Galileo To Taste Jupiter Before Taking Final Plunge

Donald Savage
Headquarters, Washington September 17, 2003
(Phone: 202/358-1547)

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

RELEASE: 03-297

GALILEO TO TASTE JUPITER BEFORE TAKING FINAL PLUNGE

In the end, the Galileo spacecraft will get a taste of
Jupiter before taking a final plunge into the planet's
crushing atmosphere, ending the mission on Sunday, Sept. 21.
The team expects the spacecraft to transmit a few hours of
science data in real time leading up to impact.

The spacecraft has been purposely put on a collision course
with Jupiter 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. The
long-planned impact is necessary now that the onboard
propellant is nearly depleted.

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.

"It has been a fabulous mission for planetary science, and it
is hard to see it come to an end," said Dr. Claudia
Alexander, Galileo project manager at NASA's Jet Propulsion
Laboratory, Pasadena, Calif. "After traversing almost 3
billion miles and being our watchful eyes and ears around
Jupiter, we're keeping our fingers crossed that, even in its
final hour, Galileo will still give us new information about
Jupiter's environment."

Although scientists are hopeful to get every bit of data back
for analysis, the likelihood of getting anything is unknown
because the spacecraft has already endured more than four
times the cumulative dose of harmful jovian radiation it was
designed to withstand. The spacecraft will enter an
especially high-radiation region again as it approaches
Jupiter.

Launched in the cargo bay of Space Shuttle Atlantis in 1989,
the mission has produced a string of discoveries while
circling the solar system's largest planet, Jupiter, 34
times. Galileo was the first mission to measure Jupiter's
atmosphere directly with a descent probe and the first to
conduct long-term observations of the jovian system from
orbit.

It found evidence of subsurface liquid layers of salt water
on Europa, Ganymede and Callisto and it examined a diversity
of volcanic activity on Io. Galileo is the first spacecraft
to fly by an asteroid and the first to discover a moon of an
asteroid.

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.

From launch to impact, the spacecraft has traveled
4,631,778,000 kilometers (about 2.8 billion miles).

Its entry point into the giant planet's atmosphere is about
1/4 degree south of Jupiter's equator. If there were
observers floating along at the cloud tops, they would see
Galileo streaming in from a point about 22 degrees above the
local horizon. Streaming in could also be described as
screaming in, as the speed of the craft relative to those
observers would be 48.2 kilometers per second (nearly 108,000
miles per hour). That is the equivalent of traveling from Los
Angeles to New York City in 82 seconds. In comparison, the
Galileo atmospheric probe, aerodynamically designed to slow
down when entering, and parachute gently through the clouds,
first reached the atmosphere at a slightly more modest 47.6
kilometers per second (106,500 miles per hour).

"This is a very exciting time for us as we draw to a close on
this historic mission and look back at its science
discoveries. Galileo taught us so much about Jupiter but
there is still much to be learned, and for that we look with
promise to future missions," said Dr. Charles Elachi,
director of JPL.

JPL, a division of the California Institute of Technology in
Pasadena, manages the Galileo mission for NASA's Office of
Space Science, Washington.

Additional information about the Galileo mission and its
discoveries is available online at:
http://galileo.jpl.nasa.gov

For information about NASA TV on the Internet, visit:
http://www.nasa.gov/multimedia/nasatv/index.html

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

-end-

Ron Baalke wrote:
....
RELEASE: 03-297

GALILEO TO TASTE JUPITER BEFORE TAKING FINAL PLUNGE

In the end, the Galileo spacecraft will get a taste of
Jupiter before taking a final plunge into the planet's
crushing atmosphere, ending the mission on Sunday, Sept. 21.
....
The spacecraft has been purposely put on a collision course
with Jupiter 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.

At some heights in the Jupiter atmosphere the physical
conditions might be suitable to sustain life.
Since temperature increases inward, at some level it must
traverse the 0-100 C interval in layers where water and organic
molecules must be present, and well shielded from cosmic rays.

