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At least 307 records · Page 17

Scientific objectives of the Solar Mesosphere Explorer mission

The paper describes the NASA Solar Mesosphere Explorer mission which will study mesospheric ozone and the processes which form and destroy it, measure the ozone density and its altitude distribution from 30 to 80 km, monitor incoming solar UV radiation, and provide a rigorous test of the photochemical equilibrium theory of the mesospheric oxygen-hydrogen system. Five instruments will be carried on the polar-orbiting spacecraft: UV ozone, IR airglow, and visible NO2 programmable Ebert-Fastie spectrometers, a four-channel IR radiometer, and a solar UV spectrometer. Atmospheric measurements will be made of the mesospheric and stratospheric ozone density distribution, water vapor density distribution, temperature profile, ozone photolysis rate, and NO2 density distribution. In addition, the solar UV monitor will measure both the 0.2-0.31 micron spectral region and the Lyman-alpha (0.1216 micron) contribution to the solar irradiance.

Thomas, G. E.↗

The Potential for Health Monitoring in Expandable Space Modules: The Bigelow Expandable Activity Module on the ISS

Expandable modules for use in space and on the Moon or Mars offer a great opportunity for volume and mass savings in future space exploration missions. This type of module can be compressed into a relatively small shape on the ground, allowing them to fit into space vehicles with a smaller cargo/fairing size than a traditional solid, metallic structure based module would allow. In April 2016, the Bigelow Expandable Activity Module (BEAM) was berthed to the International Space Station (ISS). BEAM is the first human-rated expandable habitat/module to be deployed and crewed in space. BEAM is a NASA managed ISS payload project in partnership with Bigelow Aerospace. BEAM is intended to stay attached to ISS for an operational period of 2 years to help advance the technology readiness for future expandable modules. BEAM has been instrumented with a suite of space flight certified sensors systems which will help characterize the module's performance for thermal, radiation shielding and impact monitoring against potential Micro Meteoroid/Orbital Debris (MM/OD) providing fundamental information on the BEAM environment for potential health monitoring requirements and capabilities. This paper will provide an overview of how the sensors/instrumentation systems were developed, tested, installed and an overview of the current sensor system operations. It will also discuss how the MM/OD impact detection system referred to as the Distributed Impact Detection System (DIDS) data is being processed and reviewed on the ground by the principle investigators.

Wells, Nathan D.↗

Monitoring Jupiter's hectometric emission

The feasibility of long-term monitoring of the Jovian hectometric radiation component (nominal range between 0.3 to 3 MHz) is considered. It is recommended that long-term monitoring of Jupiter at frequencies around 1 MHz should be conducted either from a high-orbit earth satellite or from the surface of the moon. Such a program would eventually provide a record of rotation period changes revealing secular variations in the Jovian magnetic field, with a sensitivity much higher than could be achieved from the earth.

Carr, Thomas D.↗

First-Principle Dynamic Electro-Thermal Numerical Model of a Scanning Radiometer for Earth Radiation Budget Applications

Low Earth Observing instruments that are used to monitor the incoming solar and outgoing long wave radiation have been a crucial part of studying the Earth’s radiation budget for the past three decades. These instruments go through several robust design phases followed by vigorous ground calibration campaigns to set their baseline characterization spectrally, spatially, temporally and radiometrically. The knowledge from building and calibrating these instruments has aided in technology advancements and the need for developing more accurate instruments has increased. In order to understand the on-ground instrument performance, NASA Langley Research Center has partnered with the Thermal Radiation Group of Virginia Tech to develop a first-principle, dynamic, electrothermal, numerical model of a scanning radiometer that can be used to enhance the interpretation of an Earth radiation budget-like instrument on orbit. This paper will summarize the current efforts of developing this high-fidelity end-to-end model and also highlight how it can be applied to an Earth radiation budget instrument.

