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At least 649 records · Page 36

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NASA NTRS1993

Where no flag has gone before: Political and technical aspects of placing a flag on the Moon

The flag on the Moon represents an important event in vexillological history. The political and technical aspects of placing a flag on the Moon, focusing on the first Moon landing, is examined. During their historic extravehicular activity, the Apollo 11 crew planted the flag of the United States on the lunar surface. This flag-raising was strictly a symbolic activity, as the United Nations Treaty on Outer Space precluded any territorial claim. Nevertheless, there were domestic and international debates over the appropriateness of the event. Congress amended the agency's appropriations bill to prevent the National Aeronautics and Space Administration (NASA) from placing flags of other nations, or those of international associations, on the Moon during missions funded solely by the United States. Like any activity in space exploration, the Apollo flag-raising also provided NASA engineers with an interesting technical challenge. They designed a flagpole with a horizontal bar allowing the flag to 'fly' without the benefit of wind to overcome the effects of the Moon's lack of an atmosphere. Other factors considered in the design were weight, heat resistance, and ease of assembly by astronauts whose space suits restricted their range of movement and ability to grasp items. As NASA plans a return to the Moon and an expedition to Mars, we will likely see flags continue to go 'where no flag has gone before'.

Platoff, Anne M.↗

NASA NTRS1993

Measurement of HO2 and other trace gases in the stratosphere using a high resolution far-infrared spectrometer at 28 km

This report covers the time period 1 January 1993 to 30 June 1993. During this reporting period we had our third Upper Atmosphere Research Satellite (UARS) correlative balloon flight and submitted the results from this flight to the Central Data Handling Facility (CDHF). We made a number of improvements in our data processing software in preparation for a new analysis of our old balloon data sets. Finally, we continue to analyze the data obtained during the second Airborne Arctic Stratospheric Expedition (AASE 2).

Traub, Wesley A.↗

NASA NTRS1993

Develop advanced nonlinear signal analysis topographical mapping system

The SSME has been undergoing extensive flight certification and developmental testing, which involves some 250 health monitoring measurements. Under the severe temperature pressure, and dynamic environments sustained during operation, numerous major component failures have occurred, resulting in extensive engine hardware damage and scheduling losses. To enhance SSME safety and reliability, detailed analysis and evaluation of the measurements signal are mandatory to assess its dynamic characteristics and operational condition. Efficient and reliable signal detection techniques will reduce catastrophic system failure risks and expedite the evaluation of both flight and ground test data, and thereby reduce launch turn-around time. The basic objective of this contract are threefold: (1) Develop and validate a hierarchy of innovative signal analysis techniques for nonlinear and nonstationary time-frequency analysis. Performance evaluation will be carried out through detailed analysis of extensive SSME static firing and flight data. These techniques will be incorporated into a fully automated system. (2) Develop an advanced nonlinear signal analysis topographical mapping system (ATMS) to generate a Compressed SSME TOPO Data Base (CSTDB). This ATMS system will convert tremendous amounts of complex vibration signals from the entire SSME test history into a bank of succinct image-like patterns while retaining all respective phase information. A high compression ratio can be achieved to allow the minimal storage requirement, while providing fast signature retrieval, pattern comparison, and identification capabilities. (3) Integrate the nonlinear correlation techniques into the CSTDB data base with compatible TOPO input data format. Such integrated ATMS system will provide the large test archives necessary for a quick signature comparison. This study will provide timely assessment of SSME component operational status, identify probable causes of malfunction, and indicate feasible engineering solutions. The final result of this program will yield an ATMS system of nonlinear and nonstationary spectral analysis software package integrated with the Compressed SSME TOPO Data Base (CSTDB) on the same platform. This system will allow NASA engineers to retrieve any unique defect signatures and trends associated with different failure modes and anomalous phenomena over the entire SSME test history across turbo pump families.