Apparently NASA seems to be sure enough that either no life
can exist within Jupiter, or that Galileo will be completely
sterilized before entering such "comfortable" atmospheric layers.

Dan

"DP" wrote in message
...
Ron Baalke wrote:
...
RELEASE: 03-297

GALILEO TO TASTE JUPITER BEFORE TAKING FINAL PLUNGE

In the end, the Galileo spacecraft will get a taste of
Jupiter before taking a final plunge into the planet's
crushing atmosphere, ending the mission on Sunday, Sept. 21.
...
The spacecraft has been purposely put on a collision course
with Jupiter 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.

At some heights in the Jupiter atmosphere the physical
conditions might be suitable to sustain life.
Since temperature increases inward, at some level it must
traverse the 0-100 C interval in layers where water and organic
molecules must be present, and well shielded from cosmic rays.

Apparently NASA seems to be sure enough that either no life
can exist within Jupiter, or that Galileo will be completely
sterilized before entering such "comfortable" atmospheric layers.

The Galileo spacecraft will be entering Jupiter's atmosphere
at about 105,000 mph. It would pass through any "comfortable"
atmospheric layers in a few seconds at most.
The heat of the entry is expected to vaporize it entirely.

In article , DP wrote:
Apparently NASA seems to be sure enough that either no life
can exist within Jupiter, or that Galileo will be completely
sterilized before entering such "comfortable" atmospheric layers.

That issue goes back farther: the Galileo atmosphere probe was not
sterilized.
--
MOST launched 1015 EDT 30 June, separated 1046, | Henry Spencer
first ground-station pass 1651, all nominal! |

DP wrote in message ...

Apparently NASA seems to be sure enough that either no life
can exist within Jupiter, or that Galileo will be completely
sterilized before entering such "comfortable" atmospheric layers.

Well, yeah. Re-entry at Jovian orbital velocities? Even if it
reached the comfortable atmospheric layers, Galileo would be
in a state (generally referred to as "a frickin' hot fireball")
that would not be conducive to transferring terrestrial bacteria
to a hydrogen-helium Jovian environment.

Mike Miller, Materials Engineer

DP writes:

Ron Baalke wrote:
...
RELEASE: 03-297
GALILEO TO TASTE JUPITER BEFORE TAKING FINAL PLUNGE
In the end, the Galileo spacecraft will get a taste of Jupiter
before taking a final plunge into the planet's crushing atmosphere,
ending the mission on Sunday, Sept. 21.
...
The spacecraft has been purposely put on a collision course with Jupiter
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.

At some heights in the Jupiter atmosphere the physical
conditions might be suitable to sustain life.
Since temperature increases inward, at some level it must
traverse the 0-100 C interval in layers where water and organic
molecules must be present, and well shielded from cosmic rays.

Apparently NASA seems to be sure enough that either no life
can exist within Jupiter, or that Galileo will be completely
sterilized before entering such "comfortable" atmospheric layers.

1.) Galileo's impact velocity will be so high it will wiff to plasma.
It is highly unlikely anything living would survive the process ---
or even the very molecules it was formerly made of.

2.) Jupiter's environment is most likely too alien for anything that
evolved on Earth to survive there --- even in the "water zone."

3.) Jupiter has almost certainly already been hit by terrestrial material
ejected by asteroid impacts, just as Earth has been hit by Mars rocks;
hence, if terrestrial microorganisms _can_ survive on Jupiter, they are
probably already there.

Note that all of the above are likewise true of an impact on Europa,
so this whole self-immolation maneuver is almost certainly pointless ---
it is basically just a misguided PR exercise to demonstrate JPL's
"environmental responsibility" to people who are still going to hate
and oppose them as a knee-jerk reflex response, no matter _what_ JPL does.


