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At least 217 records · Page 12

Two-mirror projection systems for simulating telescopes

Optical instruments designed for use with large telescopes need to be tested before being installed at their work site. This is especially true for space-based instruments. To perform these tests, an auxiliary optical system is required which simulates the telescope exit pupil. Two-mirror projection systems can be used for this purpose. In this paper the first-order geometric properties and third-order aberrations of the general two-mirror system used at finite conjugates are examined. Relations are given in terms of five design parameters: object distance, image distance, exit pupil size, and the two mirror magnifications. A particular application of these relations is presented for a system designed to simulate the HST, for ground testing of the next generation of scientific instruments to be installed in the observatory. We show that a sufficient number of degrees of freedom are available to meet requirements when both mirrors are conics.

Hannan, Paul G.↗

Development of a Methodology to Conduct Usability Evaluation for Hand Tools that May Reduce the Amount of Small Parts that are Dropped During Installation while Processing Space Flight Hardware

Foreign object debris (FOD) is an important concern while processing space flight hardware. FOD can be defined as "The debris that is left in or around flight hardware, where it could cause damage to that flight hardware," (United Space Alliance, 2000). Just one small screw left unintentionally in the wrong place could delay a launch schedule while it is retrieved, increase the cost of processing, or cause a potentially fatal accident. At this time, there is not a single solution to help reduce the number of dropped parts such as screws, bolts, nuts, and washers during installation. Most of the effort is currently focused on training employees and on capturing the parts once they are dropped. Advances in ergonomics and hand tool design suggest that a solution may be possible, in the form of specialty hand tools, which secure the small parts while they are being handled. To assist in the development of these new advances, a test methodology was developed to conduct a usability evaluation of hand tools, while performing tasks with risk of creating FOD. The methodology also includes hardware in the form of a testing board and the small parts that can be installed onto the board during a test. The usability of new hand tools was determined based on efficiency and the number of dropped parts. To validate the methodology, participants were tested while performing a task that is representative of the type of work that may be done when processing space flight hardware. Test participants installed small parts using their hands and two commercially available tools. The participants were from three groups: (1) students, (2) engineers / managers and (3) technicians. The test was conducted to evaluate the differences in performance when using the three installation methods, as well as the difference in performance of the three participant groups.

Miller, Darcy↗

Central Data Processing System (CDPS) user's manual: Solar heating and cooling program

The software and data base management system required to assess the performance of solar heating and cooling systems installed at multiple sites is presented. The instrumentation data associated with these systems is collected, processed, and presented in a form which supported continuity of performance evaluation across all applications. The CDPS consisted of three major elements: communication interface computer, central data processing computer, and performance evaluation data base. Users of the performance data base were identified, and procedures for operation, and guidelines for software maintenance were outlined. The manual also defined the output capabilities of the CDPS in support of external users of the system.

Source record↗

Micro-Vibration Measurements on Thermally Loaded Multi-Layer Insulation Samples in Vacuum

Some scientific missions require to an extreme extent the absence of any on-board microvibration. Recent projects dedicated to measuring the Earth's gravity field and modeling the geoid with extremely high accuracy are examples. Their missions demand for extremely low micro-vibration environment on orbit for: (1) Not disturbing the measurement of earth gravity effects with the installed gradiometer or (2) Even not damaging the very high sensitive instruments. Based on evidence from ongoing missions multi-layer insulation (MLI) type thermal control blankets have been identified as a structural element of spacecrafts which might deform under temperature variations being caused by varying solar irradiation in orbit. Any such deformation exerts tiny forces which may cause small reactions resulting in micro-vibrations, in particular by exciting the spacecraft eigenmodes. The principle of the test set-up for the micro-vibration test was as follows. A real side wall panel of the spacecraft (size about 0.25 m2) was low-frequency suspended in a thermal vacuum chamber. On the one side of this panel, the MLI samples were fixed by using the standard methods. In front of the MLI, an IR-rig was installed which provided actively controlled IR-radiation power of about 6 kW/m2 in order to heat the MLI surface. The cooling was passive using the shroud temperature at a chamber pressure <1E-5mbar. The resulting micro-vibrations due to MLI motion in the heating and the cooling phase were measured via seismic accelerometers which were rigidly mounted to the panel. Video recording was used to correlate micro-vibration events to any visual MLI motion. Different MLI sample types were subjected to various thermal cycles in a temperature range between -60 C to +80 C. In this paper, the experience on these micro-vibration measurements will be presented and the conclusions for future applications will be discussed

