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NASA NTRS2004

Extrasolar Planet Inferometric Survey (EPIcS)

The discovery of the nature of the solar system was a crowning achievement of Renaissance science. The quest to evaluate the properties of extrasolar planetary systems is central to both the intellectual understanding of our origins and the cultural understanding of humanity's place in the Universe; thus it is appropriate that the goals and objectives of NASA's breakthrough Origins program emphasize the study of planetary systems, with a focus on the search for habitable planets. We propose an ambitious research program that will use SIM - the first major mission of the Origins program - to explore planetary systems in our Galactic neighborhood. Our program is a novel two-tiered SIM survey of nearby stars that exploits the capabilities of SIM to achieve two scientific objectives: (i) to identify Earth-like planets in habitable regions around nearby Sunlike stars: and (ii) to explore the nature and evolution of planetary systems in their full variety. The first of these objectives was recently recommended by the Astronomy and Astrophysics Survey Committee (the McKee-Taylor Committee) as a prerequisite for the development of the Terrestrial Planet Finder mission later in the decade. Our program combines this two-part survey with preparatory and contemporaneous research designed to maximize the scientific return from the limited and thus precious observing resources of SIM.

Shao, Michael↗
NASA NTRS2005

ASK Magazine; No. 21

THIS ISSUE FEATURES A VISUAL DEPICTION OF THE ACADEMY of Program and Project Leadership (APPL). I imagine a variety of initial reactions to the drawing. One might be, "What is a cartoon doing in a magazine about project management?" Or perhaps, "Wow, nice colors-and fun." Another may be to closely search the image for signs, symbols and meaning. Still another, to read a new level of innovation and creativity into the picture. Undoubtedly, some readers will raise questions about the cost. Of course, any reaction is a sign of engagement. The stronger, the more energized the emotional and cognitive processing, the better. It is a sign of attention and interaction. For I've heard it said, "You only need to worry if they don t care one way or the other." So what is the point of the picture? To stimulate interest, raise questions, promote discussion, and maybe raise a smile.. .That, at least, was my initial reaction when I was introduced to the work of Nancy Hegedus, who helps to create these drawings for Root Learning Inc. At the NASA PM Conference, I was first shown the work Nancy had been doing with the help of Goddard s Knowledge Management Architect, Dr. Ed Rogers. I was immediately drawn into the power of visualization as a tool for more effective learning, communicating, and conveying complex knowledge concepts. We need new tools in today s world, where information and data overwhelms by sheer volume. There are articles, pamphlets, communications, and white papers-all aiming to convince and influence. Reactions to these tend to be either avoidance or mind-numbing, heavy-eyed consent; the message never registers or enters the soul. That s one of the reasons that APPL s Knowledge Sharing Initiative (KSI) has turned to storytelling as a memorable way of transfer- ring knowledge, inspiring imitation of best practices, and spurring reflection. ASK Magazine s recent fourth birthday marks an important milestone in APPL s continuing quest to provide ongoing support to project managers and to promote mission success. And similar to storytelling, the power of visualization is receiving increasing attention in recent years as a way to stimulate engagement. Pictures and visual graphs are viewed as one of the most effective ways for displaying, describing, and generating discussion about quantitative and technically complex information. Prototypes, models, and simulations are considered essential for stimulating innovation through open and engaging discussions. There has also been extensive writing on the use of visual graphics, pictures, and cartoons to facilitate memory, creativity, openness, attention-and even well-being. For many of these reasons, I am excited to have a colorful visual depiction of the APPL world included in ASK. Without the addition of text or slides, the intent is to invite people into the world of the APPL mission-as well as its products, services, customers, and partners- in a fun and engaging manner. As project leaders strive to find ways to encourage engagement, learning, and transmission of knowledge, traditional technologies are proving to be as valuable as modern technologies. (But for those who want more information in the form of texts and slide presentations, we certainly have an abundance of those as well.)