Jong, Jen-Yi↗

NASA NTRS1993

Euromet Ureilite Consortium: A preliminary report on carbon and nitrogen geochemistry

The first Euromet expedition to the Frontier Mountain in Antarctica in December 1990 recovered two ureilites, FRO 90036 (34.6g) and FRO 90054 (17.5g). Preliminary classification indicated that the specimens had very different textures and mineral chemistries, and hence were not paired. A third ureilite, Acfer 277 (41.0 g), has also recently been returned from the Sahara. Due to the small sample sizes of the meteorites, and the unusual mineralogy of FRO 90054, a consortium was established to ensure the most effective study of these samples; this abstract reports on the carbon and nitrogen stable isotope geochemistry of two of the three ureilites issued to the consortium.

Grady, Monica M.↗

NASA NTRS1988

Ozone Hole

Ozone hole airborne Arctic stratospheric expedition (pre-flight)

Source record↗

NASA NTRS1994

Develop advanced nonlinear signal analysis topographical mapping system

The Space Shuttle Main Engine (SSME) has been undergoing extensive flight certification and developmental testing, which involves some 250 health monitoring measurements. Under the severe temperature, pressure, and dynamic environments sustained during operation, numerous major component failures have occurred, resulting in extensive engine hardware damage and scheduling losses. To enhance SSME safety and reliability, detailed analysis and evaluation of the measurements signal are mandatory to assess its dynamic characteristics and operational condition. Efficient and reliable signal detection techniques will reduce catastrophic system failure risks and expedite the evaluation of both flight and ground test data, and thereby reduce launch turn-around time. The basic objective of this contract are threefold: (1) develop and validate a hierarchy of innovative signal analysis techniques for nonlinear and nonstationary time-frequency analysis. Performance evaluation will be carried out through detailed analysis of extensive SSME static firing and flight data. These techniques will be incorporated into a fully automated system; (2) develop an advanced nonlinear signal analysis topographical mapping system (ATMS) to generate a Compressed SSME TOPO Data Base (CSTDB). This ATMS system will convert tremendous amount of complex vibration signals from the entire SSME test history into a bank of succinct image-like patterns while retaining all respective phase information. High compression ratio can be achieved to allow minimal storage requirement, while providing fast signature retrieval, pattern comparison, and identification capabilities; and (3) integrate the nonlinear correlation techniques into the CSTDB data base with compatible TOPO input data format. Such integrated ATMS system will provide the large test archives necessary for quick signature comparison. This study will provide timely assessment of SSME component operational status, identify probable causes of malfunction, and indicate feasible engineering solutions. The final result of this program will yield an ATMS system of nonlinear and nonstationary spectral analysis software package integrated with the Compressed SSME TOPO Data Base (CSTDB) on the same platform. This system will allow NASA engineers to retrieve any unique defect signatures and trends associated with different failure modes and anomalous phenomena over the entire SSME test history across turbo pump families.

Source record↗

NASA NTRS1993

The RTL-46: A simulated commercial air transportation study

The RTL-46 provides an aircraft which utilizes advanced technology within the fictional Aeroworld market to better service the air travel customers and airlines of Aeroworld. The RTL-46 is designed to serve the portion of the travel market which flies less than 10,000 feet per flight. The design cruise velocity for the aircraft is 35 ft/sec, which rapidly expedites travel through Aeroworld. The major focus of the endeavor was to design an aircraft which would serve the Aeroworld market better than the existing aircraft, the HB-40. This could have been done through targeting another portion of the Aeroworld market or through serving the current HB-40 market more effectively. Due to the fact that approximately 70 percent of the potential Aeroworld passengers desired flights of 10,000 ft or less, this range became the target market for the RTL-46.

