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Directed Energy Planetary Defense

Asteroid Ablation by Directed Energy

Planetary defense by high-powered laser: material ablated off a would-be impactor alters its trajectory by conservation of momentum to avert an impact. (Q. Zhang)

DE-STARLITE Artistic Rendering v5

Stand-on DE-STARLITE single launcher based system for planetary defense.

DE-STAR or Directed Energy System for Targeting of Asteroids and exploRation is a proposed system to deflect asteroids, comets, and other near-Earth objects (NEO) that pose a credible risk of impact. The objects that cross Earth’s orbit, even relatively small ones, can still have a devastating effect. We propose an orbital planetary defense system capable of heating the surface of potentially hazardous objects to the point of vaporization.  DE-STAR is a modular phased array of kilowatt class lasers powered by photovoltaics.

We consider two classes of systems:

  1. large “stand-off” DE-STAR arrays, which remain in Earth orbit and deflect the target from afar, and
  2. much smaller “stand-on” DE-STARLITE systems which travel to and deflect from alongside the target

The modular design allows for incremental development and test, lowering cost, minimizing risk, and allowing for technological co-development. While DE-STAR is designed as a stand-off system (able to accomplish a task from afar), DE-STARLITE is a much smaller version which is deployable on a single launcher but still capable of mitigating large asteroids given sufficient warning.

In both cases, highly-focused energy raises the temperature of a spot on the target’s surface to ~3000 K, allowing direct vaporization and ejection of surface material altering the asteroid’s or comet’s orbit. Ideal DE-STAR systems can simultaneously engage multiple targets.

Additional applications of these arrays 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 (see DEEP-IN), composition analysis of remote objects including asteroids, and many others. The implications for SETI and ultra long range beacons extending even beyond our galaxy are also discussed.

Witches Broom by Ken Crawford 5 fitler image

Recent Publications

List of recent Directed Energy related publications: DE_STAR_and_related_References

Directed Energy Missions for Planetary Defense – Adv Space Res 2016

Orbital Simulations on Deflecting Near-Earth Objects by Directed Energy (2016)
by Q. Zhang, K. J. Walsh, C. Melis, G. B. Hughes, P. M. Lubin

This paper discusses the use of numerical simulations to evaluate the effectiveness of a range of directed energy systems on a range of potential targets, focusing on asteroids but also with a brief discussion on comets.

Preprint: arXiv:1601.03690
Publications of the Astronomical Society of the Pacific:
Volume 128, Number 962, Article 045001

Directed Energy Planetary Defense (Book Chapter – 2015)
by P. Lubin, G. B. Hughes

Chapter in Cosmic Hazards and Planetary Defense – Springer (We receive no funds from this)
Download Chapter (PDF) – Pages 941-991

Toward directed energy planetary defense (2014)
by P. Lubin, G. B. Hughes, J. Bible, J. Bublitz, J. Arriola, C. Motta, J. Suen, I. Johansson, J. Riley, N. Sarvian, D. Clayton-Warwick, J. Wu, A. Milich, M. Oleson, M. Pryor, P. Krogen, M. Kangas, H. O’Neill

Optical Engineering: Toward directed energy planetary defense (PDF)

Conferences & Proceedings

SPIE Optics + Photonics – San Diego – August, 2015

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

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

Brashears et al. “Directed Energy Deflection Laboratory Measurements”: 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 – July, 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

Hypervelocity Impact Symposium – Boulder, CO – April, 2015

Zhang et al. Orbital Simulations for Directed Energy Deflection of Near-Earth Asteroids

Planetary Defense Conference – PDC – Frascati, Italy – April, 2015
Lubin et al. Effective Planetary Defense using Directed Energy

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

News & Multimedia

The Asteroid Hunters (Popular Mechanics – Nov, 2015)

A popular overview of background and current detection and mitigation work.

FEA simulation of directed energy on a 1m diameter SiO2 rotating asteroid with a 100s period over 4 days using a 1 MW laser. Note that the small asteroid size and high speeds are due to numerical limitations and are not indicative of the project’s scale. Made with Comsol by Wu, Johansson, Griswold, and Madajian

Vacuum Chamber Demos

Rotation and Derotation – July, 2015

Planetary Defense Conference – April, 2015
Laser at >10 MW/m2 (see Brashears et al.)

PDC April 2015 Simulated Threat (click to expand)

A hypothetical threat from a large asteroid was presented at the Planetary Defense Conference in Frascati, Italy in April 2015 (see PDC 2015 threat simulation details – PDF). 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 mission designs.

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 12 N 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.

SETI – February 2014

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

Presentation: Directed Energy for Planetary Defense and Implication for Searches for Advanced Civilizations

DE-STAR: A Planetary Defense and Exploration System

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

Miscellaneous Videos

Laboratory tests of high efficiency 19 element laser at 808 nm focused onto a Basalt target at a flux of about 20 MW/m2. 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. Made by Caio Motta with Cinema 4D Studio donated by MAXON Computer.

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 3000 K for this example compound. 

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