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NASA NTRS1997

STS-85 Day 02 Highlights

On this second day of the STS-85 mission, the flight crew, Cmdr. Curtis L. Brown, Jr., Pilot Kent V. Rominger, Payload Cmdr. N. Jan Davis (Ph.D.), Mission Specialists Robert L. Curbeam, Jr. and Stephen K. Robinson (Ph.D.), and Payload Specialist Bjarni V. Tryggvason activated instruments of the Technology Applications and Science (TAS), including the Shuttle Laser Altimeter, the Infrared Spectral Imaging Radiometer (ISIR), the Cryogenic On-Orbit Long Life Active Refrigerator (COOLAR), Two Phase Flow (TPF), Critical Viscosity of Xenon (CVX) and were initializing the Solar Constant Experiment (SOLCON) and preparing for its first observation. Work with the Japanese-built Manipulator Flight Demonstration (MFD) experiment l begins when Davis begins checkout of its Small Fine Arm, destined for use outside the International Space Station's Japanese Experiment Module. Brown is seen being interviewed by WBTV-TV, Charlotte, N.C., and WTVD-TV, Raleigh-Durham, N.C.

Source record↗

NASA NTRS2014

Remote Sensing of Cloud Top Height from SEVIRI: Analysis of Eleven Current Retrieval Algorithms

The role of clouds remains the largest uncertainty in climate projections. They influence solar and thermal radiative transfer and the earth's water cycle. Therefore, there is an urgent need for accurate cloud observations to validate climate models and to monitor climate change. Passive satellite imagers measuring radiation at visible to thermal infrared (IR) wavelengths provide a wealth of information on cloud properties. Among others, the cloud top height (CTH) - a crucial parameter to estimate the thermal cloud radiative forcing - can be retrieved. In this paper we investigate the skill of ten current retrieval algorithms to estimate the CTH using observations from the Spinning Enhanced Visible and InfraRed Imager (SEVIRI) onboard Meteosat Second Generation (MSG). In the first part we compare ten SEVIRI cloud top pressure (CTP) data sets with each other. The SEVIRI algorithms catch the latitudinal variation of the CTP in a similar way. The agreement is better in the extratropics than in the tropics. In the tropics multi-layer clouds and thin cirrus layers complicate the CTP retrieval, whereas a good agreement among the algorithms is found for trade wind cumulus, marine stratocumulus and the optically thick cores of the deep convective system. In the second part of the paper the SEVIRI retrievals are compared to CTH observations from the Cloud-Aerosol LIdar with Orthogonal Polarization (CALIOP) and Cloud Profiling Radar (CPR) instruments. It is important to note that the different measurement techniques cause differences in the retrieved CTH data. SEVIRI measures a radiatively effective CTH, while the CTH of the active instruments is derived from the return time of the emitted radar or lidar signal. Therefore, some systematic differences are expected. On average the CTHs detected by the SEVIRI algorithms are 1.0 to 2.5 kilometers lower than CALIOP observations, and the correlation coefficients between the SEVIRI and the CALIOP data sets range between 0.77 and 0.90. The average CTHs derived by the SEVIRI algorithms are closer to the CPR measurements than to CALIOP measurements. The biases between SEVIRI and CPR retrievals range from −0.8 kilometers to 0.6 kilometers. The correlation coefficients of CPR and SEVIRI observations vary between 0.82 and 0.89. To discuss the origin of the CTH deviation, we investigate three cloud categories: optically thin and thick single layer as well as multi-layer clouds. For optically thick clouds the correlation coefficients between the SEVIRI and the reference data sets are usually above 0.95. For optically thin single layer clouds the correlation coefficients are still above 0.92. For this cloud category the SEVIRI algorithms yield CTHs that are lower than CALIOP and similar to CPR observations. Most challenging are the multi-layer clouds, where the correlation coefficients are for most algorithms between 0.6 and 0.8. Finally, we evaluate the performance of the SEVIRI retrievals for boundary layer clouds. While the CTH retrieval for this cloud type is relatively accurate, there are still considerable differences between the algorithms. These are related to the uncertainties and limited vertical resolution of the assumed temperature profiles in combination with the presence of temperature inversions, which lead to ambiguities in the CTH retrieval. Alternative approaches for the CTH retrieval of low clouds are discussed.

Hamann, U.↗

NASA NTRS2008

Aerosol Profile Measurements from the NASA Langley Research Center Airborne High Spectral Resolution Lidar

Since achieving first light in December of 2005, the NASA Langley Research Center (LaRC) Airborne High Spectral Resolution Lidar (HSRL) has been involved in seven field campaigns, accumulating over 450 hours of science data across more than 120 flights. Data from the instrument have been used in a variety of studies including validation and comparison with the Cloud- Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite mission, aerosol property retrievals combining passive and active instrument measurements, aerosol type identification, aerosol-cloud interactions, and cloud top and planetary boundary layer (PBL) height determinations. Measurements and lessons learned from the HSRL are leading towards next-generation HSRL instrument designs that will enable even further studies of aerosol intensive and extensive parameters and the effects of aerosols on the climate system. This paper will highlight several of the areas in which the NASA Airborne HSRL is making contributions to climate science.