Ashraf, Anum Rauf Bark↗

The Mars Environmental Dynamics Analyzer, MEDA. A Suite of Environmental Sensors for the Mars 2020 Mission

NASA’s Mars 2020 (M2020) rover mission includes a suite of sensors to monitor current environmental conditions near the surface of Mars and to constrain bulk aerosol properties from changes in atmospheric radiation at the surface. The Mars Environmental Dynamics Analyzer (MEDA) consists of a set of meteorological sensors including wind sensor, a barometer, a relative humidity sensor, a set of 5 thermocouples to measure atmospheric temperature at ∼1.5 m and ∼0.5 m above the surface, a set of thermopiles to characterize the thermal IR brightness temperatures of the surface and the lower atmosphere. MEDA adds a radiation and dust sensor to monitor the optical atmospheric properties that can be used to infer bulk aerosol physical properties such as particle size distribution, non-sphericity, and concentration. The MEDA package and its scientific purpose are described in this document as well as how it responded to the calibration tests and how it helps prepare for the human exploration of Mars. A comparison is also presented to previous environmental monitoring payloads landed on Mars on the Viking, Pathfinder, Phoenix, MSL, and InSight spacecraft.

J. A. Rodriguez-Manfredi↗

System selects framing rate for spectrograph camera

Circuit using zero-order light is reflected to a photomultiplier in the incoming radiation of a spectrograph monitor to provide an error signal which controls the advancing and driving rate of the film through the camera.

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Testing the Fraunhofer line discriminator by sensing fluorescent dye

The experimental Fraunhofer Line Discriminator (FLD) has detected increments of Rhodamine WT dye as small as 1 ppb in 1/2 meter depths. It can be inferred that increments considerably smaller than 1 ppb will be detectable in depths considerably greater than 1/2 meter. Turbidity of the water drastically reduces luminescence or even completely blocks the transmission of detectable luminescence to the FLD. Attenuation of light within the water by turbidity and by the dye itself are the major factors to be considered in interpreting FLD records and in relating luminescence coefficient to dye concentration. An airborne test in an H-19 helicopter established feasibility of operating the FLD from the aircraft power supply, and established that the rotor blades do not visibly affect the monitoring of incident solar radiation.

Stoertz, G. E.↗

Solar mesosphere explorer: Experiment description

The Solar Mesosphere Explorer (SME) satellite experiments will provide a comprehensive study of atmospheric ozone and the processes which form and destroy it. Five instruments to be carried on the spacecraft will measure the ozone density and altitude distribution, monitor the incoming solar radiation, and measure other atmospheric constituents which affect ozone. The investigative approach concept, methods and procedures, preflight studies, and orbits and mission lifetime are presented. Descriptions of the instruments are also presented.

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Solar Mesosphere Explorer mission

The Solar Mesosphere Explorer (SME) satellite experiments will provide a comprehensive study of atmospheric ozone and the processes which form and destroy it. Five instruments to be carried on the spacecraft will measure the ozone density and altitude distribution, monitor the incoming solar radiation, and measure other atmospheric constituents which affect ozone. The first objective of the SME satellite experiments is to determine what changes occur in the ozone distribution as a result of changes in the incoming solar radiation. A second objective is to measure all changes in the ozone density distribution in the altitude range of 30 to 80 km and to determine the causes of these changes.

Stuart, J. R.↗

CCE plasma wave observations during the storm of September 4, 5, 1984

Near 0700 on September 4, 1984 a series of interplanetary discontinuities arrived at earth when the AMPTE Charge Composition Explorer (CCE) was near apogee. During the next few hours the spacecraft passed in and out of the magnetosheath. At the magnetopause boundary, the CCE wave instrument detected strong electron plasma oscillations, weaker electromagnetic waves at the electron plasma frequency, and broadband electrostatic waves. During the subsequent perigee passes on September 4 and 5, the wave observations of upper hybrid resonance emissions, continuum radiation, electrostatic noise bands and unusual low latitude auroral kilometic radiation were used to monitor significant variations in the magnetospheric characteristics as the main storm phases developed.

