Traditionally, topographic maps have been generated from stereo pairs of photographs acquired from high-altitude aircraft and satellites. However, such optical systems cannot penetrate the cloud cover that blankets nearly 40 percent of the Earth’s surface. In some tropical regions the cloud cover is virtually continuous and, as a result, significant portions of our planet’s surface have never been mapped in detail.
The Shuttle Radar Topography Mission (SRTM) uses radar instruments to collect data for the most detailed, near global topographic map of the Earth ever made. SRTM will collect data over 80% of the earth’s land mass, home to nearly 95% of the world’s human population. The shuttle, (STS-99) with an instrument called an imaging radar, will be used to provide the most precise “picture” ever of Earth’s land surface.
The radar will bounce signals off the surface; these signals will be received by two on board antenna systems and combined by computers at a ground facility to produce three-dimensional (3-D) images. SRTM consists of a specially modified radar system that will fly on board the space shuttle during an 11-day mission. This radar system will gather data that will result in the most accurate and complete topographic map of the Earth’s surface that has ever been assembled.
NASA Quest and
Jet Propulsion Laboratory
http://quest.arc.nasa.gov/ltc/jpl/srtm.html
“Seeing the Earth’s Surface in 3-D”
Shuttle Radar Topography Mission
Times and dates may change depending on Launch of STS-99.
(currently scheduled for Jan. 31.)
Kate Weisberg
Project Manager
NASA QUEST
Learning Technologies Channel Project
NASA-Ames Research Center
Mail Stop T-28HÂ Â Moffet Field, CA 94035-1000
Voice (650) 604-2160
Fax (650) 604-1913
Email: kweisberg@mail.arc.nasa.gov
