Landsat 5
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| Launch date | 1 March 1984 (29 years, 2 months, and 21 days ago) |
|---|---|
| Launch vehicle | Delta 3920 |
| Launch site | Vandenberg AFB SLC-2W |
| Orbital elements | |
| Reference system | WRS-2 |
| Regime | sun-synchronous, near-polar |
| Inclination | 98.2° |
| Altitude | 705 km (438 mi) |
| Repeat interval | 16 days |
| Swath width | 185 km (115 mi) |
| Equatorial crossing time | 9:45 AM +/- 15 minutes |
Landsat 5 is the fifth satellite of the Landsat program. It was launched on March 1, 1984, with the primary goal of providing a global archive of satellite photos. The Landsat Program is managed by USGS, and data from Landsat 5 is collected and distributed from the USGS's Center for Earth Resources Observation and Science.
Landsat 5 is noted for its longevity. It is one of the longest-lasting artificial satellites in low Earth orbit.[1]
Specifications
It has a maximum transmission bandwidth of 85 Mbit/s. It was deployed at an altitude of 705.3 km (438.3 mi). It takes some 16 days to scan the entire Earth. The satellite is an identical copy of Landsat 4 and was originally intended as a backup: it therefore carries the same instruments, including the Thematic Mapper and Multi-Spectral Scanner. The Multi-Spectral Scanner was powered down in 1995;[2] it was reactivated in 2012.[1]
Longevity
Landsat 5 significantly exceeded its designed life expectancy, lasting several decades beyond its original three year mission. In March 2009, Landsat 5 celebrated its 25th anniversary of operation, 22 years over its 3-year mission.[3]
Solar array drive anomaly
On November 26, 2005, the back-up solar array drive on Landsat 5 began exhibiting unusual behavior. The solar array drive maintains the proper pointing angle between the solar array and the sun. The rotation of the solar array drive became sporadic, and the solar array was not able to provide the power needed to charge the batteries. Maintaining power to the batteries is critical to sustain proper operation of the spacecraft. The primary solar array drive failed under similar circumstances in January 2005. As a result of this situation, imaging operations were suspended.[4] After a month-long investigation in December 2005 and testing in January 2006, new operating procedures were developed that would allow Landsat 5 to continue normal operations.[5]
Transmitter anomalies
On December 18, 2009, the transmitter on Landsat 5 experienced technical difficulties.[6] Data downlink was restored on January 7, 2010 after a test successfully managed to retrieve a picture over North America. This test exercised the only remaining Traveling Wave Tube Amplifier (TWTA). The remaining TWTA is in fact the primary TWTA that was in operation when Landsat 5 launched in 1984. After several issues in late 1986 and 1987, the primary TWTA was turned off and the secondary, or redundant, TWTA had been used since. The USGS Flight Operations Team were able to apply lessons learned while operating the redundant TWTA to the primary TWTA for its first successful transmission in over 22 years.[7]
On November 18, 2011, image acquisitions were suspended for a period of 90 days, due to fluctuations in the performance of a critical amplifier that is part of the satellite's transmission system. The satellite was said by the USGS to be nearing the end of its life, after more than 27 years in space.[8]
In March 2012 the Landsat 5 mission celebrated 28 years in space.[1] The Multi-Spectral Scanner was reactivated successfully in April 2012.[1] On February 10, 2013, NASA announced that the Guinness World Records had awarded Landsat 5 the world record for "longest-operating Earth observation satellite" at 28 years, 10 months and counting.[9]
End of mission
On December 21, 2012, USGS announced that Landsat 5 will be decommissioned in the coming months following the failure of one of its gyroscopes. The satellite has three gyroscopes, and requires two to function.[10] It will likely be deactivated once the Landsat Data Continuity Mission satellite is operational.
See also
- NASA World Wind (uses Geocover 1990 layer made from Landsat 4 & 5 data)
References
- ^ a b c d Landsat 2012 Headlines
- ^ "History of Landsat 5". NASA.
- ^ Hansen, Kathryn (March 2, 2009). "Earth-Observing Landsat 5 Turns 25". NASA.
- ^ "Landsat 5 Solar Array Drive Anomaly". USGS. Archived from the original on 2007-12-13. Retrieved 2008-09-12.
- ^ Stephen Clark (28 January 2006). "Landsat 5 Satellite Recovers From Latest Glitch". SPACE.com. Retrieved 2008-09-12.
- ^ "Technical Announcement: Landsat 5 Anomaly". USGS. January 7, 2010.
- ^ "Landsat 5 Transmits Data". USGS. January 7, 2010.
- ^ "Veteran Landsat 5 satellite on the brink of failure". Spaceflight Now.
- ^ http://www.nasa.gov/mission_pages/landsat/news/landsat5-guinness.html
- ^ http://www.usgs.gov/newsroom/article.asp?ID=3485#.UNShOm_7J8E
External links
- Landsat NASA homepage
- Landsat.org Home Page
- Atlogis Maps and Atlogis Meta-Maps: Online-Viewer for Landsat 5 and Landsat 7 Natural Color Mosaic
- CEOS MIM Database Landsat 5 Entry
- Berlin, 1987
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