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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 253 records · Page 14

Reflectron Time-of-Flight Mass Spectrometer (REMAS) Instrumentation

The restricted mass and power budgets of landed science missions present a challenge to obtaining detailed analyses of planetary bodies. In situ studies, whether alone or as reconnaissance for sample return, must rely on highly miniaturized and autonomous instrumentation. Such devices must still produce useful data sets from a minimum of measurements. The great desire to understand the surfaces and interiors of planets, moons, and small bodies had driven the development of small, robotic techniques with ever-increasing capabilities. One of the most important goals on a surface mission is to study composition in many geological contexts. The mineralogical, molecular, elemental, and isotopic content of near-surface materials (regolith, rocks, soils, dust, etc.) at a variety of sites can complement broader imaging to describe the makeup and formative history of the body in question. Instruments that perform this site-to-site analysis must be highly transportable and work as a suite. For instance, a camera, microscope, spectrophotometer, and mass spectrometer can share several components and operate under a parallel command structure. Efficient use of multiple systems on a small rover has been demonstrated on the Mars Pathfinder mission.

Brinckerhoff, W. B.↗

Airframe Noise Results from the QTD II Flight Test Program

With continued growth in air travel, sensitivity to community noise intensifies and materializes in the form of increased monitoring, regulations, and restrictions. Accordingly, realization of quieter aircraft is imperative, albeit only achievable with reduction of both engine and airframe components of total aircraft noise. Model-scale airframe noise testing has aided in this pursuit; however, the results are somewhat limited due to lack of fidelity of model hardware, particularly in simulating full-scale landing gear. Moreover, simulation of true in-flight conditions is non-trivial if not infeasible. This paper reports on an investigation of full-scale landing gear noise measured as part of the 2005 Quiet Technology Demonstrator 2 (QTD2) flight test program. Conventional Boeing 777-300ER main landing gear were tested, along with two noise reduction concepts, namely a toboggan fairing and gear alignment with the local flow, both of which were down-selected from various other noise reduction devices evaluated in model-scale testing at Virginia Tech. The full-scale toboggan fairings were designed by Goodrich Aerostructures as add-on devices allowing for complete retraction of the main gear. The baseline-conventional gear, faired gear, and aligned gear were all evaluated with the high-lift system in the retracted position and deployed at various flap settings, all at engine idle power setting. Measurements were taken with flyover community noise microphones and a large aperture acoustic phased array, yielding far-field spectra, and localized sources (beamform maps). The results were utilized to evaluate qualitatively and quantitatively the merit of each noise reduction concept. Complete similarity between model-scale and full-scale noise reduction levels was not found and requires further investigation. Far-field spectra exhibited no noise reduction for both concepts across all angles and frequencies. Phased array beamform maps show inconclusive evidence of noise reduction at selective frequencies (1500 to 3000 Hz) but are otherwise in general agreement with the far-field spectra results (within measurement uncertainty).

Elkoby, Ronen↗

Passive Cooling for Mercury Surface Lander Electronics

A significant barrier to operation of a mission on the surface of Mercury is the temperature. At Mercury’s perihelion distance of 0.313 AU, the solar intensity is 10.6 times the solar flux at Earth orbit, and at the subsolar point, the maximum surface temperature reaches 427°C. For a mission landing on the surface of Mercury at latitude of 40°S, we analyzed using passive thermal control to reduce the temperature of the critical electronics to within the operation temperature limits of silicon devices. The thermal control requires reducing the thermal conductance and infrared flux from the high temperature surface and surrounding spacecraft, and moderating the solar heat input using a surface coating with high solar reflectivity, and maximizing thermal cooling with high infrared emissivity. Using this approach, we find that we can passively cool an electronics box to a temperature of 393K (120°C) using a radiator-white surface with solar absorptivity 0.11 and infrared emissivity 0.91. This temperature is well under 175C target we use for the limits of high-temperature silicon integrated circuits, including RAM and microcontrollers. We could further reduce this operating temperature to as low as 321K (48°C) with an advanced thermal coating, a temperature well within the operational limits of conventional electronics.

