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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 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
NASA NTRS1987

Apollo Lightcraft project

The detailed design of a beam-powered transatmospheric vehicle, the Apollo Lightcraft, was selected as the project for the design course. The principal goal is to reduce the LEO payload delivery cost by at least three orders of magnitude below the Space Shuttle Orbiter in the post 2020 era. The completely reusable, single-stage-to-orbit shuttlecraft will take off and land vertically, and have a reentry heat shield integrated with its lower surface. At appropriate points along the launch trajectory, the combined cycle propulsion system will transition through three or four airbreathing modes, and finally use a pure rocket mode for orbital insertion. The objective for the Spring semester propulsion source was to design and perform a detailed theoretical analysis on an advanced combined-cycle engine suitable for the Apollo Lightcraft. The preliminary theoretical analysis of this combined-cycle engine is now completed, and the acceleration performance along representative orbital trajectories was simulated. The total round trip cost is $3430 or $686 per person. This represents a payload delivery cost of $3.11/lb, which is a factor of 1000 below the STS. The Apollo Lightcraft concept is now ready for a more detailed investigation during the Fall semester Transatmosphere Vehicle Design course.

Myrabo, Leik N.↗
NASA NTRS2018

Integrated Optimization of Mars Hybrid Solar-Electric/Chemical Propulsion Trajectories

NASA’s Human Exploration and Operation Mission Directorate is developing a reusable hybrid transportation architecture in which both chemical and solar-electric propulsion systems are used to deliver crew and cargo to the Martian sphere of influence. By combining chemical and solar-electric propulsions into a single spacecraft and applying each where it is the most effective, the hybrid architecture enables a series of Mars trajectories that are more fuel efficient than an all chemical propulsion architecture without significant increase to trip time. Solving the complex problem of low-thrust trajectory optimization coupled with the vehicle sizing requires development of an integrated trajectory analysis frame- work. Previous studies have utilized a more segmented optimization framework due to the limitation of the tools available. A new integrated optimization framework was recently developed to address the deficiencies of the previous methods that enables higher fidelity analysis to be performed and increases the efficiency of large design space explorations.

Chai, Patrick R.↗
NASA NTRS2010

Hypersonic Navier-Stokes Comparisons to Orbiter Flight Data

During the STS-119 flight of Space Shuttle Discovery, two sets of surface temperature measurements were made. Under the HYTHIRM program3 quantitative thermal images of the windward side of the Orbiter with a were taken. In addition, the Boundary Layer Transition Flight Experiment 4 made thermocouple measurements at discrete locations on the Orbiter wind side. Most of these measurements were made downstream of a surface protuberance designed to trip the boundary layer to turbulent flow. In this paper, we use the US3D computational fluid dynamics code to simulate the Orbiter flow field at conditions corresponding to the STS-119 re-entry. We employ a standard two-temperature, five-species finite-rate model for high-temperature air, and the surface catalysis model of Stewart.1 This work is similar to the analysis of Wood et al . 2 except that we use a different approach for modeling turbulent flow. We use the one-equation Spalart-Allmaras turbulence model8 with compressibility corrections 9 and an approach for tripping the boundary layer at discrete locations. In general, the comparison between the simulations and flight data is remarkably good

Candler, Graham V.↗
NASA NTRS1986

Development of an arcjet nuclear electric propulsion system for a 1993 flight demonstration

The design and performance of an arcjet NEP spacecraft, suitable for use in the Space Nuclear Power System (SNPS) Reference Mission, are outlined. Several arcjet technology levels were considered in this study, and the vehicle design was based on an 30 kW ammonia arcjet system operating at an Isp of 1000 s and an efficiency of 45 percent. The arcjet/gimbal system, PPU and propellant feed-system are described. A 100 kWe SNPS was assumed and the spacecraft mass was baselined at 5500 kg excluding the propellant feed system. A radiation/arcjet efflux diagnostics package was included in the performance analysis. This spacecraft, launched from Kennedy, can perform a 50 degree inclination change and reach a final orbit of GEO with a 180 day trip time providing a six month active load for the SNPS. Advanced ammonia and hydrogen systems were examined for precursor SDI platform applications.

