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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 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
NASA NTRS2004

Evaluation of various cleaning methods to remove bacillus spores from spacecraft hardware materials

A detailed study was made of the biological cleaning effectiveness, defined in terms of the ability to remove bacterial spores, of a number of methods used to clean hardware surfaces. Aluminum (Al 6061) and titanium (Ti 6Al-4V) were chosen for the study as they were deemed the two materials most likely to be used in spacecraft extraterrestrial sampler construction. Metal coupons (1 cm x 2.5 cm) were precleaned and inoculated with 5.8 x 10(3) cultivable Bacillus subtilis spores, which are commonly found on spacecraft surfaces and in the assembly environments. The inoculated coupons were subsequently cleaned using: (1) 70% isopropyl alcohol wipe; (2) water wipe; (3) multiple-solvent flight-hardware cleaning procedures used at the Jet Propulsion Laboratory (JPL); (4) Johnson Space Center-developed ultrapure water rinse; and (5) a commercial, semi-aqueous, multiple-solvent (SAMS) cleaning process. The biological cleaning effectiveness was measured by agar plate assay, sterility test (growing in liquid media), and epifluorescent microscopy. None of the cleaning protocols tested completely removed viable spores from the surface of the aluminum. In contrast, titanium was capable of being cleaned to sterility by two methods, the JPL standard and the commercial SAMS cleaning process. Further investigation showed that the passivation step employed in the JPL standard method is an effective surface sterilant on both metals but not compatible with aluminum. It is recommended that titanium (Ti 6Al-4V) be considered superior to aluminum (Al 6061) for use in spacecraft sampling hardware, both for its potential to be cleaned to sterilization and for its ability to withstand the most effective cleaning protocols.

Spores, Bacterial/metabolism↗
NASA NTRS2014

Comm for Small Sats: The Lunar Atmosphere and Dust Environment Explorer (LADEE) Communications Subsystem

September 6, 2013 through April 21, 2014 marked the mission lifecycle of the highly successful LADEE (Lunar Atmosphere and Dust Environment Explorer) mission that orbited the moon to gather detailed information about the thin lunar atmosphere. This paper will address the development, risks, and lessons learned regarding the specification, selection, and deployment of LADEE's unique Radio Frequency based communications subsystem and supporting tools. This includes the Electronic Ground Support Equipment (EGSE), test regimes, and RF dynamic link analysis environment developed to meet mission requirements for small, flexible, low cost, high performance, fast turnaround, and reusable spacecraft communication capabilities with easy and reliable application to future similar low cost small satellite missions over widely varying needs for communications and communications system complexity. LADEE communication subsystem key components, architecture, and mission performance will be reviewed toward applicability for future mission planning, design, and utilization.

transponder↗
NASA NTRS2004

Research and Development in Optical Communications

A report in the form of lecture slides summarizes the optical-communications program of NASA s Jet Propulsion Laboratory (JPL) and describes the JPL Optical Communications Telescope Laboratory (OCTL) and its role in the program. The purpose of the program is to develop equipment and techniques for laser communication between (1) ground stations and (2) spacecraft (both near Earth and in deep space) and aircraft. The OCTL is an astronomical- style telescope facility that includes a 1-m-diameter, 75.8-m-focal length telescope in an elevation/azimuth mount, plus optical and electronic subsystems for tracking spacecraft and aircraft, receiving laser signals from such moving targets, and transmitting high-power laser signals to such targets. Near-term research at the OCTL is expected to focus on mitigating the effects of atmospheric scintillation on uplinks and on beacon-assisted tracking of ground stations by stations in deep space. Near-term experiments are expected to be performed with retroreflector-equipped aircraft and Earth-orbiting spacecraft techniques to test mathematical models of propagation of laser beams, multiple-beam strategies to mitigate uplink scintillation, and pointing and tracking accuracy of the telescope.

