NASA's Ready to Study Cool Ice, Hot Plasma and Ocean Winds

by Goddard Space Flight Center

More articles in Satellites

The month of December will see the launch of three NASA research missions to help us better understand and protect our home planet while continuing to search for life in our universe and inspire the next generation of explorers. The ICESat, CHIPS and SeaWinds missions will help improve life here while searching for life beyond Earth.

ICESat (Ice, Cloud and land Elevation Satellite) is the benchmark NASA mission for measuring ice-sheet mass balance -- knowledge vital to understanding and protecting our home planet.

The ICESat mission will use a laser instrument to provide multi-year elevation data needed to determine ice-sheet mass balance. The spacecraft also will provide surface and vegetation data around the globe, in addition to specific coverage over the Greenland and Antarctic ice sheets.

ICESat is due to launch from Vandenberg Air Force Base, Calif. on Dec. 19 at approximately 7:45 p.m. EST. Once in its final orbital position, the satellite will orbit the Earth at an altitude of approximately 373 miles (600 kilometers).

"This mission will provide revolutionary insight into changes in ice and the role ice plays in our Earth system, using a spaceborne laser to look at the topography of ice both in the Antarctic and Greenland," said Dr. Ghassem Asrar, NASA's Associate Administrator for Earth Science. "This information will help scientists determine whether the polar ice sheets are growing or shrinking, and how the ice masses may change under future climate conditions," Asrar said.

The Geoscience Laser Altimeter System, or "GLAS" instrument, on ICESat will use a laser to measure the time it takes for light to travel to the reflecting object and return to the satellite. The data on the distance to the surface, the position of the satellite in space, and the pointing of the laser are all combined to calculate the elevation and position of each point measurement on the Earth. The laser will perform these measurements 40 times each second.

The spacecraft was built by Ball Aerospace and Technologies Corporation (Ball) in Boulder, Colo. NASA's Earth Science Data and Information System will provide space and ground network support and the University of Colorado's Laboratory for Atmospheric and Space Physics, Boulder, will team with Ball to provide mission operations and flight dynamics support. The GLAS and ICESat data will be initially processed at the ICESat Investigator-led Processing System facility with support from the University of Texas's Center for Space Research, Austin.

Launching with ICESat is NASA's first University-Class Explorer mission, a suitcase-sized satellite called the Cosmic Hot Interstellar Plasma Spectrometer (CHIPS), designed to explore the birthplace of solar systems. CHIPS will study very hot, very low-density gas in the vast spaces between the stars, known as the interstellar medium, searching for important clues about formation and evolution of galaxies.

The interstellar medium literally contains the seeds of future stars, and all the stars we see were once formed out of the same kind of diffuse gas and dust. When the gas in the interstellar medium cools and collapses, the gas forms clumps that scientists believe evolve into stars and planets. One of the biggest puzzles in astrophysics is the process that turns this very diffuse, hot and cold gas and dust into stars.

Our solar system is located in a region of space scientists call the Local Bubble, which is about 300 light-years in diameter and is filled with gas much less dense than the average interstellar medium. This gas also is extremely hot - - about 1.8 million degrees Fahrenheit, or about 180 times as hot as the surface of our Sun. It is this extremely diffuse gas inside the Local Bubble that the CHIPS mission is studying.

The CHIPS satellite weighs 60 kilograms (132 pounds) and is the size of a large suitcase. It will orbit about 590 kilometers (367 miles) above the Earth and is expected to operate for one year.

The CHIPS satellite is sponsored by the Office of Space Science at NASA Headquarters in Washington. The CHIPS instrument was built at the Space Science Laboratory of the University of California, Berkeley, and the spacecraft bus was built by SpaceDev, Inc. of Poway, Calif. The project is managed at the NASA Goddard Space Flight Center's Wallops Flight Facility, Wallops Island, Va., through the NASA Explorers Program.

A third NASA mission, SeaWinds, is NASA's latest Earth- monitoring instrument for measuring the speed and direction of winds over Earth's oceans. Set to launch aboard Japan's Advanced Earth Observing Satellite II (Adeos II) at 8:31 p.m. EST on Dec.13 from the Tanegashima Space Center, the mission is expected to yield improved global weather forecasts and new insights into various Earth research investigations.

"Winds play a major role in every aspect of Earth's weather," Asrar said. "They directly affect the turbulent exchanges of heat, moisture and greenhouse gases between Earth's atmosphere and the ocean that drive ocean circulation and climate. The SeaWinds instrument will provide a critical tool for improving weather forecasting, detecting and monitoring severe marine storms, identifying subtle changes in the global climate and better understanding global weather abnormalities, such as El Nino and La Nina. NASA is pleased to partner with Japan on this important endeavor."

The mission will help scientists determine the location, structure and strength of severe marine storms -- hurricanes in the Atlantic, typhoons near Asia and mid-latitude cyclones worldwide -- which are among the most destructive of all natural phenomena. The National Oceanic and Atmospheric Administration (NOAA), a chief mission partner, will use the data to improve weather forecasting and storm warnings, helping forecasters more accurately determine the paths and intensities of tropical storms and hurricanes.

SeaWinds will map wind speed and direction across 90 percent of the Earth's ice-free oceans every two days. Up to 15 times a day, Adeos II will beam down SeaWinds science data to ground stations operated by NASA and the National Space Development Agency of Japan, which will relay them to scientists and weather forecasters.

SeaWinds is a scatterometer, which transmits high-frequency microwave pulses to the ocean surface and measures the "backscattered," or echoed, pulses as they are bounced back to the satellite. The instruments sense ripples caused by winds near the ocean's surface, from which scientists can compute the winds' speed and direction.

The 200-kilogram (441-pound) SeaWinds instrument will be launched aboard the Adeos II satellite by a Japanese H-IIA rocket. The satellite will circle Earth every 101 minutes at an altitude of 803 kilometers (499 miles). The SeaWinds instrument will make approximately 400,000 measurements every day.

SeaWinds is managed for NASA's Office of Earth Science, Washington, by JPL, which developed the instrument and performs instrument operations and science-data processing, archiving and distribution. The Japanese Space Agency provided the Adeos II spacecraft, H-IIA launch vehicle, mission operations and the Japanese ground network. NOAA provides near-real-time data processing and distribution for SeaWinds operational data users.