Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “EVA”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,225 records · Page 68
All sourcesNASA NTRSDOE OSTI
NASA NTRS2003

Metrics for in-space telescope assembly techniques

Reliable metrics are not yet available for choosing among human and robotic assets for space-based construction and servicing of large space telescopes. Using FAIR-DART as a reference design, we generated example event sequences for telescope assembly scenarios in enough detail to identify infrastructure assumptions and technology requirements. A systems trade among human and robotic techniques (human EVA, on-site telerobotic, ground-in-the- loop robotic, commanded or sequenced robotic, and autonomous/decision-making robotic) helped us to define key metrics in the human-robotic trade space, including quality, time, cost, and risk. Our methodology included examining representative end-member scenarios. Case A treated each step in the assembly sequence as if all other steps have no on-site human involvement, and Case B treated each step as if human EVA is already involved in all other steps. With this trade, we identified key enabling technologies and infrastructure for space-based assembly and servicing of large space telescopes.

space telescopes human and robotic in-space assemb↗
NASA NTRS2007

A Prototype Cryogenic Oxygen Storage and Delivery Subsystem for Advanced Spacesuits

Future spacesuit systems for the exploration of Mars will need to be much lighter than current designs while at the same time reducing the consumption of water for crew cooling. One of the technology paths NASA has identified to achieve these objectives is the replacement of current high pressure oxygen storage technology in EVA systems with cryogenic technology that can simultaneously reduce the mass of tankage required for oxygen storage and enable the use of the stored oxygen as a means of cooling the EVA astronaut. During the past year NASA has funded Hamilton Sundstrand production of a prototype system demonstrating this capability in a design that will allow the cryogenic oxygen to be used in any attitude and gravity environment. This paper will describe the design and manufacture of the prototype system and present the results of preliminary testing to verify its performance characteristics. The potential significance and application of the system will also be discussed.

Overbeeke, Arend↗
NASA NTRS2007

Development of a Rapid Cycling CO(sub 2) and H(sub 2)O Removal Sorbent

The National Aeronautics and Space Administration (NASA) planned future missions set stringent demands on the design of the Portable Life Support System (PLSS), requiring dramatic reductions in weight, decreased reliance on supplies and greater flexibility on the types of missions. Use of regenerable systems that reduce weight and volume of the Extravehicular Mobility Unit (EMU) is of critical importance to NASA, both for low orbit operations and for long duration manned missions. The carbon dioxide and humidity control unit in the existing PLSS design is relatively large, since it has to remove and store 8 hours worth of CO2. If the sorbent regeneration can be carried out during the extravehicular activity (EVA) with a relatively high regeneration frequency, the size of the sorbent canister and weight can be significantly reduced. The progress of regenerable CO2 and humidity control is leading us towards the use of a rapid cycling amine system. TDA Research, Inc. is developing compact, regenerable sorbent materials to control CO2 and humidity in the space suit ventilation loop. The sorbent can be regenerated using space vacuum during the EVA, eliminating all carbon dioxide and humidity duration-limiting elements in the life support system. The material also has applications in other areas of space exploration such as the Orion spacecraft and other longer duration exploration missions requiring regenerable technologies. This paper summarizes the results of the sorbent development, testing, and evaluation efforts to date. The results of a preliminary system analysis are also included, showing the size and volume reductions for PLSS provided by the new system.

Paul, Heather↗
NASA NTRS2007

Noninvasive Sensor for Measuring Muscle Metabolism During Exercise

The measurement of oxygen uptake (VO2) and lactate threshold (LT) are utilized to assess changes in aerobic capacity and the efficacy of exercise countermeasures in astronauts. During extravehicular activity (EVA), real-time knowledge of VO2 and relative work intensity can be used to monitor crew activity levels and organize tasks to reduce the cumulative effects of fatigue. Currently VO2 and LT are determined with complicated measurement techniques that require sampling of expired ventilatory gases, which may not be accurate in enclosed, oxygen-rich environments such as the EVA suit. The UMMS team has developed a novel near infrared spectroscopic (NIRS) system which noninvasively, simultaneously and continuously measures muscle oxygen tension, oxygen saturation, pH (pHm), and hematocrit from a small sensor placed on the leg. This system is unique in that it allows accurate, absolute measurement of these parameters in the thigh muscle by correcting spectra for the interference from skin pigment and fat. These parameters can be used to estimate VO2 and LT. A preliminary evaluation of the system s capabilities was performed in the NASA JSC Exercise Physiology Lab.