Wilson, Keith↗
NASA NTRS1984

Optimization of thermal systems with sensitive optics, electronics, and structures

A strategy was investigated by which thermal designers for spacecraft could devise an optimal thermal control system to maintain the required temperatures, temperature differences, changes in temperature, and changes in temperature differences for specified equipment and elements of the spacecraft's structure. Thermal control is to be maintained by the coating pattern chosen for the external surfaces and heaters chosen to supplement the coatings. The approach is to minimize the thermal control power, thereby minimizing the weight of the thermal control system. Because there are so many complex computations involved in determining the optimal coating design a computerized approach was contemplated. An optimization strategy including all the elements considered by the thermal designer for use in the early stages of design, where impact on the mission is greatest, and a plan for implementing the strategy were successfully developed. How the optimization process may be used to optimize the design of the Space Telescope as a test case is demonstrated.

Bettini, R. G.↗
NASA NTRS1967

Microelectronics on ATS

Fabrication, packaging, and testing of microelectronic equipment for Applications Technology Satellite /ATS/ scientific experimental package

ELECTRONIC PACKAGING↗
NASA NTRS1972

Reliability history of the Apollo guidance computer

The Apollo guidance computer was designed to provide the computation necessary for guidance, navigation and control of the command module and the lunar landing module of the Apollo spacecraft. The computer was designed using the technology of the early 1960's and the production was completed by 1969. During the development, production, and operational phase of the program, the computer has accumulated a very interesting history which is valuable for evaluating the technology, production methods, system integration, and the reliability of the hardware. The operational experience in the Apollo guidance systems includes 17 computers which flew missions and another 26 flight type computers which are still in various phases of prelaunch activity including storage, system checkout, prelaunch spacecraft checkout, etc. These computers were manufactured and maintained under very strict quality control procedures with requirements for reporting and analyzing all indications of failure. Probably no other computer or electronic equipment with equivalent complexity has been as well documented and monitored. Since it has demonstrated a unique reliability history, it is important to evaluate the techniques and methods which have contributed to the high reliability of this computer.

Hall, E. C.↗
NASA NTRS1985

Activated recombinative desorption: A potential component in mechanisms of spacecraft glow

The concept of activated recombination of atomic species on surfaces can explain the production of vibrationally and translationally excited desorbed molecular species. Equilibrium statistical mechanics predicts that the molecular quantum state distributions of desorbing molecules is a function of surface temperature only when the adsorption probability is unity and independent of initial collision conditions. In most cases, the adsorption probability is dependent upon initial conditions such as collision energy or internal quantum state distribution of impinging molecules. From detailed balance, such dynamical behavior is reflected in the internal quantum state distribution of the desorbing molecule. This concept, activated recombinative desorption, may offer a common thread in proposed mechanisms of spacecraft glow. Using molecular beam techniques and equipment available at Los Alamos, which includes a high translational energy 0-atom beam source, mass spectrometric detection of desorbed species, chemiluminescence/laser induced fluorescence detection of electronic and vibrationally excited reaction products, and Auger detection of surface adsorbed reaction products, a fundamental study of the gas surface chemistry underlying the glow process is proposed.