Laufer, Alexander↗
NASA NTRS2004

Analysis of Stainless Steel Sandwich Panels with a Metal Foam Care for Lightweight Fan Blade Design

The quest for cheap, low density and high performance materials in the design of aircraft and rotorcraft engine fan and propeller blades poses immense challenges to the materials and structural design engineers. Traditionally, these components have been fabricated using expensive materials such as light weight titanium alloys, polymeric composite materials and carbon-carbon composites. The present study investigates the use of P sandwich foam fan blade made up of solid face sheets and a metal foam core. The face sheets and the metal foam core material were an aerospace grade precipitation hardened 17-4 PH stainless steel with high strength and high toughness. The stiffness of the sandwich structure is increased by separating the two face sheets by a foam core. The resulting structure possesses a high stiffness while being lighter than a similar solid construction. Since the face sheets carry the applied bending loads, the sandwich architecture is a viable engineering concept. The material properties of 17-4 PH metal foam are reviewed briefly to describe the characteristics of the sandwich structure for a fan blade application. A vibration analysis for natural frequencies and P detailed stress analysis on the 17-4 PH sandwich foam blade design for different combinations of skin thickness and core volume %re presented with a comparison to a solid titanium blade.

Min, James B.↗
NASA NTRS2002

Active Control of Combustor Instability Shown to Help Lower Emissions

In a quest to reduce the environmental impact of aerospace propulsion systems, extensive research is being done in the development of lean-burning (low fuel-to-air ratio) combustors that can reduce emissions throughout the mission cycle. However, these lean-burning combustors have an increased susceptibility to thermoacoustic instabilities, or high-pressure oscillations much like sound waves, that can cause severe high-frequency vibrations in the combustor. These pressure waves can fatigue the combustor components and even the downstream turbine blades. This can significantly decrease the safe operating life of the combustor and turbine. Thus, suppression of the thermoacoustic combustor instabilities is an enabling technology for lean, low-emissions combustors. Under the Aerospace Propulsion and Power Base Research and Technology Program, the NASA Glenn Research Center, in partnership with Pratt & Whitney and United Technologies Research Center, is developing technologies for the active control of combustion instabilities. With active combustion control, the fuel is pulsed to put pressure oscillations into the system. This cancels out the pressure oscillations being produced by the instabilities. Thus, the engine can have lower pollutant emissions and long life.The use of active combustion instability control to reduce thermo-acoustic-driven combustor pressure oscillations was demonstrated on a single-nozzle combustor rig at United Technologies. This rig has many of the complexities of a real engine combustor (i.e., an actual fuel nozzle and swirler, dilution cooling, etc.). Control was demonstrated through modeling, developing, and testing a fuel-delivery system able to the 280-Hz instability frequency. The preceding figure shows the capability of this system to provide high-frequency fuel modulations. Because of the high-shear contrarotating airflow in the fuel injector, there was some concern that the fuel pulses would be attenuated to the point where they would not be effective for control. Testing in the combustor rig showed that open-loop pulsing of the fuel was, in fact, able to effectively modulate the combustor pressure. To suppress the combustor pressure oscillations due to thermoacoustic instabilities, it is desirable to time the injection of the fuel so that it interferes with the instability. A closed-loop control scheme was developed that uses combustion pressure feedback and a phase-shifting controller to time the fuel-injection pulses. Some suppression of the pressure oscillations at the 280-Hz instability frequency was demonstrated (see the next figure). However, the overall peak-to- peak pressure oscillations in the combustor were only mildly reduced. Improvements to control hardware and control methods are being continued to gain improved closed-loop reduction of the pressure oscillations.pulse the fuel at

