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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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All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

A multiple thruster array for 30-cm thrusters

The 3.0-m diameter chamber of the 7.6-m diameter by 21.4-m long vacuum tank at NASA LeRC was modified to permit testing of an array of up to six 30-cm thrusters with a variety of laboratory and thermal vacuum bread-board power systems. A primary objective of the Multiple Thruster Array (MTA) program is to assess the impact of multiple thruster operation on individual thruster and power processor requirements. The areas of thruster startup, steady-state operation, throttling, high voltage recycle, thrust vectoring, and shutdown are of special concern. The results of initial tests are reported.

Rawlin, V. K.↗
NASA NTRS1996

Materials Assessment of Components of the Extravehicular Mobility Unit

Current research interests for Extravehicular Mobility Unit (EMU) design and development are directed toward enhancements of the Shuttle EMU, implementation of the Mark 3 technology for Shuttle applications, and development of a next generation suit (the X suit) which has applications for prolonged space flight, longer extravehicular activity (EVA), and Moon and Mars missions. In this research project two principal components of the EMU were studied from the vantage point of the materials and their design criteria. An investigation of the flexible materials which make up the lay-up of materials for abrasion and tear protection, thermal insulation, pressure restrain, etc. was initiated. A central focus was on the thermal insulation. A vacuum apparatus for measuring the flexibility of the materials was built to access their durability in vacuum. Plans are to include a Residual Gas Analyzer on the vacuum chamber to measure volatiles during the durability testing. These tests will more accurately simulate space conditions and provide information which has not been available on the materials currently used on the EMU. Durability testing of the aluminized mylar with a nylon scrim showed that the material strength varied in the machine and transverse directions. Study of components of the EMU also included a study of the EMU Bearing Assemblies as to materials selection, engineered materials, use of coatings and flammability issues. A comprehensive analysis of the performance of the current design, which is a stainless steel assembly, was conducted and use of titanium alloys or engineered alloy systems and coatings was investigated. The friction and wear properties are of interest as are the general manufacturing costs. Recognizing that the bearing assembly is subject to an oxygen environment, all currently used materials as well as titanium and engineered alloys were evaluated as to their flammability. An aim of the project is to provide weight reduction since bearing weights constitute 1/3 of the total EMU weight. Our investigations have shown favorable properties using a titanium or nickel base alloy in conjunction with a coating system. Interest lies in developing titanium as a more nonflammable material. Methodology for doing this lies in adding coatings and surface alloying the titanium. This report is brief and does not give all necessary details. The reader should contact the authors as to the detailed study and for viewing of raw data.

Olivas, John D.↗
NASA NTRS2001

FIRST Mirror Review

As part of a JPL-funded effort to develop lightweight telescope technology suitable for far-infrared astronomy, COI designed and fabricated a spherical, f/1, 2-meter aperture prototype primary mirror using solely graphite/resin composite materials. To assess the performance of this technology, optical metrology of the mirror surface was performed from ambient to an intended operational temperature for IR-telescopes of 70K. Testing was performed horizontally in a cryogenic vacuum chamber at Arnold AFB, Tennessee. The test design had to accommodate requirements for rapid and uniform cooling across the optic, passivation of the ambient vibrational environment, and de-coupling of the mirror from the thermal strain of the test stand. An IR-wavelength phase shifting interferometer (PSI) was the primary instrument used to measure the mirror surface. From an initial surface figure of 2.1 microns RMS at ambient, a modest 3.9 microns of additional RMS surface error was induced at 70K. The thermally induced error was dominated by low-order deformations, of the type that could easily be corrected with secondary or tertiary optics. In addition to exceptional thermal stability, the mirror exhibited no measurable hysteresis between both ambient and cryo measurements.

