by Dale Elizabeth Corey
This posting covers the Space Shuttle Program’s Earth Science payloads that were flown on the Space Shuttle, America’s Space Transportation System (STS) from 1981 to 2010. (For the sake of space, not all payloads will be covered.)
STS-53/HERCULES, December 2, 1992, Earth Observation
Mission: Among other Department of Defense experiments, STS-53 used a Hand-held Earth-oriented Real-time Cooperative, User-friendly, Location, targeting, and Environmental System (HERCULES) space-borne experiment equipment allowed the astronauts to take multiple images of the same target while simultaneously keeping the edge of the Earth in view; this limited image magnification. With HERCULES, the astronaut only needed to look at the point of interest, allowing the use of many different camera lenses. HERCULES captured images digitally allowing computer analysis and data dissemination, an improvement over previous film-based Lcubed system (National Aeronautics and Space Administration Space Shuttle Mission Sts-53 Press Kit December 1992, 1992).
Hercules provided an Earth observation system for military, environmental, oceanographic and meteorological applications. It was flown again on STS-56 in 1993. Hercules was flown under the direction of the Department of Defense’s Space Test Program. For more information on STS-53 go to: http://search.nasa.gov/search/search.jsp?nasaInclude=sts-53&x=0&y=0
STS-45/ATLAS-1, January 22, 1992, Atmospheric Laboratory for Applications and Science
The first Atmospheric Laboratory for Applications and Science (ATLAS-1) was on Spacelab pallets mounted in the orbiter’s cargo bay. Equipped with 12 instruments from U.S., France, Germany, Belgium, Switzerland, the Netherlands and Japan, it conducted studies in atmospheric chemistry, solar radiation, space plasma physics and ultraviolet astronomy.
ATLAS-1 studied the middle and upper atmosphere and helped correlate atmospheric composition, temperature and pressure with altitude, latitude, longitude and changes in solar radiation. The types of environmental phenomena examined included global distribution of atmospheric components and temperatures, as well as atmospheric reaction to external influences such as solar input and geomagnetic storms. The high-altitude effects of terrestrial environmental episodes — volcanic eruptions, forest fires, massive oil fires in Kuwait — were examined. Data collection helped scientists to monitor short- and long-term environmental changes.
Gases in the upper atmosphere and ionosphere undergo constant change triggered by variations in ultraviolet light as well as by reactions between layers and air motions. Many of the photochemical reactions — the effect of light or other radiant energy that produce chemical actions — cause atoms and molecules to emit light of very specific wavelengths. These light signatures are called spectral features.
The Imaging Spectrometric Observatory (ISO) measured spectral features to determine the composition of the atmosphere, down to trace amounts of chemicals measured in parts-per-trillion. This investigation, which previously flew on Spacelab 1, added to data about the varied reactions and energy transfer processes that occur in Earth’s environment.
The Atmospheric Trace Molecule Spectroscopy (ATMOS) and the Grille Spectrometer (Grille) experiments mapped trace molecules, including carbon dioxide and ozone, in the middle atmosphere. This mapping was accomplished at orbital sunrise and sunset by measuring the infrared radiation that these molecules absorb. An orbital ‘day,’ with a sunrise and sunset, occurs approximately every 90 minutes during flight. These data were compared with information gathered during other missions to note worldwide, seasonal and long-term atmospheric changes.
The Atmospheric Lyman-Alpha Emissions (ALAE) experiment measured the abundance of two forms of hydrogen: common hydrogen and deuterium, or heavy hydrogen. ALAE observed ultraviolet light, called Lyman-alpha that hydrogen and deuterium radiate at slightly different wavelengths. Deuterium’s relative abundance compared to hydrogen at the altitude would be an indication of atmospheric turbulence. After determining the hydrogen/deuterium ratio, scientists could better study the rate of water evolution in Earth’s atmosphere.
The Millimeter-Wave Atmospheric Sounder (MAS) measured the strength of millimeter waves radiating at the specific frequencies of water vapor, chlorine monoxide and ozone. Observations of these gases enabled scientists to better understand their distribution through the upper atmosphere. MAS data was particularly valuable because they should be unaffected by the presence of aerosols, the concentrations of which have increased by the eruption of Mount Pinatubo in June 1991.