DeLaat, John C.↗
NASA NTRS2003

The NASA Microgravity Fluid Physics Program: Research Plans for the ISS

Building on over four decades of research and technology development related to the behavior of fluids in low gravity environments, the current NASA Microgravity Fluid Physics Program continues the quest for knowledge to further understand and design better fluids systems for use on earth and in space. NASA's Biological and Physical Research Enterprise seeks to exploit the space environment to conduct research supporting human exploration of space (strategic research), research of intrinsic scientific importance and impact (fundamental research), and commercial research. The strategic research thrust will build the vital knowledge base needed to enable NASA's mission to explore the Universe and search for life. There are currently five major research areas in the Microgravity Fluid Physics Program: complex fluids, niultiphase flows and phase change, interfacial phenomena, biofluid mechanics, and dynamics and instabilities. Numerous investigations into these areas are being conducted in both ground-based laboratories and facilities and in the flight experiments program. Most of the future NASA- sponsored flight experiments in microgravity fluid physics and transport phenomena will be carried out on the International Space Station (ISS) in the Fluids Integrated Rack (FIR), in the Microgravity Science Glovebox (MSG), in EXPRESS racks, and in other facilities provided by international partners. This paper presents an overview of the near- and long-term visions for NASA's Microgravity Fluid Physics Research Program and brief descriptions of hardware systems planned to enable this research.

Kohl, Fred J.↗
NASA NTRS2005

Mineralized Remains of Morphotypes of Filamentous Cyanobacteria in Carbonaceous Meteorites

The quest for conclusive evidence of microfossils in meteorites has been elusive. One difficulty arises from the fact than many abiotic or inorganic microstructures, mineral grains, and coating artifacts can mimic the smaller representatives of the microbial world that possess very simple morphologies (unicellular cocci or bacilli). However, there exist a wide variety of large, filamentous trichomic prokaryotic microorganisms (cyanobacteria and sulfur bacteria) with sufficiently well known and complex morphologies that they can be recognized and are known to be of unquestionable biogenic origin. The taphonomic modes of fossilization and their of their life habits and processes frequently result in distinctive chemical biosignatures associated with carbonization, silicification, calcification, phosphatization and metal-binding properties of their cell-walls, trichomes, sheaths and extracellular polymeric substances (EPS). Strong differences of mineral concentrations in closely associated and visibly differentiated cellular microstructures provide strong evidence of biogenicity. This evidence is further enhanced by the detection of recognizable and distinct microstructures (e.g., uniseriate or multiseriate filaments, trichomes, sheaths, cells of proper sizes and size distributions) and growth characteristics (e.g., basal or apical cells, true or false branching of trichomes, tapered or uniform filaments, robust or thin sheaths) and reproductive and nitrogen fixation habits (e.g., baeocytes, hormogonia, akinetes and heterocysts), Microfossils of cyanobacteria and cyanobacterial mats and stromatolites have been recognized a described from many of the most ancient rocks on Earth. The crucial problem lies in developing valid protocols and methodologies for establishing that the putative microfossils are truly indigenous and not merely recent microbial contaminants. During the past several years, we have conducted Field Emission Scanning Electron Microscopy (FESEM) investigations of freshly fractured interior surfaces of carbonaceous meteorites, terrestrial rocks, and recent microbial extremophiles and filamentous cyanobacteria. These studies have resulted in the detection in a several carbonaceous meteorites of the mineralized remains of a wide variety of complex filamentous trichomic microorganisms. These embedded forms are consistent in size and microstructure with well-preserved morphotypes of mat- forming filamentous trichomic cyanobacteria and the degraded remains of microfibrils of cyanobacterial sheaths. We present the results of comparative imaging studies and EDAX elemental analyses of recent cyanobacteria (e.g. Calothrix, Oscillatoria, and Lyngbya) that are similar in size, morphology and microstructure to morphotypes found embedded in meteorites. EDAX elemental studies reveal that forms found in carbonaceous meteorites often have highly carbonized sheaths in close association with permineralized filaments, trichomes and microbial cells. Ratios of critical bioelements (C:O, C:N, C:P, and C:S) reveal dramatic differences between microfossils in Earth rocks and meteorites and in filaments, trichomes, hormogonia, and cells of recent cyanobacteria.