Mercury↗

Passive Cooling for Mercury Surface Lander Electronics

A significant barrier to operation of a mission on the surface of Mercury is the temperature. At Mercury’s perihelion distance of 0.313 AU, the solar intensity is 10.6 times the solar flux at Earth orbit, and at the subsolar point, the maximum surface temperature reaches 427°C. For a mission landing on the surface of Mercury at latitude of 40°S, we analyzed using passive thermal control to reduce the temperature of the critical electronics to within the operation temperature limits of silicon devices. The thermal control requires reducing the thermal conductance and infrared flux from the high temperature surface and surrounding spacecraft, and moderating the solar heat input using a surface coating with high solar reflectivity, and maximizing thermal cooling with high infrared emissivity. Using this approach, we find that we can passively cool an electronics box to a temperature of 393K (120°C) using a radiator-white surface with solar absorptivity 0.11 and infrared emissivity 0.91. This temperature is well under 175C target we use for the limits of high-temperature silicon integrated circuits, including RAM and microcontrollers. We could further reduce this operating temperature to as low as 321K (48°C) with an advanced thermal coating, a temperature well within the operational limits of conventional electronics

Mercury↗

Power System Redundancy Design Trends for All-Electric eVTOL Quadrotors

Electrical vertical takeoff and landing (eVTOL) vehicles promise to enable a variety of new local and intraregional air transport missions. However, there are significant challenges that must be solved to enable their use. One challenge is the relatively low reliability of power components (e.g. motors, power electronic devices, and batteries). No clear development path to create reliable eVTOL power systems has been articulated in the literature, though it is generally assumed redundancy is part of the solution. This work proposes an analysis process to examine the redundancy design space and select mass optimal designs for eVTOL power systems. The process is applied to a six passenger quadrotor vehicle, and results are used to highlight redundancy design trends for this class of vehicle. This process and associated data can help vehicle designers more effectively develop eVTOLs that meet reliability requirements.

Electric vertical takeoff and landing↗

Power System Redundancy Design Trends for All-Electric eVTOL Quadrotors

Electrical vertical takeoff and landing (eVTOL) vehicles promise to enable a variety of new local and intraregional air transport missions. However, there are significant challenges that must be solved to enable their use. One challenge is the relatively low reliability of power components (e.g. motors, power electronic devices, and batteries). No clear development path to create reliable eVTOL power systems has been articulated in the literature, though it is generally assumed redundancy is part of the solution. This work proposes an analysis process to examine the redundancy design space and select mass optimal designs for eVTOL power systems. The process is applied to a six passenger quadrotor vehicle, and results are used to highlight redundancy design trends for this class of vehicle. This process and associated data can help vehicle designers more effectively develop eVTOLs that meet reliability requirements.

