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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 289 records · Page 16
All sourcesNASA NTRSDOE OSTI
NASA NTRS1991

Induced gravity Mars transportation systems configuration and hardware penalties

The need for an induced gravity environment in-transit to Mars is assessed based on current knowledge. Two possible alternatives to constant in-transit spinning, periodic spinning and Mars surface reconditioning are discussed and compared. Four propulsion options: cryogenic/aerobraking, solid core nuclear thermal, solar electric and nuclear electric are evaluated for concept adaptability to induced gravity, and salient differences from their microgravity counterparts are assessed. Configurations to the systems level are presented and accompanied by mass estimates. Hardware subsystems required for induced gravity vehicles, such as tether crawlers, tether reels, high-power roll-ring assemblies, etc., have been defined to a sufficient level of detail to confidently determine mass penalties. Results of this study show the mass penalties and complexity involved in producing an induced gravity environment.

Capps, Stephen↗
NASA NTRS1982

Gravity receptors in a microcrustacean water flea - Sensitivity of antennal-socket setae in Daphnia magna

Gravity receptors of Dephnia magna were discovered on the basal segment of the swimming antennae and were shown to respond to upward water currents that pass the animal as it sinks between swimming strokes. Sensitivity of the gravity perceiving mechanism was tested by subjecting daphnids to a series of five decreasingly dense aqueous solutions (neutral density to water) in darkness (to avoid visual cues). Three-dimensional, video analysis of body position (pitch, yaw and roll) and swimming path (hop and sink, vertical and horizontal patterns) revealed a gradual threshold that occurred near a density difference between the animal and its environment of less than 0.25%. Because daphnids do not sink but continue to slide after stroking in the increased density solutions, gravity perception appears to occur during a vertical swing of the longitudinal body axis to the vertical plane, about their center of gravity, and, thereby, implies a multidirectional sensitivity for the antennal-socket setae.

Meyers, D. G.↗
NASA NTRS1999

Affordable Precursor Flight Experiment for Ultra Lightweight Mirror Technologies

As a follow-on to the spectacular success of the Hubble Space Telescope (HST), NASA is currently conducting pre-phase A studies of an even larger aperture telescope, called NGST (Next Generation Space Telescope), that will continue the phenomenal flow of astrophysical discoveries well into the next millennium. Because of the very large aperture required, current NGST concepts have been driven to elaborate schemes of foldable ultra thin and ultra light mirror segment systems that can be deployed on orbit. Due to the complexity of these optical systems, it is imperative that adequate demonstration experiments be flown to verify these new technology concepts before committing to the final design and implementation of the NGST. This paper presents a proposal for a very simple, inexpensive Hitchhiker flight experiment that will determine gravity release effects on very thin mirror segments made from current competitive materials. These experiments will provide the initial data that will be needed before more extensive demonstration flights of the NGST system can be flown.

Guffin, Orville T.↗
NASA NTRS1984

Somali current studied from SEASAT altimetry

Mesoscale variability has been obtained for the world ocean from satellite altimetry by using the repetitive tracks data of SEASAT. No significant results were obtained for the Somali current area for two main reasons: the repetitive tracks are too sparse to cover the expected eddy pattern and these data were obtained in late September and early October when the current is strongly decaying. The non-repetitive period of SEASAT offers the possibility to study a dozen of tracks parallel to the eddy axis or crossing it. These are used here to deduce the dynamic topography of the Somali current. Data error reduction and tide and orbit corrections are addressed. A local geoid was built using a collocation inverse method to combine surface gravity data and altimetry: the repetitive tracks show no variability (which confirms that the current is quasi-inexistent at that time) and can be used as data for the local geoid. This should provide a measure of the absolute dynamic topography of the Somali current.

