Galileo End of Mission Status

Carolina Martinez (818) 354-9382
Jet Propulsion Laboratory, Pasadena, Calif.

News Release: 2003-129
September 21, 2003

Galileo End of Mission Status

The Galileo spacecraft's 14-year odyssey came to an end on Sunday,
Sept. 21, when the spacecraft passed into Jupiter's shadow then
disintegrated in the planet's dense atmosphere at 11:57 a.m. Pacific
Daylight Time. The Deep Space Network tracking station in Goldstone,
Calif., received the last signal at 12:43:14 PDT. The delay is due to
the time it takes for the signal to travel to Earth.

Hundreds of former Galileo project members and their families were
present at NASA's Jet Propulsion Laboratory in Pasadena, Calif., for a
celebration to bid the spacecraft goodbye.

"We learned mind-boggling things. This mission was worth its weight
in gold," said Dr. Claudia Alexander, Galileo project manager.

Having traveled approximately 4.6 billion kilometers (about 2.8
billion miles), the hardy spacecraft endured more than four times the
cumulative dose of harmful jovian radiation it was designed to
withstand. During a previous flyby of the moon Amalthea in November
2002, flashes of light were seen by the star scanner that indicated
the presence of rocky debris circling Jupiter in the vicinity of the
small moon. Another measurement of this area was taken today during
Galileo's final pass. Further analysis may help confirm or constrain
the existence of a ring at Amalthea's orbit.

"We haven't lost a spacecraft, we've gained a steppingstone into the
future of space exploration," said Dr. Torrance Johnson, Galileo
project scientist.

The spacecraft was purposely put on a collision course with Jupiter
because the onboard propellant was nearly depleted and to eliminate
any chance of an unwanted impact between the spacecraft and Jupiter's
moon Europa, which Galileo discovered is likely to have a subsurface
ocean. Without propellant, the spacecraft would not be able to point
its antenna toward Earth or adjust its trajectory, so controlling the
spacecraft would no longer be possible. The possibility of life
existing on Europa is so compelling and has raised so many unanswered
questions that it is prompting plans for future spacecraft to return
to the icy moon.

Galileo was launched from the cargo bay of Space Shuttle Atlantis in
1989. The exciting list of discoveries started even before Galileo
got a glimpse of Jupiter. As it crossed the asteroid belt in October
1991, Galileo snapped images of Gaspra, returning the first ever
close-up image of an asteroid. Less then a year later, the spacecraft
got up close to yet another asteroid, Ida, revealing it had its own
little "moon," Dactyl, the first known moon of an asteroid. In 1994
the spacecraft made the only direct observation of a comet impacting a
planet-- comet Shoemaker-Levy 9's collision with Jupiter.

The descent probe made the first in-place studies of the planet's
clouds and winds, and it furthered scientists' understanding of how
Jupiter evolved. The probe also made composition measurements designed
to assess the degree of evolution of Jupiter compared to the Sun.

Galileo made the first observation of ammonia clouds in another
planet's atmosphere. It also observed numerous large thunderstorms on
Jupiter many times larger than those on Earth, with lightning strikes
up to 1,000 times more powerful than on Earth. It was the first
spacecraft to dwell in a giant planet's magnetosphere long enough to
identify its global structure and to investigate the dynamics of
Jupiter's magnetic field. Galileo determined that Jupiter's ring
system is formed by dust kicked up as interplanetary meteoroids smash
into the planet's four small inner moons. Galileo data showed that
Jupiter's outermost ring is actually two rings, one embedded within
the other.

Galileo extensively investigated the geologic diversity of Jupiter's
four largest moons: Ganymede, Callisto, Io and Europa. Galileo found
that Io's extensive volcanic activity is 100 times greater than that
found on Earth. The moon Europa, Galileo unveiled, could be hiding a
salty ocean up to 100 kilometers (62 miles) deep underneath its frozen
surface containing about twice as much water as all the Earth's
oceans. Data also showed Ganymede and Callisto may have a
liquid-sal****er layer. The biggest discovery surrounding Ganymede
was the presence of a magnetic field. No other moon of any planet is
known to have one.

The prime mission ended six years ago, after two years of orbiting
Jupiter. NASA extended the mission three times to continue taking
advantage of Galileo's unique capabilities for accomplishing valuable
science. The mission was possible because it drew its power from two
long-lasting radioisotope thermoelectric generators provided by the
Department of Energy.

