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This is an Archive of a Live Event!

The Shuttle Radar Topography Mission (SRTM)

Seeing the Earth in 3-D

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Archive of Webcast
Mission Overview

Mission Background Video
This is a RealMedia Video file and requires download and installation of RealPlayer (above).

To extract the most accurate and useful information from radar echoes, scientists need data that are calibrated. Desert areas, such as Death Valley, provide an ideal background calibration because they are relatively smooth and vegetation free.
This is a computer generated view of the Shuttle Radar Topography Mission (SRTM) scheduled to fly in January 2000. SRTM will re-use the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994.

The Shuttle Radar Topography Mission (SRTM) uses radar instruments to obtain the most complete, near-global high-resolution database of the Earth's topography. 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 onboard 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 onboard 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.

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.

Poster Images Courtesy of Ball Aerospace & Technologies Corp.

January 21 Panel of Guests

Mike Dickerson, Terry Wysocky, Andy Berkun and Charles White

Mike, Jennifer Cruz, Robert Crippen and Charles

Mike, Eric Rignot, Gilles Peltzer and Charles

Mike, Annie Richardson, Debra Higuera and Charles

Archive of Webcast
Mission Status during 11-day orbit.

The mast, which was developed using the design for the truss structure of the International Space Station, will extend sideways from the orbiter's cargo bay.


SRTM will use single-pass interferometry, which means that the two images will be acquired at the same time -- one from the radar antennas in the shuttle's payload bay, the other from the radar antennas at the end of a 60-meter (200-foot) mast extending from the shuttle. Combining the two images produces a single 3-D image.

The mission is a partnership between NASA and the National Imagery and Mapping Agency (NIMA). In addition, the German and Italian space agencies are contributing an experimental high-resolution imaging radar system. Analysts will use the SRTM data to generate 3-D topographic maps called digital elevation models. EndeavourThese digital topographic maps can be combined with other data for analysis. The SRTM data will also be used to generate digital elevation maps of Earth's surface that scientists will use to study planetary geophysics, hydrologic drainage system modeling, more realistic flight simulators for military aircraft, as well as commercial uses like better locations for cellular phone towers and improved maps for backpackers.

The system will be launched in a stowed, compact configuration. When the shuttle reaches orbit, the mast will deploy, creating a 60-meter-baseline, fixed-length interferometer at both C-band and X-band frequencies. The X-band interferometer has been supplied by the German and Italian space agencies.

February 15 Panel of Guests

Ron Blom SRTM Science
Bursik Photo
Marcus Bursik
SRTM Science

Sharon Okonek
Website Development
Paul Rosen
SRTM Real Time Science

Jim Garvin

SRTM Science
Eric Fielding
SRTM Real Time Science
Mouginis Photo
Peter Mouginis-Mark
SRTM Science

Archive of Webcast
Mission follow-up.
Three sided corner reflectors. Corner reflectors are passive devices that reflect the radar signal in a concentrated, well understood fashion. When these bright reflections are analyzed in the radar image, their expected brightness can be used to adjust the measured brightness, calibrating the rest of the image. Surveying the location and elevation of the reflectors helps check the geometric accuracy of the SRTM maps, as well.

Charles Morris

Visit the Collector Site
with Charley White
and Charles Morris

This is a RealMedia Video file and requires download and installation of RealPlayer (above). Map

Data sufficient to produce a rectified, terrain corrected, C-band (5.6 centimeters wavelength) radar image mosaic of 80 percent of Earth's land surface at 30 meter resolution.

ClickAstronaut Janice Voss spent 11-days in space and will join us by phone during the webcast.

It will take one to two years to process the SRTM data to create the digital elevation maps. However, during the mission a portion of the data will be sent back to Earth and visualizations of preliminary digital elevation maps will be made from these data. You can read about these products in the Mission Products Summary. During the mission, you will be able to click on a section of this map to see the mission products that are available in that region. The resulting data formats will be compatible with standard cartographic data-analysis software and tailored to the needs of the civil, military, and scientific user communities. Much of the data from the mission will be made available to these users in accordance with release guidelines mutually developed by NIMA and NASA. SRTM data will be collected over all land surfaces that lay between 60 degrees north latitude and 54 degrees south latitude. That's about 80% of all the land on the Earth. The map to the left shows all the regions where data will be collected. To learn more about the types of data products collected during the flight: Click Here.

March 28th Panel of Guests

Thomas Farr
SRTM Project Science
Janice Voss
Astronaut STS-99 crew

Mike Kobrick

SRTM Project Science

Riley Duren
SRTM Hardware

Delia McWatters
SRTM Engineering

Paul Andres


Related URLs for more information on this event:
SRTM Mission Information-http://www.jpl.nasa.gov/srtm/
SRTM Mission Information- http://www.jpl.nasa.gov/srtm/factsheet_pub.html
STS-99 Launch and Shuttle Information- http://www.ksc.nasa.gov/shuttle/missions/sts-99/mission-sts-99.html

Responsible NASA Quest Contact Kate Weisberg LTC Project Manager.

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