Soller, B. R.↗
NASA NTRS2007

Comparison of V-4 and V-5 Exercise/Oxygen Prebreathe Protocols to Support Extravehicular Activity in Microgravity

The Prebreathe Reduction Program (PRP) used exercise during oxygen prebreathe to reduce necessary prebreathe time prior to depressurizing to work in a 4.3 psi suit during extravehicular activity (EVA). Initial testing produced a two-hour protocol incorporating ergometry exercise and a 30 min cycle of depress/repress to 10.2 psi where subjects breathed 26.5% oxygen/balance nitrogen (Phase II - 10 min at 75% peak oxygen consumption [VO2 peak] followed by 40 min intermittent light exercise [ILE] [approx. 5.8 mL-per kilogram- per minute], then 50 min of rest). The Phase II protocol (0/45 DCS) was approved for operations and has been used on 40 EVAs, providing significant time savings compared to the standard 4 h resting oxygen prebreathe. The Phase V effort focused on performing all light in-suit exercise. Two oxygen prebreathe protocols were tested sequentially: V-4) 160 min prebreathe with 150 min of continuous ILE. The entire protocol was completed at 14.7 psi. All exercise involved upper body effort. Exercise continued until decompression. V-5) 160 min prebreathe with 140 min of ILE - first 40 min at 14.7 psi, then 30 min at 10.2 psi (breathing 26.5% oxygen) after a 20 min depress, simulating a suit donning period. Subjects were then repressed to 14.7 psi and performed another 50 min of lower body ILE, followed by 50 min rest before decompression. The V-4 protocol was rejected with 3 DCS/6 person-exposures. Initial V-5 testing has produced 0 DCS/11 person-exposures (ongoing trials). The difference in DCS rate was significant (Fisher Exact p=0.029). The observations of DCS were significantly lower in early V-5 trials than in V-4 trials. Additional studies are required to evaluate the relative contribution of the variables in exercise distribution, the 10.2 psi depress/repress component, pre-decompression rest, or possible variation in total oxygen consumption.

Pollock, N. W.↗
NASA NTRS2007

Development of a Rapid Cycling CO2 and H2O Removal Sorbent

The National Aeronautics and Space Administration (NASA) planned future missions set stringent demands on the design of the Portable Life Support System (PLSS), requiring dramatic reductions in weight, decreased reliance on supplies and greater flexibility on the types of missions. Use of regenerable systems that reduce weight and volume of the Extravehicular Mobility Unit (EMU) is of critical importance to NASA, both for low orbit operations and for long duration manned missions. The carbon dioxide and humidity control unit in the existing PLSS design is relatively large, since it has to remove and store eight hours worth of carbon dioxide (CO2). If the sorbent regeneration can be carried out during the Extravehicular Activity (EVA) with a relatively high regeneration frequency, the size of the sorbent canister and weight can be significantly reduced. TDA Research, Inc. is developing compact, regenerable sorbent materials to control CO2 and humidity in the space suit ventilation loop. The sorbent can be regenerated using space vacuum during the EVA, eliminating all CO2 and humidity duration-limiting elements in the life support system. The material also has applications in other areas of space exploration including long duration exploration missions requiring regenerable technologies and possibly the Crew Exploration Vehicle (CEV) spacecraft. This paper summarizes the results of the sorbent development, testing, and evaluation efforts to date.

