Launch Of Ocean-Viewing Sensor Set For August 1

Allen KenitzerGoddard Space Flight Center, Greenbelt, MD(Phone: 301/286-8955)

RELEASE: 97-161

LAUNCH OF OCEAN-VIEWING SENSOR SET FOR AUGUST 1

The launch of the Sea-viewing Wide Field-of-View Sensor (SeaWiFS), onboard the Orbital Sciences Corporation (OSC), Dulles, VA, SeaStar spacecraft, is scheduled for Aug. 1, 1997, from Vandenberg Air Force Base, CA. The launch window opens at 4:17 p.m. EDT (1:17 p.m. PDT), with a ten-minute window available.

The SeaWiFS project is part of NASA's Mission to Planet EarthEnterprise, a long-term, coordinated research effort to study the Earthas a global system. Using the unique perspective available from space, NASA is observing, monitoring and assessing large-scale environmental processes, such as the oceans' productivity, focusing on climate change. In line with Mission to Planet Earth's commercial strategy, government-industry partnerships such as SeaStar provide NASA with needed data and may lead to practical commercial data use such as the development of fishing maps and estimation of crop yields for farmers and commodities markets.

"We're looking forward to this upcoming launch," said Dr. Mary Cleave, SeaWiFS Project Manager, at NASA's Goddard Space Flight Center, Greenbelt, MD. "The data from SeaWiFS will be of great benefit to our understanding of global carbon cycling."

Understanding the role of the oceans in the global carbon cycle -- the process by which carbon travels through the Earth's atmosphere, oceans, land and living organisms -- is essential to understanding climate change. Phytoplankton, microscopic marine plants, remove carbon dioxide from the atmosphere for internal use. Scientists are eager to understand this exchange of carbon dioxide and the role it plays in the global climate.

The SeaWiFS instrument will study the carbon cycle by observing the world's oceans from space and measuring "ocean color." The color of most of the worldÕs oceans varies with the concentration of phytoplankton, which contain chlorophyll, a green pigment. Near coastlines, the color of the ocean is affected by chlorophyll, dissolved organic material and suspended sediments from rivers and lagoons. By observing the color of different parts of the oceans, scientists can measure the amount of these materials in ocean water.

"A SeaWiFS launch at this time will be particularly important given what appears to be a very intense El Nino event developing in the equatorial Pacific Ocean," said Dr. Charles McClain, SeaWiFS Project Scientist, of Goddard. "SeaWiFS data will allow us to assess the global impact of the El Nino on marine ecosystems, including coastal waters off the U.S. West Coast."

SeaWiFS represents a new way of doing business for NASA. Rather than building, launching, and controlling a satellite to study an important aspect of the Earth's environment, NASA will purchase commercially available data from a privately built satellite and use the data for environmental research.

The SeaWiFS Team has developed, and will operate, a data system that will process, calibrate, validate, archive, and distribute SeaWiFS data for research. All other aspects of the mission -- satellite construction, launch, command and control and tracking -- are the responsibility of OSC. NASA has contracted with OSC to provide, for five years, the raw satellite data which will be used for research purposes. OSC will own the data rights for operational and commercial purposes.

OSC has integrated the SeaWiFS instrument, built by Hughes Electronics at the Santa Barbara Remote Sensing, Goleta, CA, into its SeaStar satellite and will market the data for commercial and operational use following launch.

SeaWiFS will be launched from a modified Lockheed L-1011 aircraft aboard an OSC Pegasus XL expendable launch vehicle. The Pegasus XL will be released from the L-1011 at an altitude of 39,000 feet over the Pacific Ocean. Following payload separation, an onboard hydrazine propulsion system will then raise the spacecraft to its final 440-mile (705-kilometer) circular orbit within approximately 20 days after launch.

SeaWiFS can view the world's oceans every two days. Since oceans cover 70 percent of the Earth's surface, SeaWiFS will provide information on a large part of the global biosphere. SeaWiFS also will provide important information for fisheries and coastal zone management. SeaWiFS data, which also are useful for viewing plants on land, can be combined with plant productivity data from other satellites, such as Landsat and other operational weather satellites, to measure the role of the biosphere in the total global carbon exchange.

NASA's Mission to Planet Earth Program Office, located at Goddard, manages the SeaWiFS contract and is developing and will operate the research data system for NASA's Office of Mission to Planet Earth, Washington, DC.

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