"The mission was a testimonial to the persistence of NASA even through
tremendous challenges. It was a phenomenal mission," said Sean
O'Keefe, NASA administrator.

JPL, a division of the California Institute of Technology in Pasadena,
manages the Galileo mission for NASA's Office of Space Science,
Washington, D.C. JPL designed and built the Galileo orbiter, and
operated the mission.

Additional information about the Galileo mission and its discoveries
is available online at:

http://www.jpl.nasa.gov/galileo-legacy and
http://galileo.jpl.nasa.gov .

For information about NASA, visit:
http://www.nasa.gov/ .

-end-

Ron Baalke wrote:

The spacecraft was purposely put on a collision course with Jupiter
because the onboard propellant was nearly depleted and to eliminate
any chance of an unwanted impact between the spacecraft and Jupiter's
moon Europa, which Galileo discovered is likely to have a subsurface
ocean. Without propellant, the spacecraft would not be able to point
its antenna toward Earth or adjust its trajectory, so controlling the
spacecraft would no longer be possible. The possibility of life
existing on Europa is so compelling and has raised so many unanswered
questions that it is prompting plans for future spacecraft to return
to the icy moon.

You know NASA keeps claiming that Galileo was responsible for the
subsurface ocean on Europa idea; this is not the case...the first time
that good images of Europa were received from the Voyager probes, its
relatively crater free surface was noticed and speculation started on it
having a subsurface ocean.

Pat

On Mon, 22 Sep 2003 00:40:37 -0500, Pat Flannery
wrote:

You know NASA keeps claiming that Galileo was responsible for the
subsurface ocean on Europa idea; this is not the case...the first time
that good images of Europa were received from the Voyager probes, its
relatively crater free surface was noticed and speculation started on it
having a subsurface ocean.

....And not to steal *either* of their thunder, but Galileo didn't 100%
*confirm* the existence of a subsurface ocean. The evidence it
gathered increased the probability to 1 closer than any other probe so
far, but until a probe is landed to penetrate and see what's under
there and/or an orbiter observes the surface breaking through to
deposit more of those pink lines, it's still going to be just a theory
that's more likely than not a very correct one.

Which is why an orbiter needs to be built and launched, say, by next
week, and a lander by the following week, and the first congressdork
who balks at the funding required should be shot in the middle of the
Rotunda as a lesson to the rest...


OM

--

"No ******* ever won a war by dying for | http://www.io.com/~o_m
his country. He won it by making the other | Sergeant-At-Arms
poor dumb ******* die for his country." | Human O-Ring Society

- General George S. Patton, Jr

In article , Ron Baalke wrote:

"We learned mind-boggling things. This mission was worth its weight
in gold," said Dr. Claudia Alexander, Galileo project manager.

Hmm... Galileo was 3,900kg or so; ~125,000 troy oz... forty-eight and a
quarter million dollars, unless my sums have lost a place or two. I
can't find a cost for Galileo offhand, but I think it certainly tops out
the gold standard comfortably ;-)

--
-Andrew Gray

"Andrew Gray" schrieb im Newsbeitrag . ..
In article , Ron Baalke wrote:

"We learned mind-boggling things. This mission was worth its weight
in gold," said Dr. Claudia Alexander, Galileo project manager.

Hmm... Galileo was 3,900kg or so; ~125,000 troy oz... forty-eight and a
quarter million dollars, unless my sums have lost a place or two. I
can't find a cost for Galileo offhand, but I think it certainly tops out
the gold standard comfortably ;-)
Not if jupiter was part of the mission...

Lots of Greetings!
Volker

In article ,
Pat Flannery wrote:
You know NASA keeps claiming that Galileo was responsible for the
subsurface ocean on Europa idea; this is not the case...the first time
that good images of Europa were received from the Voyager probes, its
relatively crater free surface was noticed and speculation started on it
having a subsurface ocean.

Believe it or not, speculation about a subsurface ocean in Europa started
*before* the Voyager images. If (dim) memory serves, the same guys who
predicted volcanic activity on Io had a paper in press at the time of the
Voyager encounter, suggesting that tidal heating might produce an internal
ocean in Europa.