Obland, Michael D.↗

NASA NTRS2007

Imaging Sensor Flight and Test Equipment Software

The Lightning Imaging Sensor (LIS) is one of the components onboard the Tropical Rainfall Measuring Mission (TRMM) satellite, and was designed to detect and locate lightning over the tropics. The LIS flight code was developed to run on a single onboard digital signal processor, and has operated the LIS instrument since 1997 when the TRMM satellite was launched. The software provides controller functions to the LIS Real-Time Event Processor (RTEP) and onboard heaters, collects the lightning event data from the RTEP, compresses and formats the data for downlink to the satellite, collects housekeeping data and formats the data for downlink to the satellite, provides command processing and interface to the spacecraft communications and data bus, and provides watchdog functions for error detection. The Special Test Equipment (STE) software was designed to operate specific test equipment used to support the LIS hardware through development, calibration, qualification, and integration with the TRMM spacecraft. The STE software provides the capability to control instrument activation, commanding (including both data formatting and user interfacing), data collection, decompression, and display and image simulation. The LIS STE code was developed for the DOS operating system in the C programming language. Because of the many unique data formats implemented by the flight instrument, the STE software was required to comprehend the same formats, and translate them for the test operator. The hardware interfaces to the LIS instrument using both commercial and custom computer boards, requiring that the STE code integrate this variety into a working system. In addition, the requirement to provide RTEP test capability dictated the need to provide simulations of background image data with short-duration lightning transients superimposed. This led to the development of unique code used to control the location, intensity, and variation above background for simulated lightning strikes at user-selected locations.

Freestone, Kathleen↗

NASA NTRS2016

Thermal Vacuum Chamber Repressurization with Instrument Purging

At the end of James Webb Space Telescope (JWST) OTIS (Optical Telescope Element-OTE-Integrated Science Instrument Module-ISIM) cryogenic vacuum testing in NASA Johnson Space Centers (JSCs) thermal vacuum (TV) Chamber A, contamination control (CC) engineers are mooting the idea that chamber particulate material stirred up by the repressurization process may be kept from falling into the ISIM interior to some degree by activating instrument purge flows over some initial period before opening the chamber valves. This memo describes development of a series of models designed to describe this process. These are strung together in tandem to estimate overpressure evolution from which net outflow velocity behavior may be obtained. Creeping flow assumptions are then used to determine the maximum particle size that may be kept suspended above the ISIM aperture, keeping smaller particles from settling within the instrument module.

Venting↗

NASA NTRS2017

Thermal Vacuum Chamber Repressurization with Instrument Purging

Repressurization↗

NASA NTRS2018

Investigations of Hail Damage Swaths Using Various Satellite Remote Sensing Platforms

Severe thunderstorms that bring damaging winds and large hail can cause significant damage to agricultural crops. Severe thunderstorms can cause upwards of several hundreds of millions of dollars in damage to agricultural areas. Formal ground surveys are not conducted on these areas of damage, like they are for suspected tornado damaged areas. IF ground surveys were conducted, they would likely be time and resources consuming due to their large spatial extent. Satellite remote sensing has been frequently used in identification and analysis of these hail damage swaths. Previous analysis have looked at the simple change in damaged vegetation to looking at the damage areas in satellite imagery with varying spatial resolutions. One study has even looked at the impacts that these damage swaths can have on the land surface, associated fluxes and how they affect numerical weather prediction. Previous studies have focused on using optical remote (VIS, NIR, SWIR) sensing instruments and derived indices, such as Normalized Difference Vegetation Index (NDVI) for analysis. NDVI is used to monitor the health (greenness) of the vegetation. Optical sensors however are limited by sky conditions over the areas they are imaging and certain bands are further limited by the diurnal cycle. These limitations can lead to sometimes upwards of 7 to 10 day gaps of the surface not being imaged, especially during the height of summer convection. One way to obtain more views of the surface, regardless of the sky conditions or time of day is through the use of synthetic aperture radar (SAR). SAR sensors are active instruments that transmit in the microwave portion of the EM spectrum. The surface and its characteristics will determine the amount of energy scattered back to the sensor. The SAR sensors then measure amplitude and phase of wavelength coming back from surface.

