Galileo Spacecraft

1
Galileo Spacecraft

• Named for Galileo Galilei, the mission was to
  study Jupiter and its moons.

2
The Spacecraft

• Divided into 2 sections.
• One section rotates at 3 rpm
• Keeps the spacecraft stable.
• Allows the instruments in this section to acquire
  data from many different directions.
• The other section stays steady
• Has instruments that need to be aimed
  continuously at a target.

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The Spacecraft Being Prepared (08-03-1989)
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Specs.

• Controlled by a RCA 1802 Cosmac microprocessor
  CPU
• Propulsion system included a 400N main engine as
  well at 12 10N thrusters.
• 925kg of monomethyl hydrazine and nitrogen
  tetroxide fuel.
• Power
• RTGs (Radioisotope Thermoelectric Generators)
• Decay of plutonium-238 which has a half-life of
  87.8 years.

5
Onboard Instruments (Despun)

• Solid State Imager (SSI)
• 800 by 800 pixel solid state camera
• Array of silicon sensors (CCD)
• Spectral range from 0.4 to 1.1 micrometers
• Near Infrared Mapping Spectrometer (NIMS)
• Spectral range from 0.7 to 5.2 micrometers
• Ultraviolet Spectrometer/ Extreme Ultraviolet
  Spectrometer (UVS/EUV)
• Photopolarimeter-Radiometer (PPR)
• Spectral ranges from 17 to 110 micrometers

6
Onboard Instruments (Spun)

• Dust Detector Subsystem (DDS)
• Measures mass, electric charge, and velocity of
  incoming particles
• Energetic Particles Detector (EPD)
• Measures numbers and energies of ion and
  electrons
• Can also measure direction of travel and in some
  instances composition
• Heavy Ion Counter (HIC)
• Detects heavy ions using stacks of silicon wafers
• Measured energy waves include all atomic
  substances between carbon and nickle
• Magnetometer (MAG)
• Plasma Subsystem (PLS)
• Collects charged particles for energy and mass
  analysis
• Plasma Wave Subsystem (PWS)
• Electric dipole antenna used to study electric
  fields while 2 coil magnetic antennas study
  magnetic fields

7
The Entry Probe

• 339kg
• 1.3 meters across
• 2.5 meter parachute
• 2 L-band transmitters at 128 bits per sec
• Powered by a lithium sulfur dioxide (LiSO2)
  battery
• Atmospheric structure instrument group
• Neutral mass spectrometer
• Helium-abundance interferometer
• Nephelometer (cloud location)
• Net-flux radiometer
• Radio Emission instrument w/ energetic particle
  detector

8
The Journey
9
Launch

• Significantly delayed after the Challenger
  disaster
• Launch Date 10-18-1989
• Weight 2,223 kg
• Height 5.3 meters
• Payload of the Space Shuttle Atlantis

10
Travel

• VEEGA
• Venus-Earth-Earth Gravity Assist
• Venus Flyby 02-10-1990
• 16,000 km
• Earth Flyby 1 10-08-1990
• 960 km
• Earth Flyby 2 12-08-1992
• 305 km
• Jupiter Arrival December 1995

Venus Flyby
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Travel Discoveries

• First Earth Flyby
• Remote Detection of Life
• Sagan criteria for life
• Strong absorption at the red end of spectrum
• Absorption bands of molecular oxygen
• Infrared absorption (due to methane)
• Modulated narrowband radio wave transmissions
  uncharacteristic of any known natural source

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Travel Discoveries

• Second Earth Flyby
• Galileo Optical Experiment (GOPEX)
• Optical communication through lasers
• Used two separate lasers to send pulses to the
  spacecraft

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Travel Discoveries
Gaspra

• Asteroid Encounters
• 951 Gaspra
• October 29, 1991
• 243 Ida
• Discovery of asteroid moon Dactyl

Ida and Dactyl
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Travel Discoveries(Front Row Seat for
Shoemaker-Levy 9 Impact)
July 22, 1994
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Jupiter

• The Entry Probe
• Probe released July 13, 1995
• Entry Date 12-07-1995
• Entered the atmosphere at 106,000 mph
• Descended 124 miles (200km)
• 58 minutes of data

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Jupiter
Callisto

• 2 Year study
• Elongated Orbits
• Flybys of largest moons
• Extended Study
• Starting December7, 1995
• Close flybys of Europa and Io

Io
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Spacecraft Malfunctions

• Main Antenna Failure
• Attributed to evaporated lubricants
• Tape Recorder Troubles
• Stuck in re-wind for 15 hours
• Jupiters Radiation causes instruments to go into
  safe mode
• Near Failure of Probe Parachute
• Faulty wiring

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End Of Mission

• 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 1157 a.m.
  (PDT). The Deep Space Network tracking station in
  Goldstone, Calif., received the last signal at
  124314 (PDT). The delay is due to the time it
  takes the signal to travel to Earth.
• 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.

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Any Questions?

• NASA Galileo Legacy Site
• http//galileo.jpl.nasa.gov/
• Galileo spacecraft From Wikipedia
• http//en.wikipedia.org/wiki/Galileo_spacecraft