Deutsch, Georg↗

Testing of lift/cruise fan exhaust deflector

A lift/cruise exhaust deflector system for the LF336/A tip turbine lift fan was designed, built, and tested to determine the design and performance characteristics of a large-scale, single swivel nozzle thrust vectoring system. The exhaust deflector static testing was performed at the Ames Research Center outside static test stand facilities. The test hardware was installed on a hydraulic lift platform to permit both in and out of ground effect testing. The exhaust flow of the LF336/A lift fan was vectored from 0 degrees through 130 degrees during selected fan speeds to obtain performance at different operating conditions. The system was operated with and without flow vanes installed in the small radius bends to evaluate the system performance based on a proposed method of improving the internal flow losses. The program also included testing at different ground heights, to the nozzle exhaust plane, to obtain ground effect data, and the testing of two methods of thrust spoiling using a duct bypass door system and nozzle flap system.

Schlundt, D. W.↗

Underground storage systems for high-pressure air and gases

This paper is a discussion of the safety and cost of underground high-pressure air and gas storage systems based on recent experience with a high-pressure air system installed at Moffett Field, California. The system described used threaded and coupled oil well casings installed vertically to a depth of 1200 ft. Maximum pressure was 3000 psi and capacity was 500,000 lb of air. A failure mode analysis is presented, and it is shown that underground storage offers advantages in avoiding catastrophic consequences from pressure vessel failure. Certain problems such as corrosion, fatigue, and electrolysis are discussed in terms of the economic life of such vessels. A cost analysis shows that where favorable drilling conditions exist, the cost of underground high-pressure storage is approximately one-quarter that of equivalent aboveground storage.

Beam, B. H.↗

Thermal arcjet technology for space propulsion

Advanced space propulsion systems are required to meet projected Air Force needs through the year 2000. Most of these missions require a large, on-orbit impulse capability. High specific impulse (I sub sp) electric engines can provide this impulse while consuming relatively little propellant. An arcjet engine system, which operates in the range of 800 to 2000 s I sub sp, is a promising candidate to meet these projected Air Force mission needs. This electric propulsion system is ideally suited to missions currently under consideration, such as the Space-based Radar and other space platforms, because sufficient power is already installed for other functions on the spacecraft. Also, arcjet systems are attractive for NASA near-term, low-cost Mariner Mark II missions to Saturn and Uranus. Development of arcjet engines was an Air Force and NASA-sponsored activity that proceeded vigorously from its inception during the late 1950's up to the mid-1960's when the programs were terminated. This paper describes thermal arcjet technology as it was developed over two decades ago and points to the direction this technology development should proceed in the future. In particular, operation with storable propellants such as ammonia and hydrazine are considered. The performance, applicability and advantages of these systems in terms of increased payload and/or decreased trip times are discussed.

Pivirotto, T. J.↗

Theoretical and experimental investigations of sensor location for optimal aeroelastic system state estimation

One of the major concerns in the design of an active control system is obtaining the information needed for effective feedback. This involves the combination of sensing and estimation. A sensor location index is defined as the weighted sum of the mean square estimation errors in which the sensor locations can be regarded as estimator design parameters. The design goal is to choose these locations to minimize the sensor location index. The choice of the number of sensors is a tradeoff between the estimation quality based upon the same performance index and the total costs of installing and maintaining extra sensors. An experimental study for choosing the sensor location was conducted on an aeroelastic system. The system modeling which includes the unsteady aerodynamics model developed by Stephen Rock was improved. Experimental results verify the trend of the theoretical predictions of the sensor location index for different sensor locations at various wind speeds.

