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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 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
NASA NTRS2011

Seating Considerations for Spaceflight: The Human to Machine Interface

Seating is one of the most critical components to be considered during design of a spacecraft. Since seats are the final interface between the occupant and the vehicle wherein all launch and landing operations are performed, significant effort must be spent to ensure proper integration of the human to the spacecraft. The importance of seating can be divided into two categories: seat layout and seat design. The layout of the seats drives the overall cabin configuration - from displays and controls, to windows, to stowage, to egress paths. Since the layout of the seats is such a critical design parameter within the crew compartment, it is one of the first design challenges that must be completed in the critical path of the spacecraft design. In consideration of seat layout in the vehicle, it is important for the designers to account for often intangible factors such as safety, operability, contingency performance, crew rescue. Seat layout will lead to definition of the quantity, shape, and posture of the seats. The seats of the craft must restrain and protect the occupant in all seated phases of flight, while allowing for nominal mission performance. In design of a spacecraft seat, the general posture of the occupant and the landing loads to be encountered are the greatest drivers of overall design. Variances, such as upright versus recumbent postures will dictate fit of the seat to the occupant and drive the total envelope of the seat around the occupant. Seat design revolves around applying sound principles of seated occupant protection coupled with the unique environments driven by the seat layout, landing loads, and operational and emergency scenarios.

Gohmert, Dustin M.↗
NASA NTRS1997

(abstract) Case Study of the Design of a Viterbi Decoder

This paper describes the design of an ASIC performing the Viterbi decoder function with a constraint length of 15 and at a speed of 4.4 Mb/s. The architecture of the chip is described, as well as the design challenges which were overcome. The author also describes the successful application of the design system.

Viterbi decoders ASIC chip architecture constraint↗
NASA NTRS1997

Case Study of the Design of a Viterbi Decoder

This paper describes the design of an ASIC performing the Viterbi decoder function with a constraint length of 15 and a speed of 4.4 Mb/s. The architecture of the chip is described, as well as the design challenges which were overcome. The author also describes the successful application of the design system.

Viterbi decoder ASIC microprocessor design↗
NASA NTRS2014

Wide Range Vacuum Pumps for the SAM Instrument on the MSL Curiosity Rover

Creare Incorporated and NASA Goddard Space Flight Center developed and space qualified two wide range pumps (WRPs) that were included in the Sample Analysis at Mars (SAM) instrument. This instrument was subsequently integrated into the Mars Science Laboratory (MSL) "Curiosity Rover," launched aboard an Atlas V rocket in 2011, and landed on August 6, 2012, in the Gale Crater on Mars. The pumps have now operated for more than 18 months in the Gale Crater and have been evacuating the key components of the SAM instrument: a quadrupole mass spectrometer, a tunable laser spectrometer, and six gas chromatograph columns. In this paper, we describe the main design challenges and the ways in which they were solved. This includes the custom design of a miniaturized, high-speed motor to drive the turbo drag pump rotor, analysis of rotor dynamics for super critical operation, and bearing/lubricant design/selection.

Sorensen, Paul↗
NASA NTRSDate not supplied

Tesla Valve Integration into Propulsion Systems for Water Hammer Mitigation

Water hammer is a pressure surge or wave caused when a liquid in motion is forced to stop or change direction suddenly. Satellite and in-space propulsion systems exhibit this effect when valves, which can pulse several times per second, close quickly to isolate propellant from thrusters. The inherent nature of pulsing thrusters quickly has made water hammer a constant design challenge for these systems. Historically, the standard is to accept that the Maximum Design Pressure (MDP) of the system must account for a full worst case water-hammer event, which can be several times the Maximum Expected Operating Pressure (MEOP). An investigation is being conducted to determine the effectiveness of tesla valves in reducing water hammer amplitudes. Tesla Valves can be used in-line within propulsion systems to allow unrestricted flow in one direction and restricted flow in the opposite direction without the use of added mechanical or electrical components. Tesla valves use fixed internal geometry to allow for this unrestricted and restricted flow. With the increase and capability of Additive Manufacturing (AM), different configurations and concepts of tesla valves can be manufactured and tested at minimal cost. This concept could possibly be used to allow for a less complicated, or robust satellite and in-space propulsion system. This presentation will cover topics of additive manufactured design of tesla valves, testing, and variables to consider within tesla valve creation.