The Shuttle Solar Backscatter Ultraviolet Spectrometer (SSBUV) was a calibrating experiment. Its measurements were compared to those from ozone-observing instruments aboard the National Oceanic and Atmospheric Administration’s (NOAA)-9 and NOAA-11 satellites and NASA’s NIMBUS-7 satellite. The SSBUV assessed instrument performance by directly comparing data from identical instruments aboard the NOAA spacecraft and NIMBUS-7 as the Shuttle and satellite passed over the same Earth location within an hour. SSBUV data was compared to data obtained by the Upper Atmosphere Research Satellite, which was launched in September 1991 to study the processes that lead to ozone depletion. Click here for more information on STS-45: http://science1.nasa.gov/missions/atlas/
STS-52/LAGEOS-II, October 22, 1992, Laser Geodynamic Satellite II
LAGEOS II (LAser GEOdetic Satellite) was a very dense (high mass-to-area ratio) laser retroreflector satellite that provided a permanent reference point in a very stable orbit for precision Earth dynamics measurements such as crustal motions, regional strains, and fault and polar motion. The satellite provided a reference point for measurement of Earth rotation variations, solid earth tides and other kinematic and dynamic parameters associated with earthquake assessment and alleviation.
LAGEOS II, launched from the Shuttle STS 52, was a joint project between NASA and the Italian Space Agency (ASI). LAGEOS II was a passive satellite consisting of 426 reflectors designed to return a laser beam to the originating station. Of the 426 reflectors (called ‘cube corner retroreflectors’), 422 were made of fused silica and four of germanium. Its compact and dense design ensured its orbit stability. Lageos II is predicted to re-enter the atmosphere in 8.4 million years.
The high-accuracy range measurements from LAGEOS II’s reference point were used to accomplish many extreme precision earth-dynamics measurements required by the earthquake hazard assessment and alleviation made b y Crustal Dynamics Project. The performance of LAGEOS II in orbit was limited only by degradation of the retroreflectors, so many decades of useful life can be expected. Click here for more information on STS-52: http://science1.nasa.gov/missions/lageos-1-2/
STS-56/ATLAS-2, April 8, 1993, Atmospheric Laboratory for Applications and Science-2
The primary payload of the flight was the Atmospheric Laboratory for Applications and Science-2 (ATLAS-2), designed to collect data on the relationship between the sun’s energy output and Earth’s middle atmosphere and how these factors affect ozone layer. ATLAS-2 was one element of NASA’s Mission to Planet Earth program. All seven of its instruments first flew on ATLAS-I during STS-45, and flew a third time in late 1994.
Throughout this 9-day mission, the crew of Discovery conducted atmospheric and solar studies to better understand the effect of solar activity on the Earth’s climate and environment. Click here for more information on STS-56: http://search.nasa.gov/search/search.jsp?nasaInclude=atlas+2&entqr=0&output=xml_no_dtd&sort=date%3AD%3AL%3Ad1&ud=1&site=nasa_collection&client=nasa_production&ie=UTF-8&oe=UTF-8&simple_start=&news_start=&images_start=&videos_start=&podcasts_start=&baynote_start=&baynoteOrGSA=baynote
For a Space Shuttle mission chronology please take a look at SPACE.com’s summaries below:
In the meantime, please stay tuned as we will be following up with installments 3 and 4 of this series in the near future.
ATLAS-1: The First Atmospheric Laboratory for Applications and Science. Accessed 27 July, 2011: http://www.nasa.gov/audience/formedia/factsheet/Atlas-1_factsheet.html.
Lageos. Accessed 9 August, 2011. http://en.wikipedia.org/wiki/LAGEOS.
LAGEOS II. Accessed 27 July, 2011: http://nssdc.gsfc.nasa.gov/nmc/spacecraftDisplay.do?id=1992-070B.
Orloff, R. National Aeronautics and Space Administration Space Shuttle Mission Sts-53 Press Kit December 1992. Access 26 July, 2011: http://www.shuttlepresskit.com/sts-53/sts53.pdf.
Space Shuttle Mission Chronology: Part 3 — 1989-1994. Accessed 27 July, 2011: http://www.space.com/12063-space-shuttle-missions-1989-1994.html.
STS-53 Discovery, OV-103, DOD Hercules digital electronic imagery equipment. Accessed 26 July, 2011: http://www.nasaimages.org/luna/servlet/detail/nasaNAS~7~7~38993~142839:STS-53-Discovery,-OV-103,-DOD-Hercu