Asteroid Mitigation Strategy

By Emily Reit, Trevor Barton, Mark Fischer, Eric Swank, and Garrett Baerr

Impact History

• 65 mya- End of the Jurassic Period

• 3.3 mya- Impact in Argentina

• 50,000 ya- Barringer Crater in Arizona

• 1490 AD- 10,000 people die in Chiling-yang, China

• 1908 AD- Tunguska, Siberia

• 1937 AD- Asteroid Hermes narrowly misses Earth

Tunguska's Possible Relative Impact Size

Threats

1994 Comet Shoemaker-Levy 9 Incident

• Comet that broke apart and smashed into Jupiter

• SL9 fragments ranged in size from a few hundred metres to a couple of kilometres across

• Original comet's nucleus up to 5 km

“Shoemaker was a turning point. If it can happen in front of your nose— practically in your backyard-- it can also happen on Earth".

-Benny Peiser

-Liverpool’s John Moore’s University at the American Association for the Advancement of Science meeting in 2000

Recent Findings2008: NASA reports approximately 5,600 Near Earth Objects

967 are Potentially Hazardous Asteroids Objects 150 m or larger which come w/in 0.05 astronomical units (about 7.5 million km) of Earth

Search programs over the next 15 years will add to the NEO database 200,000 to 400,000 potential impactors

Current Committees

The United Nations Committee on the Peaceful Uses of Outer Space (COPUOS)

The Mission Planning and Operations Group (MPOG) NASA

ASE (Association of Space Explorers

Secure World Foundation

United Nations Platform for Space-based Information for Disaster Management and Emergency Response (UN-SPIDER)

Asteroid Threats: A Call For Global Response

• Submitted for consideration and subsequent action by the United Nations

• A report on the need to develop an international decision-making program for global response to Near Earth Object threats.

• Three Part Consideration:

• Information Gathering, Analysis, and Warnin

• Mission Planning and Operations

• Mission Authorization and Oversight Group

Things to Consider• Responsibility

• Consequences

• Timing

• Information Sharing

• Cooperation

Why?

• International Effect

• Capabilities

• Discovery

• The Sooner the Bettero Lead Time o Delays Limit Options

Detection Goals

• Near Earth Object (NEO) Survey Program (2005)o Detect, catalogue and characterize 90% of PHO's by

2020o Asteroids greater than 140 meters within .05 AU of

Earth

• National Research Council (2008)o Asked to find best strategy to complete this goalo Impossible under current funding

• Current funding $4 million, asking $16 million

Current Detection

• Ground-based telescopeso Charged Couple Devices (CCDs) - digital images of skyo Compare relative location, direction and brightness -

streakso Requires a clear, night sky

• RAPTORo Stereo vision to measure parallax - objects heading for

Earth

• Yarkovsky Effecto Heating and cooling from suno Impact on orbit in the long run

• Radar - Arecibo, Goldstoneo Close-range classification and refined tracking

Future of Detection

• Infrared space-telescopeso Eliminates albedo problem - size measurementso No need for clear, night sky

• Pan-STARRS - Maui High Performance Computer Centero 1.4 Gigapixel Camera - detects objects 100x faintero Higher spatial resolution - can see through cluttered regionso 3-16x more effective than current NEO telescopes

• Improved telescopes, radaro RAPTOR, 1 meter telescopes would increase warning by many

timeso Help to characterize from further distances

Ok, So We Found An Asteroid

Source: CSA 2005 Planetary Defense Report

Short Term Mitigation Strategies

• Harsh reality of limited resources and timeo Social and political challenges in this situation

• Actions on the Asteroido Deflection or Destruction

§ Deflection is the best solution, but more difficulto Nuclear or Kinetic

§ Nuclear weapons can be detonated off the surface, on the surface, or in the interior

§ Kinetic weapons are simpler, but less effective

• Ground-based responseso Mapping of impact location and timingo Evacuation and shelter construction

§ Long-term vs. short-term shelter design depends on the characterization of the impact event

Mitigation Strategies Comparison

• All strategies are a function of the asteroid characterization

Source: CSA 2005 Planetary Defense Report

Long Term Threat Mitigation• Instantaneous Force Method (IF)

o Projectile Into Asteroido Explosive (Nuclear Missile)

§ Too Unpredictable

• Continuous Force Method (CF)

o Ion Thruster§ Electrostatic (Coulomb Force)

o Mass Driver§ Electromagnetic Catapult

o Gravity Tractor§ Gravitational Field

Risk Corridor• Potential Impact Zone

§ Wavy Due to Tilt of Earth§ Probability Usually 1:1000 to 1:1,000,000

• Raises More Political Issues

Keyholes• Asteroid Misses Earth

o Gravity Puts it on a Collision Course for Earth in the Future

• Usually Adds at Least a Few Years• 2011 AG5 passes in 2023

o Could Keyhole into 2040

"The dinosaurs became extinct because they didn't have a space program. And if we become extinct because we don't have a space program, it'll serve us right!"

-Arthur C. Clarke