Cross, J. B.↗
NASA NTRS2009

Kennedy's Biomedical Laboratory Makes Multi-Tasking Look Easy

If it is one thing that Florida has in abundance, it is sunshine and with that sunshine heat and humidity. For workers at the Kennedy Space Center that have to work outside in the heat and humidity, heat exhaustion/stroke is a real possibility. It might help people to know that Kennedy's Biomedical Laboratory has been testing some new Koolvests(Trademark) that can be worn underneath SCAPE suits. They have also been working on how to block out high noise levels; in fact, Don Doerr, chief of the Biomedical Lab, says, "The most enjoyable aspect is knowing that the Biomedical Lab and the skills of its employees have been used to support safe space flight, not only for the astronaut flight crew, but just as important for the ground processing personnel as well." The NASA Biomedical Laboratory has existed in the John F. Kennedy's Operations and Checkout Building since the Apollo Program. The primary mission of this laboratory has been the biomedical support to major, manned space programs that have included Apollo, Apollo-Soyuz, Skylab, and Shuttle. In this mission, the laboratory has been responsible in accomplishing much of the technical design, planning, provision, fabrication, and maintenance of flight and ground biomedical monitoring instrumentation. This includes the electronics in the launch flight suit and similar instrumentation systems in the spacecraft. (Note: The Lab checked out the system for STS-128 at Pad A using Firing room 4 and ground support equipment in the lab.) During Apollo, there were six engineers and ten technicians in the facility. This has evolved today to two NASA engineers and two NASA technicians, a Life Science Support contract physiologist and part-time support from an LSSC nurse and physician. Over the years, the lab has enjoyed collaboration with outside agencies and investigators. These have included on-site support to the Ames Research Center bed rest studies (seven years) and the European Space Agency studies in Toulouse, France (two years). The lab has also actively collaborated with the US Army Institute for Surgical Research, the USAF School of Aerospace Medicine, and the USN Naval Experimental Diving Unit. Because the lab often evaluates various forms of commercial-off-the-shelf life support equipment, the laboratory works closely with private companies, both domestic and foreign. The European companies seem to be more proactive and participatory with the advancement of personal protective equipment. Because these companies have viewed the space program's unique need for advanced forms of personal protective equipment, some have responded with new designs based on the prediction that these advances will soon find markets in the commercial sector. Using much of the same skills and equipment, the laboratory also addresses physiological testing of humans by supporting flight experiments and personnel involved with ground processing. While Johnson Space Center is primarily responsible for flight experiments, the Kennedy's Biomedical Lab provides the local support. However, as stated above, there are many challenges facing KSC workers that gain the attention of this lab in the measurement of the problem and the selection and testing of countermeasures. These include respiratory protection, whole body suits, hearing protection and heat stress, among many others.

Dunn, Carol Anne↗
NASA NTRS2008

Cluster Inter-Spacecraft Communications

A document describes a radio communication system being developed for exchanging data and sharing data-processing capabilities among spacecraft flying in formation. The system would establish a high-speed, low-latency, deterministic loop communication path connecting all the spacecraft in a cluster. The system would be a wireless version of a ring bus that complies with the Institute of Electrical and Electronics Engineers (IEEE) standard 1393 (which pertains to a spaceborne fiber-optic data bus enhancement to the IEEE standard developed at NASA's Jet Propulsion Laboratory). Every spacecraft in the cluster would be equipped with a ring-bus radio transceiver. The identity of a spacecraft would be established upon connection into the ring bus, and the spacecraft could be at any location in the ring communication sequence. In the event of failure of a spacecraft, the ring bus would reconfigure itself, bypassing a failed spacecraft. Similarly, the ring bus would reconfigure itself to accommodate a spacecraft newly added to the cluster or newly enabled or re-enabled. Thus, the ring bus would be scalable and robust. Reliability could be increased by launching, into the cluster, spare spacecraft to be activated in the event of failure of other spacecraft.

Cox, Brian↗
NASA NTRS2014

NASA Tech Briefs, February 2014

Topics include: JWST Integrated Simulation and Test (JIST) Core; Software for Non-Contact Measurement of an Individual's Heart Rate Using a Common Camera; Rapid Infrared Pixel Grating Response Testbed; Temperature Measurement and Stabilization in a Birefringent Whispering Gallery Resonator; JWST IV and V Simulation and Test (JIST) Solid State Recorder (SSR) Simulator; Development of a Precision Thermal Doubler for Deep Space; Improving Friction Stir Welds Using Laser Peening; Methodology of Evaluating Margins of Safety in Critical Brazed Joints; Interactive Inventory Monitoring; Sensor for Spatial Detection of Single-Event Effects in Semiconductor-Based Electronics; Reworked CCGA-624 Interconnect Package Reliability for Extreme Thermal Environments; Current-Controlled Output Driver for Directly Coupled Loads; Bulk Metallic Glasses and Matrix Composites as Spacecraft Shielding; Touch Temperature Coating for Electrical Equipment on Spacecraft; Li-Ion Electrolytes Containing Flame-Retardant Additives; Autonomous Robotic Manipulation (ARM); CARVE Log; Platform Perspective Toolkit; Convex Hull-Based Plume and Anomaly Detection; Pre-Filtration of GOSAT Data Using Only Level 1 Data and an Intelligent Filter to Remove Low Clouds; Affordability Comparison Tool - ACT; "Ascent - Commemorating Shuttle" for iPad; Cassini Mission App; Light-Weight Workflow Engine: A Server for Executing Generic Workflows; Model for System Engineering of the CheMin Instrument; Timeline Central Concepts; Parallel Particle Filter Toolkit; Particle Filter Simulation and Analysis Enabling Non-Traditional Navigation; Quasi-Terminator Orbits for Mapping Small Primitive Bodies; The Subgrid-Scale Scalar Variance Under Supercritical Pressure Conditions; Sliding Gait for ATHLETE Mobility; and Automated Generation of Adaptive Filter Using a Genetic Algorithm and Cyclic Rule Reduction.

