Utilization of Virtual Environments for Astronaut Crew Training

<div class="htmlview paragraph">In February 2004 NASA released “The Vision for Space Exploration.” The important goals outlined in this document include extending human presence in the solar system culminating in the exploration of Mars. Unprocessed waste poses a biological hazard to crew health and morale. The waste processing methods currently under consideration include incineration, microbial oxidation, pyrolysis and compaction. Although each has advantages, no single method has yet been developed that is safe, recovers valuable resources including oxygen and water, and has low energy and space requirements. Thus, the objective of this project is to develop a low temperature oxidation process to convert waste cleanly and rapidly to carbon dioxide and water.</div> <div class="htmlview paragraph">In the Phase I project, TDA Research, Inc. demonstrated the potential of a low temperature oxidation process using ozone. In the current Phase II project, TDA and NASA Ames Research Center are developing a pilot scale low temperature ozone oxidation system. We are conducting tests in a reactor design that maximizes the contact between the ozone and the waste bed. In initial tests with a large volume reactor we were able to achieve higher oxidation rates than we obtained in the Phase I portion of this project. However, on occasion, the waste began to burn rapidly, producing high temperature and pressure spikes in the reactor. Therefore, we redesigned the reactor to mitigate the rapid ignition of the waste. In initial tests, we found that adding water to the waste bed and flowing ozone through the water-waste mixture provides much better control of the low temperature oxidation process. The addition of water likely produces a more uniform temperature throughout the waste, reducing localized hot spots that initiated the rapid combustion process. In addition, we have obtained better agreement between the gravimetric data and the results calculated with integrated CO<sub>2</sub> data, indicating that a higher percentage of waste has been oxidized to CO<sub>2</sub> and H<sub>2</sub>O before exiting the reactor.</div> <div class="htmlview paragraph">Once we have optimized the reactor design and waste oxidation process we will incorporate the design into a closed loop, fully automated system that will convert the waste into H<sub>2</sub>O and CO<sub>2</sub>, remove both compounds, and replenish the circulating gas stream with oxygen and ozone as needed. In addition, the system will contain the analytical equipment necessary to carry out a complete material balance and monitor the formation of pollutants such as NO<sub>X</sub> and SO<sub>X</sub>. At the conclusion of the project the system will be delivered to NASA Ames for their use and evaluation.</div>

The Office of Aeronautics and Space Technology has granted approval for a multi-year sequence of demonstrations to develop, test, and evaluate automation technologies for potential use in the Space Station. This program, called the Systems Autonomy Demonstration Program, is a cooperative venture between NASA Ames Research Center and NASA Johnson Space Center. The Systems Autonomy Demonstration Program has a number of ambitious goals whose attainment is based in part upon results anticipated from a vigorous core research and technology effort.

<div class="htmlview paragraph">The X-36 is a remotely piloted 28% scale model of a two-axis-unstable notional future fighter aircraft with canards, a mid-wing and features the absence of any vertical control surfaces, <span class="xref">Figure 1</span>. The aircraft was jointly developed by the NASA Ames Research Center and McDonnell Aircraft & Missile Systems and flight tested at the NASA Dryden Flight Research Center. Objectives of this program were to demonstrate fighter aircraft agility for a vertical tailless configuration and to demonstrate the development of a low cost alternative to full size prototype aircraft. This paper presents some aspects of the subsystem integration methodology used to develop the X-36 Tailless Agility Research Aircraft.</div>

