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NASA NTRS2018

E-Glider: Active Electrostatic Flight for Airless Body Exploration

The environment near the surface of asteroids, comets, and the Moon is electrically charged due to the Sun's photoelectric bombardment and lofting dust, which follows the Sun illumination as the body spins. Chargeddust is ever present, in the form of dusty plasma, even at high altitudes, following the solar illumination. If abody with high surface resistivity is exposed to the solar wind and solar radiation, sun-exposed areas andshadowed areas become differentially charged. The E-Glider (Electrostatic Glider) is an enabling capability foroperation at airless bodies, a solution applicable to many types of in-situ mission concepts, which leverages thenatural environment. With the E-Glider, we transform a problem (spacecraft charging) into an enablingtechnology, i.e. a new form of mobility in microgravity environments using new mechanisms and maneuveringbased on the interaction of the vehicle with the environment. Consequently, the vision of the E-Glider is toenable global scale airless body exploration with a vehicle that uses, instead of avoids, the local electricallycharged environment. This platform directly addresses the "All Access Mobility" Challenge, one of the NASA'sSpace Technology Grand Challenges. Exploration of comets, asteroids, moons and planetary bodies is limitedby mobility on those bodies. The lack of an atmosphere, the low gravity levels, and the unknown surface soilproperties pose a very difficult challenge for all forms of know locomotion at airless bodies. This E-Gliderlevitates by extending thin, charged, appendages, which are also articulated to direct the levitation force in themost convenient direction for propulsion and maneuvering. The charging is maintained through continuouscharge emission. It lands, wherever it is most convenient, by retracting the appendages or by firing a cold-gasthruster, or by deploying an anchor. The wings could be made of very thin Au-coated Mylar film, which areelectrostatically inflated, and would provide the lift due to electrostatic repulsion with the naturally chargedasteroid surface. Since the E-glider would follow the Sun's illumination, the solar panels on the vehicle wouldconstantly charge a battery. Further articulation at the root of the lateral strands or inflated membrane wings,would generate a component of lift depending on the articulation angle, hence a selective maneuveringcapability which, to all effects, would lead to electrostatic (rather than aerodynamic) flight. Preliminarycalculations indicate that a 1 kg mass can be electrostatically levitated in a microgravity field with a 2 mdiameter electrostatically inflated ribbon structure at 19kV, hence the need for a "balloon-like" system. Due tothe high density and the photo-electron sheath and associate small Debye length, significant power is requiredto levitate even a few kilograms. The power required is in the kilo-Watt range to maintain a constant chargelevel.

Electrostatic Flight↗

NASA NTRS1992

Studies on the longitudinal and lateral transport of IAA in the shoots of etiolated corn seedlings

The auxin, indole-3-acetic acid, and the symplastic probe, carboxyfluorescein diacetate, were applied to the cut mesocotyl base or coleoptile apex of etiolated Zea mays seedlings and their transport measured and tissue distribution determined. The longitudinal transport of indole-3-acetate was strongly basipolar, while that of carboxyfluorescein was essentially apolar. The longitudinal transport of IAA, like carboxyfluorescein, was mainly in the stele. IAA exhibited a much higher lateral mobility from stele to cortex than did carboxyfluorescein. Based on the calculation of moles probe/kg fw, IAA is 4 times more concentrated in the stele than in the cortex while CF is 24 times higher in concentration in the stele than in the cortex. The structure of the node and the mesocotyl regions just below the node, regions of maximum growth, were examined and plasmodesmatal structure and frequency in these regions determined. The plasmodesmatal frequency, about 3 per micrometer2, between all cell types of the mesocotyl was found to be about 5-8 fold higher than that found for the root. Hypotheses of lateral auxin transport are discussed.

