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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 253 records · Page 14
All sourcesNASA NTRSDOE OSTI
NASA NTRS1999

Integrated Computational System for Aerodynamic Steering and Visualization

In February of 1994, an effort from the Fluid Dynamics and Information Sciences Divisions at NASA Ames Research Center with McDonnel Douglas Aerospace Company and Stanford University was initiated to develop, demonstrate, validate and disseminate automated software for numerical aerodynamic simulation. The goal of the initiative was to develop a tri-discipline approach encompassing CFD, Intelligent Systems, and Automated Flow Feature Recognition to improve the utility of CFD in the design cycle. This approach would then be represented through an intelligent computational system which could accept an engineer's definition of a problem and construct an optimal and reliable CFD solution. Stanford University's role focused on developing technologies that advance visualization capabilities for analysis of CFD data, extract specific flow features useful for the design process, and compare CFD data with experimental data. During the years 1995-1997, Stanford University focused on developing techniques in the area of tensor visualization and flow feature extraction. Software libraries were created enabling feature extraction and exploration of tensor fields. As a proof of concept, a prototype system called the Integrated Computational System (ICS) was developed to demonstrate CFD design cycle. The current research effort focuses on finding a quantitative comparison of general vector fields based on topological features. Since the method relies on topological information, grid matching and vector alignment is not needed in the comparison. This is often a problem with many data comparison techniques. In addition, since only topology based information is stored and compared for each field, there is a significant compression of information that enables large databases to be quickly searched. This report will (1) briefly review the technologies developed during 1995-1997 (2) describe current technologies in the area of comparison techniques, (4) describe the theory of our new method researched during the grant year (5) summarize a few of the results and finally (6) discuss work within the last 6 months that are direct extensions from the grant.

Hesselink, Lambertus↗
NASA NTRS2004

Mission Steering Profiles of Outer Planetary Orbiters Using Radioisotope Electric Propulsion

Radioisotope Electric Propulsion (REP) has the potential to enable small spacecraft to orbit outer planetary targets with trip times comparable to flyby missions. The ability to transition from a flyby to an orbiter mission lies in the availability of continuous low power electric propulsion along the entire trajectory. The electric propulsion system s role is to add and remove energy from the spacecraft s trajectory to bring it in and out of a heliocentric hyperbolic escape trajectory for the outermost target bodies. Energy is added and the trajectory is reshaped to rendezvous with the closer-in target bodies. Sample REP trajectories will be presented for missions ranging for distances from Jupiter orbit to the Pluto-Kuiper Belt.

Fiehler, Douglas↗
NASA NTRS2006

Steering Aircraft Clear of Choppy Air

AeroTech Research (U.S.A.), Inc., a leader in turbulence-detection and warning systems, has been involved with NASA Aviation Safety research since 1998. AeroTech served as a contractor for the TPAWS government/industry development project, and was funded by NASA to develop the E-Turb Mode Radar algorithms and the TAPS software. (Other contributors to this project include the National Center for Atmospheric Research, the FAA, North Carolina State University, and the Research Triangle Institute.) The radar algorithms combine an aircraft's turbulenceresponse characteristics with radar measurements to determine the predicted turbulence loads the aircraft will experience, and present this information to the pilot. The TAPS software monitors and processes onboard aircraft sensor data; generates automatic reports when an aircraft encounters turbulence and a set turbulence threshold is exceeded; and then displays the reports and underlying information to ground personnel to improve situational awareness of the location and the severity of the turbulence encounter.

Source record↗
NASA NTRS1985

Aircraft roll steering command system

Aircraft roll command signals are generated as a function of the Microwave Landing System based azimuth, groundtrack, groundspeed and azimuth rate or range distance input parameters. On initial approach, roll command signals are inhibited until a minimum roll command requirement is met. As the aircraft approaches the centerline of the runway, the system reverts to a linear track control.

Lambregts, Antonius A.↗
NASA NTRS1990

Body steered rover

A rough terrain vehicle is described which includes auxiliary wheels that can be deployed to avoid overturning the vehicle when turning while traversing a slope, to climb an embankment or the like, and to right the vehicle when it is overturned. The vehicle includes a pair of front and rear primary wheels, and a pair of auxiliary arms having inner ends pivotally mounted on the front wheel axes and outer ends that carry auxiliary wheels. A motor can turn the arms to move the auxiliary wheels from a stowed position about halfway between the front and rear wheels and above the ground, to a second position against the ground to stabilize the vehicle. The arms can be turned more than 180.degree. to move the auxiliary wheels in front of the front primary wheels to help climb an embankment. The primary wheels can be mounted at the end of primary arms, so when the primary arms are turned they not only move the primary front wheels but also the inner ends of the auxiliary arms.

