Research and Development of an Instrument for Detection of Extraterrestrail Life by Optical Rotatory Dispersion Final Technical Report
Polarimeter for extraterrestrial life detection by optical rotatory dispersion
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Polarimeter for extraterrestrial life detection by optical rotatory dispersion
Design, fabrication, and testing of breadboard model of instrument for detection of extraterrestrial life by means of optical rotatory dispersion
A system for the evaluation of interference patterns was evaluated. A picture analysis system based on a computer with a television digitizer was used for digitizing and processing interferograms.
A new instrument capable of computing in real time the per-cycle indicated mean effective pressure (IMEP) of internal combustion engines and compressors was designed and tested. The values of IMEP obtained with the new instrument were found to be in excellent agreement with values obtained by previous postrun data reduction techniques.
The mechanisms of the instrument pointing system (IPS) are described. Particular emphasis is placed on the actuators which are necessary for operating the IPS. The actuators are described as follows: (1) two linear actuators that clamp the gimbals down during ascent and descent; (2) two linear actuators that attach the payload to the IPS during the mission, and release it into the payload clamps; (3) one rotational actuator that opens and closes the payload clamps; and (4) three identical drive units that represent the three orthogonal gimbal axes and are the prime movers for pointing. Design features, manufacturing problems, test performance, and results are presented.
The use of nonintrusive instrumentation in high-enthalpy facilities offers the opportunity to collect data that has previously been difficult or impossible to obtain. Three such instruments, now under development, are described: an OH absorption system which can measure OH species concentration and temperature, a holographic interferometer for flow visualization and density measurement at low density, and a telemetry system which allows the measurement of surface quantities on model in free-flight at hypervelocity. The challenges and opportunities encountered when employing these advanced diagnostics to high-enthalpy facilities are discussed.
The cleanliness requirements of the Cryogenic Limb Array Etalon Spectrometer (CLAES) are described and the control program is assessed with particular emphasis given to the effects of particulate interference. The use of the CLAES is reviewed, and off-axis scatter from the earth is identified as an important noise source. Since the CLAES altitude of interest causes a low-altitude detection of 0.2 deg above the earth's surface, straylight controls are important in the development of the instrument. The development of off-axis rejection and the particulate-cleanliness level are evaluated in terms of those required for a certain BRDF. The control plan is described, and procedures are outlined including cleaning methods and facilities. The modeling predictions and procedural controls are found to effectively satisfy requirements for low scatter levels and out-of-field view-rejection by maximizing straylight control and allowing a margin against noise-equivalent radiance.
Several generations of micromechanical gyros and accelerometers have been developed at Draper. Current design effort centers on tuning-fork gyro design and pendulous accelerometer configurations. Over 200 gyros of different generations have been packaged and tested. These units have successfully performed across a temperature range of -40 to 85 degrees C, and have survived 30,000-g shock tests along all axes. Draper is currently under contract to develop an integrated micro-mechanical inertial sensor assembly (MMISA) and global positioning system (GPS) receiver configuration. The ultimate projections for size, weight, and power for an MMISA, after electronic design of the application specific integrated circuit (ASIC ) is completed, are 2 x 2 x 0.5 cm, 5 gm, and less than 1 W, respectively. This paper describes the fabrication process, the current gyro and accelerometer designs, and system configurations.
Laser diode technology continues to advance at a very rapid rate due to commercial applications such as telecommunications and data storage. The advantages of laser diodes include, wide diversity of wavelengths, high efficiency, small size and weight and high reliability. Semiconductor and fiber optical-amplifiers permit efficient, high power master oscillator power amplifier (MOPA) transmitter systems. Laser diode systems which incorporate monolithic or discrete (fiber optic) gratings permit single frequency operation. We describe experimental and theoretical results of laser diode based instruments currently under development at NASA Goddard Space Flight Center including miniature lidars for measuring clouds and aerosols, water vapor and wind for Earth and planetary (Mars Lander) use.
The NEAR Mission was launched on February 17, 1996 for a three year cruise to the asteroid 433 Eros. During October, November, and December 1998 cruise measurements with the gamma-ray spectrometer were made at three different escape-window-width settings. These were done in order to understand how the count rate and peak width change as the window width settings change. Analysis of these spectra was completed using the latest version of the spectral analysis program, RobWin. Results as a function of energy were combined with the results from the Schlumberger-Doll Research experiments (described below). Laboratory measurements were needed to confirm efficiency calculations above 6 MeV and to understand the relationship between the full energy peak areas and the areas of the first and second escape peaks as a function of the escape peak widths. A week of measurements was made at Schlumberger-Doll Research using their 14-MeV pulsed neutron generator and large soil samples. Data were collected after adding iron and nickel to the sample to increase the emission of high-energy lines. Approximately 24 hours of data were accumulated at each of three escape peak window widths. These data were analyzed with RobWin. Combining results from the cruise measurements and the laboratory measurements indicated that both data sets had similar energy dependence and that this energy dependence was different from that obtained using standard Monte Carlo calculations. Alternate methods of simulating the response of the detector to changes in the escape window widths are being investigated.