Source record↗
NASA NTRS1977

Pioneer Venus spacecraft charging model

Five environmental models were constructed to represent the solar wind and the upper, middle, and lower ionosphere of Venus. The spacecraft structure was modeled with over 140 passive electrical elements representing structural elements of the spacecraft. Electron, ion, secondary electron, and photocurrents to the spacecraft from the plasma were calculated, ignoring sheath effects. In all but one case, potentials of interest were less than 1 volt. Potential differences between widely separated points on the equipment shelf were less than 1 mV. The one area of concern is the solar panel potential when the orbiter is passing through the bowshock region.

Robinson, P. A., Jr.↗
DOE OSTI2020

Literature Review of Optocouplers, Their polymer Components and Current Applicaitons

Optocouplers, also called optoisoloators and photocouplers, are devices that use a light emitting diode (LED) to conduct an electrical signal. The LED receives an electrical signal and emits light proportional to that signal. The light is then received by a photodetector and the signal is propagated. Optocouplers provide a high degree of electrical isolation and are therefore used extensively in commercial electronic equipment. Variations in optocouplers come from the type of photodetector used, the anatomy of the contents and the encapsulating polymers used. Current research involves investigating the tolerance of optocouplers to radiation for the purpose of improving spacecraft and satellites, as well as identifying failure mechanisms and improving design.

42 ENGINEERING↗
DOE OSTI2020

Optocouplers: Polymer Components, Current Applications and My Project Involvement [Slides]

Optocouplers, also called optoisolators and photocouplers, are devices that use a light emitting diode (LED) to conduct an electrical signal. The LED receives an electrical signal and emits light proportional to that signal. The light is then received by a phototransistor and the signal is propagated. Optocouplers provide a high degree of electrical isolation and are therefore used extensively in commercial electronic equipment. Variations in optocouplers come from the type of photodetector used, the anatomy of the contents and the encapsulating polymers used. Current research involves investigating the tolerance of optocouplers to radiation for the purpose of improving spacecraft and satellites, as well as identifying failure mechanisms and improving design. My project involvement at LANL includes conducting thermal and mechanical tests on three different cure profiles of epoxy to collect data about shrinkage, coefficient of thermal expansion, and degree of cure for a group wanting to produce their own optocoupler.

42 ENGINEERING↗
NASA NTRS2012

EMI from Spacecraft Docking Systems Spacecraft Charging - Plasma Contact Potentials

The plasma contact potential of a visiting vehicle (VV), such as the Orion Service Module (SM), is determined while docking at the Orion Crew Exploration Vehicle (CEV). Due to spacecraft charging effects on-orbit, the potential difference between the CEV and the VV can be large at docking, and an electrostatic discharge (ESD) could occur at capture, which could degrade, disrupt, damage, or destroy sensitive electronic equipment on the CEV and/or VV. Analytical and numerical models of the CEV are simulated to predict the worst-case potential difference between the CEV and the VV when the CEV is unbiased (solar panels unlit: eclipsed in the dark and inactive) or biased (solar panels sunlit: in the light and active).