-- Gordon D. Pusch

perl -e '$_ = \n"; s/NO\.//; s/SPAM\.//; print;'

"Gordon D. Pusch" wrote in message
...
DP writes:
Note that all of the above are likewise true of an impact on Europa,
so this whole self-immolation maneuver is almost certainly pointless ---
it is basically just a misguided PR exercise to demonstrate JPL's
"environmental responsibility" to people who are still going to hate
and oppose them as a knee-jerk reflex response, no matter _what_ JPL does.

Partly.

I think it's partly that if we DO find life on Europa, especially "Earth
like" we can at least rule out Galileo.

Which means it was either indigenous or it's at least been there for awhile.




-- Gordon D. Pusch

perl -e '$_ = \n"; s/NO\.//; s/SPAM\.//; print;'

In article ,
Gordon D. Pusch wrote:
1.) Galileo's impact velocity will be so high it will wiff to plasma.
2.) Jupiter's environment is most likely too alien for anything that
evolved on Earth to survive there --- even in the "water zone."
3.) Jupiter has almost certainly already been hit by terrestrial material
ejected by asteroid impacts...

Possibly not since life evolved, though; it takes a really huge impact to
get stuff off Earth. The other two points I generally agree with.

Note that all of the above are likewise true of an impact on Europa,

No, the lack of an atmosphere changes the picture. The impact energy is
not necessarily uniformly distributed; fragments could survive.

so this whole self-immolation maneuver is almost certainly pointless ---
it is basically just a misguided PR exercise to demonstrate JPL's
"environmental responsibility" to people who are still going to hate
and oppose them...

If memory serves, the recommendation for disposal of Galileo by Jupiter
impact came from a science advisory panel, not from JPL.
--
MOST launched 1015 EDT 30 June, separated 1046, | Henry Spencer
first ground-station pass 1651, all nominal! |

Henry Spencer wrote:
In article ,
Gordon D. Pusch wrote:

1.) Galileo's impact velocity will be so high it will wiff to plasma.
2.) Jupiter's environment is most likely too alien for anything that
evolved on Earth to survive there --- even in the "water zone."
3.) Jupiter has almost certainly already been hit by terrestrial material
ejected by asteroid impacts...


Possibly not since life evolved, though; it takes a really huge impact to
get stuff off Earth. The other two points I generally agree with.

The Chicxulub meteor wasn't big enough?

Hop
http://clowder.net/hop/index.html

Gordon D. Pusch wrote:

1.) Galileo's impact velocity will be so high it will wiff to plasma.
It is highly unlikely anything living would survive the process ---
or even the very molecules it was formerly made of.

Bacteria resist to incredible high accelerations (some were tested to
survive 1e5G) and pressure, such that shocked rocks accelerated to
escape velocities due to big meteorite impacts can be considered
as bacteria transporters to other planets.

Of course sufficiently high temperatures decompose any
material. But it is far from obvious that a complex structure
such as Galileo must be fully raised to high temperature.
After all meteorites do reach the ground keeping cold core although
entering the atmosphere with similar speeds as Galileo. Some
components of Galileo (presumably the one with plutonium) must be
built to resist terrestrial atmosphere re-entry.

2.) Jupiter's environment is most likely too alien for anything that
evolved on Earth to survive there --- even in the "water zone."

It would be safer here to say that today we don't know the limits of
adaptability of life. Already on Earth different life forms proved
to survive well in exotic conditions not expected by life experts.

3.) Jupiter has almost certainly already been hit by terrestrial material
ejected by asteroid impacts, just as Earth has been hit by Mars rocks;
hence, if terrestrial microorganisms _can_ survive on Jupiter, they are
probably already there.

This is the good scientific argument to use, but of course then the
whole dramatic crash justification appears as a lie to the public.

Note that all of the above are likewise true of an impact on Europa,
so this whole self-immolation maneuver is almost certainly pointless ---
it is basically just a misguided PR exercise to demonstrate JPL's
"environmental responsibility" to people who are still going to hate
and oppose them as a knee-jerk reflex response, no matter _what_ JPL does.