<div class="section abstract"><div class="htmlview paragraph">During this study, the conceptual design of a 19 passenger turbofan transport aimed primarily at the regional/ commuter market was synthesised. Final configuration selection was based on a method conceived by the author which incorporates a hybrid of the conventional intuitive conceptual design process with overtones of a non-hierarchic multi-disciplinary optimisation philosophy. To ensure validity of the aforementioned design and optimisation algorithms, the General Aviation Synthesis Program (GASP) software developed by NASA-Ames Research Centre and subsequently refined by Williams- Rolls Inc. was used. In addition, attention was paid during the design sequence to minimise the alterations necessary for variants of the basic design, i.e. future extended range and stretched versions. The final proposal ended with a vehicle that displays marketing flexibility, competitive field performance, superior climb capability with significant increases in block speed, and more poignantly, higher potential for profit upon comparison to contemporary turboprops.</div></div>

<div class="htmlview paragraph">A supersonic STOVL fighter aircraft aerodynamic research program is being conducted at NASA Ames Research Center. The research focuses on technology development for this type of aircraft and includes generating an extensive aerodynamic database and resolving particular aerodynamic uncertainties for various twin- and single-engine aircraft concepts. Highlights of the results from this program are presented. The highlights include propulsion-induced effects on the aircraft drag, prediction capabilities, volume integration for minimizing drag, and wave drag and aerodynamic efficiency comparisons. Results indicate that estimated STOVL fighter performance is roughly comparable to the performance of modern conventional fighters in terms of wave drag and aerodynamic efficiency.</div>

<div class="htmlview paragraph">For the last two years, the University of Utah and Reaction Engineering International, in cooperation with NASA Ames Research Center (ARC), have been developing a waste incineration system for regenerative life support systems. The system is designed to burn inedible plant biomass and human waste. The goal is to obtain an exhaust gas clean enough to recycle to either the plant or human habitats. The incineration system, a fluidized bed reactor, has been designed for a 4-person mission. This paper will detail the design of the units. In addition, results will be presented from testing at the University of Utah. Presently, the unit has been shipped to Ames Research Center for more tests prior to delivery to Johnson Space Center for testing in a 90-day, 4-person test.</div>

<div class="htmlview paragraph">Biological wastewater processing has been under investigation by AlliedSignal Aerospace and NASA Johnson Space Center (JSC) for future use in space. Testing at JSC in the Hybrid Regenerative Water Recovery System (HRWRS) in preparation for future closed human testing has been performed. Computer models have been developed to aid in the design of a new four-person immobilized cell bioreactor. The design of the reactor and validation of the computer model is presented. In addition, the total organic carbon (TOC) computer model has been expanded to begin investigation of nitrification. This model is being developed to identify the key parameters of the nitrification process, and to improve the design and operating conditions of nitrifying bioreactors. In addition, the model can be used as a design tool to rapidly predict the effects of changes in operational conditions and reactor design, significantly reducing the number and duration of experiments required.</div>

<div class="htmlview paragraph">The Space Station Projects Office (SSPO) at NASA's Ames Research Center (ARC) is responsible for operational plans for plant and animal research in the Life Sciences Research Facility (LSRF) aboard the Space Station. As a planning database, the SSPO uses scientists' descriptions of experiment operations, configured into scenarios for typical 90-day missions. Both research tasks and tasks involving specimen care and housekeeping are included. Four of these scenarios were used to test a computer program named <i>OpSim</i>, developed by the ARC Space Human Factors Office specifically to simulate Space Station operations. The tasks for each scenario were set up for inputting to <i>OpSim</i>, simulations were executed and program output was analyzed. Some scenarios were simulated more than once, at different levels of crew time availability and of laboratory automation. The test showed that <i>OpSim</i> gives an informative picture of mission operations, and that it responds appropriately to changes in variables such as crew availability and automation. <i>OpSim</i> should become widely used to model Space Station operations and develop realistic plans.</div>

<div class="htmlview paragraph">Significant progress has been made at NASA Ames Research Center in the development of a heat melt compaction device called the Plastic Melt Waste Compactor (PMWC). The PMWC was designed to process wet and dry wastes generated on human space exploration missions. The wastes have a plastic content typically greater than twenty percent. The PMWC removes the water from the waste, reduces the volume, and encapsulates it by melting the plastic constituent of the waste. The PMWC is capable of large volume reductions. The final product is compacted waste disk that is easy to manage and requires minimal crew handling. This paper describes the results of tests conducted using the PMWC with a wet and dry waste composite that was representative of the waste types expected to be encountered on long duration human space exploration missions.</div>

