Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Directed Energy Missions for Planetary Defense   Directed energy for planetary defense is now a viable option and is superior
in many ways to other proposed technologies, being able to defend the Earth
against all known threats. This paper presents basic ideas behind a directed
energy planetary defense system that utilizes laser ablation of an asteroid to
impart a deflecting force on the target. A conceptual philosophy called
DE-STAR, which stands for Directed Energy System for Targeting of Asteroids and
exploRation, is an orbiting stand-off system, which has been described in other
papers. This paper describes a smaller, stand-on system known as DE-STARLITE as
a reduced-scale version of DE-STAR. Both share the same basic heritage of a
directed energy array that heats the surface of the target to the point of high
surface vapor pressure that causes significant mass ejection thus forming an
ejection plume of material from the target that acts as a rocket to deflect the
object. This is generally classified as laser ablation. DE-STARLITE uses
conventional propellant for launch to LEO and then ion engines to propel the
spacecraft from LEO to the near-Earth asteroid (NEA). During laser ablation,
the asteroid itself provides the propellant source material; thus a very modest
spacecraft can deflect an asteroid much larger than would be possible with a
system of similar mission mass using ion beam deflection (IBD) or a gravity
tractor. DE- STARLITE is capable of deflecting an Apophis-class (325 m
diameter) asteroid with a 1- to 15-year targeting time (laser on time)
depending on the system design. The mission fits within the rough mission
parameters of the Asteroid Redirect Mission (ARM) program in terms of mass and
size. DE-STARLITE also has much greater capability for planetary defense than
current proposals and is readily scalable to match the threat. It can deflect
all known threats with sufficient warning.

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The categories of this paper are: nucl-th
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The categories of this paper are: gr-qc
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The categories of this paper are: hep-th
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The categories of this paper are: solv-int
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The categories of this paper are: nlin
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The categories of this paper are: econ
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The categories of this paper are: cond-mat
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The categories of this paper are: adap-org
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The categories of this paper are: quant-ph
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The categories of this paper are: math
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The categories of this paper are: plasm-ph
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The categories of this paper are: cs
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The categories of this paper are: hep-ph
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The categories of this paper are: chem-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: comp-gas