Electric vertical takeoff and landing↗

Moon Base Transportation - Deliveries to the Lunar Surface

Development of the Moon Base will enable a home away from home for astronauts who will live and work at humanity’s first lunar outpost. In this effort, NASA’s Moon Transportation Office is responsible for enabling the transformational missions required to deliver habitats, supplies, science payloads, and all other elements needed to cultivate a permanent presence on the Lunar Surface. The Mission Concept (MC) is characterized through evaluation of an end-to-end architecture that can successfully deliver a generalized heavy large-volume payload, in excess of 4000 kg, to a precision landing and touchdown on the lunar surface. The mission architecture utilizes a single launch configuration of a Lunar Lander (LL) with a unique propellant system. The LL has an integral orbital transfer capability and features jettisonable elements. The design circumvents the need for prop transfer on orbit and multiple launch configurations. The launch vehicle (LV) for this work will assume the capability to deliver a payload in excess of 40,000 kg to orbit, affording multiple LV solutions. Considerations for the LL and payload deployment from the fairing are assumed to be handled through compliance with a launch providers’ Interface Requirements Document (IRD). The MC will span from launch at Kennedy Space Center (KSC) to terminal descent and touchdown on the lunar surface, requiring a total ΔV on the order of 6 km/s beyond what is required to get the vehicle stack to a 200 km circular Low Earth Orbit (LEO). Major mission phases include: launch and launch vehicle separation, transfer operations, pre-landing navigation, and lunar descent and touchdown. A Concept of Operations (ConOps) is used as the primary design driver for defining architecture of the vehicles necessary to achieve final payload delivery. Numerous ground rules and assumptions will be provided for each phase of the mission. Concept designs for the LL is presented. An emphasis of the design maximizes a feasible path for maturation, manufacturing, and operation. A self-imposed practical consideration for this effort is the incorporation of legacy designed hardware to minimize expensive, time-intensive, and high-risk hardware development cycles. The propulsion system of the LL adopts a conventional storable bipropellant configuration of monomethyl hydrazine (MMH) and mixed oxides of nitrogen (MON3). This effort will showcase a unique propellant delivery system to minimize the reliance on propellant management devices (PMDs) during descent. Numerous key constraints have been considered, across the multiple segments of the mission. These include the unique aspects of center of gravity (CG) management, thruster plume effects including self-impingement, propulsion system hardware limitations, navigation during multiple mission phases, and landing gear geometry for uneven terrain. These constraints shape the trades necessary for precision landing of heavy cargo and ensure compatibility with broader Moon Base Transportation concepts. The resulting insights inform future transportation strategies for the Moon and beyond; directly contributing to the development of cargo‑delivery standards that will support the long‑term buildup of a sustainable, continuously inhabited Moon Base.

Lunar Habitat↗

Combination spacer and gasket provides effective static seal

Closely machined steel ring having narrow sealing lands on both faces and a thin coating of a commercially available halocarbon polymer combines the functions of a spacer and static seal ring or gasket having a minimum of potential leak paths. The device is effective over a wide range of temperatures down to minus 423 deg F and at pressure up to 180 psig.

Jones, F. B.↗

Electrical generator uses ocean waves

Device converts up-and-down motion of ocean to electrical energy. Plunging generator delivers energy to be stored in battery and used to operate remote data gathering stations. Concept may be applied to land or air use if plunging motion is supplied.

Grana, D. C.↗

Basic studies on delta wing flow modifications by means of apex fences

The effectiveness of apex fences on a 60-deg delta wing at low speeds was experimentally investigated. Resembling highly swept spoilers in appearance, the fences are designed to fold out of the wing apex region upper surface near the leading edges, where they generate a powerful vortex pair. The intense suction of the fence vortices augments lift in the apex region, the resulting positive pitching moment being utilized to trim trailing edge flaps for lift augmentation during approach and landing at relatively low angles of attack. The fences reduce the apex lift at high angles of attack, leading to a desirable nose-down moment. The above projected functions of the apex fence device were validated and quantified through low speed tunnel tests, comprising upper surface pressure surveys on a semispan model and balance measurements on a geometrically similar fully span wing/body configuration. Fence parameters such as area, shape, hinge position and deflection angle were investigated. Typical results are presented indicating the apex fence potential in controlling the longitudinal characteristics of a tail-less delta.