Hoover, Richard B.↗
NASA NTRS2005

III-V Compound Detectors for CO2 DIAL Measurements

Profiling of atmospheric carbon dioxide (CO2) is important for understanding the natural carbon cycle on Earth and its influence on global warming and climate change. Differential absorption lidar is a powerful remote sensing technique used for profiling and monitoring atmospheric constituents. Recently there has been an interest to apply this technique, at the 2 m wavelength, for investigating atmospheric CO2. This drives the need for high quality detectors at this wavelength. Although 2 m detectors are commercially available, the quest for a better detector is still on. The detector performance, regarding quantum efficiency, gain and associated noise, affects the DIAL signal-to-noise ratio and background signal, thereby influencing the instrument sensitivity and dynamic range. Detectors based on the III-V based compound materials shows a strong potential for such application. In this paper the detector requirements for a long range CO2 DIAL profiles will be discussed. These requirements were compared to newly developed III-V compound infrared detectors. The performance of ternary InGaSb pn junction devices will be presented using different substrates, as well as quaternary InGaAsSb npn structure. The performance study was based on experimental characterization of the devices dark current, spectral response, gain and noise. The final results are compared to the current state-of-the-art InGaAs technology. Npn phototransistor structure showed the best performance, regarding the internal gain and therefore the device signal-to-noise ratio. 2-micrometers detectivity as high as 3.9 x 10(exp 11) cmHz(sup 1/2)/W was obtained at a temperature of -20 C and 4 V bias voltage. This corresponds to a responsivity of 2650 A/W with about 60% quantum efficiency.

Refaat, Tamer F.↗
NASA NTRS2006

THE MATERIALS ON INTERNATIONAL SPACE STATION EXPERIMENT (MISSE): FIRST RESULTS FROM MSFC INVESTIGATIONS

Marshall Space Flight Center worked with the Air Force Research Laboratory, Naval Research Laboratory, Langley Research Center, Glenn Research Center, the Jet Propulsion Laboratory, Johnson Space Center, Boeing, Lockheed Martin, TRW, the Aerospace Corporation, Triton Systems, AZ Technology, Alion (formerly IITRI), ENTECH, and L'Garde to bring together the first external materials exposure experiment on International Space Station (ISS). MISSE re-uses hardware from the MEEP flown on the Russian space station Mir. MISSE has returned a treasure trove of materials data that will be useful not only for ISS but also for programs as diverse as the new Crew Exploration Vehicle, the James Webb Telescope, the Lunar Surface Access Module, the Robotic Lunar Exploration Program, High Altitude Airships, and solar sails. MISSE-1 and -2 (Figure 1) were attached to the Quest airlock on ISS for 4 years and were retrieved during STS-114. MISSE-3 and -4 were bumped fr-om STS-114 and are currently slated for deployment during STS-121. MISSE-5 (Figure 2) was deployed during STS-114.

Finckenor, Miria↗
NASA NTRS2005

Making Human Spaceflight as Safe as Possible

We articulated the safety hierarchy a little over two years ago, as part of our quest to be the nation s leader in safety and occupational health, and in the safety of the products and services we provide. The safety hierarchy stresses that we are all accountable for assuring that our programs, projects, and operations do not impact safety or health for the public, astronauts and pilots, employees on the ground, and high-value equipment and property. When people are thinking about doing things safely, they re also thinking about doing things right. And for the past couple of years, we ve had some pretty good results. In the time since the failures of the Mars 98 missions that occurred in late 1999, every NASA spacecraft launch has met the success objectives, and every Space Shuttle mission has safely and successfully met all mission objectives. Now I can t say that NASA s safety program is solely responsible for these achievements, but, as we like to say, "mission success starts with safety." In the future, looking forward, we will continue to make spaceflight even safer. That is NASA s vision. That is NASA s duty to both those who will travel into space and the American people who will make the journey possible.

