Historical research guide · 0371 · 2010
DIRD Space Access: Where We’ve Been and Where We Could Go
DIA / AAWSAP contractor
In one minute
This is the Defense Intelligence Agency’s engineering history of getting to orbit and back, written by someone who was inside it: the author’s job at Wright-Patterson turned to hypersonics in October 1958, and he spent the rest of his career on these vehicles at McDonnell Douglas. His argument is blunt. The United States knew how to build a reusable, schedulable spaceplane in the 1960s and chose a different path. The Air Force Flight Dynamics Laboratory’s FDL-7 lifting bodies and McDonnell’s Model 176 were wind-tunnel tested from Mach 22 down to landing speed, carried all-metal heat shields that could be repaired in a hangar or in orbit, glided far enough to reach the continental United States from any orbit without waiting, and were sized to fly a hundred missions a year. Sodium heat-pipe leading edges were built and never failed in test. A shuttle-class engine, the XLR-129, ran forty-two simulated flights without an overhaul and was cancelled. The limit, he insists, is not technology but continuity.
Connection
Chapter 13 keeps a ledger of what actually blocks a capability, and this report answers that question for the incumbent architecture with unusual authority: hardware that was built, tested and then discarded, and an orbital infrastructure nobody funded. Its own diagnosis — that skill, continuity and demonstrated components are the limiting resource rather than physics — is the same conclusion the vacuum-energy programmes of chapters 6 and 13 reach from the opposite direction, and it sets the engineering baseline chapter 1 measures new claims against.
From the source
The key requirement for commercial access to low Earth orbit is a robust operational infrastructure built on durable, reliable, demonstrated components and operational systems — a matter of skill rather than necessarily a matter of technology — and without an orbital infrastructure there is no commerce, just as neither the United Kingdom nor the United States had long-distance two-way commerce before the railroads.Introduction, p. v; Conclusion, pp. 38-42
The Air Force Flight Dynamics Laboratory FDL-7C/D and McDonnell Douglas Model 176 lifting bodies were shown by wind tunnel data to be inherently stable and controllable from at least Mach 22 to landing speed, and their hypersonic lift-to-drag ratios above 2.7 give unpowered cross ranges above 4,500 nautical miles, so a crew could leave an orbital station on any inclination and be on the ground in the continental United States in less than 90 minutes with no waiting.Hypersonic Configuration Concepts, pp. 2-15
The thermal protection was built and tested, not merely proposed: sodium-filled stainless-steel heat-pipe leading edges tested at McDonnell Douglas and in NASA Langley’s High-Temperature Structures Tunnel never failed and equalled installed carbon-carbon in weight; a sintered-nickel transpiration-cooled nose tip ran 4,300 seconds until the arc heater’s cathode failed, and was flight tested on the BGRV in 1966; and the ASSET vehicle flew from orbital speeds and was recovered, with only its carbon leading edges proving less durable than required.Thermodynamics and Materials, pp. 16-22
The Pratt and Whitney XLR-129, a shuttle-class engine running at 3,500 psi turbopump exit pressure, was brought to full pressure operation in just over three months and accumulated a run record of 42 simulated flights in the test chamber without an overhaul; the comparable Russian RD-0120 for Energia ran 80 simulated flights before overhaul was necessary. Both were lost to terminated programmes.Rocket Propulsion, pp. 25-26
An air-breathing rocket operating to Mach 5.5 — the LACE, deeply cooled and KLIN cycles — reduces the liftoff gross weight of a transport-launched orbital vehicle by 150 metric tons and raises its useful payload above 11 metric tons using the same rocket motor with a different propellant mix; but imposing horizontal takeoff a priori drives the gross weight from about 300 tons to over 1,000 tons, and that dictated takeoff mode, not the propulsion system, is what has defeated air-breathing solutions since 1958.Rocket Propulsion, pp. 26-29; Up-and-Down Operations, pp. 30-32
The Qu tube, or Supertube, is a sealed tube whose measured effective thermal conductivity is at least 30,000 times that of an equivalently sized solid silver rod, with an essentially constant temperature along a ten-foot length heated from one end; the tests at the University of Alabama in Huntsville also report puzzling temperature distributions unlike any conventional conductor or liquid-vapour heat pipe, and any attempt to open a tube reduces its contents to an inert powder.The Qu Tube, pp. 23-24
The way in
https://documents2.theblackvault.com/documents/dia/AAWSAP-DIRDs/DIRD_06-DIRD_Space_Access-Where_Weve_Been_and_Where_We_Could_Go.pdfHow to cite it
DIA / AAWSAP contractor (2010) DIRD Space Access: Where We’ve Been and Where We Could Go https://documents2.theblackvault.com/documents/dia/AAWSAP-DIRDs/DIRD_06-DIRD_Space_Access-Where_Weve_Been_and_Where_We_Could_Go.pdf