Bell, Jordan R.↗

NASA NTRS2023

Developing a Radar Signal Simulator for the Community Radiative Transfer Model

Active radar instruments provide vertically resolved clouds and precipitation measurements that cannot be provided by the passive instruments. These active measurements are not conventionally assimilated into the data assimilation systems because of the lack of fast forward radiative transfer models and also difficulties in the error modelling of the measurements. This paper describes the development, evaluation, and sensitivity analysis for a forward radar model implemented in the Community Radiative Transfer Model (CRTM). The scattering properties required by the forward model are provided by the hydrometeor lookup tables that were generated using the discrete dipole approximation. The model is able to calculate both the reflectivity and the attenuated reflectivity for any given radar instrument at any given zenith angles as long as CRTM instrument specific coefficients are available. The evaluation using CloudSat measurements shows a very good agreement between the simulations and measurements as long as the input profiles of hydrometeors are consistent with the measured reflectivity profiles. Major sources contributing to the differences between the measured and simulated reflectivities are input hydrometeor profiles, scattering lookup tables, lack of melting layer in the forward model, CRTM scattering solvers, and attenuation calculations. In addition to the forward model, both Tangent Linear and Adjoint of the model are also implemented and tested within CRTM. These components may be required by some data assimilation systems for the assimilation of radar measurements.

radar↗

NASA NTRS1970

Elemental abundances of major, minor and trace elements in Apollo 11 lunar rocks, soil and core samples

Apollo 11 lunar rocks, soil and core samples major, minor and trace elements abundance by radiochemical and instrumental activation analyses

Rey, P.↗

NASA NTRS1975

Lunar polymict breccia 14321 - A compositional study of its principal components

Forty-nine sub-samples of the polymict breccia 14321,184 have been excavated from the rock and analyzed by instrumental activation analysis techniques, specially modified to allow examination of small samples. Two distinct types of microbreccia clasts were analysed. A mare-type basalt of unusual composition is present as several discrete clasts. Mixing models for the clastic components of the breccia illustrate that at least three stages of assembly may be distinguished on compositional grounds. The first was at a site such that KREEP-rich materials dominated the clastic rocks formed, although a variety of lithic fragments were apparently present. The second assembly stage may have been primarily that of comminution and mixing of the more primitive materials, with addition of mare-type basalt clasts. The third stage saw addition of clasts of 14321-type basalt. In the final assembly stage, the light matrix was apparently formed entirely by mutual abrasion of the pre-existing clasts, resulting in little or no change in bulk composition.

Duncan, A. R.↗

NASA NTRS1982

Status of the national transonic facility

The National Transonic Facility at NASA Langley Research Center, scheduled for completion in July, 1982, is described with emphasis on model and instrumentation activities, calibration plans and some initial research plans. Performance capabilities include a Mach number range of 0.2-1.2, a pressure range of 1-9 atmospheres, and a temperature range of 77-350 K, which will produce a maximum Reynolds number of 120 million at a Mach number of 1.0, based on a 0.25 m chord. A comprehensive tunnel calibration program is planned, which will cover basic tunnel calibration, data qualities, and data comparisons with other facilites and flights.

Mckinney, L. W.↗

NASA NTRS1985

The middle atmosphere above Andoya Norway during the winter 1983/84 as derived from metrockets and OH nightglow observations

A total of 110 wind measurements were performed in the middle atmosphere above Andoya (69N, 16E) during the MAP/WINE Campaign from December 2, 1983 to February 23, 1984 using 57 inflatable passive falling spheres, 33 datasondes, 18 foil clouds and 2 instrumented active spheres. Temperature profiles were derived from 42 falling spheres, 26 datasondes and 2 active spheres. Near-mesopause temperatures were determined from OH nightglow observations. Synthesized charts of the temperatures as well as the zonal and meridional wind components between 0 and 90 km altitudes are presented. The temperature measurements indicate the occurrence of several minor and one major stratospheric warming, the latter being observed over Andoya at the end of the launch series.

Meyer, W.↗

NASA NTRS1988

An overview of a tether deployment monitoring system

A study was conducted to investigate the feasibility of monitoring the position of a tether during tether deployment. Several major configurations were investigated, including considerations of passive or active optical detection, radar, lidar, and active instrumentation packages. Cost, weight, the impact on tether operational dynamics, and the orbiter integration considerations were studied for each of these methods. Results indicated that implementation of such a monitoring system can be accomplished with little or no impact on tether deployment operations. Design diagrams are presented for two launchers and a tether attitude/tension detector.

