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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 91 records · Page 5

NOAA-17 Break-up Engineering Investigation Board Final Report

The NOAA-17 break-up was found to be a single, localized debris event producing about100 trackable pieces; there is likely no catastrophic damage to the whole spacecraft. NOAA-17 debris is very much in family with NOAA-16 debris, and DMSP F11 and F13 are very much in family with each other and share similarities with NOAA-16 and 17; it is likely all four (“The Big Four”) share the same debris source. DMSP F13 break-up occurred simultaneous with a known battery overcharge and therefore battery rupture is most likely intermediate cause of the Big Four break-ups; this is a low confidence assessment since other debris sources cannot be definitively ruled out. No root cause was found as the NOAA-17 batteries were all confirmed to have been disconnected from the charge path as intended. Possible conditions for reconnection are all unlikely including short circuits and commanding from a “bad actor.” All related spacecraft pose a risk of similar break-ups for decades to come and are a threat to the critical 800-850 km polar orbit regime; even appropriately decommissioned spacecraft appear to be at risk. Recommendations include an update to the decommissioning procedure and consideration of further investigations and active debris removal, consistent with national policy.

Maggie Atkinson↗

Habitability study shuttle orbiter

Habitability design concepts for the Shuttle Orbiter Program are provided for MSC. A variety of creative solutions for the stated tasks are presented. Sketches, mock-ups, mechanicals and models are included for establishing a foundation for future development.

Source record↗

Habitability study, earth orbital space stations

Work is reported aimed at supporting the shuttle payload carriers, such as, the Sortie Carrier and RAM. Sketches, renderings, descriptions of scale models and full scale mock-ups, and reports required to fully explain the design recommendations are presented.

Source record↗

Impact resistance of fiber composite blades used in aircraft turbine engines

Resistance of advanced fiber reinforced epoxy matrix composite materials to ballistic impact was investigated as a function of impacting projectile characteristics, and composite material properties. Ballistic impact damage due to normal impacts, was classified as transverse (stress wave delamination and splitting), penetrative, or structural (gross failure). Steel projectiles were found to be gelatin ice projectiles in causing penetrative damage leading to reduced tensile strength. Gelatin and ice projectiles caused either transverse or structural damage, depending upon projectile mass and velocity. Improved composite transverse tensile strength, use of dispersed ply lay-ups, and inclusion of PRD-49-1 or S-glass fibers correlated with improved resistance of composite materials to transverse damage. In non-normal impacts against simulated blade shapes, the normal velocity component of the impact was used to correlate damage results with normal impact results. Stiffening the leading edge of simulated blade specimens led to reduced ballistic damage, while addition of a metallic leading edge provided nearly complete protection against 0.64 cm diameter steel, and 1.27 cm diameter ice and gelatin projectiles, and partial protection against 2.54 cm diameter projectiles of ice and gelatin.

Friedrich, L. A.↗

Mare ridges and lava lakes

The autointrusive hypothesis of the origin of several vagaries of prominent mare ridges is explained. Data are based on a comparison between the structure of a Hawaiian lava lake and the mare ridges. Resulting data suggest that these ridges may have formed as squeeze-ups and autointrusives in tension fractures over buried topography in the crust of luna lava lakes. Data also suggest that mare ridges may result from: (1) pressure ridges in flows, (2) compressional features resulting from subsidence of mare lava, (3) volcanic ring structures and extrusives, or loccoliths fed by lunar grid controlled dikes, (4) draped topography and fissure eruptives, (5) drag folds or tension-gash dikes caused by wrench faulting at depth, and (6) postmare thrust faults.

Hodges, C. A.↗

Crystallization of dense neutron matter

The equation of state for cold neutron matter at high density is studied in the t-matrix formulation, and it is shown that energetically it is convenient to have neutrons in a crystalline configuration rather than in a liquid state for values of the density exceeding 1600 Tg/cu cm. The study of the mechanical properties indicates that the system is stable against shearing stresses. A solid core in the deep interior of heavy neutron stars appears to offer the most plausible explanation of speed-ups observed in the Vela pulsar.

