STS-99
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This is a mission of the United States Space Shuttle
| Space Shuttle program | |
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| Mission Insignia | |
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| Mission Statistics | |
| Mission: | STS-99 |
| Shuttle: | Endeavour |
| Launch Pad: | 39-A |
| Launch: | February 11, 2000. 12:43 pm EST (17:43 UTC) |
| Landing: | KSC Runway 33 Feb. 22, 2000 6:23 p.m. EST. |
| Duration: | 11 days, 5 hours, 39 minutes 41 seconds. |
| Orbit Altitude: | 126nm |
| Orbit Inclination: | 57 deg. |
| Distance Traveled: | 4 million 64 thousand miles |
| Crew photo | |
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Missing image | Previous Mission: STS-103 |
Next Mission: STS-101 |
| Contents |
Crew
- Kevin R. Kregel (4), Mission Commander
- Dominic L. Pudwill Gorie (2), Pilot
- Janet L. Kavandi (2), Mission Specialist
- Janice E. Voss (5), Mission Specialist
- Mamoru Mohri (2), Mission Specialist (NASDA) - Japan
- Gerhard P.J. Thiele (1), Mission Specialist - Germany
Mission Parameters
- Mass:
- Orbiter Liftoff: 116,376 kg
- Orbiter Landing: 102,363 kg
- Payload: 13,154 kg
- Perigee: 224 km
- Apogee: 242 km
- Inclination: 57°
- Period: 89.2 min
Mission Highlights
The Shuttle Radar Topography Mission (SRTM) is an international project spearheaded by the National Imagery and Mapping Agency and NASA, with participation of the German Aerospace Center DLR. Its objective is to obtain the most complete high-resolution digital topographic database of the Earth. SRTM consists of a specially modified radar system that will flew onboard the space shuttle during its 11-day mission. This radar system gathered around 8 terabytes of data to produce unrivaled 3-D images of the Earth's surface.
SRTM uses C-band and X-band interferometric synthetic aperture radars (IFSARs) to acquire topographic data of Earth's land mass (between 600N and 560S). It produces digital topographic map products which meet Interferometric Terrain Height Data (ITHD)-2 specifications (30 meter x 30 meter spatial sampling with 16 meter absolute vertical height accuracy, 10 meter relative vertical height accuracy and 20 meter absolute horizontal circular accuracy).
The result of the Shuttle Radar Topography Mission could be close to 1 trillion measurements of the Earth's topography. Besides contributing to the production of better maps, these measurements could lead to improved water drainage modeling, more realistic flight simulators, better locations for cell phone towers, and enhanced navigation safety.
The Shuttle Radar Topography Mission mast was deployed successfully to its full length, and the antenna was turned to its operation position. After a successful checkout of the radar systems, mapping began at 12:31 a.m., less than 12 hours after launch. Crewmembers, split into two shifts so they could work around the clock, began mapping an area from 60 degrees north to 56 degrees south. Data was sent to Jet Propulsion Laboratory for analysis and early indications showed the data to be of excellent quality.
Mapping proceeded fairly smoothly, but during an attitude-hold period for payload mapping during the second day of flight, it was determined that orbiter propellant usage had doubled from 0.07 to 0.15 percent an hour. The increase was caused by a failure of the payload cold-gas thrust system that was used to offset the gravity gradient torque of the mast.
As a result of this failure, orbiter propellant was being used at a higher-than-planned rate to maintain the attitude of the vehicle. Measures to reduce the expenditure were evaluated and based on the analysis, enough propellant could be saved to complete the planned 9-day plus science mission.
The first of a series of "flycast" maneuvers during the mission was also made on the second day of flight. The flycast maneuver was designed to reduce strain on the almost-200-foot mast extending from Endeavour's cargo bay when adjustments to Endeavour's orbit were needed.
The orbiter, which flies tail-first during mapping operations, is moved to a nose-first attitude with the mast extending upward. A brief reaction control system pulse begins the maneuver. The mast deflects slightly backwards, then rebounds forward. As it reaches vertical, a stronger thrust is applied, arresting the mast's motion and increasing the orbiter's speed.
Radar data gathering concluded at 6:54 a.m. EST on the tenth day of flight after a final sweep across Australia. During 222 hours and 23 minutes of mapping, Endeavour's radar images filled 332 high density tapes and covered 99.98 percent of the planned mapping area - land between 60 degrees north latitude and 56 degrees south latitude - at least once and 94.6 percent of it twice. Only about 80,000 square miles in scattered areas remained unimaged, most of them in North America and most already well mapped by other methods. Enough data was gathered to fill the equivalent of 20,000 CDs.
Also aboard Endeavour was a student experiment called EarthKAM, which took 2,715 digital photos during the mission through an overhead flight-deck window. The NASA-sponsored program lets middle school students select photo targets and receive the images via the Internet. The pictures are used in classroom projects on Earth science, geography, mathematics and space science. More than 75 middle schools around the world participated in the experiment, which set a record. On four previous flights combined, EarthKAM sent down a total of 2,018 images.
Related articles
- Space science
- Space shuttle
- List of space shuttle missions
- List of human spaceflights chronologically
External links
- NASA mission summary (http://science.ksc.nasa.gov/shuttle/missions/sts-99/mission-sts-99.html)
- USGS: Shuttle Radar Topography Mission (SRTM) Fact Sheet 071-03 (July 2003) (http://erg.usgs.gov/isb/pubs/factsheets/fs07103.html)
- Geospace.com: Endeavour Maps the World in Three Dimensions (http://www.geoplace.com/gw/2000/0400/0400tec.asp)
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Space Shuttle program | Next Mission: STS-101 |