Dunbar, Christian↗

NASA NTRS1992

Project Minerva: A low-cost manned Mars mission based on indigenous propellant production

Project Minerva is a low-cost manned Mars mission designed to deliver a crew of four to the Martian surface, using only two sets of two launches. Key concepts which make this mission realizable are the use of near-term technologies and in-situ propellant production, following the senario originally proposed by R. Zubrin of Martin Marietta. The first set of launches delivers two unmanned payloads into low earth orbit (LEO): one consists of an Earth Return Vehicle (ERV), a propellant production plant, and a set of robotic vehicles, and the second consists of the upper stage/trans-Mars injection (TMI) booster. In LEO, the two payloads are joined and inserted into a Mars transfer orbit. The landing on Mars is performed with the aid of multiple aerobraking maneuvers. On the Martian surface, the propellant production plant uses a Sabatier/electrolysis-type process to combine six tons of hydrogen brought from earth with carbon dioxide from the Martian atmosphere to produce 100 tons of liquid oxygen and methane, which are later used as the propellants for the rover expeditions and the manned return journey of the ERV. Once the in-situ propellant production is completed, approximately two years after the first set of launches, the manned portion of the mission leaves earth. This set of two launches is similar to that of the unmanned vehicles; the two payloads are the Manned Transfer Vehicle (MTV) and the upper stage/TMI booster. The MTV contains the manned rover and the habitat which houses the astronauts enroute to Mars and on the Martian surface. During the 180-day trip to Mars, artificial gravity is created by tethering the MTV to the TMI booster and inducing rotation. Upon arrival the MTV performs aerobraking maneuvers to land near the fully-fueled ERV, which will be used by the crew a year and a half later to return to earth. The mission entails moderate travel times with relatively low-energy conjunction-class trajectories and allows ample time for scientific exploration. This set of missions can be repeated every two years in order to continue exploration at a variety of sites and gradually establish the infrastructure for a permanent base on Mars.

Bruckner, Adam P.↗

NASA NTRS1993

Computing in space: Issues and answers

Future plans for space exploration call for scientific instruments whose data is increasingly voluminous, far exceeding constraints set by telemetry rates, and therefore, an increased role for spaceborne computing. Three issues that greatly influence the realization of spaceborne computing systems are addressed. The first involves the identification of those research problems which are unique to space computing. Resources must be expended on these problems if efforts are to add value to, and have impact on, the technology of computing in space. The second addresses the transfer of new technology from the research laboratory to use in space. What can be done to expedite this process and shrink the technology gap that separates Earth and space based systems must be assessed. The third issue involves the user's point of view of what is required of new space computing systems. That is, what are the driving forces that most influence customers' decisions to use or not use new technology? Issues of design environment for spaceborne computers, tools for modeling and evaluation of flight systems, and validation of space flight hardware and software are also discussed.

Davidson, John M.↗

NASA NTRS1993

Telepresence in the human exploration of Mars: Field studies in analog environments

This paper describes the role of telepresence in performing exploration of Mars. As part of an effort to develop telepresence to support Mars exploration, NASA is developing telepresence technology and using it to perform exploration in space analog environments. This paper describes experiments to demonstrate telepresence control of an underwater remotely operated vehicle (TROV) to perform scientific field work in isolated and hostile environments. Toward this end, we have developed a telepresence control system and interfaced it to an underwater remotely operated vehicle. This vehicle was used during 1992 to study aquatic ecosystems in Antarctica including a study of the physical and biological environment of permanently ice-covered lake. We also performed a preliminary analysis of the potential for using the TROV to study the benthic ecology under the sea ice in McMurdo sound. These expeditions are opening up new areas of research by using telepresence control of remote vehicles to explore isolated and extreme environments on Earth while also providing an impetus to develop technology which will play a major role in the human exploration of Mars. Antarctic field operations, in particular, provide an excellent analog experience for telepresence operation in space.