Canuto, V.↗

Cooling of dense stars

Some recent work on thermal properties of dense stars is described. It is now generally believed that pulsars are rotating, magnetic neutron stars (Gold, 1968). Moreover, theoretical considerations and some observational evidence (such as the speed-ups of the Crab and Vela pulsars) suggest the presence of superfluids in neutron stars. In the earlier cooling calculations the effect of magnetic fields and superfluidity was not taken into account. In the recent work, emphasis was placed on the effect of these new factors, which were expected to reduce cooling rates significantly. The new outcome may prove valuable for the understanding of pulsar and X-ray star problems.

Tsuruta, S.↗

Control logic for a 30 cm diameter ion thruster

The various missions to be performed by the 30-cm diameter mercury bombardment thruster engine are discussed. The operating constraints imposed by the thermal environment, allowable time to reach steady state operation, and the number of start-ups required are examined. The variety of requirements is further analyzed for the impact on the basic control logic for the engine. The control logic is divided into the start-up, run, and shutdown modes of operation. The start-up mode is reported.

Bechtel, R. T.↗

Flight flutter testing using pulse techniques

A case of flutter developed at a speed lower than had been flown previously. This incident precipitated the routine procedure of pulsing control surfaces as well as the firing of explosive charges during speed build-ups. In the interest of rapid evaluation of results, simple methods of data reduction were used. A case history is presented where in the pulse technique predicted flutter by extrapolating decay rates obtained at subcritical speeds; in addition, a case is presented where no valid extrapolation could be made.

Stringham, R. H., Jr.↗

Effect of hinge-moment parameters on elevator stick forces in rapid maneuvers

The importance of the stick force per unit normal acceleration as a criterion of longitudinal stability and the critical dependence of this gradient on elevator hinge moment parameters are investigated with special reference to transient effects for maneuvers of short duration. The analysis shows that different combinations of elevator parameters, which give the same stick force per unit acceleration in turns, give widely different force variations during the entries into and recoveries from steady turns and during maneuvers of short duration such as abrupt pull-ups. The stick force per unit acceleration is greater for abrupt than for gradual control movements.

Jones, R. T.↗

Heat pipe heat rejection system

A prototype of a battery heat rejection system was developed which uses heat pipes for more efficient heat removal and for temperature control of the cells. The package consists of five thermal mock-ups of 100 amp-hr prismatic cells. Highly conductive spacers fabricated from honeycomb panels into which heat pipes are embedded transport the heat generated by the cells to the edge of the battery. From there it can be either rejected directly to a cold plate or the heat flow can be controlled by means of two variable conductance heat pipes. The thermal resistance between the interior of the cells and the directly attached cold plate was measured to be 0.08 F/Watt for the 5-cell battery. Compared to a conductive aluminum spacer of equal weight the honeycomb/heat pipe spacer has approximately one-fifth of the thermal resistance. In addition, the honeycomb/heat pipe spacer virtually eliminates temperature gradients along the cells.

Kroliczek, E. J.↗

Spacelab Mission Simulation-II

The NASA Johnson Space Center conducted the second in a series of Spacelab mission simulations during the week of January 26-February 1, 1976. The facilities that supported the Spacelab Mission Simulation-II (SMS-II) included mock-ups of Spacelab, the Orbiter mid-deck and aft flight deck areas, and support areas simulating a mission control area and a payload operation control area. The SMS-II encompassed presently identified Spacelab mission requirements including experiment solicitation, evaluation, selection, and prioritization; crew selection and training; experiment hardware development, integration, and evaluation. The payload chosen included a cosmic ray physics experiment which was located on a pallet aft of the Spacelab and 20 biomedical experiments which were performed in the Spacelab. This paper will summarize simulation experience to date and list areas requiring substantial evaluation in the future.