Perigaud, C.↗
NASA NTRS1973

Recent results from satellite beacon measurements

The techniques are reviewed for measuring ionospheric electron content, the most important parameter in the study of transionospheric propagation. Data collected since 1964 have yielded a synoptic description of the behavior of the electron content in midlatitudes. Empirical relationships between the level of solar activity and the electron content were developed permitting the prognostication of the electron content values. Construction of such prognostication schemes was stimulated by current efforts to create accurate satellite borne navigation systems. Gravity waves propagating in the thermosphere leave a signature in the electron content records. Studies of such records have allowed the identification of the position of the gravity wave source, and its radiation pattern. A one-to-one relationship between these waves and polar substorms was revealed. Electron content measurements were used to monitor the protonosphere with good time resolution. Protonospheric storms were observed with this technique. Slab thickness data obtained from content measurements were used to determine the neutral air temperature in the thermosphere.

Darosa, A. V.↗
NASA NTRS1975

Attitude capture procedures for GEOS-C

The Geodynamics Experimental Ocean Satellite utilizes an extendable 6-meter gravity-gradient boom, a momentum flywheel, and an eddy current damper to achieve requisite stability. Because 1/e libration damping time constants were expected to be in excess of 1 week after boom extension, dynamic studies were undertaken to reduce the 30 to 40 days required to satisfy attitude constraints and begin experimental operations. A three-phase series of maneuvers requiring real-time attitude determination and precise timing resulted from these studies. These maneuvers were successfully executed and achieved three-axis attitude stabilization in 75 hours with librations of 3.6 degrees in pitch and less than 1.5 degrees in roll and yaw.

Lerner, G. M.↗
NASA NTRS1984

L-1011 testing with relaxed static stability

Wind tunnel and flight tests indicate that fuel savings of 2 percent can be achieved by center of gravity (C.G.) management for an L-1011 with the current wing configuration. The normal c.b. location is at 25 percent mean aerodynamic center (MAC). The maximum fuel saving occurs for a C.G. location of 35 percent MAC. However, flight at 35 percent requires that the C.G. range be extended aft of the 35-percent point. Flight at C.G. locations aft or 35 percent requires a pitch active control system (PACS) so that handling qualities are not significantly degraded. The development of this PACS is discussed.

Rising, J. J.↗
NASA NTRS1983

Muscle and the physiology of locomotion

NASA's past, current, and planned research on muscle deterioration at zero gravity and development of countermeasures are reviewed; Soviet studies are discussed as well. A definition of muscle mass and strength regulation factors, and improved measurement methods of muscle atrophy are needed. Investigations of tissue growth factors and their receptors, endogenous and exogenous anabolic protein synthesis stimulation, and a potential neurotropic factor are among the projects in progress or planned. At present, vigorous physical exercise during spaceflight is recommended as the most effective countermeasure against skeletal muscle atrophy.

Rambaut, P. C.↗
NASA NTRS1984

Human response to vibroacoustic environments of space vehicles

To insure efficient utilization of the system, space station design and operations will require special habitability considerations for the occupants and crew because of the relatively long duration missions. Of particular concern is the environment in which the personnel will live and work, and how it affects both the performance and comfort of the occupants. Current criteria do not consider possible effects of reduced gravity, long duration, and confinement. Preliminary to developing space station vibroacoustic habitability criteria, the adequacy of criteria for other space vehicles has been reviewed. In this paper, responses to the noise and vibration environments of both Skylab and Shuttle are discussed. Some astronauts have reported sleep interference, communication interference, distraction, and general annoyance as noise related complaints. In addition, information from the Russian Salyut missions, as well as similar based situtations (e.g., submarines), is reviewed.

Willshire, K. F.↗
NASA NTRS1985

Effects of buoyancy on gas jet diffusion flames - Experiment and theory

Theoretical and experimental research on the effects of buoyancy on gas-jet diffusion flames is described. Part of this research involves an assessment of existing data obtained under reduced-gravity conditions. The results show that uncertainties in the current understanding of flame structure exist and further research is required before reliable predictions of ignition, stabilization, and propagation of flames under microgravity conditions can be made. Steady-state and transient theories have been developed and used in the analysis of existing drop-tower data and new data obtained from a stationary experiment involving inverted flames. The result of this research has led to the definition of a microgravity experiment to be performed in space.

