Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Feature Space”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 973 records · Page 54
All sourcesNASA NTRSDOE OSTI
NASA NTRS1978

Strip cell test and evaluation program

The performance characteristics of alkaline fuel cells to be used for space power systems were tested. Endurance tests were conducted on the cells during energy conversion operations. A feature of the cells fabricated and tested was the capability to evaporate the product water formed during the energy conversion reaction directly to space vacuum. A fuel cell powerplant incorporating these cells does not require a condenser and a hydrogen recirculating pump water separator to remove the product water. This simplified the fuel cell powerplant system, reduced the systems weight, and reduced the systems parasite power.

Gitlow, B.↗
NASA NTRS1973

Variable features on Mars. II - Mariner 9 global results.

Systematic Mariner 9 monitoring of the space and time distribution of Martian bright and dark markings, the streaks and splotches, indicates a range of global correlations. The time-variable classical dark markings owe their configurations and variability to their constituent streaks and splotches, produced by windblown dust. Streaks and splotches are consistent wind direction indicators. Correlation of global streak patterns with general circulation models shows that velocities of about 50 to 90 m/sec above the boundary layer are necessary to initiate grain motion on the surface and to produce streaks and splotches. Detailed examples of changes in Syrtis Major, Lunae Palus, and Promethei Sinus are generally consistent with removal of bright sand and dust and uncovering of darker underlying material as the active agent in such changes, although dark mobile material probably also exists on Mars. The generation of streaks and the progressive albedo changes observed require only threshold velocities of about 2 m/sec for about 1 day at the grain surface.

Sagan, C.↗
NASA NTRS1979

The ratio of deuterium to hydrogen in interstellar space. IV - The lines of sight to Delta, Epsilon, and Iota Orionis

Deuterium absorption features in spectra of Delta, Epsilon, and Iota Ori obtained with Copernicus are analyzed. The Iota Ori line-of-sight analysis, which is quite detailed because of the high-velocity H I components superposed on the deuterium features, gives a D/H ratio (which is uncertain because of a complex profile) of 0.000014. A D/H ratio of the order of 7 millionths is determined for Delta and Epsilon Ori. For the complex line profiles involved, one may regard this as a formal lower limit. Several attempts were made to increase the ratio N(D I)/N(H I) in the context of reasonable models for the line of sight, but with no success; the derived values are therefore regarded as actual values, not lower limits. Since the derived value is an average on the line of sight, the possibility cannot be ruled out that the true ratios N(D I)/N(H I) in individual nearby components differ from the mean values. The mean value for these two directions is lower by a factor of 4 than the best value for the Zeta Pup line of sight (the highest yet derived for path lengths greater than 50 pc).

Laurent, C.↗
NASA NTRS1985

Wideband Disturbance Accomodation in Precision Flexible Space Structures

Numerous spacecraft missions currently being formulated exhibit several basic and sharply conflicting features: selected components (e.g., an optical train) of inherently flexible structures are to maintain precision pointing performance in a wideband disturbance environment. Within the overall process of synthesizing an active controller to deal with this difficult problem, the aspects of reduced-order modelling and of actuator and sensor selection are crucial to the successful implementation of any controller feedback strategy. The principal focus in this paper is on the influence of actuator and sensor selection upon the effectiveness of a specified controller strategy for wideband disturbance accommodation. A genetic optical support structure is used for a number of design examples. Active transducer selections are made systematically based upon their direct contributuion to optical pointing error. Controller designs incorporating the various transducer selections exhibit stability in the presence of unmodeled modes over a frequency range substantially beyond the bandwidth of the disturbance.

Hegg, D. R.↗
NASA NTRS1987

Technological status and future challenges of deep space optical communication

An account is given of the concepts, techniques, and system design features that may be used to realize an optical communications link for future planetary missions. Such a spacecraft subsystem would encompass a 10-30 cm aperture optical telescope for both transmitting and receiving. Uplink from a laser, in the form of pulsed ranging signals or command information, will be extracted by a tracking detector; downlink data, as well as detected ranging pulses, will be properly formatted and used to modulate the downlink laser. The optical receiving station may be either on the ground or in earth orbit.

Lesh, James R.↗
NASA NTRS1991

Aero-Space Plane: Flexible Access to Space

The most recently designed X-30 (National Aerospace Plane) is described. The video feature also chronicles the development of the X-plane series, beginning with the X-1.