Liu, G.↗

Experimental studies of 90 deg corner cascades in the National Full-Scale Aerodynamic Complex

Two 90 deg, fixed geometry, turning vane cascades were replaced in the 40- by 80-foot wind tunnel circuit of the National Full-Scale Aerodynamic Complex as a part of a major facility upgrade. Prior to the replacement of these vanes, small-scale, two-dimensional tests were conducted to assess the aerodynamic performance of the original, 1930's technology vane geometry and a new vane geometry which was developed using a modern cascade design code. The small scale tests were conducted in the 1/10th-Scale Cascade Test Facility and included measurements of total pressure, static pressure, and flow angularity distributions in the wake of the cascade and static pressure distributions along the vane profiles. Test results and a detailed comparison of the two vanes designs are presented. Based on these results, the new design was chosen and subsequently installed in the wind tunnel. During the integrated systems test of the upgraded facility, two of the 52 vanes in the first cascade were instrumented near midspan. The full-scale test results are presented, these show the cascade pressure loss coefficient to be slightly larger than obtained in the small-scale tests. Elements of the three-dimensional flow field upstream of the cascade, which effect can impact cascade performance, are discussed and recommendations for future research are given.

Meyn, Larry A.↗

AI mass spectrometers for space shuttle health monitoring

The facility Hazardous Gas Detection System (HGDS) at Kennedy Space Center (KSC) is a mass spectrometer based gas analyzer. Two instruments make up the HGDS, which is installed in a prime/backup arrangement, with the option of using both analyzers on the same sample line, or on two different lines simultaneously. It is used for monitoring the Shuttle during fuel loading, countdown, and drainback, if necessary. The use of complex instruments, operated over many shifts, has caused problems in tracking the status of the ground support equipment (GSE) and the vehicle. A requirement for overall system reliability has been a major force in the development of Shuttle GSE, and is the ultimate driver in the choice to pursue artificial intelligence (AI) techniques for Shuttle and Advanced Launch System (ALS) mass spectrometer systems. Shuttle applications of AI are detailed.

Adams, F. W.↗

Polar Cirrus Cloud Properties Through Long-Term Lidar and Radiometer Observations

In comparison to mid latitude cloud cover, knowledge of polar cirrus and other cloud cover is limited. The interpretations of satellite-based cloud imaging and retrievals in polar regions have major problems due to factors such as darkness and extreme low temperatures. Beginning in 2002 a NASA orbiting lidar instrument, GLAS, (Geoscience Laser Altimeter System) will unambiguously define cloud type and fraction with good coverage of polar regions. Active laser sensing gives the spatial and temporal distribution of clouds and diamond dust. In preparation for, and supplementing the GLAS measurements are ground based MP (micro pulse) lidar experiments providing continuous profiling. MP lidar installations have been operating at the South Pole since December 1999 and at the Atmospheric Radiation Measurement (ARM) program arctic site since 1996. Both at the ARM Barrow, Alaska site and at the South Pole station, Fourier-transform interferometers also observe clouds in the wavelength intervals between approximately 5 and 18 microns. Spectral instruments can yield cloud microphysical properties with additional information from lidar about the vertical extent of clouds being modeled. We examine the simultaneous lidar and spectral data from both Barrow and South Pole, to obtain cloud properties (optical depth, particle size) by the use of both instruments. The results have applications to interpretation of current satellite data, and GLAS measurements when available.