<div class="htmlview paragraph">Advanced space life support systems, especially systems that include growing plants to produce food, require the recovery of resources - primarily carbon dioxide and water - from various hydrocarbon wastes. Supercritical water oxidation (SCWO) of wastes is one of several possible techniques for oxidizing waste organics to recover the carbon dioxide and water. Supercritical water oxidation has the advantages of fast kinetics, complete oxidation, and the minimization of undesirable side products. However, the SCWO process requires further development before the process can be implemented in space life systems. One of the SCWO development needs is in the area of destruction of insoluble solids - such as inedible biomass or human wastes. Insoluble solids have to be introduced into a SCWO reactor as particles, and it can be expected that the particle size of the solids will affect the rate of reaction. Once the effects of particle size are understood, then the requirements for grinding or other preparation of feed solids before introduction into the reactor can be defined. To study the effects of particle size an experimental effort was begun at NASA Ames Research Center. Particles of polystyrene bead ranging in diameter from 3.4 μm to 220 μm were tested. A significant particle size effect on the rate of reaction was measured at 720°F.</div>

<div class="htmlview paragraph">This paper describes current work at NASA Ames Research Center on the development of a heat melt compactor that can be used on both near term and far term missions. Preliminary tests have been performed to characterize the behavior of composite wastes that are representative of the types of wastes produced on current and previous space missions such as International Space Station, Space Shuttle, MIR and Skylab. Preliminary tests were conducted to characterize the volume reduction, bonding, encapsulation and plastic extrusion of the waste composite. The preliminary tests are designed to provide the data needed to design the first prototype Plastic Melt Waste Compactor.</div>

<div class="htmlview paragraph">The 1/8-scale Generic Conventional Model was studied experimentally in two wind tunnels at NASA Ames Research Center. The investigation was conducted at a Mach number of 0.15 over a Reynolds number range from 1 to 6 million. The experimental measurements included total and component forces and moments, surface pressures, and 3-D particle image velocimetry. Two configurations (trailer base flaps and skirts) were compared to a baseline representative of a modern tractor aero package. Details of each configuration provide insight into the complex flow field and the resulting drag reduction was found to be sensitive to Reynolds number.</div>

<div class="htmlview paragraph">This paper reviews recent human factors research studies conducted in the Aerospace Human Factors Research Division at NASA Ames Research Center on superimposed symbology and head-up displays (HUDs). We first identify various performance problems that have been associated with HUD use. Results of experiments that suggest an attentional account of these problems are described. A design solution involving the concept of “scene-linked” HUDs is developed, and an experiment testing the design solution is discussed.</div>

<div class="htmlview paragraph">The first government-conducted piloted flight simulation of the Grumman-designed twin turbofan-powered tilt-engine V/STOL aircraft (design 698) was conducted at NASA Ames Research Center. The aircraft is discussed with an emphasis on its unique hover characteristics. These characteristics include the adverse nonminimum phase that occurs in lateral and longitudinal translation, and the large attitude control power available. Both of these features are attributes of the control vanes (a Grumman-patented concept) buried in the fan exhaust flow. The simulation used the following NASA Ames Research Center facilities: The Vertical Motion Simulator with the interchangeable cab, the Sigma 8 computer, and the Computer-Generated Image system with a four-window display.</div>