I don't believe NASA has claimed that Galileo originated the idea (or at
least not often -- one has to allow for occasional overenthusiasm by
careless press-release writers). What Galileo has done is to produce a
pile of evidence supporting the idea.
--
MOST launched 1015 EDT 30 June, separated 1046, | Henry Spencer
first ground-station pass 1651, all nominal! |

Jonathan Silverlight wrote:


I hope the orbiter is built as soon as possible (with, just possibly,
the ability to do the Jupiter atmosphere work Galileo couldn't) but
they don't yet have a safe method of breaking into Lake Vostok, which
is a lot closer to home.

I figured out how to do this years ago; the lander carries a probe with
a fiber optic cable wrapped around a spool inside of it; on the nose of
the probe is mounted a radioisotope heat source. The probe is released,
and under it's own weight begins melting its way through the moon's ice
covering, laying out the fiber optic cable as it goes.. the water
refreezes above it, but it keeps moving constantly downwards until
hopefully it reaches the water layer. When this happens, it stops
lowering itself and deploys its sensors- powered either by a power cable
from the surface incorporated in the fiber optic cable, or by power
provided by its nose RTG. The probe then does its sensor scans, and
transmits the data up the fiber optic cable to the lander section- from
where it is transmitted to Earth.
After a set period the nose radioisotope is released from the probe; it
is designed to be lighter in weight than the water it displaces, so it
rises back up against the lower surface of the ice, and starts burrowing
itself upwards to remove the radiation danger from the water layer
(eventually it reaches the surface of the moon again- and remains there,
in an already highly radioactive environment, until its fuel decays)
meanwhile, down in the water layer, the probe- either drawing power down
from it's data cable- or operating on batteries- begins descending into
the ocean; relaying data at several stop points till it either runs out
of cable, or the water pressure destroys it. If there is sea life down
there it may well communicate via either sound or (more likely in my
opinion) electrical impulses; and a hydrophone, an electrical signal
receiver, as well as lights and a camera, would seem to be obvious
instruments on this probe.
In the best of all possible worlds, the rising radioisotope unit brings
up a water sample with it for more detailed study by the surface
lander...or automated return to Earth.

Pat

On Mon, 22 Sep 2003 16:22:15 +0000, Henry Spencer wrote:

I don't believe NASA has claimed that Galileo originated the idea

For all it's merits, I don't think that Galileo had enough on-board
intelligence to originate any ideas.

On the other hand, maybe it did, and the real reason they crashed it into
Jupiter was to avoid it getting a wild hare and coming back like V'ger in
Star Trek: The Motion Picture! G

On Mon, 22 Sep 2003 15:43:48 -0400, Rick DeNatale
wrote:

On Mon, 22 Sep 2003 16:22:15 +0000, Henry Spencer wrote:

I don't believe NASA has claimed that Galileo originated the idea

For all it's merits, I don't think that Galileo had enough on-board
intelligence to originate any ideas.

...."Shall. We. Play. A. Game?"

On the other hand, maybe it did, and the real reason they crashed it into
Jupiter was to avoid it getting a wild hare and coming back like V'ger in
Star Trek: The Motion Picture! G

"Gallo is that which seeks the Creator."

"Fascinating. Captain, why would a brand of Earth wine be looking for
its creator?"

....or:

"G'ili is that which seeks the Creator."

"I see. Where is Weird and the rest of the Spiders from Mars, then?"


OM

--

"No ******* ever won a war by dying for | http://www.io.com/~o_m
his country. He won it by making the other | Sergeant-At-Arms
poor dumb ******* die for his country." | Human O-Ring Society

- General George S. Patton, Jr

OM wrote:

...Not only that, but have you ever frozen a fiber optic cable? Even
the non-glass nowhere-near-optical-grade cheapo plastic fiber cables
get really ****ing brittle when you get below 10 degrees F. The heat
on the RHS won't conduct deep enough to keep the fiber warm and
flexible for the full length.

Considering that the cable's going to be frozen in ice around ten
minutes after its laid, it shouldn't need almost any flexibility at all-
it's going straight down through the ice; and I don't think the ice is
going to shift all that much in the few days it needs to reach the water
layer (if the front of the probe is almost red hot, it's going to
descend at well over one mile per hour. Hell, I've drilled through three
feet of ice with water at around 150 degrees F in under five minutes)

Pat