Ibanez, P.↗

NASA NTRS1992

SeaWiFS technical report series. Volume 1: An overview of SeaWiFS and ocean color

The purpose of this series of technical reports is to provide current documentation of the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) Project activities, instrument performance, algorithms, and operations. This documentation is necessary to ensure that critical information related to the quality and calibration of the satellite data is available to the scientific community. SeaWiFS will bring to the ocean community a welcomed and improved renewal of the ocean color remote sensing capability lost when the Nimbus-7 Coastal Zone Color Scanner (CZCS) ceased operating in 1986. The goal of SeaWiFS, scheduled to be launched in August 1993, is to examine oceanic factors that affect global change. Because of the role of phytoplankton in the global carbon cycle, data obtained from SeaWiFS will be used to assess the ocean's role in this cycle, as well as other biogeochemical cycles. SeaWiFS data will be used to help elucidate the magnitude and variability of the annual cycle of primary production by marine phytoplankton and to determine the distribution and timing of spring blooms. The observations will help to visualize the dynamics of ocean and costal currents, the physics of mixing, and the relationships between ocean physics and large-scale patterns of productivity. The data will help fill the gap in ocean biological observations between those of the CZCS and the upcoming Moderate Resolution Imaging Spectrometer (MODIS) on the Earth Observing System-A (EOS-A) satellite.

Hooker, Stanford B.↗

NASA NTRS1992

Long Duration Space Materials Exposure (LDSE)

The Center on Materials for Space Structures (CMSS) at Case Western Reserve University is one of seventeen Commercial Centers for the Development of Space. It was founded to: (1) produce and evaluate materials for space structures; (2) develop passive and active facilities for materials exposure and analysis in space; and (3) develop improved material systems for space structures. A major active facility for materials exposure is proposed to be mounted on the exterior truss of the Space Station Freedom (SSF). This Long Duration Space Materials Exposure (LDSE) experiment will be an approximately 6 1/2 ft. x 4 ft. panel facing into the velocity vector (RAM) to provide long term exposure (up to 30 years) to atomic oxygen, UV, micro meteorites, and other low earth orbit effects. It can expose large or small active (instrumented) or passive samples. These samples may be mounted in a removable Materials Flight Experiment (MFLEX) carrier which may be periodically brought into the SSF for examination by CMSS's other SSF facility, the Space Materials Evaluation Facility (SMEF), which will contain a Scanning Electron Microscope, a Variable Angle & Scanning Ellipsometer, a Fourier Transform Infrared Spectrometer, and other analysis equipment. These facilities will allow commercial firms to test their materials in space and promptly obtain information on their materials survivability in the LEO environment.

Allen, David↗

NASA NTRS1993

Microwave Limb Sounder measurement of stratospheric SO2 from the Mt. Pinatubo volcano

The Microwave Limb Sounder (MLS) experiment on the Upper Atmosphere Research Satellite (UARS) began atmospheric measurements on September 19, 1991. Residual SO2 from the Pinatubo eruption was detected immediately after instrument activation. The SO2 was 1ocated in a tropical band with peak mixing ratios of about 15 ppbv near 26 km altitude. The observed decay of SO2 has provided an estimate of the OH concentration in the plume.

Read, W. G.↗

NASA NTRS1995

Orbital atomic oxygen effects on materials: An overview of MSFC experiments on the STS-46 EOIM-3

The third Evaluation of Oxygen Interaction with Materials experiment was flown on Space Shuttle Mission STS-46 (July 31 - August 8, 1992), representing a joint effort of several NASA centers, universities, and contractors. This array of active instrumentation and material exposure sub-assemblies was integrated as a Shuttle cargo bay pallet experiment for investigating the effects of orbital atomic oxygen on candidate space materials. Marshall Space Flight Center contributed several passive exposure trays of material specimens, uniform stress and static stress material exposure fixtures, the Atomic Oxygen Resistance Monitor (AORM), and specimens of thermal coatings for the EOIM-3 variable exposure mechanisms. As a result of 42 hours of spacecraft velocity vector-oriented exposure during the later phases of the STS-46 mission in LEO, EOIM-3 materials were exposed to an atomic oxygen fluence of 2.2 x 10(exp 20) atoms/sq cm. In this paper, an overview is presented of the technical approaches and results from analyses of the MSFC flight specimens, fixtures, and the AORM. More detailed results from earlier EOIM missions, the LDEF, and from laboratory testing are included in associated papers of this conference session.

Linton, Roger C.↗

NASA NTRS1995

STS-46 plasma composition measurements using the EOIM-3 mass spectrometer

One of the active instruments incorporated into the Evaluation of Oxygen Interactions with Materials - 3 experiment was a quadrupole mass spectrometer. The primary objectives for this instrument, which was built by the Air Force Phillips Laboratory and was a veteran of the STS-4 flight in 1982, were to quantify the flux of atomic oxygen striking the test surfaces in the EOIM-3 payload and to detect surface reaction products from the materials in the carousel. Other speakers in this session have covered the results of these experiments. Prior to the 40-hour-long dedicated EOIM-3 mission segment at the end of the STS-46 flight, the authors used the mass spectrometer to make measurements of ion and neutral gas composition in the shuttle environment. About 25 hours of data were collected during a variety of mission events, including Eureca deployment at high altitude and many tethered satellite system operations.

Hunton, Donald E.↗