Gregory, Frederick D.↗
NASA NTRS2006

MISSE Scattered Atomic Oxygen Characterization Experiment

An experiment designed to measure the atomic oxygen (AO) erosion profile of scattered AO was exposed to Low Earth Orbital (LEO) AO for almost four years as part of the Materials International Space Station Experiment 1 and 2 (MISSE 1 and 2). The experiment was flown in MISSE Passive Experiment Carrier 2 (PEC 2), Tray 1, attached to the exterior of the International Space Station (ISS) Quest Airlock. The experiment consisted of an aperture disk lid of Kapton H (DuPont) polyimide coated on the space exposed surface with a thin AO durable silicon dioxide film. The aperture lid had a small hole in its center to allow AO to enter into a chamber and impact a base disk of aluminum. The AO that scattered from the aluminum base could react with the under side of the aperture lid which was coated sporadically with microscopic sodium chloride particles. Scattered AO erosion can occur to materials within a spacecraft that are protected from direct AO attack but because of apertures in the spacecraft the AO can attack the interior materials after scattering. The erosion of the underside of the Kapton lid was sufficient to be able to use profilometry to measure the height of the buttes that remained after washing off the salt particles. The erosion pattern indicated that peak flux of scattered AO occurred at and angle of approximately 45 from the incoming normal incidence on the aluminum base unlike the erosion pattern predicted for scattering based on Monte Carlo computational predictions for AO scattering from Kapton H polyimide. The effective erosion yield for the scattered AO was found to be a factor of 0.214 of that for direct impingement on Kapton H polyimide.

Banks, Bruce A.↗
NASA NTRS2003

Analysis and training - why different?

It is tempting to seek universal combat simulations, optimized for both analysis and training. Such a quest would be quixotic, however, because the two environments place conflicting requirements.

simulation modeling training analysis↗
NASA NTRS2006

Reference Guide to the International Space Station

The International Space Station (ISS) is a great international, technological, and political achievement. It is the latest step in humankind's quest to explore and live in space. The research done on the ISS may advance our knowledge in various areas of science, enable us to improve life on this planet, and give us the experience and increased understanding that can eventually equip us to journey to other worlds. As a result of the Station s complexity, few understand its configuration, its design and component systems, or the complex operations required in its construction and operation. This book provides high-level insight into the ISS. The ISS is in orbit today, operating with a crew of three. Its assembly will continue through 2010. As the ISS grows, its capabilities will increase, thus requiring a larger crew. Currently, 16 countries are involved in this venture. This CD-ROM includes multimedia files and animations.

Kitmacher, Gary H.↗
NASA NTRS2006

MISSE PEACE Polymers Atomic Oxygen Erosion Results

Forty-one different polymer samples, collectively called the Polymer Erosion and Contamination Experiment (PEACE) Polymers, have been exposed to the low Earth orbit (LEO) environment on the exterior of the International Space Station (ISS) for nearly 4 years as part of Materials International Space Station Experiment 2 (MISSE 2). The objective of the PEACE Polymers experiment was to determine the atomic oxygen erosion yield of a wide variety of polymeric materials after long term exposure to the space environment. The polymers range from those commonly used for spacecraft applications, such as Teflon (DuPont) FEP, to more recently developed polymers, such as high temperature polyimide PMR (polymerization of monomer reactants). Additional polymers were included to explore erosion yield dependence upon chemical composition. The MISSE PEACE Polymers experiment was flown in MISSE Passive Experiment Carrier 2 (PEC 2), tray 1, on the exterior of the ISS Quest Airlock and was exposed to atomic oxygen along with solar and charged particle radiation. MISSE 2 was successfully retrieved during a space walk on July 30, 2005, during Discovery s STS-114 Return to Flight mission. Details on the specific polymers flown, flight sample fabrication, pre-flight and post-flight characterization techniques, and atomic oxygen fluence calculations are discussed along with a summary of the atomic oxygen erosion yield results. The MISSE 2 PEACE Polymers experiment is unique because it has the widest variety of polymers flown in LEO for a long duration and provides extremely valuable erosion yield data for spacecraft design purposes.

deGroh, Kim, K.↗
NASA NTRS2007

Coupled Nd-142, Nd-143 and Hf-176 Isotopic Data from 3.6-3.9 Ga Rocks: New Constraints on the Timing of Early Terrestrial Chemical Reservoirs

