Gl bal Last-Line of Defense (GOLD) John Marcy ASTE 527 Concept October 9, 2012

Background ObjectYearPotentialImpactV infinity Est. DesignationRangeImpactsProb.Diam. (cum. %) (km/s)(km) 2010 RF JY AG FD SG AM BE LG Earth has experienced the extinction of a species, the Tunguska event within the past 100 years, and will experience a close call in the year 2029 Example NASA programs involved in the discovery of Near-Earth Objects: Spaceguard: 93% of objects found with diameter > 1 km NEOWISE: 20-23% of objects found with diameter > 100 m LINEAR: Adapting technology to follow satellites to discover NEO’s

History July 1991 – STrategic Arms Reduction Treaty (START I) signed 1998 – Congress mandates for discovery of 90% of asteroids greater than 1 km 2005 – Congress mandates for discovery of 90% of asteroids greater than 140 m by the year 2020, funds pending 1908 – A 50 m asteroid exploded over Siberia with the equivalent damage of 600 Hiroshima nuclear bombs – Tunguska Event April 2010 – New START treaty signed between the U.S. and Russia January 1967 – Outer Space Treaty signed between the U.S., Russia, and the U.K. The same year, a group of MIT students look to develop first asteroid interceptor with Project Icarus 2029 – The 300 m asteroid Apophis will miss Earth by approximately one tenth the distance from the Earth to Moon

Context For impacts predicted with lead times greater than 10 years, altering the orbit of the asteroid’s trajectory can cause it to miss Earth Completely There currently exists no mitigation plan against eventual Earth impact with these smaller, yet still powerful asteroids Deep Impact has previewed the necessary technology to enable GOLD Method Lead Time NecessaryΔV Required KEI> 10 years1-2 cm/s Slow-Pull GT> 10 years1-2 cm/s Nuclear Deflection> 10 years1-2 cm/s Laser/Solar Deflection> 10 years1-2 cm/s GOLD15 days2-30 km/s Deep ImpactGOLD Size of impacting body (km) ΔV (km/s) Crater Size (depth) (m)23 m3-5 Miss Distance (m)30010 SensorHRI/MRI/IRIR Launch VehicleDelta IIAtlas V? NEO Discovery1867? Orbital Period (years)5.5? Mission Length6 years> 15 days

The Scenario / Assumptions With very little warning, an asteroid has been discovered to impact a highly populated city For example, a minivan size meteor struck northern California, on April 26, 2012 This concept addresses taking out aggressor with existing nuclear warhead with a penetrator/subsurface detonation first, not a stand off detonation GOLD provides Earth with a last line of defense

The GOLD Spacecraft The Exoatmospheric Kill Vehicle (EKV) is a missile that has been in service since 2004 and widely tested against an array of targets Nuclear Device Heat Shield Adaptor with expeller 55 in 23in Mass = 65.3 kg Nuc Mass = 1100 kg Total Dry Mass = 1500 kg Total Wet Mass = 3000 kg Cooling System

Timeline > 15 day launch window needed Launch for a ΔV ranging from 2-30 km/s ~3 min into flight separation Initial maneuver and Guide autonomously for ~24-48 hours Sensors on with ~24 hours to go EKV separates and detonates Nuclear warhead detonates on area impacted by EKV

The Need vs. Risk for Nuclear The momentum/energy transfer created by a shallow subsurface nuclear explosion is at least 100 times more effective than that of a standoff nuclear explosion

Limitations Develop a more adaptable system NEO’s can vary in size, shape, orientation, spin, etc Extreme high velocities already a major concern Ensure the system is as 100% reliable There is a known issue with EKV and multiple objects – dual salvo?

Future Studies Develop choreographed response to incoming threat Send multiple GOLD spacecraft to repeatedly strike the incoming asteroid Decrease the threat of nuclear fallout This will alleviate some of the political and environmental worries Adapt the system to counter the possible comet impact Comets move on the order 10 times faster and could be bigger than asteroids Long term – use possible Lunar base as a way to track potential threats, and launch for quicker deployment and smaller ΔV’s

The Global Planetary Defensive Agency (GPDA) Tasks: Maintain the three stations across the Equator Monitor the skies for incoming threats Reallocate of the global nuclear arsenal Analyze the scenario for the last line of defense Location of impact vs. potential nuclear fallout

References Houdu, Guillaume. “Hypervelocity Nuclear Interceptor Proposed for Asteroid Impactors”. spacecraft-mitigating-impact-threat-asteroids/. 25 September 2012 Thangavelu, Madhu. “Putting Surplus Nukes to Good Use” April Wei, Bong. “Hypervelocity Nuclear Interceptors for Asteroid Deflection or Disruption” IAA Planetary Defense Conference, May breaking-NASA-s-budget harm-earth-nasa/ /

Backup Slides

Interceptor Options Kinetic Energy Interceptor (KEI) – Only takes 3 hours to set up battery of 10 missiles – Max possible ΔV of only 10 km/s – Complete missile – hard to modify – 12 m long, 1 m wide NASA “Cradle” – To carry B83 nuc – 8.9 m long, 11,035 kg – Planned to use un- funded Ares V launch vehicle

The Need for Nuclear The momentum/energy transfer created by a shallow subsurface nuclear explosion is at least 100 times more effective than that of a standoff nuclear explosion Extensive research shows only 3% of asteroid mass to impact Earth with a 15 days lead time Only 0.2% if intercepted along the asteroid trajectory, i.e. anti-parallel If capable of launching with a greater lead time, the probability of impacted mass as well as nuclear fallout greatly decreases This 15 day period is simply a last resort limit

Testing Asteroid surveying missions not only raise awareness, but also detect possible test sites for the GOLD project Optimal candidate: Impact point behind Earth, to decrease nuclear fallout risk Size of asteroid should start large and decrease to test sensor capabilities Possible candidates 2012 DA14 in February Apophis which will have 2 flybys, 2029 and April 2036 Liens: The trajectories will be better understood First shot without active nuclear device Can increase in fidelity from there