NASA Discipline Number 40-50↗

NASA NTRS2017

The Resource Prospector Neutron Spectrometer System: RP's Bloodhound

The primary goal of the Resource Prospector Neutron Spectrometer System (NSS) is to locate and characterize hydrogen-bearing volatile deposits, especially subsurface ice, that may exist at the lunar poles. A key objective is to detect water-equivalent hydrogen concentrations of 0.5 wt% or greater while on a moving rover. A second objective is to determine approximate burial depth of enhanced hydrogen-bearing materials up to 1 meter below otherwise dry regolith. The instrument will be carried aboard a landed mobility system at the lunar poles. The instrument operates by measuring the changes in the leakage flux of low energy neutrons out of the regolith. These neutrons are produced by galactic cosmic rays, which are so energetic that they shatter the nuclei in surface materials. The neutrons interact with other nuclei and lose energy, becoming thermalized in the process. Hydrogen is most efficient at thermalizing neutrons owing to protons' similar mass - statistically, neutrons lose half their energy per collision with protons. With hydrogen in the soil, leakage fluxes of neutrons in the 0.5 eV to 500 keV energy range are reduced. A concentration of only1-2 wt% water-equivalent hydrogen results in a decrease in epithermal leakage flux of a factor of two. The leakage flux of thermal neutrons, from 0 to 0.5 eV in energy, can either increase or decrease depending on the hydrogen abundance and stratigraphy. As with the highly successful Lunar Prospector Neutron Spectrometer, the RP NSS detects both thermal and epithermal neutrons by using two helium-3 gas proportional counters, one covered by cadmium and the other uncovered. The former detects only epithermal neutrons with energies above approximately 0.5 eV, the latter detects both thermal (less than 0.5 eV) and epithermal energies (greater than 0.5 eV). When a neutron enters the detector tube and interacts with a helium-3 nucleus, the resulting reaction produces an energetic proton and triton that ionize the gas. The resulting electrons are accelerated toward a high-voltage anode and cascade, amplifying the net charge, which is collected at the anode. The number of electrons produced is proportional to the energy that the triton and proton deposit in the gas. A charge sensitive pre-amplifier converts the total charge to a step voltage output. A shaper amplifier then shapes this step into a uni-polar waveform with peaking time appropriate for the detection depending on the event rate. The integrated shaped waveform, representing the deposited triton/proton energy, is then measured. A histogram, or pulse height analysis, is performed to record the main capture peak and wall effect pulses. A threshold for detection is also required to limit the low amplitude counting rate such as noise floor. The system electronics consists of 2 modules - the Sensor Module (SM) front-end and the Data Processing Module (DPM) back-end circuits. SM is designed as a light-weight and low power front-end housing the two helium-3 proportional counter detectors, preamp and HVPS. It is mounted external to the rover body to detect the thermalized neutron flux with a minimum of host background. The DPM is located inside the rover; it digitizes the SM signals, performs pulse height analysis and accumulates the count rate for each spectral channel. The DPM controls high voltage and thresholding, and sends the science data to the host craft via an RS422 serial asynchronous protocol. The payload host provides all thermal management and control for the SM and DPM.

hydrogen-bearing volatile deposits↗

NASA NTRSDate not supplied

Space Suit Portable Life Support System Oxygen Regulator History, Development, & Testing Results

An oxygen regulator has been in development for the space suit Exploration Extravehicular Mobility Unit (xEMU) Portable Life Support System (PLSS). The regulator provides the necessary oxygen pressure for the crew member during pre-breathe, extra-vehicular activity (EVA), post EVA airlock operations, and decompression sickness treatment. The last time a spacesuit oxygen regulator was designed was for the Space Shuttle Program EMU. The regulator & EMU were then used on the International Space Station (ISS) with no significant changes to the regulator throughout its life. This xEMU PLSS spacesuit oxygen regulator implements many elements of the previous EMU Secondary Oxygen Pack (SOP) design while integrating numerous new improvements and changes. There are changes both to the high-level regulator architecture approach in the suit itself, in addition to modernizations with electrical motor control & sensing. For architecture, there are two oxygen regulators for each space suit, a primary and secondary that are nearly identical to each other and have the same maximum design pressure of 3750 Pounds per Square Inch Absolute (PSIA). The primary regulator provides nominal pressure during EVA, while the secondary provides a backup pressure only in case of primary regulator failure or if an emergency purge of the suit oxygen is required. The design was based originally off of the secondary oxygen regulator on the EMU which utilizes a two-stage regulator to improve safety and controllability. The xEMU PLSS Oxygen Regulator development started with a modification to add a linear actuator to the design to control the downstream pressure electronically instead of a manual control with a wire linkage system used with the EMU. The design was iterated to include a Monel body for oxygen fire safety, and sensors for pressure verification at each stage. Then the regulator design was packaged to fit into the xEMU PLSS envelope. Development included extensive testing which brought to light some issues with the design which were addressed at each stage of development. This paper will review the design history, development, testing results, and lessons learned designing the xEMU PLSS Oxygen Regulator.

