Release No. 93-047STS-57 ASTRONAUTS TO DOCUMENT EARTH OBSERVATIONS
Low Earth orbit gives space shuttle astronauts a unique vantage point from which to observe and document in photographs a variety of meteorological, environmental, oceanographic and geological features for scientific researchers back home.
STS-57 will not be an exception. The nine-day mission will orbit at an altitude of 250 nautical miles and an inclination of 28.45 degrees, taking the astronauts over the Kennedy Space Center in Florida, the Red Sea, and the Himalayas to the north and over Asuncion, Paraguay; Johannesburg, South Africa; and Brisbane, Australia, to the south.
Besides the traditional photo documentation activities, the Space Shuttle Endeavour also will serve as a platform for a student Earth observation project that is part of the CAN DO Getaway Special experiment sponsored by the Charleston County School District. The primary payload of CAN DO, known as GEOCAM, contains four Nikon 35-mm cameras equipped with 250 exposure film backs. The GEOCAM system will closely match the larger Skylab film format in both coverage and quality allowing students to directly examine and compare global changes that have occurred. The experiment is designed to take 1,000 photographs of the Earth allowing students to make observations and compare their photos with those taken 20 years ago.
The effort will be managed through a student-run mission control team at the Medical University of South Carolina. Student-teacher teams of 12 to 20 individuals will operate four desks monitoring crew activities and mission timeline, monitoring weather data, targeting geological or environmental interests and communicating the target objectives with NASA's Johnson Space Center's Earth Observations Laboratory and the Shuttle Small Payload Customer Support Room.-more-
The photographic documentation of Earth observations is dependent on several factors including lighting, crew activities and weather. A change in the launch time could affect the daytime lighting conditions at planned observation points. Steering maneuvers may turn orbiter windows away from the Earth. Crew activities with higher priority often are rescheduled during missions, thus precluding planned Earth observations, and clouds frequently interfere with the planned photography.
Still, Earth Observation is a favorite activity for astronauts, and crew members usually return from space with hundreds of photographs and thousands of feet of film. A large assortment of cameras, lenses and films are carried on each shuttle flight, and astronauts participate in a series of science training sessions before their mission so they can optimize the limited observation time. The STS-55 crew members, for example, took more than 5,350 photographs including pictures of a 30-mile-wide thunderstorm over the coast of Nigeria, a water temperature boundary in the Timor Sea, the nearly complete conversion of forest land to farm and ranch land in an area of northern Argentina, Lake Natron in the East African Rift Valley colored red with white spots by the algae living on the salts from nearby sodium carbonate volcanoes.
Following each mission people working on the Space Shuttle Earth Observations Project catalog each photograph for an electronic data base which is used by hundreds of researchers. SSEOP personnel also describe and analyze many of these photographs for their scientific colleagues, students and the public.
For STS-57, the subjects chosen for thorough Earth observation are
East African Rift Valley System -- The East African Rift Valley System, a series of rift valleys and interconnecting troughs with numerous lakes, is a continuation of a larger trenchlike fracture in the Earth's crust which begins in northern Syria and extends across East Africa to Mozambique. Geologists explain the origin of the East African Rift Valley using the concept of plate tectonics which postulates that the Earth's crust is made up of a number of rigid plates that move laterally. Great mountain ranges are produced where the plates collide and rifts occur where the plates pull apart. The western edge of the system is one of the youngest rifts on Earth. Study of this young system provides a clue to initial processes thought to have caused the opening of the Kenya Rift and ultimately ocean basins. The Western Rift is made up of fault-bounded linear depressions, volcanoes and an unusual uplifted mountain range. The Virunga Volcanic Field contains the most active volcanoes in Africa, two of which are located in heavily populated areas and erupt frequently. Frequent cloud cover has hampered observation and documentation of these volcanoes. Space photographs will provide basic data for mapping the structures and their changes- more -
over time. The Ruwenzori Range is an unusual uplifted-block mountain system
located in a region where the land is generally sinking to elevations below sea level along parallel faults. Glaciers, remnants of much larger features that existed during the Ice Age, dominate the landscape elevation above 4,200 meters. Photographs will assist in accurately mapping glacial features as well as movements, which are indicators of climate changes.
Madagascar -- Madagascar has one of the highest soil erosion rates in the world. Before the arrival of humans, Madagascar, a land of rain forests and lush vegetation, was home to many unique species of plants and animals. Intensive deforestation and massive soil erosion have destroyed the ecological habitat of many of these species. A thousand years of slash-and-burn agriculture began the deforestation problems; recent tropical hardwood lumbering and conversion of forest to grazing land and plantation agriculture have intensified the trend. Range land overgrazing by some 10 million Xebu cattle, which are used for food, plowing and transportation, has significantly increased land erosion and subsequent river siltation. Devegetated slopes, subject to episodic, seasonal rainfall runoff, are quickly gullied and eroded. The resulting sediment load has created rapidly advancing deltas in the Betsiboka and Mahajamba River estuaries. There is a need for more timely and repetitive surveys and monitoring of these environmental changes. Shuttle photography will map volcano features and help researchers define forests, cropland, range land, bare soil and areas of increased erosion and siltation.
Simpson Desert, South Australia -- The Simpson Desert occupies the western portion of the Great Artesian Basin, one of the world's largest regions of internal drainage. For 45 million years, the rivers of central Australia have been prevented from reaching the sea by the lack of rainfall and by the upwarping of coastal areas. The land forms that develop when a river dies out in a desert are still largely unknown. River courses seem to degrade into a series of connected playas. Other playas, called "floodouts," develop in side valleys to accommodate peak floods. The low-gradient rivers themselves develop extreme widths, possibly in response to very high rates of sedimentation, as the capacity of the river to carry sediment rapidly drops off. During periods of intense aridity, the wind has excavated ancient river channels and lake sediments to produce long sand ridges. The Simpson Desert dunes were formed during the last ice age between 16,000 and 20,000 years ago when much of the North Hemisphere was covered by ice sheets. The chief interest of geologists is in understanding why the dune fields are located where they are.
Texas Gulf Coast -- This is a splendid example of a "trailing-edge- more -
coast" in plate tectonic terminology. The Balcones Fault System that separates central Texas from the coastal plains was active about 25 million years ago. Since then, the only structural movements have been near salt domes in and around the Gulf of Mexico. Because of the abundance of oil, natural gas, sulfur and ground water within the sediment, this is an excellent area in which to study geologic processes on a trailing coast. Many effects of an increasing human population, unpredictable climate and changes in technology leave their mark on the land surface and can be readily tracked from space.
Central American Volcanoes -- Part of the Pacific "Ring of Fire," the Central American volcanic region displays not only active volcanism but also major earthquake activity. Many volcanoes are presently active and others have the potential to erupt at any time. Cloud cover in this region persists throughout the year, except from late November through February. In the past, shuttle photography has covered the volcanic belt in El Salvador and Nicaragua but not farther south in Costa Rica. Scientists will use the shuttle photographs to map and document recent lava flows, ash deposits and vegetation regeneration and to note and record actively erupting volcanoes.
Southern Amazon River Basin -- The tropical rain forest ecosystem of the Southern Amazon River Basin is being irretrievably altered by rapid human settlement in the region. The expected population expansion and the resulting land clearing follow and radiate outward from the Trans-Amazon Highway and associated secondary roads. Resettlement programs and mining activities have followed these routes. Photographs illustrating change -- clearings, field patterns, slash-and-burn activities and roads -- provide scientists with insight into the rate at which this tropical rain forest is being destroyed. The challenge is understanding the implications of this change.- end -
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