Deininger, W. D.↗
NASA NTRS2000

Forced Boundary-Layer Transition on X-43 (Hyper-X) in NASA LaRC 20-Inch Mach 6 Air Tunnel

Aeroheating and boundary layer transition characteristics for the X-43 (Hyper-X) configuration have been experimentally examined in the Langley 20-Inch Mach 6 Air Tunnel. Global surface heat transfer distributions, and surface streamline patterns were measured on a 0.333-scale model of the Hyper-X forebody. Parametric variations include angles-of-attack of 0-deg, 2-deg, and 4-deg; Reynolds numbers based on model length of 1.2 to 15.4 million; and inlet cowl door both open and closed. The effects of discrete roughness elements on the forebody boundary layer, which included variations in trip configuration and height, were investigated. This document is intended to serve as a release of preliminary data to the Hyper-X program; analysis is limited to observations of the experimental trends in order to expedite dissemination.

Berry, Scott A.↗
NASA NTRS2000

Forced Boundary-Layer Transition on X-43 (Hyper-X) in NASA LaRC 31-Inch Mach 10 Air Tunnel

Aeroheating and boundary layer transition characteristics for the X-43 (Hyper-X) configuration have been experimentally examined in the Langley 31-Inch Mach 10 Air Tunnel. Global surface heat transfer distributions, and surface streamline patterns were measured on a 0.333-scale model of the Hyper-X forebody. Parametric variations include angles-of-attack of 0-deg, 2-deg, 3-deg, and 4-deg; Reynolds numbers based on model length of 1.2 to 5.1 million; and inlet cowl door both open and closed. The effects of discrete roughness elements on the forebody boundary layer, which included variations in trip configuration and height, were investigated. This document is intended to serve as a release of preliminary data to the Hyper-X program; analysis is limited to observations of the experimental trends in order to expedite dissemination.

Berry, Scott A.↗
NASA NTRS2017

A Science-Driven Mission Concept to An Exoplanet

A concept for a science-driven robotic mission to an exoplanet was developed by a team of scientists and engineers from NASA and academia. The concept and scope were based on key mission and science requirements designed to address the question: “What makes a flight mission to an exoplanet compelling, in terms of science return, compared to what we will be able to learn in the next few decades with large near-Earth telescopes or other remote sensing techniques such as a telescope at the Solar Gravity Lens Focus?” By thinking systematically through mission and science goals and objectives, key requirements were developed that would drive technology developments in all necessary aspects, not just on propulsion. Unique science measurements would be performed en route to the exoplanet, including exploring the environment in the outer regions of our solar system, the Oort Cloud, the local interstellar medium, and the astrospheric environment around the host star. One of the key mission science objectives, and one that addresses why a mission to an exoplanet is compelling, was to confirm and characterize life. This objective is fundamental and drives the need for a precursor exoplanet characterization program to search for Earth-centric biosignatures and also drives key aspects of the mission concept. The team concluded that a direct confirmation of life would require in situ observations and measurements which cannot be performed on a fast (~10% of the speed of light) flyby; thus, the mission would require a method to slow down, orbit, or send a probe to the exoplanet’s surface. This capability drives a trade between interstellar travel velocity, trip duration, and propulsion architecture, as well as a high level of onboard autonomy, including adaptive science data collection, on-board data processing, and analysis. This paper describes our mission concept, the key requirements, and open trades.

Bennett, Gary↗
NASA NTRS1974

Geologic guide to the island of Hawaii: A field guide for comparative planetary geology

With geological data available for all inner planets except Venus, we are entering an era of true comparative planetary geology, when knowledge of the differences and similarities for classes of structures (e.g., shield volcanoes) will lead to a better understanding of general geological processes, regardless of planet. Thus, it is imperative that planetologists, particularly those involved in geological mapping and surface feature analysis for terrestrial planets, be familiar with volcanic terrain in terms of its origin, structure, and morphology. One means of gaining this experience is through field trips in volcanic terrains - hence, the Planetology Conference in Hawaii. In addition, discussions with volcanologists at the conference provide an important basis for establishing communications between the two fields that will facilitate comparative studies as more data become available.