Ryan Ogilvie↗

NASA NTRS2007

Robotics

Lunar robotic functions include: 1. Transport of crew and payloads on the surface of the moon; 2. Offloading payloads from a lunar lander; 3. Handling the deployment of surface systems; with 4. Human commanding of these functions from inside a lunar vehicle, habitat, or extravehicular (space walk), with Earth-based supervision. The systems that will perform these functions may not look like robots from science fiction. In fact, robotic functions may be automated trucks, cranes and winches. Use of this equipment prior to the crew s arrival or in the potentially long periods without crews on the surface, will require that these systems be computer controlled machines. The public release of NASA's Exploration plans at the 2nd Space Exploration Conference (Houston, December 2006) included a lunar outpost with as many as four unique mobility chassis designs. The sequence of lander offloading tasks involved as many as ten payloads, each with a unique set of geometry, mass and interface requirements. This plan was refined during a second phase study concluded in August 2007. Among the many improvements to the exploration plan were a reduction in the number of unique mobility chassis designs and a reduction in unique payload specifications. As the lunar surface system payloads have matured, so have the mobility and offloading functional requirements. While the architecture work continues, the community can expect to see functional requirements in the areas of surface mobility, surface handling, and human-systems interaction as follows: Surface Mobility 1. Transport crew on the lunar surface, accelerating construction tasks, expanding the crew s sphere of influence for scientific exploration, and providing a rapid return to an ascent module in an emergency. The crew transport can be with an un-pressurized rover, a small pressurized rover, or a larger mobile habitat. 2. Transport Extra-Vehicular Activity (EVA) equipment and construction payloads. 3. Transport habitats and power modules over long distances, pre-positioning them for the arrival of crew on a subsequent lander. Surface Handling 1. Offload surface system payloads from the lander, breaking launch restraints and power/data connections. Payloads may be offloaded to a wheeled vehicle for transport. 2. Deploy payloads from a wheeled vehicle at a field site, placing the payloads in their final use site on the ground or mating them with existing surface systems. 3. Support regolith collection, site preparation, berm construction, or other civil engineering tasks using tools and implements attached to rovers. Human-Systems Interaction 1. Provide a safe command and control interface for suited EVA to ride on and drive the vehicles, making sure that the systems are also safe for working near dismounted crew. 2. Provide an effective control system for IV crew to tele-operate vehicles, cranes and other equipment from inside the surface habitats with evolving independence from Earth. .. Provide a supervisory system that allows machines to be commanded from the ground, working across the Earth-Lunar time delays on the order of 5-10 seconds (round trip) to support operations when crew are not resident on the surface. Technology Development Needs 1. Surface vehicles that can dock, align and mate with outpost equipment such as landers, habitats and fluid/power interfaces. 2. Long life motors, drive trains, seals, motor electronics, sensors, processors, cable harnesses, and dash board displays. 3. Active suspension control, localization, high speed obstacle avoidance, and safety systems for operating near dismounted crew. 4. High specific energy and specific power batteries that are safe, rechargeable, and long lived.

Ambrose, Robert O.↗

NASA NTRS2026

Dynamic Regulation of Sub-Atmospheric Pressure for Constant and Cyclic Gas Loads During Testing of Spacesuit Components

New iterations of the various subsystems within the spacesuit will benefit from a new sorbent technology. For example, sorbents used in the Trace Contaminant Control (TCC) and the Rapid Cycle Amine (RCA) systems within the Exploration Portable Life Support System (xPLSS), part of the Extra-Vehicular Mobility Unit (xEMU). For proper validation, the sub-atmospheric pressure needs to be maintained within a simulated 2 ft 3 spacesuit volume. The traditional approach, which involves placing the entire vent loop within a hypobaric chamber, is not practical for the widespread testing of components and prototypes, as these specialized chambers are costly and not widely available. A two-stage regulator based sub-atmospheric pressure system is presented in this work. The method regulates the pressure based on pressure differentials between the pressure regulation pump, the test system, and the ambient environment. The performance of this system is demonstrated using data collected during a 150+ hour non-regenerative TCC sorbent evaluation, several 24-hour regenerative TCC sorbent evaluations with different regeneration cycles, and an 8-hour RCA sorbent evaluation, all under xEMU operating conditions. For regulation, the inlet regulator was set to propagate a small leak to increase the stability of the system as the gas load from the testing system changes. It was also found that controlling the input flow rate that replaces the material lost during regeneration is critical for ensuring the stability of the system. This system provided excellent pressure regulation, without adjustments, for constant loads during shorter time evaluations (hours), while longer time evaluations (days) are easily obtainable with periodic regulator adjustments. A second method is under development to address longer-term stability and to automate pressure regulation. It will incorporate flow and pressure measurements to dynamically control a set of electronically controlled proportional valves for adjusting the pumping speed and air bleed supply.

