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Near-Earth Objects Finding Them Before They Find Us. Don Yeomans NASA/JPL. 2. What are Near-Earth Objects?. Comet Hartley 2, Nov. 4, 2010. Comets (Weak and very black icy dirt balls) Weak collection of talcum-powder sized silicate dust - PowerPoint PPT Presentation
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Don Yeomans NASA/JPL
Near-Earth Objects
Finding Them Before They Find Us
Itokawa
What are Near-Earth Objects?
Comets (Weak and very black icy dirt balls)
•Weak collection of talcum-powder sized silicate dust
•About 30% ices (mostly water ice) just below surface dust. CO2 ices also present further below surface.
•Fairly recent resurfacing and few impact craters
Asteroids (run the gamut from wimpy ex-comet fluff balls to slabs of iron
•Most are shattered fragments of larger asteroids
•Rubble rock piles - like Itokawa
•Shattered (but coherent) rock - like Eros
•Solid rock
•Solid slabs of iron like Meteor crater object
Comet Hartley 2, Nov. 4, 2010
Itokawa
2
18001800
History of Known NEO Population
ArmaghObservatory
OutsideEarth’s Orbit
EarthCrossing
3
180018001900
History of Known NEO Population
ArmaghObservatory
OutsideEarth’s Orbit
EarthCrossing
4
1800180019001950
History of Known NEO Population
ArmaghObservatory
OutsideEarth’s Orbit
EarthCrossing
5
1800180019001950
History of Known NEO Population
ArmaghObservatory
1990
OutsideEarth’s Orbit
EarthCrossing
6
1800180019001950
History of Known NEO Population
ArmaghObservatory
19901999
OutsideEarth’s Orbit
EarthCrossing
7
1800180019001950
History of Known NEO Population
ArmaghObservatory
19901999
OutsideEarth’s Orbit
EarthCrossing
ScottManley
2012Known• 600,000 minor planets • 9450 NEOs• 1350 PHAs
The Inner Solar System in 2006
8
The Importance of Near-Earth Asteroids
• Science• Future Space Resources• Exploration• Planetary Defense
9
10
Human Accessible Targets11
JPL’s SENTY NEO Risk Pagehttp://neo.jpl.nasa.gov/risk/
12
NASA’s NEO Observation Program
LINEAR
13
NEO-WISE
Catalina Sky Survey Pan-STARRS
13
Radar Studies
14Shape, Size of 6489 Golevka
Study of Shape, Size, Motion and mass of near-Earth object 66391 (1999 KW4)
Goldstone, CA Arecibo, Puerto Rico
14
NASA’s NEO Program Office at JPL
Automatic orbit updates Are any of the NEOs a threat?Relational databaseStudy deflection strategies
Additional Information Impact warnings & outreach
http://www.jpl.nasa.gov/asteroidwatch/Widget available giving next 5 Earth close approachesNEO Program Office: http://neo.jpl.nasa.gov/
15
Recent NEO Program Office Activities
• Human Exploration Target Body Identification– Which NEAs are desirable RT mission targets?– When are they next observable (optical & radar)?
• Deflection mission study for asteroid 2011 AG5 IP = 1/500 for Feb. 5, 2040
• Educational site for designing asteroid deflection missions.
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2011 AG517
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Near-Earth Asteroid ApophisPredicted Close
Approach of Apophis(~270m Object)
on April 13, 2029
CLOSE-UP VIEW
Geosynchronous Orbit
20
Near-Earth Asteroid 2012 DA14 in Feb. 2013 21
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2012 DA14
Asteroid 2012 DA14February 15, 2013
23
Deep ImpactComet Tempel 1 on July 4, 2005
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Comet ISON25
Observing Comet ISON26
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