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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Figure 39 shows the deviation from the 1962 standard atmosphere for a hypersonic
glider entering the atmosphere from the central South Pacific (summer) to northeastern
Russia (winter). The deviations from constant-density shells based on the 1962
standard atmosphere are significant. With today's computers, not ignoring the actual
atmosphere is only a bookkeeping task. Hypersonic glide ranges at near maximum L/D
ratio are to be generated. The local density is critically important, as it is determined
by the lift coefficient for L/D maximum .
2 2
q = W/ Splan { 1- ( --y ) ] =1188 5 ~--y ) 0 CT (5)
(CL)maxL/D 25,535 • 1000 °
The seasonal variations are enough that the glider should have the correct density and
temperature distribution in its flight-control computer so that unexpected alterations in
the flight trajectory are not mandated during entry. The atmosphere is analogous to a
constant-energy system-if the lower altitudes are hotter, the upper altitudes are
colder, and vice versa.
In terms of deviations from the standard, the coldest upper-altitude temperatures most
likely encountered are at 50,000 feet over Saudi Arabia in summer, and the warmest
atmospheric temperatures are at 27,000 feet over Russia in winter.
1962 Standard Atmosphere
1966 Standard Atmosphere Supplement
1959 Selected Meridional Cross sections of the Northern Hemisphere NAVAIR-50-1 C-59
-48%
-•-
Figure 39. Earth's Atmosphere. Earth's atmosphere is not a series of concentric, constant-density shells or
globally uniform, and fly ing from one hemisphere to another enta ils significant deviations from standard definitions.
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