Shuttle Radar Topography Mission
Space shuttle mission that mapped Earth's topography in high resolution.
- field
- Topographic mapping / Remote sensing
- nationality
- International (led by U.S. NGA and NASA)
- known_for
- First near-global high-resolution digital elevation model
- coverage
- 56°S to 60°N
- resolution
- 1 arcsecond (30 m) for most land; 3 arcsecond (90 m) globally
Lore & Background
The Shuttle Radar Topography Mission was an international project spearheaded by the U.S. National Geospatial-Intelligence Agency (NGA) and NASA. It used an interferometric synthetic aperture radar system based on the older SIR-C/X-SAR, but with two antennas—one in the payload bay and one on a 60-meter mast—allowing single-pass interferometry. The radar operated in both X-band and C-band; C-band provided wider coverage, while X-band offered higher resolution but had many gaps due to the mission orbit being designed for C-band coverage. Udvar-Hazy Center in Chantilly, Virginia.
Reader's Guide
The SRTM dataset revolutionized geographic information systems by providing freely downloadable, high-resolution elevation models in .hgt format. The C-band data, processed at 1-arcsecond resolution, covers Africa, Europe, North America, South America, Asia, and Australia; the rest of the world is available at 3-arcsecond resolution. Third-party derivatives like CGIAR-CSI version 4.1 and HydroSHEDS further filled voids. The X-band dataset, operated by the German Aerospace Center and Italian Space Agency, offers 25-meter resolution but with many gaps.
Did You Know?
- The SRTM used a 60-meter mast extending from the shuttle's payload bay to enable single-pass interferometry.
- The SRTM payload is on display at the Steven F. Udvar-Hazy Center in Chantilly, Virginia.
- The X-band dataset has many gaps because the mission orbit was designed for C-band coverage.
Frequently Asked Questions
What are the Shuttle Radar Topography Mission's powers/role?
SRTM's core ability is generating high-resolution digital elevation models of Earth's land surface, achieving roughly 30-meter resolution over most terrain and 90-meter resolution across the full globe. It accomplished this through an 11-day radar mapping campaign that produced the most complete high-resolution topographic dataset of its era.
Why is the Shuttle Radar Topography Mission important?
Before SRTM, no single effort had produced a near-global, high-resolution digital topographic map of Earth's landmasses. It filled that gap by delivering the first comprehensive elevation database spanning 56°S to 60°N, fundamentally changing how researchers and engineers model terrain.
What territory does the Shuttle Radar Topography Mission cover?
SRTM mapped land surfaces between roughly 56 degrees south latitude and 60 degrees north latitude, encompassing nearly all inhabited and ecologically significant regions on the planet. The 30-meter resolution applies to most land areas, while the 90-meter resolution extends across the full global coverage.
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