Greeley, R.↗
NASA NTRS2024

BOLT-2 Roughness Side Flight Data Results and Analysis

This report provides an in-depth review of the flight data obtained from Side B, also known as the roughness side, of BOLT-2, which was developed and designed to measure the effectiveness of boundary layer trips at hypersonic conditions. Three discrete-roughness trips were implemented on Side B at specific locations, with the necessary sensor layout, to investigate the flight conditions at which they no longer maintained turbulence behind them. All three trips were the same type that were scaled and sized based on predictions of local boundary layer thicknesses to provide the same level of effectiveness. One trip was on the vehicle centerline, where the boundary layer is relatively thick, while the other two were symmetrically located outboard where the boundary layer is much thinner. The relative difference in boundary layer thickness between these locations was roughly on the order of 3-to-1, thus the centerline trip was geometrically about three times larger than the outboard trips. A first order assessment of the Side B flight results is indicated by these three trips forcing transition onset at the same time during flight. The enclosed flight data shows that the performance of each individual trip was nearly identical, with allowances for minor variations attributed to measurement accuracy.

Flight Data↗
NASA NTRS2009

Computational Analysis for Roughness-Based Transition Control

Suitably placed discrete roughness elements are known to delay or hasten the onset of transition, depending on requirements. In this paper, 2D eigenvalue analysis is used to study the effects of surface roughness in the context of transition delay over subsonic and supersonic swept wing configurations, as well as boundarylayer tripping on the forebody of a hypersonic air breathing vehicle.

Li, Fei↗
NASA NTRSDate not supplied

The Effect of Boundary Layer Character on Stochastic Rotor Blade Vortex Shedding Noise

This work illustrates the effect of a rotor blade’s boundary layer on the broadband LBL-VS self-noise emitted from an optimum hovering rotor through experimental and multi-fidelity computational studies. Blade surface roughness effects associated with different manufacturing techniques and the effect of adding a boundary layer trip were shown to decrease LBL-VS noise by upwards of 30 dB at the frequency of maximum emission with a slight penalty in aerodynamic performance when compared with smooth rotor blades. Low-fidelity 2-D viscous flow analysis verified the presence of laminar separation bubbles on the rotor blades which are responsible for LBL-VS noise. Three high-fidelity lattice-Boltzmann simulations were conducted with different wall-functions to predict the boundary layer character correspondent to their experimental counterpart and the resultant presence or absence of LBL-VS noise. Excellent aerodynamic and aeroacoustic agreement was seen between the lattice-Boltzmann simulations and the experimental data for the cases with surface roughness and the boundary layer trip, with the broadband noise results from the simulation with fully turbulent wall-functions diverging from the experimental results above 5 kHz. The transitional wall-function simulation which emulated the smooth experimental blades underpredicted thrust by 14% and broadband noise by a minimum of 10 dB with an accurately predicted broadband noise trend.

Christopher S Thurman↗
NASA NTRS1984

Preliminary evaluation of the airborne imaging spectrometer for vegetation analysis

The primary goal of the project was to provide ground truth and manual interpretation of data from an experimental flight of the Airborne Infrared Spectrometer (AIS) for a naturally vegetated test site. Two field visits were made; one trip to note snow conditions and temporally related vegetation states at the time of the sensor overpass, and a second trip following acquisition of prints of the AIS images for field interpretation. Unfortunately, the ability to interpret the imagery was limited by the quality of the imagery due to the experimental nature of the sensor.

Strahler, A. H.↗
NASA NTRS1980

Pioneer Saturn celestial mechanics experiment

The paper investigates a continuous round-trip radio link at S band (2.2 GHz) that was maintained during the Pioneer Saturn encounter between stations of the Deep Space Network and the spacecraft. From an analysis of the Doppler shift in the radio carrier frequency, a number of gravitational effects on the trajectory were determined. Gravitational moments for Saturn were found from a preliminary analysis, as well as mass values for the Saturn satellites Rhea, Iapetus, and Titan. It was determined that the densities of all three satellites are low and consistent with the compositions of ices. Theoretical calculations for the Saturn interior are described which use the latest observational data, including Pioneer Saturn and state-of-the-art physics for the internal composition.