Nicholas F Materer↗

NASA NTRS2009

Cooperative Three-Robot System for Traversing Steep Slopes

Teamed Robots for Exploration and Science in Steep Areas (TRESSA) is a system of three autonomous mobile robots that cooperate with each other to enable scientific exploration of steep terrain (slope angles up to 90 ). Originally intended for use in exploring steep slopes on Mars that are not accessible to lone wheeled robots (Mars Exploration Rovers), TRESSA and systems like TRESSA could also be used on Earth for performing rescues on steep slopes and for exploring steep slopes that are too remote or too dangerous to be explored by humans. TRESSA is modeled on safe human climbing of steep slopes, two key features of which are teamwork and safety tethers. Two of the autonomous robots, denoted Anchorbots, remain at the top of a slope; the third robot, denoted the Cliffbot, traverses the slope. The Cliffbot drives over the cliff edge supported by tethers, which are payed out from the Anchorbots (see figure). The Anchorbots autonomously control the tension in the tethers to counter the gravitational force on the Cliffbot. The tethers are payed out and reeled in as needed, keeping the body of the Cliffbot oriented approximately parallel to the local terrain surface and preventing wheel slip by controlling the speed of descent or ascent, thereby enabling the Cliffbot to drive freely up, down, or across the slope. Due to the interactive nature of the three-robot system, the robots must be very tightly coupled. To provide for this tight coupling, the TRESSA software architecture is built on a combination of (1) the multi-robot layered behavior-coordination architecture reported in "An Architecture for Controlling Multiple Robots" (NPO-30345), NASA Tech Briefs, Vol. 28, No. 10 (October 2004), page 65, and (2) the real-time control architecture reported in "Robot Electronics Architecture" (NPO-41784), NASA Tech Briefs, Vol. 32, No. 1 (January 2008), page 28. The combination architecture makes it possible to keep the three robots synchronized and coordinated, to use data from all three robots for decision- making at each step, and to control the physical connections among the robots. In addition, TRESSA (as in prior systems that have utilized this architecture) , incorporates a capability for deterministic response to unanticipated situations from yet another architecture reported in Control Architecture for Robotic Agent Command and Sensing (NPO-43635), NASA Tech Briefs, Vol. 32, No. 10 (October 2008), page 40. Tether tension control is a major consideration in the design and operation of TRESSA. Tension is measured by force sensors connected to each tether at the Cliffbot. The direction of the tension (both azimuth and elevation) is also measured. The tension controller combines a controller to counter gravitational force and an optional velocity controller that anticipates the motion of the Cliffbot. The gravity controller estimates the slope angle from the inclination of the tethers. This angle and the weight of the Cliffbot determine the total tension needed to counteract the weight of the Cliffbot. The total needed tension is broken into components for each Anchorbot. The difference between this needed tension and the tension measured at the Cliffbot constitutes an error signal that is provided to the gravity controller. The velocity controller computes the tether speed needed to produce the desired motion of the Cliffbot. Another major consideration in the design and operation of TRESSA is detection of faults. Each robot in the TRESSA system monitors its own performance and the performance of its teammates in order to detect any system faults and prevent unsafe conditions. At startup, communication links are tested and if any robot is not communicating, the system refuses to execute any motion commands. Prior to motion, the Anchorbots attempt to set tensions in the tethers at optimal levels for counteracting the weight of the Cliffbot; if either Anchorbot fails to reach its optimal tension level within a specified time, it sends message to the other robots and the commanded motion is not executed. If any mechanical error (e.g., stalling of a motor) is detected, the affected robot sends a message triggering stoppage of the current motion. Lastly, messages are passed among the robots at each time step (10 Hz) to share sensor information during operations. If messages from any robot cease for more than an allowable time interval, the other robots detect the communication loss and initiate stoppage.