Dodson, Kelly↗
NASA NTRS2017

Characterization of the Teledyne CHROMA HgCdTe Detector for Imaging Spectrometers

Imaging spectroscopy places high demands upon detector performance. The dynamic range, linearity, and sensitivity must be maintained at high frame rates, and artifacts must be minimized across large focal plane array (FPA) formats. In this contribution, we discuss the Teledyne CHROMA HgCdTe FPA in the context of imaging spectrometer applications. The FPA was characterized in a laboratory thermal-vacuum chamber that allowed the read noise, dark current, well capacity, linearity, and crosstalk to be measured. Results are presented across a range of operating temperatures and pixel clock rates. Additionally, the outcomes of radiation testing to 100 krad TID are discussed. The results of these characterizations are critical to the designs and performance predictions of future imaging spectrometers utilizing the HgCdTe CHROMA FPA.

Green, Robert↗
NASA NTRSDate not supplied

Instrument Level TVAC Testing of the PACE OCI Loop Heat Pipes

The Thermal Control System (TCS) of the Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) Ocean Color Instrument (OCI) incorporates two propylene Loop Heat Pipes (LHP). A Thermal Vacuum (TVAC) test was conducted at NASA Goddard Space Flight Center to characterize the fully integrated OCI in the test-as-you-fly configuration. Within the constraints of movement of the OCI in the TVAC chamber, an elaborate series of trending and calibration tests have been accomplished. This paper presents the measured LHP performance along with lessons learned.

loop heat pipe↗
NASA NTRS1975

Centaur Standard Shroud (CSS) Heated Altitude Jettison Tests

Altitude jettison tests, at a pressure of 20 torr (0.39 psia), were performed on the Centaur Standard Shroud (CSS) in a 100-foot diameter vacuum chamber. These jettison tests were part of a series of flight qualification tests which were performed on the new CSS system in preparation for the Helios and Viking missions. The first two tests subjected the CSS to a thermal cycle which simulated aerodynamic heating during ascent flight and the third test was performed at altitude pressure and in ambient temperature conditions. The purpose of the ambient temperature test was to provide base line data by which the separate machanical and thermal factors that influence jettison performance could be evaluated individually. The CSS was successfully jettisoned in each of the three tests. Also, thermal, stress, and structural deflection data were obtained which verified the analytical predictions of CSS response to flight environmental conditions and performance during jettison. In addition, much important information was obtained on critical CSS-to-payload clearance losses due to shell motions prior to and during jettison. The effectiveness of the separation system was successfully demonstrated at maximum flight temperatures.

Source record↗
NASA NTRS1990

Space simulation facilities providing a stable thermal vacuum facility

CBI has recently constructed the Intermediate Thermal Vacuum Facility. Built as a corporate facility, the installation will first be used on the Boost Surveillance and Tracking System (BSTS) program. It will also be used to develop and test other sensor systems. The horizontal chamber has a horseshoe shaped cross section and is supported on pneumatic isolators for vibration isolation. The chamber structure was designed to meet stability and stiffness requirements. The design process included measurement of the ambient ground vibrations, analysis of various foundation test article support configurations, design and analysis of the chamber shell and modal testing of the chamber shell. A detailed 3-D finite element analysis was made in the design stage to predict the lowest three natural frequencies and mode shapes and to identify local vibrating components. The design process is described and the results are compared of the finite element analysis to the results of the field modal testing and analysis for the 3 lowest natural frequencies and mode shapes. Concepts are also presented for stiffening large steel structures along with methods to improve test article stability in large space simulation facilities.

Tellalian, Martin L.↗
NASA NTRS2006

Laser Shearography Inspection of TPS (Thermal Protection System) Cork on RSRM (Reusable Solid Rocket Motors)

Laser Shearography is a viable inspection method for detection of de-bonds and voids within the external TPS (thermal protection system) on to the Space Shuttle RSRM (reusable solid rocket motors). Cork samples with thicknesses up to 1 inch were tested at the LTI (Laser Technology Incorporated) laboratory using vacuum-applied stress in a vacuum chamber. The testing proved that the technology could detect cork to steel un-bonds using vacuum stress techniques in the laboratory environment. The next logical step was to inspect the TPS on a RSRM. Although detailed post flight inspection has confirmed that ATK Thiokol's cork bonding technique provides a reliable cork to case bond, due to the Space Shuttle Columbia incident there is a great interest in verifying bond-lines on the external TPS. This interest provided and opportunity to inspect a RSRM motor with Laser Shearography. This paper will describe the laboratory testing and RSRM testing that has been performed to date. Descriptions of the test equipment setup and techniques for data collection and detailed results will be given. The data from the test show that Laser Shearography is an effective technology and readily adaptable to inspect a RSRM.