Sawin, C. F.↗

The imaging photopolarimeter - The first extraterrestrial spin-scan imager

The paper describes the imaging photopolarimeter used to take close-ups of Jupiter from Pioneers 10 and 11. The instrument operates in a steerable spin-scan mode of operation, contains a 1 in. diameter, f/3.4 Maksutov telescope with a focal plane aperture whose size is selectable. The paper examines those aspects of the design that are substantially influenced by the unusual design constraints, such as choice of detector and method of steering the telescope, and demonstrates the image processing and display techniques used to create the images from the telemetry and correct them for distortion and other defects.

Swindell, W.↗

Evacuation of coal from hoppers/silos with low pressure pneumatic blasting systems

The need for an efficient, economical, effective and quiet device for moving coal and other difficult bulk solids was recognized. Thus came the advent of the low pressure pneumatic blasting system - a very efficient means of using a small amount of plant air (up to 125 PSI) to eliminate the most troublesome material hang-ups in storage containers. This simple device has one moving part and uses approximately 3% of the air consumed by a pneumatic vibrator on the same job. The principle of operation is very simple: air stored in the unit's reservoir is expelled directly into the material via a patented quick release valve. The number, size, and placement of the blaster units on the storage vessel is determined by a series of tests to ascertain flowability of the problem material. These tests in conjunction with the hopper or silo configuration determine specification of a low pressure pneumatic blasting system. This concept has often proven effective in solving flow problems when all other means have failed.

Fischer, J. S.↗

Solventless LARC-160 Polyimide Matrix Resin

The addition polyimide, LARC-160, which was originally synthesized from low cost liquid monomers as a laminating resin in ethanol, was prepared as a solventless, high viscosity, neat liquid resin. The resin was processed by hot-melt coating techniques into graphite prepreg with excellent tack and drape. Comparable data on graphite reinforced laminates made from solvent-coated and various hot-melt coated prepreg were generated. LARC-160, because of its liquid nature, can be easily autoclave processed to produce low void laminates. Liquid chromatographic fingerprints indicate good reaction control on resin scale ups. Minor changes in monomer ratios were also made to improve the thermal aging performance of graphite laminates.

Stclair, T. L.↗

An investigation of the side force that is sometimes observed in rocket start-up

The occurrence of a large but momentary side force during the start-up of rocket motors employing convergent-divergent nozzles has been noted occasionally. Asymmetric flow separation within the divergent section of the nozzle is proposed as the principal source of this lateral force. A method for estimating this force and its concomitant lateral impulse is outlined, and results obtained by applying the method to Scout vehicle first-, second-, and third-stage rocket motor start-ups are presented and compared with similar estimates that other researchers obtained by a different method.

Bowyer, J. M., Jr.↗

Application of multispectral color photography to flame flow visualization

For flames of short duration and low intensity of radiation a spectroscopical flame diagnostics is difficult. In order to find some other means of extracting information about the flame structure from its radiation, the feasibility of using multispectral color photography was successfully evaluated. Since the flame photographs are close-ups, there is a considerable parallax between the single images, when several cameras are used, and additive color viewing is not possible. Each image must be analyzed individually, it is advisable to use color film in all cameras. One can either use color films of different spectral sensitivities or color films of the same type with different color filters. Sharp cutting filters are recommended.

Stoffers, G.↗

A flight investigation of basic performance characteristics of a teetering-rotor attack helicopter

Flight data were obtained with an instrumented AH-16 helicopter having uninstrumented, standard main-rotor blades. The data are presented to facilitate the analysis of data taken when the same vehicle was flown with instrumented main-rotor blades built with new airfoils. Test results include data on performance, flight-state parameters, pitch-link loads and blade angles for level flight, descending turns and pull-ups. Flight test procedures and the effects of both trim variations and transient phenomena on the data are discussed.

Morris, C. E. K., Jr.↗