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ISINGLASS Boost Glide Device

ISINGLASS [seemingly not ISIYNGLASS] was a hypersonic, Mach 20 boost-glide vehicle proposed by McDonnell Aircraft Corporation for reconnaissance purposes. Isinglass is a transparent, almost pure gelatin prepared from the swim bladder of the sturgeon and certain other fishes and used as an adhesive and a clarifying agent. Isinglass, More famously referred to as muscovite, is also a type of mica usually found in sheets. It is extracted from different compound minerals for creating window glass. Its versatile properties led to the employment of mica sheets within the windows of furnace and oven doors and in lanterns.

A requirement existed for high resolution wide swath width photography, and the boost glide approach appears attractive from both the launch/recovery and vulnerapility aspects. In all phases of military operations, it is imperative that accurate information be obtained relative to conditions within an enemy territory by reconnaissance techniques. These reconnaissance techniques include military ground and sea reconnaissance, battle field surveillance, weather data collection, boundary penetration, collection of data during penetration of atomic clouds, and many other analogous areas where remote intelligence gathering is desired.

Present reconnaissance techniques included the use of aerial dynamic vehicles of the piloted variety and also pilotless aircraft or drones. These vehicles are not amenable to rapid and simple deployment and are not suitable for prolonged high altitude operation. Also such vehicles require a degree of support which is unacceptable for many applications. The piloted reconnaissance aircraft presently in use usually consisted of high speed, unarmed aircraft, and an extreme degree of risk is experienced by the crew of such aircraft while gathering information over enemy targets.

The drone or pilotless aircraft, which are often utilized to replace the piloted reconnaissance aircraft, are equipped with control systems, guidance equipment, and aerial dynamic controls which are used to provide a controlled turn-about at the target and a controlled flight back to a desired point within friendly territory. The guidance equiment necessary to perform a control turn over target and a return flight to a friendly base is extremely expensive to build and is very complex in nature and therefore subject to a large degree of malfunction.

Isinglass was the code name for a rocket-powered, air-launched boost-glide aircraft studied by the Central Intelligence Agency as an A-12/SR-71 successor in 1964-1968. The Agency's contractors studied several technologies that would be used in later shuttle and SSTO programs, including light weight structure and thermal protection system concepts, and diffusion-bonded titanium. A large scale test article was built and tested to prove these features.

General Dynamics designed the initial ISINGLASS concept based on work done on the B-58-launched Super Hustler, Fish, and Kingfish programs of 1958-1960. The new design would use modern avionics and hydraulics systems developed for the F-111 and be capable of air-breathing Mach 4-5 cruise at 30 km altitude. The General Dynamics feasibility study was completed in the fall of 1964.

An alternative design completed by McDonnell Aircraft in 1965, submitted to the CIA independently of the Convair Isinglass proposals, was designated Project RHEINBERRY. McDonnell's proposed boost-glide vehicle featured a small, manned, rocket-powered craft with a high lift-to-drag ratio that would be air-launched by a B-52 bomber while flying over the Atlantic Ocean. The aircraft would ignite its rocket engine and fly over the Soviet Union at speeds of Mach 20 and at an altitude of over 200,000 feet (60 km). It would descend over the Pacific Ocean to land at Groom Lake, NV, as a glider, landing on the lake bed using a skid landing gear.

By 1965 McDonnell had voluntarily invested about $1,500,000 of corporate funds in background development toward the ISINGLASS solution, and was proceeding at the rate of approximately $150,000 per month. But a program of the size and scope of that was visualized could not practicably be carried out in a clandestine manner.

The McDonnell work in the areas of technology pertinent to ISINGLASS stemmed from their participation in earlier Air Force programs related to the DYNASOAR program. McDonnell was the contractor on the ASSET Program -- a $40 million scale-model flight test effort in support of DYNA- SOAR structural and aerothermodynamic technology. This technology has been advanced considerably since the inception of the DYNASOAR Project, and the hypersonic lift-to-drag ratio specifically has been advanced from 1.8 in DYNASOAR to values of 3, both at McDonnell and at Lockheed (under an Air Force White Contract). The results of ongoing Air Force technology programs were generally been made available to the aerospace industry except where contractor proprietary information was involved.