Lingbloom, Mike↗
NASA NTRSDate not supplied

Designing the PLANET Chamber for Lunar Environment Ground Testing

The Planetary, Lunar, and Asteroid Natural Environments Testbed (PLANET) is a new 2m x 3m high-vacuum chamber facility currently being designed and built at NASA’s Marshall Space Flight Center. When completed, it will be one of the highest-fidelity space/surface environment simulation chambers in existence. Instrumented with equipment to produce charged particle radiation, full spectrum ultraviolet, low-density plasma, and thermal extremes, PLANET can be configured to recreate the most challenging space environments. Additionally, a large regolith bed and distribution system will expose hardware to lunar regolith simulants and dust. This paper will describe the process of designing and optimizing PLANET and discuss some common considerations for performing ground-based environmental testing for lunar exploration.

Erin G Hayward↗
NASA NTRS2018

High Power Advanced Solar Electric Propulsion Development Under NASA's NextSTEP Project

Human missions to Mars will require next generation solar electric propulsion (SEP) systems that can operate at power levels of 300 kW or higher to efficiently transport crew and cargo. In the mid-2020s, NASA is planning to launch the Deep Space Gateway (DSG), which is a crew-tended habitat that will be placed in orbit around the Moon. NASA is developing 12.5 kW Hall thrusters for the DSG. In the late 2020s, the DSG will be followed by a second vehicle, called the Deep Space Transport (DST), which will simulate a crewed Mars mission in cislunar space. In parallel with the 12.5 kW thrusters for the DSG, NASA is initiating development of 100 kW thrusters for potential demonstration on the DST. In 2016, NASA issued a Next Space Technologies for Exploration Partnerships (NextSTEP) Broad Agency Announcement to solicit proposals for development of high-power electric thrusters. The partnerships require at least 50 percent cost sharing by the companies. Three companies were selected for development activities lasting up to three years: Ad Astra, Aerojet Rocketdyne, and MSNW. Ad Astra is developing a Variable Specific Impulse Magnetoplasma Rocket (VASIMR), Aerojet Rocketdyne is developing a Nested Hall Thruster (NHT), and MSNW is developing an Electrodeless Lorentz Force (ELF) plasma thruster. The primary goal of these activities is to operate the thrusters at 100 kW for 100 continuous hours in a vacuum chamber. In addition to the thrusters, the companies are developing Power Processing Units (PPUs), propellant feed systems, and thermal management systems. This presentation will describe the three activities, the progress they have made in achieving the primary testing goal, the technical challenges they have encountered, and discuss the importance of extensibility.

Moore, Chris↗
NASA NTRS2014

Insulation Test Cryostat with Lift Mechanism

A multi-purpose, cylindrical thermal insulation test apparatus is used for testing insulation materials and systems of materials using a liquid boil-off calorimeter system for absolute measurement of the effective thermal conductivity (k-value) and heat flux of a specimen material at a fixed environmental condition (cold-side temperature, warm-side temperature, vacuum pressure level, and residual gas composition). The apparatus includes an inner vessel for receiving a liquid with a normal boiling point below ambient temperature, such as liquid nitrogen, enclosed within a vacuum chamber. A cold mass assembly, including the upper and lower guard chambers and a middle test vessel, is suspended from a lid of the vacuum canister. Each of the three chambers is filled and vented through a single feedthrough. All fluid and instrumentation feedthroughs are mounted and suspended from a top domed lid to allow easy removal of the cold mass. A lift mechanism allows manipulation of the cold mass assembly and insulation test article.

