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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Rocket Propulsion
The photo in Figure 27 is from the Society of Automotive Engineers book, Advanced
Engine Development at Pratt & Whitney: The Inside Story of Eight Special Projects 146-
1971, by Dick Mulready. Chapter 6 of this book, "Boost Glide and the XLR-129 - mach
20 at 200,000 Feet," mentions the McDonnell Douglas boost-glide strategic veh icle, as
well as citing the key personnel at McDonnell Aircraft Company. Some time ago, a
model showed up on the desk of a now-Boeing employee that was not readily
identifiable. The author has an original model of this boot-glide strategic veh icle, and it
matched the unidentified model shown in Figure 27.
The XLR-129 was a shuttle-class engine that operated with turbopump exit pressures of
3,500 psi. It was brought to full pressure operation for the U.S. Air Force in just over 3
months. 14 In comparison, the space shuttle main engine (shown in Figure 28),
operating with a lesser turbopump exit pressure, required 3 years to reach full pressure
operation and never demonstrated reusability without overhaul.
Figure 27. Boost-Glide Strategic Vehicle With Pratt
& Whitney XLR-129 Rocket Engine Installed, Circa
1964
Figure 28. XLR-129 , a Shuttle-Class Eng ine That Ran
for 40 Test Cycles With Only Component Maintenance and
No Engine Rebuilding
The final paragraph of chapter 6 in Mulready's book contains the following passage:
"The liquid oxygen turbopump was the next component in line. However, before it was
funded, NASA had started the space shuttle campaign, and the Air Force gave the XLR-
129 program to NASA granting free use of the existing hardware to Pratt & Whitney.
NASA promptly canceled the liquid oxygen turbopump because it would be unfair to our
competitors to fund it." With the demise of the XLR-129, a rocket engine with a run
record of 42 simulated flights (in the test chamber) without any overhau l disappeared.
Th is engine was really the type of hardware a Kelly Johnston would oversee-that is,
the best application of the industrial capabilities available in the skilled mechanics,
engineers, and manufacturers. The only other eng ine of its class is the Russian RD-
0120 engine manufactured by Autokinamatiki for the Energia launcher. This engine
functioned on the test stand for 80 simulated flights to space and return before
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