Source record↗
NASA NTRS1987

Space Technology for Deepwater Divers

Can-Dive Services Ltd.'s Newtsuit offers several features that the Canadian company feels will attract divers and their employers. Although it is a hard shell armored suit, it is a relatively light 400 pounds made of aluminum. Future Newtsuits may be made of carbon fiber composite material that is lighter, yet stronger than steel. It has a constant pressure of one atmosphere meaning the pressure all the way down to the suits 1,000 feet limit will be the same as on the surface. Newtsuit, like a spacesuit, has a self contained backpack breathing system with a duration of 48 hours. It employs a series of patented low friction fluidic joints designed to make underwater motion easier and permit 75 percent; normal human mobility.

Source record↗
NASA NTRS1992

Integration of task level planning and diagnosis for an intelligent robot

A satellite floating space is diagnosed with a telerobot attached performing maintenance or replacement tasks. This research included three objectives. The first objective was to generate intelligent path planning for a robot to move around a satellite. The second objective was to diagnose possible faulty scenarios in the satellite. The third objective included two tasks. The first task was to combine intelligent path planning with diagnosis. The second task was to build an interface between the combined intelligent system with Robosim. The ability of a robot to deal with unexpected scenarios is particularly important in space since the situation could be different from time to time so that the telerobot must be capable of detecting that the situation has changed and the necessity may exist to alter its behavior based on the new situation. The feature of allowing human-in-the-loop is also very important in space. In some extreme cases, the situation is beyond the capability of a robot so our research project allows the human to override the decision of a robot.

Chan, Amy W.↗
NASA NTRS2000

One year old and growing: a status report of the International Space Station and its partners

The International Space Station (ISS), as the largest international science and engineering program in history, features unprecedented technical, cost, scheduling, managerial, and international complexity. A number of major milestones have been accomplished to date, including the construction of major elements of flight hardware, the development of operations and sustaining engineering centers, astronaut training, and eight Space Shuttle/Mir docking missions. International partner contributions and levels of participation have been baselined, and negotiations and discussions are nearing completion regarding bartering arrangements for services and new hardware. As ISS is successfully executed, it can pave the way for more inspiring cooperative achievements in the future. Published by Elsevier Science Ltd.

Spacecraft↗
NASA NTRS2006

Laser Mapping for Visual Inspection and Measurement

Each space shuttle orbiter has 38 Primary Reaction Control System (PRCS) thrusters to help power and position the vehicle for maneuvers in space, including reentry and establishing Earth orbit. Minor flaws in the ceramic lining of a thruster, such as a chip or crack, can cripple the operations of an orbiter in space and jeopardize a mission. The ability to locate, measure, and monitor tiny features in difficult-to-inspect PRCS thrusters improves their overall safety and lifespan. These thrusters have to be detached and visually inspected in great detail at one of two NASA facilities, the White Sands Test Facility or the Kennedy Space Center, before and after each mission, which is an expense of both time and money.

Source record↗
NASA NTRS1992

Application of optical distributed sensing and computation to control of large space structures

A real time holographic sensing technique is introduced and its advantages are investigated from the filtering and control point of view. A feature of holographic sensing is its capability to make distributed measurements of the position and velocity of moving objects, such as a vibrating flexible space structure. This work is based upon the distributed parameter models of linear time invariant systems, particularly including the linear oscillator equations describing the vibration of large flexible space structures. The general conclusion is that application of optical distributed sensors bring gains in the situation where Kalman filtering is necessary for state estimation. In this case, both steady state and transient filtering error covariance become smaller. This in turn results in smaller cost in the LQG problem.

Balakrishnan, A. V.↗
NASA NTRSDate not supplied

Veggie on Ice: The Effects of Plant Production on Human Behavioral Health Long-Duration Antarctic Overwintering Missions

Exploration class missions pose an increased risk of adverse crew behavioral health and psychiatric conditions. Identifying and developing effective and efficient countermeasure strategies are necessary to maintain crew health and performance. Previous studies (VEG-04A and VEG-04B) in the Veggie vegetable-production system on the International Space Station have evaluated the behavioral health effects of caring for plants as a potential countermeasure for crew stresses in spaceflight. The presence of plants can augment sensory stimulation (visual, tactile, and olfactory), provide a psychological link to Earth, reduce stress, and increase happiness. However, further research is needed to understand this strategy for longer-duration missions in isolated, confined, extreme (ICE) environments. The Neumayer III Station in Antarctica is one such environment that hosts a small crew for fourteen-month missions, of which eight to nine months are the remote overwintering phase. Neumayer III also features EDEN ISS, a greenhouse facility with 12.5 m2 plant cultivation space that, like Veggie, currently supplements the crew diet with a variety of fresh produce. Up to nine crew members of the 2021 overwintering mission will complete behavioral health surveys that are designed to capture enjoyment and time spent conducting various plant-related activities, sensory stimulation, and active and passive psychological effects of having live plants and available fresh food in an ICE environment. Data will be collected once pre-mission, up to ten times in-mission at monthly increments, and once post-mission. This study aims to quantify the impact of plant care as a countermeasure strategy for human spaceflight and Antarctic exploration missions.