Alptekin, Gokhan↗
NASA NTRS2005

SAFER Inspection of Space Shuttle Thermal Protection System

In the aftermath of the space shuttle Columbia accident, it quickly became clear that new methods would need to be developed that would provide the capability to inspect and repair the shuttle's thermal protection system (TPS). A boom extension to the Remote Manipulator System (RMS) with a laser topography sensor package was identified as the primary means for measuring the damage depth in acreage tile as well as scanning Reinforced Carbon- Carbon (RCC) surfaces. However, concern over the system's fault tolerance made it prudent to investigate alternate means of acquiring close range photographs and contour depth measurements in the event of a failure. One method that was identified early was to use the Simplified Aid For EVA Rescue (SAFER) propulsion system to allow EVA access to damaged areas of concern. Several issues were identified as potential hazards to SAFER use for this operation. First, the ability of an astronaut to maintain controlled flight depends upon efficient technique and hardware reliability. If either of these is insufficient during flight operations, a safety tether must be used to rescue the crewmember. This operation can jeopardize the integrity of the Extra-vehicular Mobility Unit (EMU) or delicate TPS materials. Controls were developed to prevent the likelihood of requiring a tether rescue, and procedures were written to maximize the chances for success if it cannot be avoided. Crewmember ability to manage tether cable tension during nominal flight also had to be evaluated to ensure it would not negatively affect propellant consumption. Second, although propellant consumption, flight control, orbital dynamics, and flight complexity can all be accurately evaluated in Virtual Reality (VR) Laboratory at Johnson Space Center, there are some shortcomings. As a crewmember's hand is extended to simulate measurement of tile damage, it will pass through the vehicle without resistance. In reality, this force will push the crewmember away from the vehicle, and could induce a moment which, if strong enough, could saturate the attitude control system in SAFER. This raises the concern that additional propellant will be consumed to maintain controlled flight. To account for this, the fidelity of the Virtual Reality simulation was improved to include the effect of crewmember contact with the vehicle during SAFER flight. In addition, while participating in VR simulations, the subject is in shirt sleeves and sits in a chair. This does not provide a flight-like representation of body position awareness. To prevent inadvertent contact with tile or RCC, other facilities were utilized to establish crew preferences for body attitude and tool configuration. Finally, a study was performed to determine if attitude constraints are needed for the Space shuttle and International Space Station to reduce SAFER flight difficulty.

Scoville, Zebulon C.↗
NASA NTRS2007

Exploration Challenges: Transferring Ground Repair Techniques to Space Flight Application

Fulfilling NASA's Vision for Space Exploration will demand an extended presence in space at distances from our home planet that exceed our current experience in space logistics and maintenance. The ability to perform repairs in lieu of the customary Orbital Replacement Unit (ORU) process where a faulty part is replaced will be elevated from contingency to routine to sustain operations. The use and cost effectiveness of field repairs for ground based operations in industry and the military have advanced with the development of technology in new materials, new repair techniques and new equipment. The unique environments, accessibility constraints and Extra Vehicular Activity (EVA) issues of space operations will require extensive assessment and evolution of these technologies to provide an equivalent and expected level of assurance to mission success. Challenges include the necessity of changes in design philosophy and policy, extremes in thermal cycling, disruptive forces (such as static charge and wind entrainment) on developed methods for control of materials, dramatically increased volatility of chemicals for cleaning and other compounds due to extremely low pressures, the limits imposed on dexterity and maneuverability by current EVA equipment and practices, and the necessity of unique verification methodology. This paper describes these challenges in and discusses the effects on the established ground techniques for repair. The paper also describes the leading repair methodology candidates and their beneficial attributes for resolving these issues with the evolution of technology.

McLemore, Carole A.↗
NASA NTRS2007

Recommendations for Exploration Space Medicine from the Apollo Medical Operations Project

Introduction: A study was requested in December, 2005 by the Space Medicine Division at the NASA-Johnson Space Center (JSC) to identify Apollo mission issues relevant to medical operations that had impact to crew health and/or performance. The objective was to use this new information to develop medical requirements for the future Crew Exploration Vehicle (CEV), Lunar Surface Access Module (LSAM), Lunar Habitat, and Advanced Extravehicular Activity (EVA) suits that are currently being developed within the exploration architecture. Methods: Available resources pertaining to medical operations on the Apollo 7 through 17 missions were reviewed. Ten categories of hardware, systems, or crew factors were identified in the background research, generating 655 data records in a database. A review of the records resulted in 280 questions that were then posed to surviving Apollo crewmembers by mail, face-to-face meetings, or online interaction. Response analysis to these questions formed the basis of recommendations to items in each of the categories. Results: Thirteen of 22 surviving Apollo astronauts (59%) participated in the project. Approximately 236 pages of responses to the questions were captured, resulting in 107 recommendations offered for medical consideration in the design of future vehicles and EVA suits based on the Apollo experience. Discussion: The goals of this project included: 1) Develop or modify medical requirements for new vehicles; 2) create a centralized database for future access; and 3) take this new knowledge and educate the various directorates at NASA-JSC who are participating in the exploration effort. To date, the Apollo Medical Operations recommendations are being incorporated into the exploration mission architecture at various levels and a centralized database has been developed. The Apollo crewmembers input has proved to be an invaluable resource, prompting ongoing collaboration as the requirements for the future exploration missions continue to evolve and be refined.