Norgard, John D.↗
NASA NTRS2003

Enhancing DSN Operations Efficiency with the Discrepancy Reporting Management System (DRMS)

The DRMS is the Discrepancy Reporting Management System used by the Deep Space Network (DSN). It uses a web interface and is a management tool designed to track and manage: data outage incidents during spacecraft tracks against equipment and software known as DRs (discrepancy Reports), to record "out of pass" incident logs against equipment and software in a Station Log, to record instances where equipment has be restarted or reset as Reset records, and to electronically record equipment readiness status across the DSN. Tracking and managing these items increases DSN operational efficiency by providing: the ability to establish the operational history of equipment items, data on the quality of service provided to the DSN customers, the ability to measure service performance, early insight into processes, procedures and interfaces that may need updating or changing, and the capability to trace a data outage to a software or hardware change. The items listed above help the DSN to focus resources on areas of most need.

Discrepancy Reporting Management Systems (DRMS)↗
NASA NTRS2006

Modern Space Craft - Antique Specifications

Spacecraft now and of the future are being controlled by EMC requirements of the past. Little has been done by the launch vehicle/spacecraft manufacturers to abandon MIL-STD-461C which was released in 1986 because most of the electronics equipment being used aboard current launch vehicles is approved by similarity and heritage to MIL-STD-46 1 C and its predecessors. Twenty years later these electronic equipment items are still not tested to today's MIL-STD-461E requirements because there is a risk that the items will fail to meet the requirements and thus the cost will increase if it becomes necessary to redesign the equipment. That cost is insignificant compared with the cost of losing an entire mission! In the 20 years that have elapsed since MIL-STD-461C was released, the EMC environment has undergone major changes. High speed digital devices have been created that have fundamental clock and bus frequencies that span the entire LV/SC frequency range from the Flight Termination Systems through C and S-Band telemetry. Personnel involved in ground operations routinely carry and use hand held transceivers and cellular telephones close by sensitive electronics equipment. There are now many more orbiting receivers and emitters, plus range assets have increased dramatically since 2001. It's way past time to bring requirements up-to-date!

Brewer, Ron↗
NASA NTRS1969

Proceedings of the Second Workshop on Voltage Breakdown in Electronic Equipment at Low Air Pressure

The Second Workshop on Voltage Breakdown in Electronic Equipment at Low Air Pressure was sponsored by the Jet Propulsion Laboratory, Pasadena, California. It has been three and one-half years since the convening of the first workshop on voltage breakdown. In this interval, gains are evidenced in the progress and sophistication in solving voltage breakdown problems affecting electronic equip­ment operating at high altitudes or other low air pressure environments. Although space applications predominate the area of concern, other projects such as the SST are becoming increasingly involved with voltage breakdown. High-voltage breakdown in spacecraft continues; however, the incidences of occurrence appear to have decreased in spite of an increase in the number of missions flown. This, it is felt, is due to many project managers now requiring all equipment with voltage in excess of 270-V peak to be designed to operate in the critical pressure region without damage, even though its normal functional environment is sea level pressure and the hard vacuum of space. In addition, designers are becoming more aware of the principle of good high-voltage design by selecting void-free components, proper spacing of conductors, isolating high-­voltage circuitry from lower voltage areas, etc. The consensus seems to be that the slight increase in cost to achieve a provable corona-free design is more than offset by the increase in confidence that the equipment will survive accidental loss of vacuum during high-vacuum tests, inadvertent turn on while passing through the critical air-pressure region of earth after launch or outgassing in flight pressurizing the enclosure into the critical pressure region.

E. R. Bunker, Jr.↗
NASA NTRS1976

Apollo-Soyuz Doppler-tracking experiment MA-089

The Doppler tracking experiment was designed to test the feasibility of improved mapping of the earth's gravity field by the low-low satellite-to-satellite tracking method and to observe variations in the electron density of the ionosphere between the two spacecraft. Data were taken between 1:01 and 14:37 GMT on July 24, 1975. Baseline data taken earlier, while the docking module was still attached to the command and service module, indicated that the equipment operated satisfactorily. The ionospheric data contained in the difference between the Doppler signals at the two frequencies are of excellent quality, resulting in valuable satellite-to-satellite observations, never made before, of wave phenomena in the ionosphere. The gravity data were corrupted by an unexpectedly high noise level of as-yet-undetermined origin, with periods greater than 150 seconds, that prevented unambiguous identification of gravity-anomaly signatures.

Weiffenbach, G. C.↗