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Stethoscope in the sky: Terra launched to track Earth's health

The $1.3 billion satellite will enable scientists to conduct daily checkups on Earth's health  

Mission a 'planetary equivalent of a house call'

December 18, 1999
Web posted at: 3:31 p.m. EST (2031 GMT)

In this story:

Viewing Earth as a system

Global effort to monitor Earth


By Interactive Writer Amanda Barnett

VANDENBERG AIR FORCE BASE, California (CNN) -- NASA on Saturday launched a $1.3 billion satellite that will enable scientists from the United States, Canada and Japan to conduct daily checkups on the health of planet Earth.

High winds threatened to scrub the liftoff, but the 10,700-pound Terra satellite went aloft aboard an Atlas 2 rocket about 11 a.m. (2 p.m. EST), moments before a launch window of some 40 minutes was to close.

Within minutes, the satellite dropped its rocket boosters as planned, separated from the main rocket and raced toward orbit, prompting a burst of applause from NASA controllers back on Earth.

NASA had delayed the liftoff from Thursday, when on-board computers detected a problem with only seconds remaining in the countdown. An automatic software check indicated that rocket's "power-on-internal" status was not confirmed. Mission technicians verified that Atlas power was on internal status.

Terra is the flagship of the Earth Observing System, a series of spacecraft that NASA plans to put in orbit to measure how Earth's oceans, air, land and people function together.

Terra project scientist Yoram Kaufman calls the mission the planetary equivalent of a house call and says it will "start the first comprehensive and well-deserved checkup of the planet."

Viewing Earth as a system

Unlike previous missions that focused on one aspect of the Earth's environment, Kaufman says Terra will use new instruments to allow scientists to "look on the Earth as a system."

Scientists from the around the world collaborated to identify key measurements that will be taken by the five instruments on board the satellite.

Some of the things Terra will monitor include changes in land cover, climate change, ozone and natural disasters such as wildfires, droughts and floods.

"This is a very complex living, changing climate," Kaufman said.

Having a satellite with multiple instruments will give scientists a "fresh view that could never have been obtained before," he said.

Global effort to monitor Earth

The satellite will sweep the Earth every 100 minutes in a near polar orbit. The data collected will be shared by hundreds of scientists around the world.

According to Michael King, the senior U.S. project scientist for the mission, Terra will go "from pole to pole" to observe, document and study every aspect of Earth.

Scientist believe the satellite will help them understand how Earth's climate will evolve and how best to manage the planet's natural resources.

The five instruments on Terra:

  • ASTER: Advanced Spaceborne Thermal Emission and Reflection Radiometer. This instrument will take high resolution infrared images of the Earth. ASTER is a cooperative effort between NASA and Japan's Ministry of International Trade and Industry.

  • CERES: Clouds and the Earth's Radiant Energy System. This device consists of two broadband scanning radiometers that will measure the Earth's radiation balance and the role clouds play in maintaining that balance.

  • MISR: Multi-angle Imaging SpectroRadiometer. This is a new type of instrument that will let scientists view the Earth with cameras pointed at nine different angles.

  • MODIS: Moderate-resolution Imaging Spectroradiometer. This instrument will view the entire surface of the Earth every one to two days, making observations of land and ocean surface temperature, land surface cover, clouds, aerosols, water vapor and fires.

  • MOPITT -- Measurements Of Pollution In The Troposphere. An instrument designed to study the lower atmosphere and observe how it interacts with the land and ocean. MOPITT is provided by Canada and will be managed by the Canadian Space Agency.

Data from the Terra satellite will be downlinked by the Tracking and Data Relay Satellites that are also used to monitor space shuttles.

NASA postpones Terra satellite launch until Saturday
December 17, 1999
NASA scrubs launch of Terra satellite
December 16, 1999
Shuttle launch delayed because of worries over welds
December 16, 1999
Terra satellite to give Earth a 'checkup'
November 24, 1999

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