Anderson, J. D.↗
NASA NTRS1987

Design and performance of an arcjet nuclear electric propulsion system for a mid-1990's reference mission

The design and performance of an arcjet nuclear-electric-propulsion spacecraft, suitable for use in the Space Nuclear Power System (SNPS) reference mission, are outlined. The vehicle design was based on a 30-kW ammonia arcjet system operating at an Isp of 1050 s and an efficiency of 45 percent. The arcjet/gimbal system, power-processing unit, and propellant-feed system are described. A 100-kWe SNPS was assumed, and the spacecraft mass was baselined at 5250 kg (excluding the propellant-feed system). A radiation/arcjet efflux diagnostics package was included in the performance analysis. This spacecraft, assuming a Shuttle launch from KSC, can perform a 50-deg inclination change and reach a final orbit of 35,860 km with a 120-d trip time providing a 4-mo active load for the SNPS. Alternatively, a Titan IV launch would provide a mass margin of 120 kg to a 10,000-km, 58-deg final orbit in 74 d. This spacecraft meets the reference-mission constraint of low developmental risk, and is scalable to power levels projected for future space platforms.

Deininger, William D.↗
NASA NTRS1993

The measurement and analysis of leaf spectral reflectance of two stands of loblolly pine populations

My research was conducted under the mentorship of Dr. Jeff Luvall. I worked at Marshall from June 1 through August 6, 1993. My proposal is titled 'The Measurement and Analysis of Leaf Spectral Reflectance of Two Stands of Loblolly Pine Populations.' The populations for this study were chosen from a larger population of 31 families managed by the International Forest Seed Company, Odenville, Alabama. The technology for mobile ground base spectral detecting is new and therefore the majority of time, June 2 through July 9, was spent on learning the techniques of the Spectrometer 2 spectroradiometer used in the gathering of spectra information. The activities included in the learning process were as follows: calibration of the equipment, programming the associated computer for data management, operation of the spectral devices, and input and output of data. From July 12 through August 3 the time was spent on learning the 'STATGRAP' computer software. This software will be used in the analysis of the data retrieved by the Spectrometer 2 spectroradiometer. Dr. Greg Carter, at Stennis, a colleague of Dr. Luvall, has been conducting similar work with different instruments and procedures and has agreed to host us for a training session on data gathering and analysis. This visit, which has previously planned for July 9, 1993, but had to be postponed because of schedule conflicts, is now confirmed for August 18-22, 1993. This trip to Stennis will provide the knowledge for conducting the field operations in my study, i.e., gathering of data and file conversions.

Paul, Anthony D.↗
NASA NTRS2004

An aerobot for global in situ exploration of Titan

This paper describes the design and component testing of an aerobot that would be capable of global in situ exploration of Saturn's moon, Titan, over a 6 to 12 month mission lifetime. The proposed aerobot is a propeller-driven, buoyant vehicle that resembles terrestrial airships. However, the extremely cold Titan environment requires the use of cryogenic materials of construction and careful thermal design for protection of temperature-sensitive payload elements. Multiple candidate balloon materials have been identified based on extensive laboratory testing at 77 K. The most promising materials to date are laminates comprised of polyester fabrics and/or films with areal densities in the range of 40-100 g/m2. The aerobot hull is a streamlined ellipsoid 14 meters in length with a maximum diameter of 3 meters. The enclosed volume of 60 m3 is sufficient to float a mass of 234 kg at a maximum altitude of 8 km at Titan. Forward and aft ballonets are located inside the hull to enable the aerobot to descend to the surface while preserving a fully inflated streamlined shape. Altitude changes are effected primarily through thrust vectoring of the twin main propellers, with pressure modulated buoyancy change via the ballonets available as a slower backup option. A total of 100 W of electrical power is provided to the vehicle by a radioisotope power supply. Up to half of this power is available to the propulsion system to generate a top flight speed in the range of 1-2 m/s. This speed is expected to be greater than the near surface winds at Titan, enabling the aerobot to fly to and hover over targets of interest. A preliminary science payload has been devised for the aerobot to give it the capability for aerial imaging of the surface, atmospheric observations and sampling, and surface sample acquisition and analysis. Targeting, hovering, surface sample acquisition and vehicle health monitoring and automatic safing actions will all require significant on-board autonomy due to the over two hour round trip light time between Titan and Earth. An autonomy architecture and a core set of perception, reasoning and control technologies is under development using a free-flying airship testbed of approximately the same size as the proposed Titan aerobot. Data volume from the Titan science mission is expected to be on the order of 100-300 Mbit per day transmitted either direct to Earth through an 0.8 m high gain antenna or via an orbiter relay using an omni-directional antenna on the aerobot.

mobility↗