Hoffler, K. D.↗

Aerodynamic Decelerators for Planetary Exploration: Past, Present, and Future

In this paper, aerodynamic decelerators are defined as textile devices intended to be deployed at Mach numbers below five. Such aerodynamic decelerators include parachutes and inflatable aerodynamic decelerators (often known as ballutes). Aerodynamic decelerators play a key role in the Entry, Descent, and Landing (EDL) of planetary exploration vehicles. Among the functions performed by aerodynamic decelerators for such vehicles are deceleration (often from supersonic to subsonic speeds), minimization of descent rate, providing specific descent rates (so that scientific measurements can be obtained), providing stability (drogue function - either to prevent aeroshell tumbling or to meet instrumentation requirements), effecting further aerodynamic decelerator system deployment (pilot function), providing differences in ballistic coefficients of components to enable separation events, and providing height and timeline to allow for completion of the EDL sequence. Challenging aspects in the development of aerodynamic decelerators for planetary exploration missions include: deployment in the unusual combination of high Mach numbers and low dynamic pressures, deployment in the wake behind a blunt-body entry vehicle, stringent mass and volume constraints, and the requirement for high drag and stability. Furthermore, these aerodynamic decelerators must be qualified for flight without access to the exotic operating environment where they are expected to operate. This paper is an introduction to the development and application of aerodynamic decelerators for robotic planetary exploration missions (including Earth sample return missions) from the earliest work in the 1960s to new ideas and technologies with possible application to future missions. An extensive list of references is provided for additional study.

Juan R Cruz↗

Gondola for High Altitude Planetary Science (GHAPS) Telescope Secondary Mirror Positioning Hexapod Issues and Alternatives

Active positioning of the GHAPS secondary telescope mirror is desired to correct for rigid body deflections due to temperature variations and gravity sag in the telescope structure that may impact optical performance. The current design concept for the secondary mirror mount uses a Commercial-Off -the-Shelf hexapod for mirror positioning and fine adjustment. The Hexapod specification states that motions as small as 0.1 microns along the optical axis and 2 microns perpendicular to the optical axis will cause optical aberrations that will require correction by repositioning the secondary mirror. In addition, the secondary mirror mount and positioning system must survive a 15g shock of parachute opening and landing during the instrument recovery operation. The secondary mirror positioning system must operate at a minimum specified temperature of -50 C. The telescope operates in the IR and the secondary mirror mount and positioning device is in the metering path between the primary and secondary mirrors. I2R losses in positioning system actuator devices, which may cause heating of the positioning system and secondary mirror, must be minimized due to the previously mentioned alignment sensitivity and the viewing spectrum of interest. The GHAPs project was cancelled on June 30, 2017. The purpose of this study is to address some of the issues identified with the hexapod secondary mirror positioning system and identify alternative approaches. This information may be used if the project is re-started at a later date.

Gondola Mirror Hexapo↗

Mars Science Laboratory Boot Robustness Testing

Mars Science Laboratory (MSL) is one of the most complex spacecrafts in the history of mankind. Due to the nature of its complexity, a large number of flight software (FSW) requirements have been written for implementation. In practice, these requirements necessitate very complex and very precise flight software with no room for error. One of flight software's responsibilities is to be able to boot up and check the state of all devices on the spacecraft after the wake up process. This boot up and initialization is crucial to the mission success since any misbehavior of different devices needs to be handled through the flight software. I have created a test toolkit that allows the FSW team to exhaustively test the flight software under variety of different unexpected scenarios and validate that flight software can handle any situation after booting up. The test includes initializing different devices on spacecraft to different configurations and validate at the end of the flight software boot up that the flight software has initialized those devices to what they are suppose to be in that particular scenario.

mission phases↗

Motion Perception and Manual Control Performance During Passive Tilt and Translation Following Space Flight