Stoker, Carol R.↗

NASA NTRS1994

Technology transfer and evaluation for Space Station telerobotics

The international space station (SS) must take advantage of advanced telerobotics in order to maximize productivity and safety and to reduce maintenance costs. The Automation and Robotics Division at the NASA Lyndon B. Johnson Space Center (JSC) has designed, developed, and constructed the Automated Robotics Maintenance of Space Station (ARMSS) facility for the purpose of transferring and evaluating robotic technology that will reduce SS operation costs. Additionally, JSC had developed a process for expediting the transfer of technology from NASA research centers and evaluating these technologies in SS applications. Software and hardware system developed at the research centers and NASA sponsored universities are currently being transferred to JSC and integrated into the ARMSS for flight crew personnel testing. These technologies will be assessed relative to the SS baseline, and, after refinements, those technologies that provide significant performance improvements will be recommended as upgrades to the SS. Proximity sensors, vision algorithms, and manipulator controllers are among the systems scheduled for evaluation.

Price, Charles R.↗

NASA NTRS1993

Stratospheric meteorological conditions in the Arctic polar vortex, 1991 to 1992

Stratospheric meteorological conditions during the Airborne Arctic Stratospheric Expedition II (AASE II) presented excellent observational opportunities from Bangor, Maine, because the polar vortex was located over southeastern Canada for significant periods during the 1991-1992 winter. Temperature analyses showed that nitric acid trihydrates (NAT temperatures below 195 K) should have formed over small regions in early December. The temperatures in the polar vortex warmed beyond NAT temperatures by late January (earlier than normal). Perturbed chemistry was found to be associated with these cold temperatures.

Newman, P.↗

NASA NTRS1993

Chemical loss of ozone in the Arctic polar vortex in the winter of 1991- 1992

In situ measurements of chlorine monoxide, bromine monoxide, and ozone are extrapolated globally, with the use of meteorological tracers, to infer the loss rates for ozone in the Arctic lower stratosphere during the Airborne Arctic Stratospheric Expedition II (AASE II) in the winter of 1991-1992. The analysis indicates removal of 15 to 20 percent of ambient ozone because of elevated concentrations of chlorine monoxide and bromine monoxide. Observations during AASE II define rates of removal of chlorine monoxide attributable to reaction with nitrogen dioxide (produced by photolysis of nitric acid) and to production of hydrochloric acid. Ozone loss ceased in March as concentrations of chlorine monoxide declined. Ozone losses could approach 50 percent if regeneration of nitrogen dioxide were inhibited by irreversible removal of nitrogen oxides (denitrification), as presently observed in the Antarctic, or without denitrification if inorganic chlorine concentrations were to double.

Salawitch, R. J.↗

NASA NTRS1993

Airborne tunable diode laser spectrometer for trace-gas measurement in the lower stratosphere

This paper describes the airborne tunable laser absorption spectrometer, a tunable diode laser instrument designed for in situ trace-gas measurement in the lower stratosphere from an ER-2 high-altitude research aircraft. Laser-wavelength modulation and second-harmonic detection are employed to achieve the required constituent detection sensitivity. The airborne tunable laser absorption spectrometer was used in two polar ozone campaigns, the Airborne Antarctic Ozone Experiment and the Airborne Arctic Stratospheric Expedition, and measured nitrous oxide with a response time of 1 s and an accuracy not greater than 10 percent.

Podolske, James↗

NASA NTRS1994

Specific features of space-time variations of ozone during the development of intensive tropical disturbances

An analysis of specific features of space-time variations of ozone in the tropical areas which has been performed on the basis of processing of the results of special expedition studies in the Atlantic and Pacific in 1987-1990 and the data of observations at the stations of the world ozonometric network over the 25-year period. The existence of a cause-and-effect relation has been revealed between the processes determining tropical cyclone (TC) development, and specific features of variations of the total content of ozone (TCO) and the vertical distribution of ozone (VDO) in the regions of TC action. Characteristic features of day-to-day and daily variations of TCO during TC development have been found. On the periphery of a developing TC, 1-4 days before it reaches the stage of storm, TCO increases, on average, by 5-8 percent, and a substantial increase in the concentration of ozone occurs in the middle and upper troposphere. The most probable physical mechanisms relating the observed specific features of ozone variations to TC evolution have been suggested. A hypothesis of the possibility of using ozone as an indicator for early prediction of TC development has been substantiated.