McDonnell cost-effectiveness studies and vulnerability analyses compared ISINGLASS with satellite systems. The cost effectiveness studies were conducted in accordance with ground rules which did not correspond to current satellite operations. The NRO Staff worked with the CIA to set up ground rules for a cost effectiveness model which could be used by McDonnell to compare the ISINGLASS with current and planned satellite systems. With respect to the vulnerability analysis, anti-satellite (or anti-ISINGLASS) technology comparable to that proposed for Air Force System 922, particularly the employment of IR homing, was not considered in the postulation of defensive weapons systems. Full system netting had also not been considered.

Although there was no firm intelligence information which would indicate that the Soviet Union planne to deploy such an advanced system, it was certainly within the realm of technological possibility in the time period when ISINGLASS could be available. A more balanced vulnerability assessment was not made including the consideration of advanced defensive systems.

Since the high-pressure liquid hydrogen-liquid oxygen engine was an essential feature of the proposed ISINGLASS vehicle, it should be noted that this effort was funded as an advanced development by the DOD and NASA for possible application, not only to manned vehicles such as ISINGLASS, but also to unmanned vehicles, recoverable boosters and upper stages of launch vehicles. The time scale of this development is such that a flight-rated engine for an ISINGLASS-type vehicle would not be available before 197l at the earliest and achievement of this date would require a large increase in effort on the engine program.

As a result of activities in various DOD and NASA programs, there were at least three qualified contractors other than McDonnell who could undertake the development of a vehicle such as ISINGLASS. They were Boeing, Lockheed, and Martin-Marietta. The advantage which McDonnell had lay mainly in the concentration of their efforts on this one specific vehicle design and in the contact they had with the user, which enabled them to better understand the requirements.

Since there were comprehensive DOD and NASA programs in hypersonic vehicle structures, materials and associated manufacturing processes, details of the McDonnell plans for structural element fabrication and test, as part of the advanced technology effort, would be reviewed by the CIA prior to approval to proceed.

The ISINGLASS vehicle as proposed had a range of over 7000 miles [roughly Dallas to Takshkent]. To reach this long range required a vehicle much larger and heavier - hence more expensive - than would be required to reach, say, a range of 5000 miles [roughly Chicago to Sverdlovsk]. No analysis had been provided to show that 7000 miles range was requiredd and no cost tradeoffs had been examined in this connection.

Even accepting that the requirement for a collection system having the flight performance claimed for ISINGLASS, no adequate analysis was reported to show that the specific manned vehicle that was proposed was the best way or even a desirable way to achieve that performance.

An unmanned glider for this mission would weigh very much less in flight than the 25,500 lbs. estimated for the manned vehicle. Its launched weinht would then be correspondingly less, and the whole system simpler and possibly cheaper both in developnent and in operation. It was not clear that a fully integral, completaly recovered single atage boost was the best for this mission. In particular, a smaller vehicle, properly staged in boost, might not require development of a new propulsion system.

For the CIA's reconnaissance purposes, none of these concepts were found to have advantages in comparison to satellites to justify the high development and operating risk and costs. On 21 April 1965 a CIA Deputy Director for Science and Technology memorandum stated "The Director does not wish to take this out of our reserve and asks that you prepare the necessary papers to he presented to the NRG Executive Committee so that funds will be made available from NRO."

On 24 March 1967 a memorandum to the Director of the NRO confirmed the suggestion that any further effort on the ISINGLASS-Project might best be undertaken by the Air Force. Although there is no established Air Force system requirement for a vehicle of this kind, there was a broad overlapping area of technology R&D covering both the vehicle and the engine. During 1967 a decision was made not to pursue further investigation or development of the ISINGLASS system by CIA. No effort or funding was being expended on it or any other new advanced aircraft system.

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