This joint ESA-NASA study is examining changes in motion perception following Space Shuttle flights and the operational implications of post-flight tilt-translation ambiguity for manual control performance. Vibrotactile feedback of tilt orientation is also being evaluated as a countermeasure to improve performance during a closed-loop nulling task. METHODS. Data has been collected on 5 astronaut subjects during 3 preflight sessions and during the first 8 days after Shuttle landings. Variable radius centrifugation (216 deg/s) combined with body translation (12-22 cm, peak-to-peak) is utilized to elicit roll-tilt perception (equivalent to 20 deg, peak-to-peak). A forward-backward moving sled (24-390 cm, peak-to-peak) with or without chair tilting in pitch is utilized to elicit pitch tilt perception (equivalent to 20 deg, peak-to-peak). These combinations are elicited at 0.15, 0.3, and 0.6 Hz for evaluating the effect of motion frequency on tilt-translation ambiguity. In both devices, a closed-loop nulling task is also performed during pseudorandom motion with and without vibrotactile feedback of tilt. All tests are performed in complete darkness. PRELIMINARY RESULTS. Data collection is currently ongoing. Results to date suggest there is a trend for translation motion perception to be increased at the low and medium frequencies on landing day compared to pre-flight. Manual control performance is improved with vibrotactile feedback. DISCUSSION. The results of this study indicate that post-flight recovery of motion perception and manual control performance is complete within 8 days following short-duration space missions. Vibrotactile feedback of tilt improves manual control performance both before and after flight.

Clement, Gilles↗

Studies in remote sensing of Southern California and related environments

A summary is presented of the research activities in southern California to determine whether meaningful geographic information was obtainable by use of remote sensing in an area already well documented or if the techniques and methodology could be transferred to related environments. Several broad characteristics of the regional geography were investigated with regards to their feasibility to be studied by aircraft and spacecraft sensors to improve the inventory and understanding of resources and environmental circumstances and to serve as models for future geographic analysis of other regions when using remote sensing devices. Sample activities are described in detail and three experiments producing worthwhile results are highlighted: mapping montane vegetation with color IR imagery, analysis of urban residual environment using color IR aerial photography, and regional agricultural land use mapping tested against color IR photography.

Bowden, L. W.↗

Spacecraft for flight in the atmosphere of Venus

Possible configurations of space vehicles which would be delivered to Venus by rocket system in order to autonomously carry out flights in an automatic (and possibly piloted) mode are considered with respect to mission and flight altitude. Base (high altitude) vehicles, operating at pressure, sendity, and temperature corresponding to those on Earth at sea level, will have little maneuverability, will serve as carriers for equipment, scientific devices, and other cargo, and will study the gas composition of the Venus atmosphere from above. Low altitude vehicles will explore the planet from flight altitude in the vicinity of the planet's surface, as well as land on it. Analogous to deep submergence vehicles such as the bathyscaphe and the bathyplane, they will have a certain amount of maneuverability and will study the atmospheric boundary layer from below. The advantages of aerostats in this environment are discussed. Drawings of the aerostatic base station, the variable-length aerostatic sing vehicle, and the hybrid aerostatic vehicle with attached wings are included.

Moskalenko, G. M.↗

Design concepts of the Shuttle mission simulator

The Shuttle mission simulator is designed to simulate all phases of the Space Shuttle mission from the last 30 minutes of countdown to launch, ascent, operations in orbit, deorbit, reentry, and landing with full participation by astronaut trainees and the mission control center. This paper reviews the design concepts of the simulator with attention given to the simulation hardware, crew stations, instructor/operator stations, digital computers, flight computer simulation interface device, mission control center interface, visual systems, aural cue system, mathematical modeling, digital computer complex, motion system, and the payload accommodation system.

Bird, J. D.↗

Ka-band MMIC subarray technology program (Ka-Mist)

The broad objective of this program was to demonstrate a proof of concept insertion of Monolithic Microwave Integrated Circuit (MMIC) device technology into an innovative (tile architecture) active phased array antenna application supporting advanced EHF communication systems. Ka-band MMIC arrays have long been considered as having high potential for increasing the capability of space, aircraft, and land mobile communication systems in terms of scan performance, data rate, link margin, and flexibility while offering a significant reduction in size, weight, and power consumption. Insertion of MMIC technology into antenna systems, particularly at millimeter wave frequencies using low power and low noise amplifiers in close proximity to the radiating elements, offers a significant improvement in the array transmit efficiency, receive system noise figure, and overall array reliability. Application of active array technology also leads to the use of advanced beamforming techniques that can improve beam agility, diversity, and adaptivity to complex signal environments.

Pottenger, Warren↗