Michael A Willis↗
NASA NTRS1991

Impact of Mars sand on dust on the design of space suits and life support equipment: A technology assessment

Space suits and life support equipment will come in intimate contact with Martian soil as aerosols, wind blown particles and material thrown up by men and equipment on the Martian surface. For purposes of this discussion the soil is assumed to consist of a mixture of cominuted feldspar, pyroxene, olivine, quartz, titanomagnetite and other anhydrous and hydrous iron bearing oxides, clay minerals, scapolite and water soluble chlorides and sulfates. The soil may have photoactivated surfaces that acts as a strong oxidizer with behavior similar to hydrogen peroxide. The existing data about the Mars soil suggests that the dust and sand will require designs analogous to those uses on equipment exposed to salty air and blowing sand and dust. The major design challenges are in developing high performance radiators which can be cleaned after each EVA without degradation, designing seals that are readily cleaned and possibly in selecting materials which will not be degraded by any strong oxidants in the soil. The magnitude of the dust filtration challenge needs careful evaluation in terms of the trade off between fine-particle dust filters with low pressure drop that are either physically large and heavy, like filter baghouses require frequent replacement of filter elements, of low volume high pressure thus power consumption approaches, or washable filters. In the latter, filter elements are cleaned with water, as could the outsides of the space suits in the airlock.

Simonds, Charles H.↗
NASA NTRS2010

Mars Science Laboratory Entry, Descent, and Landing System Overview

In 2012, the Mars Science Laboratory (MSL) mission will pioneer the next generation of robotic Entry, Descent, and Landing (EDL) systems by delivering the largest and most capable rover to date to the surface of Mars. In addition to landing more mass than prior missions to Mars, MSL will offer access to regions of Mars that have been previously unreachable. The MSL EDL sequence is a result of a more stringent requirement set than any of its predecessors. Notable among these requirements is landing a 900 kg rover in a landing ellipse much smaller than that of any previous Mars lander. In meeting these requirements, MSL is extending the limits of the EDL technologies qualified by the Mars Viking, Mars Pathfinder, and Mars Exploration Rover missions. Thus, there are many design challenges that must be solved for the mission to be successful. Several pieces of the EDL design are technological firsts, such as guided entry and precision landing on another planet, as well as the entire Sky Crane maneuver. This paper discusses the MSL EDL architecture and discusses some of the challenges faced in delivering an unprecedented rover payload to the surface of Mars.

Mars Science Laboratory (MSL)↗
NASA NTRS1985

Orbiter thermal protection system

The major material and design challenges associated with the orbiter thermal protection system (TPS), the various TPS materials that are used, the different design approaches associated with each of the materials, and the performance during the flight test program are described. The first five flights of the Orbiter Columbia and the initial flight of the Orbiter Challenger provided the data necessary to verify the TPS thermal performance, structural integrity, and reusability. The flight performance characteristics of each TPS material are discussed, based on postflight inspections and postflight interpretation of the flight instrumentation data. Flights to date indicate that the thermal and structural design requirements for the orbiter TPS are met and that the overall performance is outstanding.

Dotts, R. L.↗
NASA NTRS2017

Computational Assessment of a 3-Stage Axial Compressor Which Provides Airflow to the NASA 11- by 11-Foot Transonic Wind Tunnel, Including Design Changes for Increased Performance

A 24 foot diameter 3-stage axial compressor powered by variable-speed induction motors provides the airflow in the closed-return 11- by 11-Foot Transonic Wind Tunnel (11-Foot TWT) Facility at NASA Ames Research Center at Moffett Field, California. The facility is part of the Unitary Plan Wind Tunnel, which was completed in 1955. Since then, upgrades made to the 11-Foot TWT such as flow conditioning devices and instrumentation have increased blockage and pressure loss in the tunnel, somewhat reducing the peak Mach number capability of the test section. Due to erosion effects on the existing aluminum alloy rotor blades, fabrication of new steel rotor blades is planned. This presents an opportunity to increase the Mach number capability of the tunnel by redesigning the compressor for increased pressure ratio. Challenging design constraints exist for any proposed design, demanding the use of the existing driveline, rotor disks, stator vanes, and hub and casing flow paths, so as to minimize cost and installation time. The current effort was undertaken to characterize the performance of the existing compressor design using available design tools and computational fluid dynamics (CFD) codes and subsequently recommend a new compressor design to achieve higher pressure ratio, which directly correlates with increased test section Mach number. The constant cross-sectional area of the compressor leads to highly diffusion factors, which presents a challenge in simulating the existing design. The CFD code APNASA was used to simulate the aerodynamic performance of the existing compressor. The simulations were compared to performance predictions from the HT0300 turbomachinery design and analysis code, and to compressor performance data taken during a 1997 facility test. It was found that the CFD simulations were sensitive to endwall leakages associated with stator buttons, and to a lesser degree, under-stator-platform flow recirculation at the hub. When stator button leakages were modeled, pumping capability increased by over 20 of pressure rise at design point due to a large reduction in aerodynamic blockage at the hub. Incorporating the stator button leakages was crucial to matching test data. Under-stator-platform flow recirculation was thought to be large due to a lack of seals. The effect of this recirculation was assessed with APNASA simulations recirculating 0.5, 1, and 2 of inlet flow about stators 1 and 2, modeled as axisymmetric mass flux boundary conditions on the hub before and after the vanes. The injection of flow ahead of the stators tended to re-energize the boundary layer and reduce hub separations, resulting in about 3 increased stall margin per 1 of inlet flow recirculated. In order to assess the value of the flow recirculation, a mixing plane simulation of the compressor which gridded the under-stator cavities was generated using the ADPAC CFD code. This simulation indicated that about 0.65 of the inlet flow is recirculated around each shrouded stator. This collective information was applied during the redesign of the compressor. A potential design was identified using HT0300 which improved overall pressure ratio by removing pre-swirl into rotor 1, replacing existing NASA 65 series rotors with double circular arc sections, and re-staggering rotors and the existing stators. The performance of the new design predicted by APNASA and HT0300 is compared to the existing design.