Collins, Jr., Earl R.↗
NASA NTRS2015

Rocket Propulsion 21 Steering Committee Meeting (RP21) NASA In-Space Propulsion Update

In-house Support of NEXT-C Contract Status Thruster NEXT Long Duration Test post-test destructive evaluation in progress Findings will be used to verify service life models identify potential design improvements Cathode heater fabrication initiated for cyclic life testing Thruster operating algorithm definition verification initiated to provide operating procedures for mission users High voltage propellant isolator life test voluntarily terminated after successfully operating 51,200 h Power processor unit (PPU) Replaced all problematic stacked multilayer ceramic dual inline pin capacitors within PPU Test bed Rebuilt installed discharge power supply primary power board Completed full functional performance characterization Final test report in progress Transferred PPU Testbed to contractor to support prototype design effort.

Electric Propulsion↗
NASA NTRS2016

A Tall Ship and a Star to Steer Her By

Two visionary innovations were proposed to allow spacecraft to assume the burden of navigation. The first extends the International Celestial Reference Frame (ICRF) to include not only orientation references (quasars), but also time (pulsars) and frequency (maser) references that allow position and velocity to be determined relative to the terrestrial reference frame (TRF) or planetary reference frames (PRFs). The second provides spacecraft with a direct means to determine their own position relative to the ICRF.

Hecht, Michael↗
NASA NTRS2016

Rocket Propulsion (RP) 21 Steering Committee Meeting - NASA Spacecraft Propulsion Update

Lander Tech is three separate but synergistic efforts: Lunar CATALYST (Lunar Cargo Transportation and Landing by Soft Touchdown) Support U.S. industry led robotic lunar lander development via three public-private efforts. Support U.S. industry led robotic lunar lander development via three public-private partnerships. Infuse or transfer landing technologies into these public private partnerships. Advanced Exploration Systems-Automated Propellant Loading (APL) -Integrated Ground Operations. Demonstrate LH2 zero loss storage, loading and transfer operations via testing on a large scale in a relevant launch vehicle servicing environment. (KSC, GRC). Game Changing Technology-20 Kelvin -20 Watt Cryocooler Development of a Reverse Turbo-Brayton Cryocooler operating at 20 Kelvin with 20 Watts of refrigeration lift.

Propellant↗
NASA NTRS2017

Steering Concept of a 2-Blade Heliogyro Solar Sail Spacecraft

Solar sails can be classified into two groups based on their method of stabilization: 1) truss supported, and 2) centrifugally (spin) supported. The truss configuration requires masts or booms to deploy, support, and rigidize the sails whereas the spin type uses the spacecraft’s centrifugal force to deploy and stabilize the sails. The truss-supported type sail has a scaling limitation because as the sail area gets larger, the sail is increasingly more difficult to make and stow: the masts and booms get heavier, occupying more volume, and have increased risk during deployment. This major disadvantage limits the size of the sail area. The spin type comes in two configurations: 1) spinning square/disk sail and 2) heliogyro sail. This spinning square/disk sail architecture suffers the same sail area limitation as the truss-supported sail.

Wiwattananon, Peerawan↗
NASA NTRS2018

Steering of Solar Sails Using Optical Lift Force

Optical wing structures were theoretically and numerically analyzed, and prototype arrays of wings called optical flying carpets were fabricated with solar sail material clear polyimide (CP1). This material was developed at NASA Langley to better withstand damaging ultraviolet radiation found in outer space. Various optical wing sizes and shapes were analyzed to develop design strategies for thrust and torque applications. The developed ray-tracing model has undergone continual advancement, and stands as an effective tool for modeling most types of solar sails. To our understanding, such a model does not exist else where. The distributed forces and torques have been reduced to a simple theoretical whereby the fundamental mechanics may be understood in terms of the numerically determined center of pressure off set from the center of mass. This description applies to any type of solar sail, affording our ray-tracing model a general utility. This research has established a foundation for understanding the force and torque afforded by optical wings. The study began by considering transparent wings and ended by considering wings having a reflecting face. The latter was found to afford the advantages of high thrust and both intrinsic and extrinsic torque. Our discovery of the intrinsic torque on optical wings (meaning that a moment arm is not required) has no analogy for a flat reflective solar sail, and therefore provides an extra degree of control that may be useful for sail craft attitude and navigation purposes.

Swartzlander, Gover↗
NASA NTRS2020

3d Kinematic Passive-steering Control with Roll Compensation for Rover Trajectory Following Over Rough Terrain

Some of the most appealing areas for future planetary surface exploration lie in rough, uneven terrains, such as craters and cold traps, which are currently inaccessible by state-of-the-art robotic systems [1]. To provide modularity for access and in-situ sampling within such extreme environments, Jet Propulsion Laboratory (JPL) and California Institute of Technology have collaborated to develop the DuAxel rover system, a modular robot composed of two Axel rappelling vehicles docked to a central module into a four-wheeled configuration, suited for driving long distances due to articulated passivesteering capabilities [2]. Inspired by Carnegie Mellon’s Zoë rover [3], a 3D kinematic control strategy, leveraging a novel, DuAxel-centric model, has been developed to enable precise trajectory following over rough, flat terrain with presence of obstacles.

McGarey, Patrick↗