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AAWSAP DIRD, Laser Lightcraft Nanosatellites, November 2010

U.S. Department of War · 2010-11-01 · 77 pages · text from the file's own layer

This Defense Intelligence Reference Document (DIA-08-1011-001), dated 1 November 2010, was prepared by the Defense Intelligence Agency's Defense Warning Office under the Advanced Aerospace Weapon System Applications program. It covers nanosatellite technologies, laser Lightcraft propulsion, a weapon mission selection study and a multi-megawatt laser study. The author recommends that the Department of Defense, working with NASA, bring laser Lightcraft propulsion research back to the United States and restart the Air Force X-50LR test flight program.

From the source:Release of 2026-09-18 Incident: 11/1/10, Las Vegas, Nevada. Released with redactions. This document is a Defense Intelligence Reference Document (DIRD), a technical reference format used by the Defense Intelligence Agency (DIA) to capture baseline knowledge on a specific topic for later analytic use. DIRDs are best understood as reference and synthesis products rather than as original research. It is one of 38 DIRDs produced under the Advanced Aerospace Weapon System Applications Program (AAWSAP) between 2009 and 2011. Because AAWSAP’s scope permitted a broad range of supporting topics, not every DIRD in the series directly concerns aerospace systems or future threat assessment. The following summary reflects the DIRD’s scope and framing at the time of writing and should not be read as implying current validation of the concepts discussed. This DIRD examines laser-propelled “Lightcraft” as a possible low-cost method to launch very small satellites into low Earth orbit by using a remote high-energy laser to supply most of the propulsion energy rather than relying entirely on onboard energy sources. The report combines a survey of nanosatellite trends with a review of “Lightcraft” propulsion concepts, vehicle design, beam-control requirements, and mission studies, and argues that the most promising application is the launch of nano- or pico-satellites, especially Earth- and space-observing payloads of a few kilograms or less. It presents the concept as potentially much cheaper than conventional multistage rockets for very small payloads, while also noting significant practical constraints including strict beam-riding geometry, atmospheric losses, demanding pointing and adaptive-optics requirements, and heavy dependence on large ground-, sea-, or air-based laser infrastructure. Overall, the document presents laser “Lightcraft” as a technically plausible launch concept whose attractiveness depends on whether the supporting laser and beam-control system can be made reliable and economical at operational scale.

  • p. 8 …The sensor must be capable of detecting Earth over a range of orbital radii with a…
  • p. 17 …For the purpose of this report, we envision a Lightcraft Earth-to-Orbit (ETO) transportation system…
  • p. 23 …kg, and 1.0 kg into low Earth orbit (LEO). And preliminary life-cycle cost estimates…
  • p. 34 …not only placing nanosats into LEO at low cost (Figure 14 ), but also for performing much…
  • p. 42 …Each picosat is gravity gradient stable, has a dipole array facing Earth, and a broader beam…
  • p. 43 …orrlCIAE USE 014Lf pushbroom scanning mode for complete Earth coverage rather than only sampling coverage. The…
  • p. 72 …The system is single-stage-to-orbit and completely reusable with no onboard propellant required (the…
  • p. 75 …J., et al. (1991), "System Requirements for Low-Earth-Orbit Launch Using Laser Propulsion," in Proc…
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0.001 duty cycle, has a helical film antenna that increases its gain and doubles as a
solar sail for infrequent stationkeeping maneuvers, and has a tether for coarse gravity
gradient stabilization. A 50 km tether supports the feed, transmitter, and DGPS
reference assembly against a counterweight. The antenna lens is 2 km x 4 km.
The effective area of the array is the same as that of a 50 m diameter filled aperture.
The total effective RF radiated power of the system is 3 GW peak and 3 MW average.
Although specific performance calculations have not been done for this concept, these
powers are so large that the radar should have the sensitivity from its location in GEO
for detecting and tracking many targets simultaneously and most "low observable"
targets as well because they are all designed and oriented so as to have their low
observables in near-horizontal directions. Three constellations would provide
essentially complete global coverage. The entire constellation weighs about 11,000 kg
in GEO (this could be reduced in the future to 110 kg if Buckytubes are used to
construct the system) and can be emplaced and replaced incrementally using laser
powered Lightcraft launch vehicles or even small conventional launch vehicles. It could
even be funded incrementally.
Simple, Distributed, Hyperspectral Sensor
This concept presents an unconventional method of implementing a hyperspectral
sensor of great spectral and spatial resolution. Its implementation would allow the
detection of very many spectral intervals simultaneously, and it has a small field of view
from GEO so that the instrument can dwell on and resolve particular targets of interest.
It also has a large field of regard so that one spacecraft covers a significant fraction of a
hemisphere.
The concept uses a Fresnel zone plate, wh ich is oriented roughly parallel to the local
horizontal just below GEO. It is supported by a tether that extends well above the GEO
altitude, and may or may not have a counterweight at the top end . The gravity
gradient causes the ensemble to remain Earth pointing along the local vertical, with its
center of mass in GEO.
The Fresnel zone plate has a long focal length, and thus the surface and ring locations
can be imprecise compared with conventional optics. In addition, the lens is a thin film
membrane and will be light and inexpensive. It is highly frequency dispersive, and thus
its focal length is a sensitive function of wavelength. Small, self-contained optical
sensor nanosats are placed on the tether at many locations with each nanosat's optics
filtered for response at only that narrow spectral region focused at its distance from the
lens. The nanosats can transmit directly to the ground or their signals can be combined
in one transceiver, also on the tether.
This system has a 100 km long tether, which weighs only a few kilograms in GEO. The
Fresnel zone plate is 100 m in diameter, has a collecting aperture equivalent to a 30 m
filled aperture, and requires only a surface accuracy of centimeters in the visible light
region. It is constructed of thin film with deposited aluminum rings and is an adaptive
piezoelectric membrane kept flat by an electron beam in response to an optical figure
sensor. MEMS FEEP thrusters are at the sensor's periphery for attitude control, with
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Official release, from the pursue collection. The PDF is mirrored here; the original link is above. 77 pages are in the text index: search them above, or from the library's search.