The Mars environment comprises a dry, cold and low air pressure atmosphere with low gravity (0.38g) and high resistivity soil. The global dust storms that cover a large portion of Mars were observed often from Earth. This environment provides an idea condition for triboelectric charging. The extremely dry conditions on the Martian surface have raised concerns that electrostatic charge buildup will not be dissipated easily. If triboelectrically generated charge cannot be dissipated or avoided, then dust will accumulate on charged surfaces and electrostatic discharge may cause hazards for future exploration missions. The low surface temperature on Mars helps to prolong the charge decay on the dust particles and soil. To better understand the physics of Martian charged dust particles is essential to future Mars missions. We research and design two sensors, velocity/charge sensor and PZT momentum sensors, to detect the velocity distribution, charge distribution and mass distribution of Martian charged dust particles. These sensors are fabricated at NASA Kenney Space Center, Electromagnetic Physics Testbed. The sensors will be tested and calibrated for simulated Mars atmosphere condition with JSC MARS-1 Martian Regolith simulant in this NASA laboratory.
A new infrared heterodyne instrument has been developed which allows the use of both tuneable diode lasers (TDL) and quantum cascade lasers (QCL) as local oscillators (LO). The current frequency tuning range of our system extends from 900 to 1100/cm depending on the availability of lasers but is planned to be extended to 600/cm soon. The IF-bandwidth is 1.4 GHz using an acousto-optical spectrometer (AOS). The frequency resolution and stability of the system is approximately 10(exp 7). Currently, mercury-cadmium-telluride (MCT) detectors are used as mixers while new devices like quantum-well-infrared-photodetectors (QWIP) and hot-electron-bolometers (HEB) are investigated. The IF-bandwidth can be extended to about 3 GHz by using a new broadband acousto-optical spectrometer presently under development. The instrument is fully transportable and can be attached to any infrared or optical telescope. The semiconductor laser is stabilized to a Fabry-Perot ring-resonator, which is also used as an efficient diplexer to superimpose the local-oscillator and the signal radiation. As a first step measurements of trace gases in Earth's atmosphere and non-LTE emission from Venus' atmosphere were carried out as well as observations of molecular features in sunspots. Further astronomical observations from ground-based telescopes and the airborne observatory SOFIA are planned for the future. Of particular interest are molecules without a permanent dipole moment like H2, CH4, C2H2 etc.
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This paper will explore the various trades, challenges, processes and programmatic issues encountered.
NASA's Earth Venture class (EV) of missions are competitively selected, Principal Investigator (PI) led, relatively low cost and narrowly focused in scientific scope. Investigations address a full spectrum of earth science objectives, including studies of the atmosphere, oceans, land surface, polar ice regions, and solid Earth. EV has three program elements: EV-Suborbital (EVS) are suborbital/airborne investigations; EV-Mission (EVM) element comprises small complete spaceborne missions; and EV-Instrument (EVI) element develops spaceborne instruments for flight as Missions-of-Opportunity (MoO). To ensure the success of EV, frequent opportunities for selecting missions has been established in NASA's Earth Science budget. This paper will describe those opportunities and how the management approach of each element is tailored according to the specific needs of the element.
NASA's Earth Venture class (EV) of mission are competitively selected, Principal Investigator (PI) led, relatively low cost and narrowly focused in scientific scope. Investigations address a full spectrum of earth science objectives, including studies of the atmosphere, oceans, land surface, polar ice regions, and solid Earth. EV has three program elements: EV-Suborbital (EVS) are suborbital/airborne investigations; EV-Mission (EVM) element comprises small complete spaceborne missions; and EV-Instrument (EVI) element develops spaceborne instruments for flight as missions-of-opportunity (MoO). To ensure the success of EV, the management approach of each element is tailored according to the specific needs of the element.
Geochronology: More than just rock ages. What are the constraints on the time evolution ofthe dynamic solar system? When did the outerplanets migrate and the asteroid belt lose mass? How did it affect other bodies at that time?
This publication documents the scientific advances associated with new instrument systems and accessories built to improve above- and in-water observations of the apparent optical properties (AOPs) for a diversity of water masses, including optically complex waters. The principal objective is to be prepared for the launch of next-generation ocean color satellites with the most capable commercial off-the-shelf (COTS) instrumentation in the shortest time possible. The technologies described herein are entirely new hybrid sampling capabilities, so as to satisfy the requirements established for next-generation missions. Both above- and in-water instruments are documented with software options for autonomous control of data collection activities as applicable. The instruments were developed for the Hybridspectral Alternative for Remote Profiling of Optical Observations for NASA Satellites (HARPOONS) vicarious calibration project. The state-of-the-art accuracy required for vicarious calibration also led to the development of laboratory instruments to ensure the field observations were within uncertainty requirements. Separate detailed presentations of the individual instruments provide the hardware designs, accompanying software for data acquisition and processing, and examples of the results achieved.