|
BASED ON A
NASA/JPL PRESS
RELEASE
 October
8, 1999: NASA's Galileo spacecraft is gearing up for a daring
Oct. 11 rendezvous with Jupiter's moon Io
(pronounced EYE-oh), the most volcanic
body in our solar system.
Galileo will swoop down to within 380 miles (612 kilometers)
above Io's fiery surface at 1:06 a.m. EDT, snapping the closest-
ever pictures of this intriguing celestial body.
Right: A plume of gas and particles
is ejected some 100 kilometers (about 60 miles) above the surface
of Jupiters volcanic moon Io in this color image, recently taken
by NASAs Galileo spacecraft. The plume is erupting from near
the location of a plume first observed by the Voyager spacecraft
in 1979 and named Masubi. However, during the course of the Galileo
tour of Jupiter and its moons, a plume has appeared at different
locations within the Masubi region. more
information.
"Io is a natural laboratory for volcanoes," said Dr.
Duane Bindschadler, Galileo manager of science operations and
planning. "By studying Io close up, we'll learn more about
how and when volcanoes erupt and why they act the way they do.
This may even help us predict the behavior of volcanoes on Earth."
During the flyby, Galileo's science instruments will study the
chemistry, heat distribution, gravity and magnetic properties
of Io. For scientists, this thrilling encounter promises to yield
a bonanza of pictures and information, but for Galileo engineers,
the flyby presents a serious challenge with uncertain results.
Io's orbit lies in a region of intense radiation from Jupiter's
radiation belts, which could affect the performance of spacecraft
systems or even knock out various spacecraft instruments. A mere
fraction of the dose that Galileo will receive would be fatal
to a human.
"We expect that the spacecraft will survive the
flyby, although the radiation may cause its computers to reset
or may even cause irreversible damage to critical electronic
components," said Wayne Sible, Galileo deputy project manager.
"There is a possibility, if enough damage is done to the
electronics, it won't survive the flyby. Because of this possibility,
we planned the Io encounters for the end of the two-year extended
mission. After orbiting Jupiter for nearly four years, the spacecraft
has more than fulfilled its mission objectives, so it seems reasonable
to take a calculated risk for a much closer look at such a scientifically
rich target."
 Visit IoFlyBy.com
for coverage of Galileo's close encounters with Io, including
science news and the latest images of Jupiter's volcanic moon. |
Galileo was originally assigned to spend two years studying
Jupiter, its moons and its magnetic environment. When that original
mission ended in December 1997, it was followed by a two- year
extended mission, scheduled to end in January 2000. While spending
the past four years near Jupiter, Galileo has been exposed to
radiation on an ongoing basis, which has caused some of its instruments
to act up.
To prepare for any possible harm caused by radiation during the
Io flyby, engineers have designed sophisticated software to help
the spacecraft weed out a true crisis from a minor glitch caused
by radiation and respond appropriately.
| Parents
and Educators: Please visit Thursday's
Classroom for lesson plans and activities related to this
story. |
Galileo, the first spacecraft to orbit Jupiter, has revolutionized
our knowledge of Jupiter and its moons and has provided thousands
of colorful images. Data from Galileo support the premise of
a liquid ocean beneath the icy crust
of Jupiter's moon Europa, an intriguing prospect since water
is a vital ingredient for life. Thanks to information sent by
Galileo, scientists know much more about the weather on Jupiter
and the composition of its moons. En route to Jupiter, the spacecraft
took the first-ever close-up pictures of asteroids, when it photographed
Gaspra and Ida, and it returned historic images of the destruction
of comet Shoemaker-Levy 9 as its pieces slammed into Jupiter.
If all goes well with the upcoming Io flyby, the spacecraft will
make an even more daring approach of Io on Nov. 26 at an altitude
of only 186 miles (300 kilometers).
Above: This set of four images,
taken by NASA's Galileo spacecraft, shows a sequence of volcanic
activity on Jupiter's moon Io over the last two years. As seen
from left to right, the feature called Masubi was observed during
Galileos 9th, 10th, 15th, and 22nd orbits of Jupiter. These images
show that a plume deposit from Masubi appears in September 1997
and has disappeared eight months later, only to reappear in a
different place little more than a year later. The deposit, which
originated from a volcanic vent, contains snow rich in sulfur
dioxide. more
information.
New Io images taken by the spacecraft are available
at the following website: http://www.jpl.nasa.gov/pictures/io
Additional information and pictures taken by the Galileo spacecraft
are available at the redesigned Galileo website at this new Internet
address: http://galileo.jpl.nasa.gov
Galileo was launched from the Space Shuttle Atlantis on Oct.
18, 1989. It entered orbit around Jupiter on Dec. 7, 1995. The
Jet Propulsion Laboratory (JPL) manages the Galileo mission for
NASA's Office of Space Science, Washington, DC. JPL is operated
for NASA by the California Institute of Technology, Pasadena,
CA.
|
Join our growing list of subscribers
- sign up for our express
news delivery and you will receive a mail message every
time we post a new story!!!
Headlines
