Directed energy for planetary defense #44

Abstract

Directed energy in the form of photons plays an increasingly important role in everyday life, in areas ranging from communications to industrial machining. Recent advances in laser photonics now allow very large-scale modular and scalable systems that are suitable for planetary defense. The fundamental requirements of directed energy planetary defense systems are described here, along with the current state of technological readiness. A detailed design is presented for an orbital planetary defense scheme, called DE-STAR for Directed Energy System for Targeting of Asteroids and exploRation. DE-STAR is a modular phased array of kilowatt class laser amplifiers fed by a common seed and powered by photovoltaics. The main objective of DE-STAR is to use focused directed energy to raise the surface spot temperature of an asteroid to ~3,000 K, sufficient to vaporize all known substances. Ejection of evaporated material creates a large reaction force that alters the asteroid’s orbit. Both standoff (DE-STAR) and stand-on (DE-STARLITE) systems are discussed. The baseline standoff system is a DE-STAR 3 or 4 (1–10 km array) depending on the degree of protection desired. A DE-STAR 4 allows initial engagement beyond 1 AU with a spot temperature sufficient to completely evaporate up to 500 m diameter asteroids in 1 year. Small objects can be diverted with a DE-STAR 2 (100 m), while space debris is vaporized with a DE-STAR 1 (10 m). Modular design allows for incremental development, minimizing risk, and allowing for technological co-development. Larger arrays would be developed in stages, leading to an orbiting structure. The smaller stand-on systems (DE-STARLITE) are appropriate for targets with very long lead times to impact so that a dedicated mission can be implemented.