Just what do Jupiter's moons look like and how did they get that way?
Jeff Klemaszewski is a research specialist in planetary geology at Arizona
State University. He is trying to find answers to similar questions.
Klemaszewski was part of the Galileo mission that studied Jupiter and its
By analyzing images obtained by the Solid State Imaging (SSI) system on
board NASA's Galileo spacecraft, Klemaszewski studied the degradation
of impact craters on Jupiter's icy moon, Callisto.
On another moon called Europa, Klemaszewski delved into the formation and
evolution of this satellite's mottled terrain, one of this moon's
two major geologic units.
One of the major parts of studying images of these moons was actually positioning
the spacecraft to take necessary images. Klemaszewski was concerned with the
actual planning, playback and imaging of these moons.
"[I was] involved in the mission planning and helping to decide the overall
tour that [would] be taken on the mission," he says. Time and the amount of
images available were limited, so the missions needed to be pre-planned and
carefully executed. Klemaszewski had to decide where each target site would
A successful imaging mission can be stressful. "When a spacecraft is approaching
a moon, you have to be there to tell the spacecraft to take pictures at these
certain times," he says. "These times are intense and very competitive."
But all the planning and image coordination pays off in the research lab.
"I'm seeing places for the first time," he says. "It's an exciting
thing to do."
Nadine Barlow is a planetary scientist in Orlando, Florida. She specializes
in geology. She also spends much of her time researching the planets. Her
concerns lie on a planet that has captivated our imaginations for hundreds
of years. Barlow studies the geologic evolution of Mars.
By studying impact craters on Mars, Barlow can find answers to many questions.
"How old are the surfaces? How is the water distributed over the surface?"
Like Klemaszewski, Barlow enjoys making new discoveries. "Discovering something
new and utilizing new data is thrilling," she says. "I may not be the first
set of eyes to see something, but I can be the first person to figure out
and understand what's going on."
Why is it important to know what's going on on Mars? Could money be
better spent studying our own planet? Barlow says that figuring out the evolution
of Mars can help us better understand Earth.
"Mars used to be more Earth-like than it is now," she says. "Something
has happened since that time. I want to find out what happened and why it
happened." And ultimately, she wants to figure out how this might affect our
"Could something like this happen on Earth?" she asks.
Often, a planetary scientist's work will cross over between the Earth
and studying other space objects. Don Francis is an earth and planetary scientist.
He is interested in the Earth's upper mantle and the processes within
it which give rise to basaltic volcanism on Earth and other terrestrial planets.
Terrestrial planets refer to the planets closest to Earth: Venus, Mercury
"We're starting to look at a lot of planetary things that can affect
or give us an understanding of how things work on Earth, particularly in relation
to climate change," says Francis.
He also says that many more people study planetary science than actually
work in the field. "It's a great preparation to see earth science in
a planetary scale," he says.
Although the number of people working in planetary science is relatively
small, more opportunities will come in the future. "With things like the space
station going up, there will be more opportunities," says Francis. "This discipline
is in an embryonic phase and is embarking on changes."
He encourages anyone interested in the field to enter into undergraduate
earth and space sciences, whether they eventually end up working in the field
or not. For those that do eventually end up in the field, the rewards are
"When you're working at that level, the excitement is very high,"
says Klemaszewski. "This is a challenging and rewarding career."