AAWSAP DIRD, Space Access: Where We’ve Been and Where We Could Go, March 2010

This Defense Intelligence Reference Document, dated 8 March 2010, was prepared by the Defense Intelligence Agency's Defense Warning Office under the Advanced Aerospace Weapon System Applications Program. It is one of a series of advanced technology reports. It surveys the history of space access concepts, covering hypersonic gliders, air-breathing and rocket propulsion, materials, launch options and operating costs. The report argues that reliable, schedulable access to low Earth orbit is mainly a hardware and organizational problem rather than a technology problem.

From the source:Release of 2026-09-18 Incident: 3/8/10, 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 is a historical and conceptual survey of space access systems, contending that the main barrier to routine access to space is a failure to build durable, reliable, operational hardware and the supporting infrastructure needed for regular service to and from low Earth orbit. The report reviews earlier launch and aerospace concepts, especially reusable and aircraft-like approaches, and suggests that U.S. space access development became too strongly centered on expendable rockets derived from ballistic missiles rather than bespoke systems designed for repeated space access and payload delivery. Its central claim is that meaningful future progress will depend on creating a purpose-built space transportation infrastructure, including frequent round-trip capability and orbital support networks, rather than continuing to rely on one-off launch vehicles. Overall, the document presents a forceful case for infrastructure-first space development, though its characterization of past technological choices is more assertive than a fully neutral account of past U.S. space programming.

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tunnel model of the McDonnell Douglas Astronautics Company Model 176 installed in
the McDonnell Aircra~ Company Hypersonic Impulse Tunnel for a heat transfer mapping
test is shown in Figu re 17. Note that, conforming to the piloting concepts of the 1960s,
it has a clearly distinct windsh ield . The model accomplished thermal mapping to
determine the heat transfer distributions on the body and upper fins.
Figure 17. Model 176 in the McDonnell Douglas Hypervelocity Impulse Tunnel (circa 1964} for
Thermographic Phosphor Heat Transfer Mapping, Includ ing the Upper Fin.
Among the important determinations that resulted from these heat transfer tests was
that the sharp-leading-edge, flat- bottomed, trapezoidal cross section reduced the
heating to the sides and upper surfaces, as shown in Figure 18. In the range of angles
of attack corresponding to maximum hypersonic L/D ratio, the sharp leading-edge
corner separates and reduces the upper surface heating. Because of this separation,
the isotherms are parallel to the lower surface and are 2,100 to 2,400 °F (1,149 to
1,316 °C) cooler than on the compression surface. The upper control fins are hot, but
there are approaches and materials applicable to control surfaces. The temperatures
shown are radiation equilibrium temperatures. With nose water transpiration cooling
(demonstrated in a flight test in 1966) and heat pipe leading edges (demonstrated at
NASA Langley in 1967-68), the temperatures of the nose and leading edges are 212 °F
and 1,300 °F (100 °C and 704 °C ), respectively. The thermal mapping enabled
identification of primary flow characteristics in the boundary layer of the vehicle. In
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