Stroupe, Ashley↗

NASA NTRS1986

Carbon-13 NMR studies of salt shock-induced carbohydrate turnover in the marine cyanobacterium Agmenellum quadruplicatum

Carbon turnover in response to abrupt changes in salinity, including the mobilization of glycogen for use in osmoregulation was studied with pulse-chase strategies utilizing nuclear magnetic resonance (NMR)-silent and NMR-detectable 12C and 13C isotopes, respectively. Growth of Agmenellum quadruplicatum in 30%-enriched 13C bicarbonate provided sufficient NMR-detectability of intracellular organic osmoregulants for these studies. A comparison of NMR spectra of intact cells and their ethanol extracts showed that the intact cell data were suitable for quantitative work, and, when combined with ESR measurements of cell volumes, yielded intracellular glucosylglycerol concentrations without disrupting the cells. NMR pulse-chase experiments were used to show that 13C-enriched glycogen, which had previously been accumulated by the cells under nitrogen-limited growth at low salinities, could be utilized for the synthesis of glucosylglycerol when the cells were abruptly transferred to hypersaline media, but only in the light. It was also shown that the accumulation of glucosylglycerol in the light occurred on a time scale similar to that of cell doubling. Depletion of glucosylglycerol when cells abruptly transferred to lower salinities appeared to be rapid--the intracellular pool of this osmoregulant was decreased 2-fold within 2 hours of hypotonic shock.

NASA Discipline Life Support Systems↗

NASA NTRS2016

Space to Space Advanced EMU Radio

The main task for this project was the development of a prototype for the Space to Space Advanced EMU Radio (SSAER). The SSAER is an updated version of the Space to Space EMU Radio (SSER), which is the current radio used by EMUs (Extravehicular Mobility Unit) for communication between suits and with the ISS. The SSER was developed in 1999, and it was desired to update the design used in the system. Importantly, besides replacing out-of-production parts it was necessary to decrease the size of the radio due to increased volume constraints with the updated Portable Life Support System (PLSS) 2.5, which will be attached on future space suits. In particular, it was desired to fabricate a PCB for the front-end of the prototype SSAER system. Once this board was manufactured and all parts assembled, it could then be tested for quality of operation as well as compliancy with the SSER required specifications. Upon arrival, a small outline of the target system was provided, and it was my responsibility to take that outline to a finished, testable board. This board would include several stages, including frequency mixing, amplification, modulation, demodulation, and handled both the transmit and receive lines of the radio. I developed a new design based on the old SSER system and the outline provided to me, and found parts to fit the tasks in my design. It was also important to consider the specifications of the SSER, which included the system noise figure, gain, and power consumption. Further, all parts needed to be impedance matched, and spurious signals needed to be avoided. In order to fulfill these two requirements, it was necessary to perform some calculations using a Smith Chart and excel analysis. Once all parts were selected, I drew the schematics for the system in Altium Designer. This included developing schematic symbols, as well as layout. Once the schematic was finished, it was then necessary to lay the parts out onto a PCB using Altium. Similar to the schematic design, in order to accomplish this it was necessary to develop component land patterns and add component 3D models. All of this was achieved, and the PCB is currently in review. After it is finished being reviewed, this board will be sent out for manufacture. All electronic components used in the PCB have been acquired, and once the board arrives they will be soldered onto the board using a machine in building 44. Finally, the board will be tested for performance on-site. This will likely be accomplished by the end of the internship.