Scheuring, R. a.↗
NASA NTRS2007

An Evidence-based Approach to Developing a Management Strategy for Medical Contingencies on the Lunar Surface: The NASA/Haughton-Mars Project (HMP) 2006 Lunar Medical Contingency Simulation at Devon Island

The lunar architecture for future sortie and outpost missions will require humans to serve on the lunar surface considerably longer than the Apollo moon missions. Although the Apollo crewmembers sustained few injuries during their brief lunar surface activity, injuries did occur and are a concern for the longer lunar stays. Interestingly, lunar medical contingency plans were not developed during Apollo. In order to develop an evidence-base for handling a medical contingency on the lunar surface, a simulation using the moon-Mars analog environment at Devon Island, Nunavut, high Canadian Arctic was conducted. Objectives of this study included developing an effective management strategy for dealing with an incapacitated crewmember on the lunar surface, establishing audio/visual and biomedical data connectivity to multiple centers, testing rescue/extraction hardware and procedures, and evaluating in suit increased oxygen consumption. Methods: A review of the Apollo lunar surface activities and personal communications with Apollo lunar crewmembers provided the knowledge base of plausible scenarios that could potentially injure an astronaut during a lunar extravehicular activity (EVA). Objectives were established to demonstrate stabilization and transfer of an injured crewmember and communication with ground controllers at multiple mission control centers. Results: The project objectives were successfully achieved during the simulation. Among these objectives were extraction from a sloped terrain by a two-member crew in a 1 g analog environment, establishing real-time communication to multiple centers, providing biomedical data to flight controllers and crewmembers, and establishing a medical diagnosis and treatment plan from a remote site. Discussion: The simulation provided evidence for the types of equipment and methods for performing extraction of an injured crewmember from a sloped terrain. Additionally, the necessary communications infrastructure to connect multiple centers worldwide was established from a remote site. The surface crewmembers were confronted with a number of unexpected scenarios including environmental, communications, EVA suit, and navigation challenges during the course of the simulation which provided insight into the challenges of carrying out a medical contingency in an austere environment. The knowledge gained from completing the objectives will be incorporated into the exploration medical requirements involving an incapacitated astronaut on the lunar surface.

Scheuring, R. A.↗
NASA NTRS2007

Determining Desirable Cursor Control Device Characteristics for NASA Exploration Missions

A test battery was developed for cursor control device evaluation: four tasks were taken from ISO 9241-9, and three from previous studies conducted at NASA. The tasks focused on basic movements such as pointing, clicking, and dragging. Four cursor control devices were evaluated with and without Extravehicular Activity (EVA) gloves to identify desirable cursor control device characteristics for NASA missions: 1) the Kensington Expert Mouse, 2) the Hulapoint mouse, 3) the Logitech Marble Mouse, and 4) the Honeywell trackball. Results showed that: 1) the test battery is an efficient tool for differentiating among input devices, 2) gloved operations were about 1 second slower and had at least 15% more errors; 3) devices used with gloves have to be larger, and should allow good hand positioning to counteract the lack of tactile feedback, 4) none of the devices, as designed, were ideal for operation with EVA gloves.

Sandor, Aniko↗
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 NTRS2007

Automating CapCom Using Mobile Agents and Robotic Assistants

Mobile Agents (MA) is an advanced Extra-Vehicular Activity (EVA) communications and computing system to increase astronaut self-reliance and safety, reducing dependence on continuous monitoring and advising from mission control on Earth. MA is voice controlled and provides information verbally to the astronauts through programs called "personal agents." The system partly automates the role of CapCom in Apollo-including monitoring and managing navigation, scheduling, equipment deployment, telemetry, health tracking, and scientific data collection. Data are stored automatically in a shared database in the habitat/vehicle and mirrored to a site accessible by a remote science team. The program has been developed iteratively in authentic work contexts, including six years of ethnographic observation of field geology. Analog field experiments in Utah enabled empirically discovering requirements and testing alternative technologies and protocols. We report on the 2004 system configuration, experiments, and results, in which an EVA robotic assistant (ERA) followed geologists approximately 150 m through a winding, narrow canyon. On voice command, the ERA took photographs and panoramas and was directed to serve as a relay on the wireless network.

Clancey, William J.↗
NASA NTRS2007

Constellation Space Suit System Development Status

The Constellation Program has initiated the first new flight suit development project since the Extravehicular Mobility Unit (EMU) was developed for the Space Shuttle Program in the 1970s. The Constellation suit system represents a significant challenge to designers in that the system is required to address all space suit functions needed through all missions and mission phases. This is in marked contrast to the EMU, which was designed specifically for micro-gravity space walks. The Constellation suit system must serve in all of the following scenarios: launch, entry and abort crew survival; micro-gravity extravehicular activity (EVA); and lunar (1/6th-gravity) surface EVA. This paper discusses technical efforts performed from May 2006 through February 2007 for the Constellation space suit system pressure garment.