Spinhirne, James↗

STS-108 Post Flight Presentation

The crewmembers of STS-108, Commander Dominic Gorie, Pilot Mark Kelly, and Mission Specialists Linda Godwin and Daniel Tani, narrate this video as footage from the mission is shown. The crew is seen flying into Kennedy Space Center, suiting up, boarding the Endeavour Orbiter, and during launch. Various mission highlights are seen, including the rendezvous with the International Space Station (ISS) and docking of Endeavour, the unloading of the Multipurpose Logistics Module (MPLM), and the spacewalk to install thermal blankets over the Beta Gimbal Assemblies (BGAs) at the bases of the Space Station's solar panels. A glimpse is given into the difficulties of working in a microgravity environment as the crewmembers attempt to eat food before it floats away from them and drink water from a bag. The exchange of the Expedition 4 (Yuri I. Onufrienko, Carl E. Walz, and Daniel W. Bursch) for the Expedition 3 crew (Frank L. Culbertson, Mikhail Turin, and Vladimir N. Dezhurov) is also seen. The Endeavour undocks from the ISS, which is seen over the Caribbean Sea. Endeavour passes over Cuba, and footage of the Swiss Alps is shown. The video ends with the landing of the spacecraft.

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Preliminary Statistics from the NASA Alphasat Beacon Receiver in Milan, Italy

NASA Glenn Research Center (GRC) and the Politecnico di Milano (POLIMI) have initiated a joint propagation campaign within the framework of the Alphasat propagation experiment to characterize rain attenuation, scintillation, and gaseous absorption effects of the atmosphere in the 40 GHz band. NASA GRC has developed and installed a KQ-band (20-40 GHz) beacon receiver at the POLIMI campus in Milan, Italy, which receives the 20-40 GHz signals broadcast from the Alphasat Aldo Paraboni TDP5 beacon payload. The primary goal of these measurements is to develop a physical model to improve predictions of communications systems performance within the Q-band. Herein, we provide an overview of the design and data calibration procedure, and present 6 months of preliminary statistics of the NASA propagation terminal, which has been installed and operating in Milan since May 2014. The Q-band receiver has demonstrated a dynamic range of 40 dB at an 8-Hz sampling rate. A weather station with an optical disdrometer is also installed to characterize rain drop size distribution for correlation with physical based models

Radio Transmission↗

Preliminary Statistics from the NASA Alphasat Beacon Receiver in Milan, Italy

NASA Glenn Research Center (GRC) and the Politecnico di Milano (POLIMI) have initiated a joint propagation campaign within the framework of the Alphasat propagation experiment to characterize rain attenuation, scintillation, and gaseous absorption effects of the atmosphere in the 40 gigahertz band. NASA GRC has developed and installed a K/Q-band (20/40 gigahertz) beacon receiver at the POLIMI campus in Milan, Italy, which receives the 20/40 gigahertz signals broadcast from the Alphasat Aldo Paraboni TDP no. 5 beacon payload. The primary goal of these measurements is to develop a physical model to improve predictions of communications systems performance within the Q-band. Herein, we provide an overview of the design and data calibration procedure, and present 6 months of preliminary statistics of the NASA propagation terminal, which has been installed and operating in Milan since May 2014. The Q-band receiver has demonstrated a dynamic range of 40 decibels at an 8-hertz sampling rate. A weather station with an optical disdrometer is also installed to characterize rain drop size distribution for correlation with physical based models.

RF propagation↗

Sextant X-Ray Pulsar Navigation Demonstration: Initial On-Orbit Results

The Station Explorer for X-ray Timing and Navigation Technology (SEXTANT) is a technology demonstration enhancement to the Neutron-star Interior Composition Explorer (NICER) mission. SEXTANT will be a first demonstration of in-space, autonomous, X-ray pulsar navigation (XNAV). Navigating using millisecond X-ray pulsars which could provide a GPS-like navigation capability available throughout our Solar System and beyond. NICER is a NASA Astrophysics Explorer Mission of Opportunity to the International Space Station that was launched and installed in June of 2017. During NICER's nominal 18-month base mission, SEXTANT will perform a number of experiments to demonstrate XNAV and advance the technology on a number of fronts. In this work, we review the SEXTANT, its goals, and present early results from SEXTANT experiments conducted in the first six months of operation. With these results, SEXTANT has made significant progress toward meeting its primary and secondary mission goals. We also describe the SEXTANT flight operations, calibration activities, and initial results.

