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Schwinghamer, R. J.

Publications and source records attributed to Schwinghamer, R. J..

At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1993

Shield Design For Protection Against Hypervelocity Particles

Installing multilayer insulation against primary Whipple bumper reduces pressure-wall damage. Protection to Space Station based on Whipple bumper concept, "Multishock Shields Containing Aluminum Mesh" (MSC-21792). In addition to Whipple bumper, thermal insulation required and provided by multilayered insulation (MLI) consisting of 20 layers (alternating) of double-aluminized Mylar(R) and Dacron(R) netting. When MLI located against bumper, material still disintegrates, but extra space between MLI and pressure wall allows debris pressure cloud to expand so pressure cloud loading reduced. In addition, total amount of MLI material damaged considerably less when placed against Whipple bumper, which contributes to decrease in excess pressure and contents of expanding debris cloud.

Schwinghamer, R. J.↗
NASA NTRS1987

Alternating-Polarity Arc Welding

Brief reversing polarity of welding current greatly improves quality of welds. NASA technical memorandum recounts progress in art of variable-polarity plasma-arc (VPPA) welding, with emphasis on welding of aluminum-alloy tanks. VPPA welders offer important advantages over conventional single-polarity gas/tungsten arc welders.

Schwinghamer, R. J.↗
NASA NTRS1985

Unique variable polarity plasma arc welding for space shuttle

Since the introduction of the Plasma Arc Torch in 1955 and subsequent to the work at Boeing in the 1960's, significant improvements crucial to success have been made in the Variable Polarity Plasma Arc (VPPA) Process at the Marshall Space Flight Center. Several very important advantages to this process are given, and the genesis of PA welding, the genesis of VPPA welding, special equiment requirements, weld property development, results with other aluminum alloys, and the eventual successful VPPA transition to production operations are discussed.

Schwinghamer, R. J.↗
NASA NTRS1977

Materials and processes for shuttle engine, external tank, and solid rocket booster

The Shuttle flight system is composed of the Orbiter, an External Tank (ET) that contains the ascent propellant to be used by the Space Shuttle Main Engines (SSME), and two Solid Rocket Boosters (SRB). The ET is expended on each launch; the Orbiter and SRB's are reusable. It is the requirement for reuse which poses the exciting new materials and processes challenges in the development of the Space Shuttle. A brief description of the Space Shuttle and the mission profile is given. The Shuttle configuration is then described with emphasis on the SSME, ET, and SRB. The materials selection, tracking, and control system used to assure reliability and to minimize cost are described, and salient features and challenges in materials and processes associated with the SSME, ET, and SRB are subsequently discussed.

Schwinghamer, R. J.↗
NASA NTRS1976

Materials and processes for Shuttle engine, external tank, and Solid Rocket Booster

The paper deals with the materials and processes for three Space Shuttle elements: Space Shuttle Main Engines (SSME), the External Tank (ET), and the Solid Rocket Boosters (SRB), beginning with an overview of the materials selection, tracking and control system. SSME materials and processes are considered with emphasis on hydrogen environment embrittlement, LOX/GOX compatibility, stress corrosion cracking, and hydraulic fluid testing and qualification. The ET is examined with attention given to welding and fracture mechanics, and the thermal protection system. The SRB is discussed with emphasis on corrosion prevention, stress corrosion and fracture toughness, the integrated test bed for in situ corrosion protection verification, aluminum processing, and the thermal protection system.

Schwinghamer, R. J.↗
NASA NTRS1975

Performance of solar shields

The loss of the micrometeoroid shield from the Orbital Workshop section of Skylab I, about 63 seconds after lift-off, proved to be the harbinger of a prodigious effort to quickly develop a workable substitute for the carefully tailored passive portion of the thermal-control system. The paper describes the intensive ten-day around-the-clock effort in which numerous potential thermal-shield materials were assessed, and during which period ten specific shield designs were developed and carried through various stages of development and test. Thermal-shield materials data are discussed, including optical, strength, fatigue, outgassing, tackiness, ultraviolet radiation, and material 'memory' properties.

Schwinghamer, R. J.↗
NASA NTRS1974

High-Pressure Oxygen Test Evaluations

The relevance of impact sensitivity testing to the development of the space shuttle main engine is discussed in the light of the special requirements for the engine. The background and history of the evolution of liquid and gaseous oxygen testing techniques and philosophy is discussed also. The parameters critical to reliable testing are treated in considerable detail, and test apparatus and procedures are described and discussed. Materials threshold sensitivity determination procedures are considered and a decision logic diagram for sensitivity threshold determination was plotted. Finally, high-pressure materials sensitivity test data are given for selected metallic and nonmetallic materials.

Schwinghamer, R. J.↗
NASA NTRS1974

Performance of solar shields

The loss of the micrometeoroid shield from the Orbital Workshop section of Skylab 1 about 63 seconds after lift-off, was the catalyst for a prodigious effort to develop a substitute for the passive portion of the thermal control system. An intensive effort is described in which numerous potential thermal shield materials were assessed, and during which period ten specific shield designs were developed and carried through various stages of development and test. Thermal shield materials data are discussed, including optical, strength, fatigue, outgassing, tackiness, ultraviolet radiation, and material memory properties. Specifically addressed are thermal shield materials selection criteria and the design, development, and test requirements associated with the successful development of Skylab thermal shields, and specifically the two thermal shields subsequently deployed over the exposed gold foil skin of the Orbital Workshop. Also considered are the general performance and thermal improvements provided by both the parasol design deployed by the Skylab 1 crew, and the sail design deployed by the Skylab 2 crew.

Schwinghamer, R. J.↗
NASA NTRS1972

Impact sensitivity of materials in contact with liquid and gaseous oxygen at high pressure

As a result of the Apollo 13 incident, increased emphasis is being placed on materials compatibility in a high pressure GOX environment. It is known that in addition to impact sensitivity of materials, approximately adiabatic compression conditions can contrive to induce materials reactivity. Test runs at high pressure using the ABMA tester indicate the following: (1) The materials used in the tests showed an inverse relationship between thickness and impact sensitivity. (2) Several materials tested exhibited greater impact sensitivity in GOX than in LOX. (3) The impact sensitivity of the materials tested in GOX, at the pressures tested, showed enhanced impact sensitivity with higher pressure. (4) The rank ordering of the materials tested in LOX up to 1000 psia is the same as the rank ordering resulting from tests in LOX at 14.7 psia.

Schwinghamer, R. J.↗