Reusable external insulation TPS for the space shuttle
Reusable external fibrous insulation of silica, mullites, or zirconia for space shuttle thermal protection system
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Reusable external fibrous insulation of silica, mullites, or zirconia for space shuttle thermal protection system
Low speed wind tunnel tests of 1/25 scale models of reusable orbital spaceplanes for subsonic aerodynamic data at Mach 0.17
Reusable nuclear shuttle design, considering various propellant tank configurations and expendable/reusable launch modes with respect to performance, development cost and cost effectiveness
Reusable nuclear shuttle concepts, performance and design requirements
Reusable nuclear shuttle navigation systems evaluation by mission simulation, discussing reduced NERVA cooldown thrust pulses uncertainty effects
Experimental aerodynamic investigations were made in the NASA/MSFC 14 x 14 inch trisonic wind tunnel on a NR-GD/C 0.0031 scale model delta wing booster (B-15B-1) and reusable nuclear stage (RNS). Three basic configurations were tested: (1) the B-15B-1 booster alone, (2) the RNS alone, and (3) the booster with the RNS mounted piggyback. Six component force and moment data were recorded for each of these configurations over an angle of attack range from -16 deg to 4 deg at zero degrees sideslip, and over an angle of sideslip range from -10 deg to 10 deg at zero and -6 degrees angle of attack. The configurations were tested over a Mach number range of 0.6 to 5.0 with a nominal Reynolds number of 6.5 million per foot except for Mach 1.2 and 3.0 where the Reynolds number were 12.4 million and 4.4 million per foot respectively.
Parametric tradeoff analyses of a wide spectrum of alternate tank configurations to minimize both primary and secondary, direct and scattered radiation sources emanating from the NERVA are reported. The analytical approach utilizing point kernel techniques is described and detailed data are presented on the magnitude of neutron/gamma doses for different locations. Single-tank configurations utilizing smaller cone angles and end cap radii were found to minimize integral radiation levels, hence, stage shielding-weight penalties for shuttle missions. Hybrid configurations employing an upper tank with a reduced cone angle and end cap radius result in low integral payload doses primarily due to the increased separation distance caused by the elongation of the larger capacity upper tank. A preliminary radiation damage assessment is discussed of possible reusable nuclear shuttle materials, components, and subsystems, and the possible effects of the radiation environment on various phases of RNS mission operations.
Radiation analyses were performed and shielding weight requirements were estimated for various candidate vehicle and payload configurations for use with the reusable nuclear shuttle. The analyses included both point kernel and Monte Carlo approaches. The effects on reduced shield weight were determined for propellant ranks with pointed conical tank bottoms and for one case of a cluster of small tanks. This later case, however, had an arrangement which had no center tank in the upper tier of tanks. This effect negated most of the gain of going to the smaller tanks. A range of shield weights is presented for various light and heavy manned payload configurations when used in conjunction with a single liquid hydrogen propellant tank, 33 ft in diameter with a 15 deg conical tank bottom.
Alternate reusable nuclear shuttle configurations were synthesized and evaluated. Particular attention was given to design factors which reduced tank exposure to direct and scattered radiation, increased payload-engine separation, and improved self-shielding by the LH2 propellant. The most attractive RNS concept in terms of cost effectiveness consists of a single conical aft bulkhead tank with a high fineness ratio. Launch is accomplished by the INT-21 with the tank positioned in the inverted attitude. The NERVA engine is delivered to orbit separately where final stage assembly and checkout are accomplished. This approach is consistent with NERVA definition criteria and required operating procedures to support an economically viable nuclear shuttle transportation program in the post-1980 period.
The radiation environment created by the Reusable Nuclear Vehicle (RNS) in performing its normal mission functions while in the lunar vicinity and the impact of that environment on the Orbiting Lunar Station (OLS) and/or the lunar surface are examined. Lunar surface exposures from the operating reactor were evaluated for both the arrival and departure burns and while there is little probability that manned bases would lie along the paths in which measurable exposures would be recorded, the analyses do indicate the need to consider this possibility in planning such operations. Conclusions supported by the analyses and recommended operational constraints for the RNS are presented.
Preliminary engineering definition information is presented for a liquid pressure-fed reusable booster engine. The material is reported in three separate sections which include: (1) program and baseline data, (2) critical trade studies summary, and (3) methodology.
The results are presented of a program to improve the reusable surface insulation (RSI) system through the improvement of the LI-1500 material properties and the simplification of the RSI system. The improvements made include: 2500 F-capability RSI systems, water-impervious surface coatings, establishment of a high-emittance coating constituent, development of a secondary water-reduction system, and achievement of a lower density (9 pcf) RSI material.
Reusable surface insulation is considered a prime candidate for heat shielding large areas of the space shuttle vehicle. The composition and fabrication of RSI materials are discussed, followed by evolution of RSI and current problems, physical and thermal properties, arc plasma test data and results, and material improvement research. Finally, a summary of RSI technology status is presented.
Results of an extensive study conducted to evaluate multilayer insulation (MLI) materials suitable for repeated space vehicle operation are presented. Materials studied were radiation shields, shield spacers, blanket face sheets, fasteners, and adhesives. The Superfloc MLI concept - Kapton shields goldized on both sides as the radiation barrier with Dacron flock tufts as the spacers - appeared to be an excellent MLI for reusable cryogenic tankage. Superfloc configurations consisting of various combinations of film, spacer, and adhesive materials were manufactured and tested. Tensile, flexing, expansion, and cycling tests were performed on goldized Kapton and Mylar Superfloc and Beta glass reinforced Pyre ML face sheet material. A face sheet material that retains its shape was developed. Polyphenylene oxide material was selected for fabricating lightweight twin and tri-pin fasteners, together with grommets, face sheets, and reinforcement slabs. Measured material thermal conductivity values are tabulated.
Low density fiber ceramic materials coated with refractory ceramics meet the requirements of reusable low weight thermal protection systems. The structural characteristics of this class of material impose unique design and analysis requirements on the application to spacecraft structural elements. Finite element type stress analysis techniques are required to adequately predict the structural response of the system. Parametric analyses have been performed to determine the response of the system to variations in geometry, and to thermal and structural load conditions. Sensitivity of coating, insulation and attachment stresses are presented and critical failure modes are identified.
A definition of the expendable second stage for use with the reusable space shuttle booster is presented. The subjects discussed are: (1) expendable second stage design, (2) structural subsystem, (3) propulsion subsystem, (4) avionics subsystems, (5) recovery and deorbit subsystem, and (6) expendable second stage vehicle installation, assembly, and checkout.
A definition of the expendable second stage and space shuttle booster separation system is presented. Modifications required on the reusable booster for expendable second stage/payload flight and the ground systems needed to operate the expendable second stage in conjuction with the space shuttle booster are described. The safety, reliability, and quality assurance program is explained. Launch complex operations and services are analyzed.
Wind tunnel tests to evaluate the flight characteristics of several expendable second stage/payload configurations on the reusable space shuttle booster are described. Tests were conducted at appropriate speeds, angle of attack, and Reynold's number ranges to evaluate the aerodynamic characteristics of the systems. Three specified payload shapes were tested. The subjects presented are: (1) nomenclature associated with the tests, (2) description of the wind tunnel models, and (3) discussion of aerodynamic characteristics derived from tests.