Comet 67P Characteristics and Scientific Value

• Located 530 million miles from Sun
• Tiny lump of ice and rock journeying toward inner solar system
• Comets more precious than pure gold - actual time capsules
• Preserve chemistry/environment from solar system formation
• Hold clues to how chemistry arrived on Earth
• Some of most valuable scientific treasures

Comet Selection and Mission Planning

• Finding right comet for mission like "auditioning" them
• Requirements: orbit accessibility, size, activity level
• Need comet from outer solar system that heats up near Sun
• Comet 67P fits criteria perfectly
• Orbits Sun every 6.5 years
• Orbit extends only to Jupiter distance
• Provides multiple rendezvous opportunities

Rosetta Mission Launch and Challenges

• European Space Agency launched groundbreaking Rosetta probe
• First mission to study comet up close with cutting-edge technology
• Target only 2 miles wide (revealed by Hubble's blurry images)
• Moving target racing at 33,000+ mph through solar system
• Precision like "hole-in-one golf shot from New York to San Francisco"

Complex Trajectory and Slingshot Maneuver

• Couldn't achieve direct flight with current propulsion systems
• Required 10-year slingshot maneuver
• Takes energy from planets, slows them slightly
• Imparts energy into probe
• Flew past Jupiter nearly 100 million miles from Sun

Hibernation Period

• Entered most dangerous part: 31 months hibernation
• Solar panels insufficient for power at distance from Sun
• First hibernation of this duration attempted
• Constant worry about micro meteorites, system failures
• No communication during hibernation period

Reactivation and Approach

• January 20, 2014: wake-up after almost 10 years in space
• Tension palpable during reactivation
• Successfully reestablished communication
• Began sending back images of target
• Comet slowly came into focus from small dot

Comet 67P Shape Discovery

• Expected potato shape, found rubber duck shape
• Mountain floating in space of ice and rock
• Dramatic, beautiful images
• Strange shape created orbital problems
• Very small gravity field unlike planets
• Required triangular orbits and complicated maneuvers

Formation Theory Investigation

• Two competing theories for comet formation:
  • Erosion: started spherical, eroded in center
  • Collision: two separate objects combined
• Impact speeds normally 11,000+ mph (5x rifle bullet speed)
• Key evidence: distinct surface layers like onion layers
• Aligned layers = single entity erosion
• Misaligned layers = separate objects fusion

Formation Conclusion

• Layers prove 67P originally two separate objects
• Fused together in early solar system
• Both bodies formed in same area (similar composition)
• Light and fluffy - would destroy each other in fast collision
• Low-speed collision allowed sticking "like two wet snowballs"
• Teaches about early solar system processes

Water Origin Investigation

• Rosetta investigating chemical makeup of 67P
• Addresses major planetary science question
• Where did Earth's water originate?