AAWSAP DIRD, Laser Lightcraft Nanosatellites, November 2010

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.

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• Efficient, generally a FEL can transform 10% (> 60% for microwave tubes) of its
energy into laser radiation.
• Reliable, systems now run 24 hours per day for weeks.
• Can produce picosecond laser pulse widths.
• Systems are big (40 m x 60 m) and expensive ($1 Million to $100 Million).
The Naval Sea Systems Command's (NAVSEA) Directed Energy and Electric Weapon
Systems (DE&EWS) Program Office is supporting research, development and testing of
advanced high-energy/high-power FEL designs for the purpose of deploying them as
directed energy weapons onboard warships in the near future. The DE&EWS program is
emphasizing the development of disruptive innovations to reduce FEL system size,
weight, and operational (and lifetime) cost, as well as to increase overall system
operating efficiency. One design that has emerged to reach all of these goals is the
recirculating-beam FEL system (RBFEL), which uses a superconducting accelerator, RF
power liquid helium refrigerator, an electron beam injector, an electron beam dump,
and a modified laser resonator-undulator cavity that boosts the production of amplified,
coherent laser photons (see Figure 31). The superconducting accelerator gives good
efficiency and gradient while recirculation of the electron beam recovers beam energy
to increase efficiency and reduce the beam dump size.
Electron Accelerator
Beam
Dump
RF Power
Liquid Helium Refrigerator Injector
IReflecting Minor Undulator Out-Coupling Minor
Figure 31. Recirculating-Beam FEL System {courtesy of the Naval Post-Graduate School' FEL
Lab).
The key (typical) technical features of the Navy RBFEL are as follows :
• Total system volume: 16 m x 4 m x 4 m = 256 m 3 .
• Undulator/Wiggler
- Length: 46 cm to 60 cm.
- Period: 2.9 cm.
- Number of periods: 18.
- Magnetic field strength : 1 Tesla.
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