Maicke, Andrew↗

NASA NTRS2011

NASA Tech Briefs, July 2011

Topics covered include: 1) Collaborative Clustering for Sensor Networks; 2) Teleoperated Marsupial Mobile Sensor Platform Pair for Telepresence Insertion Into Challenging Structures; 3) Automated Verification of Spatial Resolution in Remotely Sensed Imagery; 4) Electrical Connector Mechanical Seating Sensor; 5) In Situ Aerosol Detector; 6) Multi-Parameter Aerosol Scattering Sensor; 7) MOSFET Switching Circuit Protects Shape Memory Alloy Actuators; 8) Optimized FPGA Implementation of Multi-Rate FIR Filters Through Thread Decomposition; 9) Circuit for Communication Over Power Lines; 10) High-Efficiency Ka-Band Waveguide Two-Way Asymmetric Power Combiner; 11) 10-100 Gbps Offload NIC for WAN, NLR, and Grid Computing; 12) Pulsed Laser System to Simulate Effects of Cosmic Rays in Semiconductor Devices; 13) Flight Planning in the Cloud; 14) MPS Editor; 15) Object-Oriented Multi Disciplinary Design, Analysis, and Optimization Tool; 16) Cryogenic-Compatible Winchester Connector Mount and Retaining System for Composite Tubes; 17) Development of Position-Sensitive Magnetic Calorimeters for X-Ray Astronomy; 18) Planar Rotary Piezoelectric Motor Using Ultrasonic Horns; 19) Self-Rupturing Hermetic Valve; 20) Explosive Bolt Dual-Initiated from One Side; 21) Dampers for Stationary Labyrinth Seals; 22) Two-Arm Flexible Thermal Strap; 23) Carbon Dioxide Removal via Passive Thermal Approaches; 24) Polymer Electrolyte-Based Ambient Temperature Oxygen Microsensors for Environmental Monitoring; 25) Pressure Shell Approach to Integrated Environmental Protection; 26) Image Quality Indicator for Infrared Inspections; 27) Micro-Slit Collimators for X-Ray/Gamma-Ray Imaging; 28) Scatterometer-Calibrated Stability Verification Method; 29) Test Port for Fiber-Optic-Coupled Laser Altimeter; 30) Phase Retrieval System for Assessing Diamond Turning and Optical Surface Defects; 31) Laser Oscillator Incorporating a Wedged Polarization Rotator and a Porro Prism as Cavity Mirror; 32) Generic, Extensible, Configurable Push-Pull Framework for Large-Scale Science Missions; 33) Dynamic Loads Generation for Multi-Point Vibration Excitation Problems; 34) Optimal Control via Self-Generated Stochasticity; 35) Space-Time Localization of Plasma Turbulence Using Multiple Spacecraft Radio Links; 36) Surface Contact Model for Comets and Asteroids; 37) Dust Mitigation Vehicle; 38) Optical Coating Performance for Heat Reflectors of the JWST-ISIM Electronic Component; 39) SpaceCube Demonstration Platform; 40) Aperture Mask for Unambiguous Parity Determination in Long Wavelength Imagers; 41) Spaceflight Ka-Band High-Rate Radiation-Hard Modulator; 42) Enabling Disabled Persons to Gain Access to Digital Media; 43) Cytometer on a Chip; 44) Principles, Techniques, and Applications of Tissue Microfluidics; and 45) Two-Stage Winch for Kites and Tethered Balloons or Blimps.

Source record↗

NASA NTRS2015

The Two-Column Aerosol Project: Phase I - Overview and Impact of Elevated Aerosol Layers on Aerosol Optical Depth

The Two-Column Aerosol Project (TCAP), conducted from June 2012 through June 2013, was a unique study designed to provide a comprehensive data set that can be used to investigate a number of important climate science questions, including those related to aerosol mixing state and aerosol radiative forcing. The study was designed to sample the atmosphere be tween and within two atmospheric columns; one fixed near the coast of North America (over Cape Cod, MA) and a second moveable column over the Atlantic Ocean several hundred kilometers from the coast. The U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Mobile Facility (AMF) was deployed at the base of the Cape Cod column, and the ARM Aerial Facility was utilized for the summer and winter intensive observation periods. One important finding from TCAP is that four of six nearly cloud-free flight days had aerosol layers aloft in both the Cape Cod and maritime columns that were detected using the nadir pointing second-generation NASA high-spectral resolution lidar (HSRL-2).These layer s contributed up to 60 of the total observed aerosol optical depth (AOD). Many of these layers were also intercepted by the aircraft configured for in situ sampling, and the aerosol in the layers was found to have increased amounts of biomass burning material and nitrate compared to aerosol found near the surface. In addition, while there was a great deal of spatial and day-to-day variability in the aerosol chemical composition and optical properties, no systematic differences between the two columns were observed.

aerosols↗