Turbomachinery↗
NASA NTRS1994

Flight Testing of Hypersonic Airbreathing Propulsion for Developing Computational Design Technology

The objective of this paper is to present and discuss a scenario and the requirements for flight testing of hypersonic airbreathing propulsion leading to the development of computational design technology. Flight Testing for this development is a significant part of a triad/synergistic, design approach which integrates computations, flight testing, and ground testing. These three complementary, design developmental tools have various capabilities and limitations. An incremental approach is necessary to use and to develop these tools effectively and efficiently. This computational technology must be developed keeping in focus the aerospace plane that is to be developed. The criteria for selecting the right plane are presented and consequently, the appropriate flight tests are identified. Two conceptual, flight-test systems are suggested considering the following: (1) the relevant, lessons learned from previous and current United States hypersonic programs, from the Apollo program, from the Space Shuttle program, and from the space station program; (2) the current need for a low risk, affordable access to space; and (3) the design challenge for hypersonic airbreathing propulsion testing. How these systems may be used for developing the computational design technology is described. The requirements for conducting propulsion- design computations, sources of uncertainties in these computations, and a guide for establishing the credibility of these computations are also presented.

Mehta, Unmeel B.↗
NASA NTRS2008

Multi-terrain Vertical Drop Tests of a Composite Fuselage Section

A 5-ft-diameter composite fuselage section was retrofitted with four identical blocks of deployable honeycomb energy absorber and crash tested on two different surfaces: soft soil, and water. The drop tests were conducted at the 70-ft. drop tower at the Landing and Impact Research (LandIR) Facility of NASA Langley. Water drop tests were performed into a 15-ft-diameter pool of water that was approximately 42-in. deep. For the soft soil impact, a 15-ft-square container filled with fine-sifted, unpacked sand was located beneath the drop tower. All drop tests were vertical with a nominally flat attitude with respect to the impact surface. The measured impact velocities were 37.4, and 24.7-fps for soft soil and water, respectively. A fuselage section without energy absorbers was also drop tested onto water to provide a datum for comparison with the test, which included energy absorbers. In order to facilitate this type of comparison and to ensure fuselage survivability for the no-energy-absorber case, the velocity of the water impact tests was restricted to 25-fps nominal. While all tests described in this paper were limited to vertical impact velocities, the implications and design challenges of utilizing external energy absorbers during combined forward and vertical impact velocities are discussed. The design, testing and selection of a honeycomb cover, which was required in soft surface and water impacts to transmit the load into the honeycomb cell walls, is also presented.

Sotirios, Kellas↗
NASA NTRS2008

Multi-Terrain Vertical Drop Tests of a Composite Fuselage Section

A 5-ft-diameter composite fuselage section was retrofitted with four identical blocks of deployable honeycomb energy absorber and crash tested on two different surfaces: soft soil, and water. The drop tests were conducted at the 70-ft. drop tower at the Landing and Impact Research (LandIR) Facility of NASA Langley. Water drop tests were performed into a 15-ft-diameter pool of water that was approximately 42-in. deep. For the soft soil impact, a 15-ft-square container filled with fine-sifted, unpacked sand was located beneath the drop tower. All drop tests were vertical with a nominally flat attitude with respect to the impact surface. The measured impact velocities were 37.4, and 24.7-fps for soft soil and water, respectively. A fuselage section without energy absorbers was also drop tested onto water to provide a datum for comparison with the test, which included energy absorbers. In order to facilitate this type of comparison and to ensure fuselage survivability for the no-energy-absorber case, the velocity of the water impact tests was restricted to 25-fps nominal. While all tests described in this paper were limited to vertical impact velocities, the implications and design challenges of utilizing external energy absorbers during combined forward and vertical impact velocities are discussed. The design, testing and selection of a honeycomb cover, which was required in soft surface and water impacts to transmit the load into the honeycomb cell walls, is also presented.

