or more Voyager
missions. There was the opportunity cost again, you
see? You could do with this one spacecraft what it would
have taken ten, or even twenty Voyagers. I spoke
to people on Capitol Hill to relay this message. The
project manager doesn't do that anymore; Headquarters
does. But even at the time, I got to do things not usually
done because a lot of people had written our project
off. The people on the Hill listened. In the end, they
supported us and gave us the money to keep going.
And we regroup
Galileo was built; we just needed to find a way
to get it to Jupiter. I engaged everyone in the project
to think this thing through. I asked them, "What are
other ways to approach this launch?"
First, we looked at using a Russian launch vehicle that
might be capable of launching our spacecraft. Though relationships
with Russia still weren't all that great at that point,
we talked to them and found out what it would take. They
were willing to discuss the idea further with us, but
we decided it was too marginal. We took a look at doing
enhancements to other launch vehicles, but saw that wouldn't
"You haven't found a solution." All I said was,
"Well, we haven't concluded that there isn't a solution."
People tried to tell me again that this mission was
never going to happen. I never accepted that. I just
kept my team going. People said to me, "Okay that's
it." I just shook my head. They said, "How do you know
that's not it? You haven't found a solution." All I
told them was, "Well, we haven't concluded that there
isn't a solution."
In order to design our original mission we had developed
the mathematics and trajectory design tools to do multiple
flybys of Jupiter's moons. So when we found ourselves
without a launch vehicle, we decided to put that technology
to use and see if we could apply it to solving the problem
of getting to Jupiter. My people sketched out all sorts
of approaches to the problem. Nothing was working.
Still, I kept them focused on the excitement of the
science we hoped to return, and kept them working on
the problem. My message to them was, "This is a good
mission. Keep your eye on the ball. Don't look down.
Look up. Together, we'll find a way out of this." I
had to keep doing that not only with our people here,
but with Congress and with the people at Headquarters.
Then -- I'll never forget the day -- I was sitting
in my office one morning when an engineer walked into
my office. He said, "You probably won't go for this,
but I think I found a way to get to Jupiter."
He went up to the white board and sketched out a trajectory.
He said, "Here is what we can do. Instead of going out
this way to Jupiter, we'll start off going to Venus. We'll
do a gravity assist at Venus to add a bit of velocity.
We'll come back to the Earth and pick up more velocity.
We'll go out past the asteroids and then we'll come back
to the Earth a second time and then back to the asteroid
belt. It will take four years, but we'll be ready to go
Io and Callisto.
I looked at this guy for a moment, thinking about
the implications. Before I could say anything he said,
"Well, I didn't think you would like it."
"Are you kidding?" I asked. "I love it. Let's do it."
He said he was worried about the changes we would need
to make the spacecraft capable of handling the increased
thermal environment near Venus and of handling the new
telecommunication geometry that would be required. "We'll
take care of that part," I said.
"You just go figure out this trajectory." He and a
couple other guys went off and did a more complete analysis
We would add about four years to the flight with the
time spent around Venus and the two passes by Earth.
Instead of getting to Jupiter in the two years and nine
months we had planned on, it would take about six years.We
had used trajectories before to gain velocity on space
missions, but we had never attempted a "triple" like
this one. It would mean trading trip time for launch
energy, and that had clear disadvantages. But it looked
as though we would only have to make moderate adjustments
to our spacecraft design.
That was good enough for me. We would use the trajectory
to get to Jupiter.
A new phase
I had been on the project for ten years, three months,
and two days, when my boss was promoted and they offered
me his job overseeing all the flight projects at the
Jet Propulsion Laboratory. It was hard to leave the
project at that point, but I did get to stay involved
and see it launched in 1989 -- even though I was no
longer the project manager.
I watched with pride as our mission flew the trajectory,
delivering valuable science data for Venus, the Earth
and moon, and the asteroid belt. Finally, Galileo
headed for its rendezvous with Jupiter and its moons
-- and arrived in December 1995. Its eight years and
35 orbits around Jupiter turned out to be everything
we hoped it would be. Tenacity certainly has its rewards.
We put Galileo to sleep last year. A lot of people
were sorry to see it go. You know, I didn't think of
it that way. It was out of fuel, and there was nothing
much more we could do with it. It was going to die one
way or another. We decided to send it on a collision
course with Jupiter, sending us back data from the planet's
magnetic field as it went. We threw a farewell party
on Galileo's last day and we celebrated its success.
Galileo gave us more science than we could
have hoped for. T.S. Eliot once speculated that the
world would end "not with a bang but a whimper." Well,
we decided that Galileo deserved to go out with
- A project team takes its lead from the project manager.
When managers make clear their own commitment to and
belief in their projects, they empower their teams
to overcome problems that crop up.
- An important part of any project manager's job is
to "sell" a project -- not just to get the project
off the ground but to keep the project alive when
surmountable obstacles arise. That "selling" may require
creative thinking to frame the project in a way that
makes its value more apparent to project sponsors.
Under what circumstances might a project manager decide
that a project should no longer be "sold"?
Search by lesson to find more on:
called the Jupiter Orbiter Probe, the Galileo
mission described in this story found evidence that
Jupiter's icy moons (Europa, Ganymede, and Callisto)
appear to have the necessary ingredients for life:
water, energy and the right chemical content.
So, who better to kick off a return mission
to study the moons than Galileo project manager
John Casani. Currently, Casani heads up
work to develop the Jupiter Icy Moons Orbiter
(JIMO) project, an ambitious proposed mission
that would return an orbiter to the Jovian system
some eight years after launch in 2011 or later.
Casani began working at the Jet Propulsion Laboratory
in 1956. In the 1960s he was spacecraft design
leader and system manager for the Mariner
spacecraft that flew to Venus, Mars, and Mercury.
He went on to serve as project manager on the
Voyager, Galileo, and Cassini
missions, and as JPL's first Chief Engineer, among
other positions. Honors for his work include NASA's
Distinguished Service, Outstanding Leadership,
and Exceptional Achievement medals.
Following his 1999 retirement, Casani served
on several JPL review and advisory boards, including
heading up the Mars Polar Lander failure investigation
board. But retirement didn't stick. Casani returned
to the JPL project management ranks in 2000.