Edelman, R. B.↗
NASA NTRS1988

Star formation and molecular clouds

Several differnt stages can be discerned within the star formation process. Star formation can be considered to start when a molecular cloud fragments into many clumps. Many different physical processes are likely to play an important role in star formation, including self-gravity, magnetic fields, rotation, winds, and radiation transport. The current knowledge on some of these processes are reviewed.

Tielens, Alexander G. G. M.↗
NASA NTRS1987

Technology base for microgravity horticulture

Advanced microgravity plant biology research and life support system development for the spacecraft environment are critically hampered by the lack of a technology base. This inadequacy stems primarily from the fact that microgravity results in a lack of convective currents and phase separation as compared to the one gravity environment. A program plan is being initiated to develop this technology base. This program will provide an iterative flight development effort that will be closely integrated with both basic science investigations and advanced life support system development efforts incorporating biological processes. The critical considerations include optimum illumination methods, root aeration, root and shoot support, and heat rejection and gas exchange in the plant canopy.

Sauer, R. L.↗
NASA NTRS1988

Tower Ocean Wave and Radar Dependence experiment - An overview

The Tower Ocean Wave and Radar Dependence experiment was conducted between October 1984 and January 1986 to study the mechanisms involved in the SAR imaging of the ocean surface. Measurements obtained included in situ capillary and short gravity waves, long surface waves and internal waves, ambient current and detailed meteorological measurements, and stereophotography. None of the hypotheses on SAR imaging of long surface waves considered are able to explain all of the present SAR observations.

Shemdin, O. H.↗
NASA NTRS1993

A Fundamental Study of Smoldering Combustion in Microgravity

A research program is being conducted to study smoldering combustion in microgravity. The program's final objective is to design and conduct smolder experiments in a space based laboratory, which will complement normal gravity ones, and that will help to: increase the current fundamental understanding of smoldering; predict smolder behavior in a space-based installation; and prevent and control smolder originated, ground or space based, fires.

Fernandez-Pello, Carlos↗
NASA NTRSDate not supplied

Alternative Treatment of Crew Wastewater Using a Hybrid Membrane Technology

Environmental Control and Life Support Systems (ECLSS) of future long-duration, deep-space human exploration missions should treat all “waste” streams for recovery and ideally by near closed-loop. Onboard the International Space Station (ISS), the Water Recovery System (WRS) does not treat urine and gray water to recover elements beyond water and utilizes physical-chemical technologies that operate with single-use and hazardous consumables. Urine offers a renewable source of nitrogen and other trace elements that can support sustainable crop production. In response to the lack of flight ready technologies capable of treating urine and gray water for water and nutrient recovery, a Suspended Aerobic Membrane Bioreactor (SAMBR) is under development between the University of South Florida and Kennedy Space Center. SAMBR is optimized for an early planetary base/partial gravity habitat and serves as a hybrid alternative to currently utilized urine treatment technologies and support closing the resource recovery loop. With its ECLSS minded form factor and modular design, SAMBR’s operation can be customized to suit the treatment objectives (i.e., nitrogen conversion) at that time. This proceeding presents preliminary research pertaining to: 1) design challenges in maximizing hydraulic throughput while minimizing mass and volume of the assembly; 2) capabilities for treating high nitrogen waste under steady and non-steady state conditions; and 3) measured performance parameters such chemical oxygen demand (COD), nitrogen conversion, nutrients, turbidity, and system throughput. Future research and development pertaining to further optimization on system safety, reliability, and expanded treatment capabilities will also be presented.