Nerushev, Alexander F.↗

NASA NTRS1994

Ozone ground-based measurements by the GASCOD near-UV and visible DOAS system

GASCOD, a near-ultraviolet and visible differential optical spectrometer, was developed at CNR's FISBAT Institute in Bologna, Italy, and first tested at Terra Nova Bay station in Antarctica (74.6 deg S, 164.6 deg E) during the summer expeditions 1988-1990 of PNRA (PNRA is the national research program in Antarctica, 'Programma Nazionale di Ricerche in Atartide'). A comparison with coincident O3 total column measurements taken in the same Antarctic area is presented, as is another comparison performed in Italy. Also introduced is an updated model for solar zenith measurements taken from a ground-based, upward-looking GASCOD spectrometer, which was employed for the 1991-92 winter campaign at Aer-Ostersund in Sweden (63.3 deg N, 13.1 deg E) during AESOE (European Arctic Stratospheric Ozone Experiment). The GASCOD can examine the spectra from 300 to 700 nm, in 50 nm steps, by moving the spectrometer's grating. At present, it takes measurements of solar zenith radiation in the 310-342 nm range for O3 and in the 405-463 nm range for NO2.

Giovanelli, G.↗

NASA NTRS1994

Development of techniques for the in situ observation of OH and HO2 for studies of the impact of high-altitude supersonic aircraft on the stratosphere

This three-year project supported the construction, calibration, and deployment of a new instrument to measure the OH and HO2 radicals on the NASA ER-2 aircraft. The instrument has met and exceeded all of its design goals. The instrumentation represents a true quantum leap in performance over that achieved in previous HO(x) instruments built in our group. Sensitivity for OH was enhanced by over two orders of magnitude as the weight fell from approximately 1500 to less than 200 Kg. Reliability has been very high: HO(x) data are available for all flights during the first operational mission, the Stratospheric Photochemistry, Aerosols, and Dynamics Expedition (SPADE). The results of that experiment have been reported in the scientific literature and at conferences. Additionally, measurements of H2O and O3 were made and have been reported in the scientific literature. The measurements demonstrated the important role that OH and HO2 play in determining the concentration of ozone in the lower stratosphere. During the SPADE, campaign the measurements demonstrated that the catalytic removal is dominated by processes involving the odd-hydrogen and halogen radicals-and extremely important constraint for photochemical models that are being used to assess the potential deleterious effects of super-sonic aircraft effluent on the burden of stratospheric ozone.

Anderson, James G.↗

NASA NTRS1994

High-performance, flexible, deployable array development for space applications

Flexible, deployable arrays are an attractive alternative to conventional solar arrays for near-term and future space power applications, particularly due to their potential for high specific power and low storage volume. Combined with low-cost flexible thin-film photovoltaics, these arrays have the potential to become an enabling or an enhancing technology for many missions. In order to expedite the acceptance of thin-film photovoltaics for space applications, however, parallel development of flexible photovoltaics and the corresponding deployable structure is essential. Many innovative technologies must be incorporated in these arrays to ensure a significant performance increase over conventional technologies. For example, innovative mechanisms which employ shape memory alloys for storage latches, deployment mechanisms, and array positioning gimbals can be incorporated into flexible array design with significant improvement in the areas of cost, weight, and reliability. This paper discusses recent activities at Martin Marietta regarding the development of flexible, deployable solar array technology. Particular emphasis is placed on the novel use of shape memory alloys for lightweight deployment elements to improve the overall specific power of the array. Array performance projections with flexible thin-film copper-indium-diselenide (CIS) are presented, and government-sponsored solar array programs recently initiated at Martin Marietta through NASA and Air Force Phillips Laboratory are discussed.

Gehling, Russell N.↗