Ross, Amy↗
NASA NTRS2008

3D Position and Velocity Vector Computations of Objects Jettisoned from the International Space Station Using Close-Range Photogrammetry Approach

Measurement of the jettisoned object departure trajectory and velocity vector in the International Space Station (ISS) reference frame is vitally important for prompt evaluation of the object s imminent orbit. We report on the first successful application of photogrammetric analysis of the ISS imagery for the prompt computation of the jettisoned object s position and velocity vectors. As post-EVA analyses examples, we present the Floating Potential Probe (FPP) and the Russian "Orlan" Space Suit jettisons, as well as the near-real-time (provided in several hours after the separation) computations of the Video Stanchion Support Assembly Flight Support Assembly (VSSA-FSA) and Early Ammonia Servicer (EAS) jettisons during the US astronauts space-walk. Standard close-range photogrammetry analysis was used during this EVA to analyze two on-board camera image sequences down-linked from the ISS. In this approach the ISS camera orientations were computed from known coordinates of several reference points on the ISS hardware. Then the position of the jettisoned object for each time-frame was computed from its image in each frame of the video-clips. In another, "quick-look" approach used in near-real time, orientation of the cameras was computed from their position (from the ISS CAD model) and operational data (pan and tilt) then location of the jettisoned object was calculated only for several frames of the two synchronized movies. Keywords: Photogrammetry, International Space Station, jettisons, image analysis.

Papanyan, Valeri↗
NASA NTRS2008

Information Presentation

The goal of the Information Presentation Directed Research Project (DRP) is to address design questions related to the presentation of information to the crew on flight vehicles, surface landers and habitats, and during extra-vehicular activities (EVA). Designers of displays and controls for exploration missions must be prepared to select the text formats, label styles, alarms, electronic procedure designs, and cursor control devices that provide for optimal crew performance on exploration tasks. The major areas of work, or subtasks, within the Information Presentation DRP are: 1) Controls, 2) Displays, 3) Procedures, and 4) EVA Operations.

Holden, Kritina↗
NASA NTRS2008

Integrated Suit Test 1 - A Study to Evaluate Effects of Suit Weight, Pressure, and Kinematics on Human Performance during Lunar Ambulation

In an effort to design the next generation Lunar suit, NASA has initiated a series of tests aimed at understanding the human physiological and biomechanical affects of space suits under a variety of conditions. The first of these tests was the EVA Walkback Test (ICES 2007-01-3133). NASA-JSC assembled a multi-disciplinary team to conduct the second test of the series, titled Integrated Suit Test 1 (IST-1), from March 6 through July 24, 2007. Similar to the Walkback Test, this study was performed with the Mark III (MKIII) EVA Technology Demonstrator suit, a treadmill, and the Partial Gravity Simulator in the Space Vehicle Mock-Up Facility at Johnson Space Center. The data collected for IST-1 included metabolic rates, ground reaction forces, biomechanics, and subjective workload and controllability feedback on both suited and unsuited (shirt-sleeve) astronaut subjects. For IST-1 the center of gravity was controlled to a nearly perfect position while the weight, pressure and biomechanics (waist locked vs. unlocked) were varied individually to evaluate the effects of each on the ability to perform level (0 degree incline) ambulation in simulated Lunar gravity. The detailed test methodology and preliminary key findings of IST-1 are summarized in this report.

Gernhardt, Michael L.↗
NASA NTRS2008

Lunar Balance and Locomotion

Balance control and locomotor patterns were altered in Apollo crewmembers on the lunar surface, owing, presumably, to a combination of sensory-motor adaptation during transit and lunar surface operations, decreased environmental affordances associated with the reduced gravity, and restricted joint mobility as well as altered center-of-gravity caused by the EVA pressure suits. Dr. Paloski will discuss these factors, as well as the potential human and mission impacts of falls and malcoordination during planned lunar sortie and outpost missions. Learning objectives: What are the potential impacts of postural instabilities on the lunar surface? CME question: What factors affect balance control and gait stability on the moon? Answer: Sensory-motor adaptation to the lunar environment, reduced mechanical and visual affordances, and altered biomechanics caused by the EVA suit.

Paloski, William H.↗