Membrane Filtration↗
NASA NTRS2012

XHAB 2012 Final Report Habitat Demonstration Unit Lite

The University of Maryland Space Systems Laboratory (SSL) was awarded a NASA X-Hab 2012 grant for the design and construction of a new Earth analogue habitat for habitability research. This work builds on the past ECLIPSE and X-Hab projects at the SSL, by combining these elements with a new habitat module in order to create a single research platform for habitability studies. The “Crew Habitat Evaluator for Long-duration Orbital, Near-earth, and Interplanetary Applications” (CHELONIA) will deliver a much more flexible architecture than the previously developed mock-ups, allowing facilitating faster modification of the interior layouts and available total volume. This will enable the investigators to evaluate crew assessments and task performance as a function of the interior layout, functional area allocation and total available volume. This paper documents the design of this new infrastructure, and includes the details of the manufacturing of a new habitat mock-up module and modifications to the existing elements. The paper also includes a brief discussion of possible future research goals. Initial layouts are implemented using foam-core volumetric mock-ups for internal equipment and outfitting. These low fidelity mock-ups constitute a “library” that will allow a very rapid evaluation of a multitude of layouts. CHELONIA is also suitable for higher fidelity functional mock-ups, as well as short to medium-duration mission simulations. This new facility will enable the examination of habitat layouts for both partial gravity and microgravity environments. While partial gravity systems will be easily evaluated with the habitat currently in development, microgravity subsystems will be studied by utilizing low fidelity volumetric neutral buoyancy mock-ups in order to determine if commonality in the design for these two environments is appropriate. Finally, this new facility is being integrated into the SSL Moonyard planetary surface simulation center. The Moonyard simulates a planetary surface by means of a large sandbox, and is used primarily for rover field trials and suit systems evaluation. This new facility will be a prime element in future Earth analog simulations at the University of Maryland in support of NASA exploration objectives.

Kevin Davis↗
NASA NTRS2002

Evaluation of GEOSAT Follow-On Precise Orbit Ephemeris

The GEOSAT Follow-On spacecraft (GFO-l), launched in 1998, began continuous radar altimeter coverage of the oceans in 2000, and after an extensive series of calibration campaigns in 1999 and 2000 was finally accepted by the US Navy on November 29, 2000. By providing high quality altimeter data, GFO can supplement TOPEX/POSEIDON(T/P), ERS-1, and ERS-2 data, providing a different synoptic sampling of the oceans with its 17-day ground track repeat cycle. Altimeter analysis suggests GFO is capable of POSEIDON class altimetry, with orbit error the largest contributor to the GFO altimeter error budget. Satellite laser ranging (SLR), especially in combination with altimeter crossover data, offer the only means of determining high-quality precise orbits. SLR tracking is also augmented by Doppler (Tranet style) beacons. These data were used to tune the gravity field and macromodel (3D representation of the spacecraft geometry and surface properties). Beginning with January 2000 GSFC has produced a 2.5 year span of the Precision Orbit Ephemeris (POE) intended for use on the GFO GDR and for the Pathfinder Project. Using GFO GDR and IGDR altimeter data from NOAA, a two year span of POE orbits are evaluated with respect to the TOPEX orbits by adjusting the GFO data into the TOPEX frame with the help of TOPEX/GFO altimeter crossovers. A 2.5 year span of orbits are also evaluated using tracking data residual analysis, GFO altimeter crossover residual analysis, and direct orbit comparison. In an effort to improve the current POE orbit several ideas are considered, including using recent gravity models which include CHAMP data, the reduced-dynamic approach, and including TOPEX/GFO altimeter crossover data in the orbit solution.

Lemoine, Frank G.↗
NASA NTRS1985

Gravitational Effects on Reproduction, Growth, and Development of Mammals

The broad objective of this research program is to determine the role which gravity plays in the growth and development of mammalian animals. Current studies are focused on the effects of graded hypergravitatinal field intensities on mice, rats and other small sized laboratory animals using the chronic centrifugation technique. They include studies on reproduction and prenatal and postnatel growth and development. Among the important questions addressed are: (1) what stage or stages in animal development are affected by hypergravity and what are the effects? (2) is there a minimum or critical body size for hypergravity to produce a significant effect on growth and development? (3) are there field intensity thresholds for the preceding questions? From analysis of the body masses at birth of rats conceived and allowed to undergo gestation under 2.1G and under normal gravity (1G), it was found that there was no significant difference between the two groups. Futhermore, their growth rates postnatally were the same until they reached a body mass of approximately 50 grams when the 2.1G group showed a significantly slower rate. Results from these studies support the conclusion that prenatal as well as the early postnatal stages of growth and development of the rat are refractory to hyper-G.

Oyama, J.↗