Direct characterization of potentially habitable terrestrial exoplanets around Sun-like stars requires extremely precise instrumentation capable of measuring a planet-star contrast ratio of 10-10. This instrumentation challenge pushes the limits of optical technology, with state-of-the-art coronagraphs requiring extremely precise wavefront control and large, complex, and expensive instrument designs. These bulk optics coronagraph instruments typically have limited measurable optical bandwidths and high sensitivity to the overall telescope pupil design (i.e. on-axis vs off-axis telescope configurations) and high sensitivity to optical aberrations. The AstroPIC project is applying programmable integrated photonics to develop a new kind of coronagraph instrument that is capable of reaching the theoretical limits of optimal coronagraph performance. This will result in a coronagraph instrument that is orders of magnitude smaller, less massive, and more flexible compared to traditional bulk optics designs, with the goal of increasing the Exo-Earth science yield of NASA’s Habitable Worlds Observatory flagship mission. The AstroPIC project is leveraging commercial silicon photonics fabrication to develop a coronagraph instrument that couples light from a telescope pupil plane into a mesh of integrated Mach-Zehnder interferometers on a photonic integrated circuit (PIC). The coupling is achieved by using a lenslet array to sample and focus the telescope pupil into an array of grating coupler waveguide inputs on the PIC, as shown in Figure 1a. Once the light from the telescope pupil is coupled onto the PIC, the interferometer mesh can be controlled by tuning thermal phase shifters in each interferometer to implement a mode-sorting algorithm in order to separate the starlight and planet light modes at high contrast levels. An integrated photonic testbed at NASA Ames Research Center is being developed to demonstrate coupling from a realistic telescope pupil into the PIC and will be used to characterize the contrast, throughput, and optical bandwidth of the coronagraph instrument. Figure 1b shows the design of the testbed, which will be used to experiment with different control algorithms for setting the tunable phase shifters in the photonic mesh and assess the factors limiting contrast on the chip to inform future iterations of the PIC design. Figure 1: (a) Diagram of AstroPIC instrument concept coupling the Habitable Worlds Observatory (HWO) pupil into an array of grating couplers using a microlens array. A mesh of Mach Zehnder Interferometers (MZIs) are tuned to separate starlight spatial modes from planet spatial modes. (b) Design of integrated photonics testbed under development at NASA Ames Research Center. The AstroPIC project has also developed simulations of the PIC coronagraph instrument concept in order to predict the coupling from the telescope pupil into the chip and simulate the photonic mesh behavior. Specifically, we are studying the application of the AstroPIC instrument concept to the NASA Habitable Worlds Observatory (HWO) flagship mission, which is currently in the pre-design phase. These simulations have shown that the AstroPIC concept is very robust to telescope pupil shape and aberrations for both on- and off-axis telescope configurations, and that the potential science yield of the AstroPIC coronagraph is very high even for relatively small numbers of input couplers. We find that the AstroPIC concept is particularly advantageous for accessing planets located at small inner working angles relative to the host star, which is extremely challenging for traditional coronagraph designs. Figure 2 shows these simulation results for an example HWO-like pupil, summarizing the predicted exo-Earth science yield as a function of (a) number of PIC input grating coupler channels, (b) starlight suppression order, and (c) end to end transmission efficiency. Figure 2: Predicted number of exo-Earths characterized over the HWO mission lifetime as a function of (a) number of input grating coupler PIC channels, (b) PIC starlight suppression order (number of output channels that are designated as starlight vs signal light), and (c) end-to-end transmission efficiency of the PIC instrument. These simulations are conducted using the FRIDAY yield calculation package.In this presentation, we will describe the AstroPIC instrument concept and how programmable photonics can be used to implement the optimal coronagraph operator. We will then present the development of an integrated photonics testbed at NASA Ames Research Center, which is being built to demonstrate the AstroPIC concept with a realistic telescope pupil directly coupled into the integrated photonic instrument. We will also review recent simulation results predicting the performance of next-generation AstroPIC instrument designs. Finally, we will discuss the next steps needed to mature this technology for future space telescope missions and ground telescope applications, including incorporating novel photonic component designs into the mesh architecture to improve the throughput and optical bandwidth of the instrument.