Directed Energy for Planetary Defense and Relativistic Probes – DE-STAR

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Directed Energy Planetary Defense

 

Asteroids and comets that cross Earth’s orbit pose a credible risk of impact, with potentially severe disturbances to Earth and society. Numerous risk mitigation strategies have been described, most involving dedicated missions to a threatening object. We propose an orbital planetary defense system capable of heating the surface of potentially hazardous objects to the vaporization point as a feasible approach to impact risk mitigation. We call the system DE-STAR for Directed Energy System for Targeting of Asteroids and exploRation. DE-STAR is a modular phased array of kilowatt class lasers powered by photovoltaic’s. Modular design allows for incremental development, test, and initial deployment, lowering cost, minimizing risk, and allowing for technological co-development, leading eventually to an orbiting structure that would be developed in stages with both technological and target milestones. While DE-STAR is designed as a stand-off system, DE-STARLITE is  a much smaller version capable of being deployed on a single launcher and capable of mitigating large asteroids given sufficient warning.

The main objective of DE-STAR and DE-STARLITE is to use the highly focused energy to raise the surface spot temperature to ~3,000 K, allowing direct vaporization of all known substances. In the process of heating, the surface material is ejected causing a large reaction which alters the asteroid’s or comet’s orbit.

The ideal system can simultaneously engage multiple targets.

Additional mission tasks include: space debris mitigation, powering or recharging of distant probes, standoff power to remote facilities, standoff photon drive propulsion of small spacecraft that can achieve relativistic speeds, laser powered conventional (thermal) propulsion (no oxidizer needed), laser powered ion dive, standoff composition analysis of remote objects including asteroids, active illumination detection of asteroids (LIDAR), space debris removal, SPS mode for sending excess powered to the ground or airborne systems  via micro or millimeter waves as well as laser,  satellite orbital boosting (LEO to GEO for example), extremely long range high speed IR communications to spacecraft and exoplanets and standoff terraforming possibilities among many others.

The implications for SETI and ultra long range beacons extending even beyond our galaxy are also discussed.

The papers and videos below describe the various applications of this technology:

 

SPIE Optics and Photonics – San Diego – August 2015

Hughes et al. “Stand-off molecular composition analysis” (Invited): Paper

Zhang et al. “Orbital simulations on the deflection of Near Earth Objects by directed energy” (Invited): Paper, Presentation

Brashears et al. “Directed Energy Deflection Laboratory Measurements” (Invited): Paper

Griswold, Madajian et al. “Simulations of directed energy thrust on rotating asteroids”: Paper

Steffanic et al. “Local phase control for a planar array of fiber laser amplifiers”: Paper

 

Research Mentorship Program – UCSB – Summer 2015

Georgieva et al. “Using a Directed Energy System to Deflect Asteroids”: Paper, Poster

Gilkes et al. “De-Spinning Asteroids: Using Laser Ablation to Manipulate Asteroid Motion”: Paper, Poster

Silverstein et al. “Space Debris Mitigation Utilizing Laser Ablation”: Paper, Poster

 

Vacuum Chamber Laser De-Spinning and Spinning Up of “Asteroid-like” Sample  – July 2015 

 

Cosmic Hazards and Planetary Defense – Springer  – May 2015

Chapter on “Direct Energy Planetary Defense” – Pages 941-991

Book available from Springer here (We receive no funds from this.)

Hypervelocity Impact Symposium – HVIS – Boulder, CO  April 2015

Conference Paper: Orbital Simulations for Directed Energy Deflection of Near-Earth Asteroids by Zhang et al.

Planetary Defense Conference – PDC – Frascati, Italy   April 2015

Brashears et al. “Directed Energy Deflection Laboratory Measurements”: Paper, Poster

Conference Paper: Effective Planetary Defense using Directed Energy by Lubin et al.

Vacuum chamber laser targeting of “asteroid like” sample at flux level >10 MW/m^2

See Brashears et al PDC 2015 above for details.

 

PDC April 2015 Simulated Threat

PDC 2015 threat simulation information

Below is a response to a hypothetical threat from a large asteroid as presented at the Planetary Defense Conference in Frascati, Italy in April 2015. The orbital simulation are done with a 3 body numerical solver and the results are compared to analytic approximations that are sometimes used (the 3 delta approximation). The numerical simulations are the proper way to look at a detailed mission while the analytic approximations are used for quick rough misision designs. See our papers for more details.

Suppose we send a DE-STARLITE mission to an asteroid and it arrives at the asteroid 4 years before impact (when the asteroid is ~2.9 au from the Earth). How far will the asteroid be deflected? Here’s a comparison of a 100 m, 200 m and a 300 m diameter asteroid with a 12N thrust (~ 100-200 kW laser). As can be seen even large asteroids can be effectively deflected even with modest DE-STARLITE missions. If we begin the interdiction process even earlier the laser power requirements are reduced or if larger power is used even short interdiction times are feasible. See our papers for more detailed mission discussions.


SPIE Optics + Photonics August 2014

Contributed Paper: DE-STARLITE – A Directed Energy Planetary Defense Mission  by Kosmo et al.

Contributed Paper: Effects of asteroid rotation on directed energy deflection by Johansson and Hummelgard et al.

Contributed Paper: Directed energy active illumination for near-Earth object detection by Riley et al.

Invited Paper: Optical modeling for a laser phased-array directed energy system by Hughes et al.

SPIE Optical Engineering Article 2014

Journal Article: Toward directed energy planetary defense by Lubin et al.

 

SPIE Optics + Photonics August 2013

Plenary Paper: Directed Energy Planetary Defense by Lubin et al.

Keynote Paper: DE-STAR: Phased-Array Laser Technology for Planetary Defense and Other Scientific Purposes by Hughes et al.

Student Paper: Relativistic Propulsion Using Directed Energy by Bible et al.

Plenary Talk Description and Video: DE-STAR: A Planetary Defense and Exploration System by Lubin

News Article Asteroid-zapping lasers step out of science fiction by Burkhart

Video Interview  Philip Lubin: A space-based array for planetary defense by Donnelly and Probasco

 

SETI Big Picture Science Radio Show – February 2014
Interview Space For Everyone: Philip Lubin by Niederhoff

 

SETI Talk – February 2014

Directed Energy for Planetary Defense and Implication for Searches for Advanced Civilizations presented by Lubin

 

 

Laboratory tests of high efficiency 19 element laser at 808 nm focused onto a Basalt target at a flux of about 20 MW/m^2. Max spot temperature is mass ejection limited at about 2600-3000K.

 

Physics based simulation of laser interaction with asteroid Apophis (325 m diameter) at 1 AU. Click on image to start and stop video. Plume ejecta speeds are approximately 1 km/s. Asteroid composition is typical high temperature rocky material (Si, Al, Fe, Mg oxides etc) with a spot temperature that is mass ejection limited at about 3000K for this example compound.

 

We gratefully acknowledge support from the NASA California Space Grant Consortium.