Increasingly precise data from a range of isotopic decay schemes, including now extinct parent isotopes, from samples of the Earth, Mars, Moon and meteorites are rapidly revising our views of early planetary differentiation. Recognising Nd-142 isotopic variations in terrestrial rocks (which can only arise from events occurring during the lifetime of now extinct Sm-146 [t(sub 1/2)=103 myr]) has been an on-going quest starting with Harper and Jacobsen. The significance of Nd-142 variations is that they unequivocally reflect early silicate differentiation processes operating in the first 500 myr of Earth history, the key time period between accretion and the beginning of the rock record. The recent establishment of the existence of Nd-142 variations in ancient Earth materials has opened a new range of questions including, how widespread is the evidence of early differentiation, how do Nd-142 compositions vary with time, rock type and geographic setting, and, combined with other types of isotopic and geochemical data, what can Nd-142 isotopic variations reveal about the timing and mechanisms of early terrestrial differentiation? To explore these questions we are determining high precision Nd-142, Nd-143 and Hf-176 isotopic compositions from the oldest well preserved (3.63- 3.87 Ga), rock suites from the extensive early Archean terranes of southwest Greenland and western Australia.

Bennett, Vickie C.↗
NASA NTRS2006

Binary Black Holes, Gravitational Waves, and Numerical Relativity

The final merger of two black holes releases a tremendous amount of energy and is one of the brightest sources in the gravitational wave sky. Observing these sources with gravitational wave detectors requires that we know the radiation waveforms they emit. Since these mergers take place in regions of extreme gravity, we need to solve Einstein's equations of general relativity on a computer in order to calculate these waveforms. For more than 30 years, scientists have tried to compute these waveforms using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. This situation has changed dramatically in the past year, with a series of amazing breakthroughs. This talk will take you on this quest for the holy grail of numerical relativity, showing how a spacetime is constructed on a computer to build a simulation laboratory for binary black hole mergers. We will focus on the recent advances that are revealing these waveforms, and the dramatic new potential for discoveries that arises when these sources will be observed by LISA and LIGO.

Centrella, Joan↗
NASA NTRS2006

The Benefits of Virtual Presence in Space (VPS) to Deep Space Missions

Understanding our place in the Universe is one of mankind's greatest scientific and technological challenges and achievements. The invention of the telescope, the Copernican Revolution, the development of Newtonian mechanics, and the Space Age exploration of our solar system; provided us with a deeper understanding of our place in the Universe; based on better observations and models. As we approach the end of the first decade of the new millennium, the same quest, to understand our place in the Universe, remains a great challenge. New technologies will enable us to construct and interact with a "Virtual Universe" based on remote and in situ observations of other worlds. As we continue the exploration that began in the last century, we will experience a "Virtual Presence in Space (VPS)" in this century. This paper describes VPS technology, the mechanisms for VPS product distribution and display, the benefits of this technology, and future plans. Deep space mission stereo observations and frames from stereo High Definition Television (HDTV) mission animations are used to illustrate the effectiveness of VPS technology.

deep space missions↗
NASA NTRS2006

Results from SIM's Thermo-Opto-Mechanical (TOM3) Testbed

Future space-based optical interferometers, such as the Space Interferometer Mission Planet Quest (SIM), require thermal stability of the optical wavefront to the level of picometers in order to produce astrometric data at the micro-arc-second level. In SIM, the internal path of the interferometer will be measured with a small metrology beam whereas the starlight fringe position is estimated from a large concentric annular beam. To achieve the micro-arc-second observation goal for SIM, it is necessary to maintain the optical path difference between the central and the outer annulus portions of the wavefront of the front-end telescope optics to a few tens of picometers. The Thermo-Opto-Mecha nical testbed (TOM3) was developed at the Jet Propulsion Laboratory to measure thermally induced optical deformations of a full-size flight-like beam compressor and siderostat, the two largest optics on SIM, in flight-like thermal environments. A Common Path Heterodyne Interferometer (COPHI) developed at JPL was used for the fine optical path difference measurement as the metrology sensor. The system was integrated inside a large vacuum chamber in order to mitigate the atmospheric and thermal disturbances. The siderostat was installed in a temperature-controlled thermal shroud inside the vacuum chamber, creating a flight-like thermal environment. Detailed thermal and structural models of the test articles (siderostat and compressor) were also developed for model prediction and correlation of the thermal deformations. Experimental data shows SIM required thermal stability of the test articles and good agreement with the model predictions.

interferometry↗