Scarf, F. L.↗

An investigation of the energy balance of solar active regions using the ACRIM irradiance data

The correlation between the irradiance (as measured by the Active Cavity Radiometer Irradiance Monitor and the Earth Radiation Budget) as corrected for sunspot flux deficit (which is responsible for most of the variance of the uncorrected signal) and both the 205 nm flux (as measured by Nimbus 7) and a photometric facular index is discussed. The computer program which simulates two-dimensional convection in a compressible, stratified medium is described. Equipment which was acquired to perform high precision, white-light observations of sunspot areas, and procedures were tested. Analysis of observations of large scale convective heat inhomogeneities which were obtained in May 1985 was begun.

Petro, L. D.↗

Infrared observations of planetary atmospheres

Infrared data was obtained on planetary atmospheres which provides critical information on atmospheric structure, composition, and cloud properties in support of planetary missions such as Voyager and Galileo. Mapping of Jupiter and Saturn in thermal and reflected solar radiation is a high-priority monitoring and exploratory activity. Some of these images of Jupiter are shown. Radiation at 17.8 micrometer probes the upper tropospheric temperature structure where spatial structure bears a strong resemblance to visible and near-infrared reflected sunlight such as at 2.0 micrometer. At 7.8 micrometer, stratospheric temperatures appear to have a three-banded structure, enhancements near the magnetic poles and occasional transient features such as the equatorial filament near the right limb. Clouds or hazes are observed high in the stratosphere looking at wavelengths such as 2.2 micrometer, where gaseous opacity is very strong. Other maps examine cloud properties from thermal radiation not strongly influenced by gaseous opacity and the distribution of condensable gases, such as ammonia. Millimeter and submillimeter filtered radiometric observations were made of Jupiter, Uranus and Neptune via collaborative work. Radiometric observations of Uranus and Neptune at 21 and 32 micrometer were acquired and analyzed as well as grating array spectra in the ranges of 8 to 14 micrometer, 16 to 23 micrometer, and 18 to 32 micrometer. These showed evidence for C2H2 in the stratosphere of Uranus and C2H4 in the stratosphere of Neptune.

Orton, G. S.↗

A Solar Constant Model for Sun-climate Studies: 1600-2000AD

Discussed here is the solar constant model published recently (Schatten, 1988), but with a modified phasing and amplitude. This model enables the known solar constant variations to be calculated from known active region and quiet region solar parameters. The features which can be modelled are sunspots and faculae, the only two features which mark the photospheric continuum with their unusual contrast behavior. They include both the active region features (sunspots and faculae) and the quiet region features (global faculae). Although the direct influences of sunspots upon the solar constant leads to short term decreases, an opposite, nearly in phase, 11 year variation in the solar constant is modelled, thereby agreeing with the Active Cavity Radiometer Irradiance Monitor (ACRIM) and Earth Radiation Budget (ERB) secular trends observed. This opposite behavior results primarily from global faculae (polar, network, and active region). The main contributors to the global behavior are the network faculae. The model attributes the observed variations in the solar constant entirely to magnetic features in the solar atmosphere. The present model serves purely to model the secular (long term) trend in the solar constant. The model suggests a change of approx. 0.5 W/sq m for the differences between the late twentieth century solar constant and the 17th century solar constant. This supports Eddy's view that this difference could give rise to the glacial increase during the little ice age of the 17th century. Important for present day climate studies, is that it shows the recent peak activity (peaking in 1958) is associated with an atypically high value of the solar constant, with respect to the past few hundred years.

Schatten, Kenneth H.↗

Nonscanning climate sensor study

The Nonscanning Climate Sensor represents a new instrument for climate research and global monitoring of the earth radiation budget. It contains a mosaic of array of detectors which measures the outgoing radiation of the earth in all directions without the need for mechanical scanning. The goal is to eliminate all moving parts and obtain highly calibrated measurements for up to one solar cycle (11 years) without being susceptible to mechanical failure. Over set intervals of time, the angular measurements are integrated up to produce total reflected and emitted flux values from each target area on the Earth. To achieve the require sensitivity while maintaining a flat spectral response, an improved dual cavity detector with digital control loop was developed. The detector is self calibrating to maintain high precision over the life of the instrument. Prototype detectors and a complete set of electronics with a microprocessor controller were fabricated and tested. Measurements show that the new detectors are more than an order of magnitude more sensitive than previous versions.