Navigatio↗

Interactive Planetary Visualization and Analysis with NASA's Solar System Treks Portals

NASA's Solar System Trek online portals provide web-based suites of interactive visualization and analysis tools enabling mission planners, planetary scientists, students, and the general public to explore planetary surfaces as seen through the eyes of many different instruments aboard a wide range of spacecraft. The portals present a vast collection of mapped data products from past and current missions for a growing number of planetary bodies. As web-based toolsets, the portals do not require users to purchase or install any software beyond current web browsers. The interactive and immersive capabilities of these portals are being used for site selection and analysis by NASA and a number of its international partners, supporting upcoming missions. They are also being used by formal and informal educators, students from elementary through university levels of study, and members of the public who are engaged in the excitement of solar system exploration. This presentation will provide an overview of the Solar System Treks and highlight many of the exciting new additions to the project implemented this past year.

Treks↗

Visualization and Analysis of Data from Small-Body Missions with NASA's Solar System Treks Portals

The portals of NASA's Solar System Trek Project (SSTP) provide web-based suites of interactive visualization and analysis tools enabling mission planners, planetary scientists, students, and the general public to explore planetary surfaces as seen through the eyes of many different instruments aboard a wide range of spacecraft. The portals present a vast collection of mapped data products from past and current missions for a growing number of planetary bodies. As web-based toolsets, the portals do not require users to purchase or install any software beyond current web browsers. They feature a common user interface and are available through a single integrated website at https://trek.nasa.gov. This presentation will highlight 4 portals focusing on small bodies. We will provide an overview of established portals for (1) Ceres and (4) Vesta, and present the early capabilities for new portals being introduced for (162173) Ryugu and (101955) Bennu.

Day, Brian↗

2021-2022 Long-Term Groundwater Monitoring Report Industrial Area Kennedy Space Center, Florida

This report presents the groundwater sampling results from the National Aeronautics and Space Administration (NASA) Industrial Area (IA) 2021-2022 Long-Term Monitoring (LTM) activities and results of the 2023 DPT activities at three of the sites. The NASA IA LTM Program includes the following 14 sites: - Ransom Road Landfill (RRLF) – Solid Waste Management Unit (SWMU) 003 - Orsino Storage Yard (ORSY) – SWMU 004 - Building M7-0505 Treatment Tank Area (M505) – SWMU 039 - Hypergol Maintenance Facility Hazardous Waste South Staging Area (HMF South) – SWMU 070 - Operations and Checkout Building (O&C) – SWMU 076 - Vertical Processing Facility (VPF) – SWMU 077 - Environmental Health Facility (EHF) – SWMU 079 - Kennedy Athletic, Recreation, and Social Park 1 (KARS Park 1) – SWMU 084 - Engineering Development Laboratory (EDL) – SWMU 085 - Launch Equipment Test Facility (LETF) – SWMU 091 - Mobil Service Station (MOBIL) – SWMU 093 - General Services Administration Seized Property (GSSP) – SWMU 095 - Space Station Processing Facility (SSPF) – SWMU 098 - Fuel Storage Area #1 Underground Storage Tank (UST) [Building 1044] (FSA1) – Potential Release Location (PRL) 157 Groundwater levels were gauged at each site during the 2021 and 2022 LTM field activities. Sampling events for the IA LTM Program are conducted seasonally during the dry and wet seasons, which occur in May and November, respectively. The sites in the NASA IA LTM Program are sampled on annual, biennial, or 5-year sampling frequencies based on historical trends. Due to contract transitions and monitoring well installations, 2021 dry season activities were conducted during September 2021, while dry season activities for 2022 resumed in May 2022.

groundwater↗