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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Up-and-Down Operations
For an aircraft, the takeoff mode is not an issue: it is a runway takeoff and runway
landing. However, for a space launcher, the issue is not so clear-cut. With mass ratios
for launchers much greater than for aircraft ( 4 to 8, compared with less than 2 for
aircraft), runway speed is impractical for some launchers with high mass ratios. The
principal option is vertical takeoff, with horizontal landing remaining viable. The
problem is that in some launcher studies, the study directives mandated horizontal
takeoff regardless of the mass ratio. Many launcher studies have been thwarted by this
a priori dictate of horizontal takeoff. Air-breathing propulsion is then stuck with a "too
heavy" label because of the dictated takeoff mode. In reality, horizontal or vertical
takeoff, like the configuration concept, is less a choice than a result of the propulsion
concept selected. Horizontal takeoff requires that the wing loading be compatible with
the lift coefficient the configuration can generate and the maximum takeoff speed limit.
Figure 33 shows results for highly swept delta planforms, such as that of the Model 176
and FDL-7. Takeoff speeds for blended bodies in the 200- to 230-knot ranges were
postulated in the 1960s by using very large gimbaled rocket motors to rotate upward
and cause the body to also rotate, lifting off the nose wheel as the vehicle lifts off with
a thrust-supported takeoff. This concept was not known to have been implemented in
an actual system. For space launchers, the takeoff speed of the basic delta is high
(square symbols). If the takeoff speed is too high for the propulsion system chosen
(because of the weight ratio), then the only way to decrease the takeoff speed is to
increase the planform area for the system volume-that is, to reduce the KUchemann
tau. This, unfortunately, introduces a cascade of incremental mass increases that
result in an exponential rise of the takeoff gross weight (as shown in Figure 34). The
only lift-increasing devices avai lable are a leading-edge vortex flap or a retractable
canard near the nose of the vehicle.
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Figure 33. Takeoff and Landing Speeds of Minimum-Sized Launchers
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