Galileo Missions to Juptier
Craig Lieneck
Galileo Spacecraft
One of the most complex
robotic spacecraft ever
flown.
Consists of two
spacecrafts:
– Orbiter:
On-orbit mass: 2380 Kg
Power System: Radioisotope
Thermal Generators (RTGs)
– Atmospheric Probe:
On-orbit mass: 335 Kg
Power System: Storage
batteries of 580 W
Mission Goals - Probe
Determine the chemical composition of the
Jovian atmosphere.
Characterize the structure of the atmosphere to
a depth of at least 10 bars.
Investigate the nature of cloud particles and the
location and structure of cloud layers.
Examine the Jovian radiative heat balance.
Study the nature of Jovian lightning activity.
Measure the flux of energetic charged particles
down to the top of the atmosphere.
Mission Goals - Orbiter
Investigate the circulation and dynamics of the Jovian
atmosphere.
Study the interaction of the Jovian magnetosphere with
the Galilean satellites.
Characterize the morphology, geology, and physical
state of the Galilean satellites.
Investigate the composition and distribution of surface
minerals on the Galilean satellites.
Determine the gravitational and magnetic fields and
dynamic properties of the Galilean satellites.
Study the atmospheres, ionospheres, and extended
gas clouds of the Galilean satellites.
Initial Setbacks
Initial Launch Plan:
– May 1986.
– Carried on Space Shuttle to low-orbit.
– Centaur Rockets to Jupiter.
Problems:
– Challenger Disaster occurred in January, 1986.
– Centaur Rockets forbidden on Space Shuttle.
The Solution
VEEGA – “Venus-Earth-Earth-Gravity-Assist”
– Galileo to use the gravity of Venus and Earth to boost
to Jupiter.
– Brought spacecraft closer than expected to sun.
– Kept spacecraft in space longer than expected.
Liftoff
Launched aboard Atlantis Space Shuttle on
October 18, 1989.
Tracking Galileo
Used Deep Space Network
Series of large antennas equally around Earth.
Venus
February 19, 1990
Galileo flies within
12,000km of Venus.
Images gave new
information about
structure and
dynamics of
atmosphere.
Earth Flyby 1
December 8, 1990
Flew 960km over
Western Atlantic
Ocean.
1000 pictures for an
Earth-Rotation movie.
Asteroid Belt - 1st Time
October 29, 1991
Encountered Asteroid 951 Gaspra
Photographed 60% of surface from 5000km.
Galileo came within 1600km.
Earth Flyby 2
December 8, 1992
Came within 305km.
Scientists calibrated
instruments one last
time.
Asteroid Belt – 2nd Time
Encountered Asteroid
Ida August 28, 2993
Twice the size of
Gaspra.
Surprise - Found
small moon orbiting
Ida (Dactyl).
Shoemaker/Levy-9
Galileo observes
impact of S/L-9 into
Jupiter in 7/94
23 fragments splash
into Juptier.
Galileo was 240
million km away.
Final Mission - Jupiter
7/13/95 –
7/27/95 –
10/9/95 –
10/11/95 –
12/7/95 –
Atmospheric Probe released
from spacecraft.
Orbiter Deflection Manuver
(ODM)
Initial descent.
Tape recorder troubles.
Probe reaches Jupiter’s
atmosphere.
Final Mission - Probe
Entered atmosphere at
160,000mph.
Deployed parachute and
released heat sheild.
58 minute descent through 95
miles of Jovian atmosphere.
Atmosphere drier than earlier
predictions. Clouds and
lightning observed in distance.
Probe vaporized after
encountering 450mph winds.
Final Mission - Orbiter
Originally planned 11 orbits.
First 11 orbits designed for
close-up pictures of moons.
At same time, measurements
made of Jupiter's
magnetosphere.
Final Misson - Extended
Mission extended for GEM – Galileo Europa Mission.
– Observed fire, ice, and water on the moon Europa.
– Supported theory of underground ocean on Europa.
– Made way through Jupiter’s radiation to observe Lava fountain on Io.
Missions would be extended two more times for further research.
Io
Europa
Ganymede
Callisto
Conclusion
9/21/03 - Galileo guided into Jupiter’s dense
atmosphere, destroying the spacecraft. Done
to avoid any impact with Galilean Satellites.
Last signal: 12:43:14 PDT.
Total Distance Traveled:
4,631,778,000km = about 2.8 billion miles
Major Accomplishments:
–
–
–
–
First mission for long-term observation of Jovian system.
Evidence of liquid layers of saltwater on Europa.
Ganymede and Castillo volcanic activity.
First observation of asteroid with moon.
References
http://www.jpl.nasa.gov/galileo/tour/tourtoc.html
http://www.jpl.nasa.gov/galileo/index.html