AAWSAP DIRD, Laser Lightcraft Nanosatellites, November 2010

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Chapter 5: Conclusion
To reduce mission costs, advanced technology components and a novel laser propulsion
system can make nanosats (and picosats) compact, lightweight, low power, and low
cost. By producing a large quantity of nanosats for a given mission, the per-unit cost
will be reduced to a small fraction of satellite procurements for traditional missions.
Mission operation costs will be minimized by the incorporation of both onboard and
ground autonomy, use of heuristic systems, and use of a novel laser propulsion system
to launch the nanosats into LEO. Laser propulsion is an enabling technology in which a
laser-propelled vehicle, called "Lightcraft," harnesses the energy of a high-energy laser
beam and converts it into propulsive thrust.
The laser-propelled Lightcraft is an ETO transportation system that develops quasi­
steady (airbreathing) thrust by pulsing at a variable rate along the flight trajectory to
orbit, and then when it climbs above the atmosphere it begins to operate in the thermal
rocket mode using onboard propellant to convert and expand the laser energy for
propulsion. The Lightcraft is spin-stabilized and can be launched vertically upward or
on a slant upward trajectory, hover in mid-air, and undergo powered descent and
landing. The system is single-stage-to-orbit and completely reusable with no onboard
propellant required (the reaction mass is free air), except for the small internal amount
of propellant needed for final ascent to orbit and orbital maneuvering. MEMS FEEP
thrusters could provide onboard attitude and stationkeeping propulsion. The Lightcraft
specific impulse is essentially infinite (several thousand seconds in rocket mode), while
payload mass fractions are 50% to 95%.
Laser-propelled Lightcraft systems are simple, reliable, safe, environmentally clean, and
could have a very high all azimuth on-demand launch rate. This novel propulsion
system reduces space launch costs by two to three orders of magnitude below today's
levels, with estimated launch costs of $20 per kg to $600 per kg of payload, not
including life-cycle and recurring launch operations costs. The entire Lightcraft launch
system is comprised of a ground, sea, or airborne laser beam generator consisting of a
power supply, a high-power (megawatt-class) laser beam generator/transmitter using
novel beam optics, and automated tracking, hand-off and safety systems.
The most promising military mission for laser-propelled Lightcraft is the placement of
Earth and space observing nano-/pico-satellites of up to 3 kg mass into LEO. Such
Lightcraft could also serve as a "Lightsat," because it would use the Lightcraft's laser
propulsion optics as a telescope for observing military targets on Earth and in space.
Such a Lightcraft system appears capable of reaching LEO at 1/Sth to 1/l0th the cost
required for placing a similar Lightsat system into LEO using multistage chemical rocket
systems. Other potential missions include using laser-propelled Lightcraft as
ground/sea- or airborne-launched kinetic kill weapons to shoot down enemy ballistic
missiles. Very innovative near-term missions could also include deploying Lightcraft
nano-/pico-satellites to form swarms of small spacecraft which cooperate coherently to
form a real distributed system in which the whole is more than the sum of the parts.
This would be a constellation of small spacecraft each performing its separate function,
but these functions combine to create at a central location a much larger virtual
spacecraft, or sensor aperture, that exists solely because of the cooperation of the
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