Hoffman, James W.↗

Heliospheric hydrogen beyond 15 AU - Evidence for a termination shock

The Voyager and Pioneer 10 spacecraft are moving upstream and downstream into the local interstellar flow, monitoring H Lyman alpha radiation resonantly scattered from heliospheric hydrogen. Voyager Cruise Maneuver observations obtained between 15 and 35 AU reveal that H Lyman alpha intensities in the upstream direction fall as r exp -0.75+/-0.05. Beyond 15 AU downstream, Pioneer 10 intensities fall as r exp -1.07+/-0.1. These trends cannot be simultaneously reproduced using a hot H distribution model that does not include termination shock structure. The Voyager H Lyman alpha intensities also show a distinctive trend to decrease less rapidly with increasing heliocentric distance. Between 15 and 20 AU, Voyager intensities fall as r exp -1, whereas between 30 and 35 AU they fall as r exp -0.35. This flattening trend implies that the upstream H density is increasing rapidly with heliocentric distance beyond about 25 AU. This steepening trend is significant because similar H density gradients are predicted in models which include the effects of the termination shock. Taken together, the Voyager and Pioneer 10 H Lyman alpha observations beyond 15 AU imply the existence of a solar wind termination shock, suggesting that it lies between 70 and 105 AU in the upstream direction.

Hall, D. T.↗

STS-68 Mission Highlights Resource Tape

The video contains important visual events including Space Radar Laboratory-2, Get Away Special canisters, Commercial Protein Crystal Growth, Biological Research in Canisters, Cosmic Radiation Effects and Activation Monitor, Military Applications of Ship Tracks, other onboard activities, earth views, and landing. Also includes Air-to-ground transmission between the crew and Mission control.

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STS-68 Space Shuttle mission report

The STS-68 Space Shuttle Program Mission Report summarizes the Payload activities as well as the Orbiter, External Tank (ET), Solid Rocket Booster (SRB), Redesigned Solid Rocket Motor (RSRM), and the Space Shuttle main engine (SSME) systems performance during the sixty-fifth flight of the Space Shuttle Program and the seventh flight of the Orbiter vehicle Endeavour (OV-105). In addition to the Orbiter, the flight vehicle consisted of an ET that was designated ET-65; three SSMEs that were designated as serial numbers 2028, 2033, and 2026 in positions 1, 2, and 3, respectively; and two SRBs that were designated BI-067. The RSRMs that were installed in each SRB were designated as 360W040A for the left SRB and 360W040B for the right SRB. The primary objective of this flight was to successfully perform the operations of the Space Radar Laboratory-2 (SRL-2). The secondary objectives of the flight were to perform the operations of the Chromosome and Plant Cell Division in Space (CHROMEX), the Commercial Protein Crystal Growth (CPCG), the Biological Research in Canisters (BRIC), the Cosmic Radiation Effects and Activation Monitor (CREAM), the Military Application of Ship Tracks (MAST), and five Get-Away Special (GAS) payloads.

Fricke, Robert W., Jr.↗

Satellite Instrument Calibration for Measuring Global Climate Change. Report of a Workshop at the University of Maryland Inn and Conference Center, College Park, MD. , November 12-14, 2002

Measuring the small changes associated with long-term global climate change from space is a daunting task. To address these problems and recommend directions for improvements in satellite instrument calibration some 75 scientists, including researchers who develop and analyze long-term data sets from satellites, experts in the field of satellite instrument calibration, and physicists working on state of the art calibration sources and standards met November 12 - 14, 2002 and discussed the issues. The workshop defined the absolute accuracies and long-term stabilities of global climate data sets that are needed to detect expected trends, translated these data set accuracies and stabilities to required satellite instrument accuracies and stabilities, and evaluated the ability of current observing systems to meet these requirements. The workshop's recommendations include a set of basic axioms or overarching principles that must guide high quality climate observations in general, and a roadmap for improving satellite instrument characterization, calibration, inter-calibration, and associated activities to meet the challenge of measuring global climate change. It is also recommended that a follow-up workshop be conducted to discuss implementation of the roadmap developed at this workshop.

NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY (NI↗