J M Bunchek↗
NASA NTRS2021

Electric Propulsion for the Psyche Mission: One Year to Launch

NASA’s Psyche mission will launch in 2022 and begin a 3.6-year cruise to the metallic asteroid Psyche, the largest metal asteroid in the solar system. The baseline spacecraft design is a hybrid of JPL’s deep-space heritage subsystems with commercial partner Maxar’s electric propulsion, power, and structure subsystems. The Psyche mission will feature the first use of Hall thrusters for a NASA mission, and the first use of Hall thrusters beyond cis-lunar space. This paper will provide an overview of the electric propulsion subsystem and details of the flight system implementation for the Psyche mission. The concept of operations is discussed including subsystem-level operations, the initial checkout after launch, and cruise and orbital operations. Command and control interfaces with the spacecraft and fault protection design are presented. Finally, the status of subsystem assembly and test is described.

Li, Julie↗
NASA NTRS1972

Gas-core reactor power transient analysis

The gas core reactor is a proposed device which features high temperatures. It has applications in high specific impulse space missions, and possibly in low thermal pollution MHD power plants. The nuclear fuel is a ball of uranium plasma radiating thermal photons as opposed to gamma rays. This thermal energy is picked up before it reaches the solid cavity liner by an inflowing seeded propellant stream and convected out through a rocket nozzle. A wall-burnout condition will exist if there is not enough flow of propellant to convect the energy back into the cavity. A reactor must therefore operate with a certain amount of excess propellant flow. Due to the thermal inertia of the flowing propellant, the reactor can undergo power transients in excess of the steady-state wall burnout power for short periods of time. The objective of this study was to determine how long the wall burnout power could be exceeded without burning out the cavity liner. The model used in the heat-transfer calculation was one-dimensional, and thermal radiation was assumed to be a diffusion process.

Kascak, A. F.↗
NASA NTRS1975

Evaluation of the suitability of Skylab data for the purpose of petroleum exploration

The author has identified the following significant results. Comparisons of the various photographic bands of Skylab imagery indicate that, overall, standard color (particularly S190B) is the most valuable for geological purposes. Detailed examination of all bands indicates that as with ERTS imagery each band contains useful information that is unique to it. The results of geological interpretations based on ERTS and Skylab imagery are strikingly similar. It appears that more information can be extracted from a single Skylab overpass than a single ERTS overpass, but that with repeated passes the lower resolution ERTS imagery may yield information comparable to that contained in S190B imagery. Comparison of Skylab photography to high altitude aircraft photography suggests that there are distinct advantages to using Skylab imagery for regional geologic interpretations. This is primarily because of the synoptic view provided by the space acquired imagery allows and encourages integration of regional geologic features.

Collins, R. J.↗
NASA NTRS1975

Ultraviolet photometry from the Orbiting Astronomical Observatory. XX - The ultraviolet extinction bump

Ultraviolet extinction bumps are investigated in the interstellar extinction curves between 1800 and 3600 A for 36 stars which have (B-V) excesses ranging from 0.03 to 0.55 and are mostly confined to the brighter OB associations distributed along the galactic plane. Each extinction curve is found to have a broad bump which peaks near 2175 A and whose position and profile appear to be constant among all the stars. It is shown that the bump is probably interstellar in origin and that the constancy of its position and shape places such severe restrictions on grain geometrical parameters that classical scattering theory cannot be used to explain the feature unless the dust grains in widely separated regions of space and with very different physical conditions are assumed to have nearly identical size and shape distributions. Three extinction curves which extend to 1100 A are examined and found to have the same general characteristics as the others. Several extinction curves are analyzed for fine structure, but no convincing evidence is found in the present interval. Some processes are discussed which may be responsible for the bumps.

Savage, B. D.↗