Fesmire, James E.↗
NASA NTRS2012

Real-Time EVA Troubleshooting

Dr. Parazynski focused on the Shuttle Transportation System (STS)-120 Solar Array Repair Extravehicular Activity (EVA) with personal anecdotes and then spoke about what it takes to have a successful EVA during the event, what types of problems can occur during an EVA, particularly with the spacesuit and the safety of the crew, and how to resolve these quickly, safely, and efficiently. He also described the participants and the types of decisions and actions each had to take to ensure success. He described "Team 4," in Houston and on-orbit, as well as anecdotes from his STS-86 and STS-100 missions. Parazynski provided a retrospective on the EVA tools and procedures NASA used in the aftermath of Columbia for shuttle Thermal Protection System (TPS) inspection and repair. He described his role as the lead astronaut during this effort, and covered all the Neutral Buoyancy Laboratory (NBL), KC-135, precision air-bearing floor (PABF), vacuum chamber, and 1-G testing performed to develop the tools and techniques that were flown. Parazynski discussed how the EVA community worked together to resolve a huge safety issue, and how his work in the spacesuit was critical to overcoming a design limitation of the Space Shuttle.

Parazynski, Scott↗
NASA NTRS1975

Thermoelastic analysis of solar window of a vacuum chamber

It has been noted during space simulation test programs that the chamber penetration window becomes the limiting factor as the solar intensity increases. The temperature at the center of the window normally attains a level of 550 C, while the edge temperature remains at about 35 C. The stresses produced by this thermal gradient combined with the atmospheric pressure are studied within the framework of classical theory of elasticity. The solution for the problem is obtained by solving the static uncoupled thermoelastic equations for a circular blank, subjected to nonuniform heat on one face, by introduction of two auxiliary variables. The displacements are expressed in terms of Bessel functions and parameters of interest are computed at various mesh points of the window. The maximum principal stresses thus obtained show that even with steep temperature gradient, the safety factor is acceptable.

Amba-Rao, C. L.↗
NASA NTRS1990

Solar thermal vacuum tests of Magellan spacecraft

The Magellen solar/thermal/vacuum test involved a number of unique requirements and approaches. Because of the need to operate in orbit around Venus, the solar intensity requirement ranged up to 2.3 suns or Earth equivalent solar constants. Extensive modification to the solar simulator portion of the test facility were required to achieve this solar intensity. Venus albedo and infrared emission were simulated using temperature controlled movable louver panels to allow the spacecraft to view either a selectable temperature black heat source with closed louvers, or the chamber coldwall behind open louvers. The test conditions included widely varying solar intensities, multiple sun angles, alternate hardware configurations, steady state and transient cases, and cruise and orbital power profiles. Margin testing was also performed, wherein supplemental heaters were mounted to internal thermal blankets to verify spacecraft performance at higher than expected temperatures. The test was successful, uncovering some spacecraft anomalies and verifying the thermal design. The test support equipment experienced some anomalous behavior and a significant failure during the test.

Neuman, James C.↗
NASA NTRS2007

Proposed Facility Modifications to Support Propulsion Systems Testing Under Simulated Space Conditions at Plum Brook Station's Spacecraft Propulsion Research Facility (B-2)

Preparing NASA's Plum Brook Station's Spacecraft Propulsion Research Facility (B-2) to support NASA's new generation of launch vehicles has raised many challenges for B-2 s support staff. The facility provides a unique capability to test chemical propulsion systems/vehicles while simulating space thermal and vacuum environments. Designed and constructed 4 decades ago to support upper stage cryogenic engine/vehicle system development, the Plum Brook Station B-2 facility will require modifications to support the larger, more powerful, and more advanced engine systems for the next generation of vehicles leaving earth's orbit. Engine design improvements over the years have included large area expansion ratio nozzles, greater combustion chamber pressures, and advanced materials. Consequently, it has become necessary to determine what facility changes are required and how the facility can be adapted to support varying customers and their specific test needs. Instrumental in this task is understanding the present facility capabilities and identifying what reasonable changes can be implemented. A variety of approaches and analytical tools are being employed to gain this understanding. This paper discusses some of the challenges in applying these tools to this project and expected facility configuration to support the varying customer needs.