Kellas, Sotiris↗
NASA NTRS2005

Mechanical Design of Carbon Ion Optics

Carbon Ion Optics are expected to provide much longer thruster life due to their resistance to sputter erosion. There are a number of different forms of carbon that have been used for fabricating ion thruster optics. The mechanical behavior of carbon is much different than that of most metals, and poses unique design challenges. In order to minimize mission risk, the behavior of carbon must be well understood, and components designed within material limitations. Thermal expansion of the thruster structure must be compatible with thermal expansion of the carbon ion optics. Specially designed interfaces may be needed so that grid gap and aperture alignment are not adversely affected by dissimilar material properties within the thruster. The assembled thruster must be robust and tolerant of launch vibration. The following paper lists some of the characteristics of various carbon materials. Several past ion optics designs are discussed, identifying strengths and weaknesses. Electrostatics and material science are not emphasized so much as the mechanical behavior and integration of grid electrodes into an ion thruster.

Haag, Thomas↗
NASA NTRS2010

Ares V: Progress Toward Unprecedented Heavy Lift

Ares V represents the vehicle that will again make possible human exploration beyond low Earth orbit. The Ares V is part of NASA s Constellation Program architecture developed to support the International Space Station (ISS), establish a permanent human presence on the Moon, and explore it to an extent far greater than was possible with the Apollo Program. Ares V will carry the lunar lander to orbit where it will join the Orion crew spacecraft, launched by the smaller Ares I launch vehicle. Then the Ares V upper stage will send the Orion and lander to the Moon. Ares V is also intended to launch automated cargo landers to the Moon. The Ares vehicles are designed to employ the proven technologies and experience from the Space Shuttle, Delta IV, and earlier U.S. programs, as well as sharing common components where feasible. The Ares V is in an early stage of concept development. However, commonality allows it to benefit from development work already under way on the Ares I, including the first stage booster, and upper stage, J-2X upper stage engine. This paper will discuss progress to date on the Ares V and its potential for freeing payload designers from current mass and volume constraints. Progress includes development progress on Ares I elements that will be shared by the two launch vehicles. The Ares I first stage recently completed a successful test firing of Development Motor 1 (DM-1). The J-2X engine is proceeding with manufacturing of components for the first development engines that will be used for testing. Several component-level tests have been completed or are under way that will help verify designs and confirm solutions to design challenges. The Ares V Earth departure stage will benefit from the Ares I upper stage development, including design, manufacturing, and materials testing. NASA is also working with government and industry to collect data on flights and testing of the operational RS-68 engine and potential upgrades. The Ares V team continues to evaluate technical options, vehicle configurations, and operations concepts for the Ares V. The team recently completed a Fall Face-to-Face meeting that served as a stepping-stone to the Systems Requirements Review (SRR). This four-day meeting served as an information exchange for the various teams at several NASA field centers and supporting contractors.

Sumrall, Phil↗
NASA NTRS2001

An Approach to Simulation of Extreme Conditions for a Planetary Lander

A "Monte Carlo-like" design analysis tool is developed and applied to an aeromaneuvering Mars entry vehicle. This tool provides realistic but challenging design cases using many fewer cases than a full Monte Carlo analysis. The problem of random input variables that are provided a priori (as opposed to being drawn from a given distribution) is addressed and a solution is found that shows prospects for future improvement.

Queen, Eric M.↗
NASA NTRS2005

Benefits of Application of Advanced Technologies for a Neptune Orbiter, Atmospheric Probes and Triton Lander

Missions with planned launch dates several years from today pose significant design challenges in properly accounting for technology advances that may occur in the time leading up to actual spacecraft design, build, test and launch. Conceptual mission and spacecraft designs that rely solely on off the shelf technology will result in conservative estimates that may not be attractive or truly representative of the mission as it actually will be designed and built. This past summer, as part of one of NASA s Vision Mission Studies, a group of students at the Laboratory for Spacecraft and Mission Design (LSMD) have developed and analyzed different Neptune mission baselines, and determined the benefits of various assumed technology improvements. The baseline mission uses either a chemical propulsion system or a solar-electric system. Insertion into orbit around Neptune is achieved by means of aerocapture. Neptune s large moon Triton is used as a tour engine. With these technologies a comprehensive Cassini-class investigation of the Neptune system is possible. Technologies under investigation include the aerocapture heat shield and thermal protection system, both chemical and solar electric propulsion systems, spacecraft power, and energy storage systems.

Somers, Alan↗
NASA NTRSDate not supplied

Thermal Challenges from GSFC Planetary Missions

Planetary science missions introduce many thermal challenges based on their varied thermal environment. Additionally planetary missions often include specific payloads that introduce further thermal design challenges. This presentation provides an overview of those challenges through the perspective of NASA planetary science missions that GSFC has been involved with. It also presents a look ahead at how these challenges will be expanded with the proposed mission concepts in the 2022 Planetary decadal survey.

Thermal Control Planetary Probe↗