Edwards, Daryl A.↗
NASA NTRS2012

TPS Inspection and Repair

Dr. Scott Parazynski provided a retrospective on the EVA tools and procedures efforts NASA went through in the aftermath of Columbia for the Shuttle Thermal Protection System (TPS) inspection and repair. He describes his role as the lead astronaut on this effort, and covered all of the Neutral Buoyancy Lab (NBL), KC 135 (reduced gravity aircraft), Precision Air Bearing Floor (PABF), vacuum chamber and 1 G testing that was done in order to develop the tools and techniques that were flown. Parazynski also discusses how the EVA community worked together to resolve a huge safety issue, and how his work in the spacesuit was critical to overcoming a design limitation of the Space Shuttle.

Parazynski, Scott↗
NASA NTRS2015

Performance and Facility Background Pressure Characterization Tests of NASAs 12.5-kW Hall Effect Rocket with Magnetic Shielding Thruster

NASA's Space Technology Mission Directorate (STMD) Solar Electric Propulsion Technology Demonstration Mission (SEP/TDM) project is funding the development of a 12.5-kW Hall thruster system to support future NASA missions. The thruster designated Hall Effect Rocket with Magnetic Shielding (HERMeS) is a 12.5-kW Hall thruster with magnetic shielding incorporating a centrally mounted cathode. HERMeS was designed and modeled by a NASA GRC and JPL team and was fabricated and tested in vacuum facility 5 (VF5) at NASA GRC. Tests at NASA GRC were performed with the Technology Development Unit 1 (TDU1) thruster. TDU1's magnetic shielding topology was confirmed by measurement of anode potential and low electron temperature along the discharge chamber walls. Thermal characterization tests indicated that during full power thruster operation at peak magnetic field strength, the various thruster component temperatures were below prescribed maximum allowable limits. Performance characterization tests demonstrated the thruster's wide throttling range and found that the thruster can achieve a peak thruster efficiency of 63% at 12.5 kW 500 V and can attain a specific impulse of 3,000 s at 12.5 kW and a discharge voltage of 800 V. Facility background pressure variation tests revealed that the performance, operational characteristics, and magnetic shielding effectiveness of the TDU1 design were mostly insensitive to increases in background pressure.

Performance↗
NASA NTRSDate not supplied

A Summary of the NEXT-C Flight Thruster Proto-flight Testing

Aerojet Rocketdyne (AR), under contract to NASA Glenn Research Center, built, tested and delivered the first flight version of the NEXT-C (NASA Evolutionary Xenon Thruster – Commercial) engine system. This system is comprised of a 7 kW thruster and power processing unit which are the commercial variants of the NEXT prototype thruster and power processing unit. In addition to developing the NEXT-C engine system for potential future NASA science missions, AR is dedicated to ensuring that this propulsion system is viable for commercial users and a wider variety of commercial applications. This paper will focus on the performance of the first flight model thruster, SN001, and presents an overview of the proto-flight testing environments and data obtained. For this first flight thruster, the proto-flight test sequence involved characterizing the performance of the thruster, in addition to vibration and thermal vacuum testing of the thruster. Between each of these environmental tests, the performance of the thruster was verified, ensuring that the environmental exposures, i.e. vibration and TVAC, did not affect the thruster performance. Specifically, the proto-flight data obtained included discharge chamber, optics and neutralizer performance. Faraday probe and ExB data obtained in the regions downstream of the thruster are presented and used to calculate thrust, and therefore specific impulse and total efficiency. Lastly, data are presented showing how the centroid of the ion beam, assumed to be indicative of the thrust vector location, varies throughout the entire proto-flight test campaign. The proto-flight testing of the NEXT-C PPU is documented in a previously published paper by Bontempo4. Following the proto-flight testing of the thruster, the thruster and its PPU successfully completed a System Integrated Test (SIT) tailored to the DART Mission. After the completion of the proto-flight testing, the SN001 thruster and SN002 PPU were delivered to APL for use on the DART mission.

Ion thruster↗