March 1, 2004, marks the 20th anniversary of operations of the NASA/USGS ‘workhorse’ satellite, Landsat 5. Landsat 5, launched on March 1, 1984, continues to provide important observations of the landmass of the planet and has established a record for reliability in the civilian space fleet.
When Landsat 5 was launched from Vandenberg Air Base in California, expectations were for two years of effective operations, with a goal of three years of data collections. Instead, after 100,000 orbits and the acquisition of over 29 million images, Landsat 5 continues to operate successfully.
“The longevity and importance of the Landsat 5 mission is nothing short of incredible,” said Darrel Williams, Landsat 7 Project Scientist at NASA’s Goddard Space Flight Center. ” The imagery provided over it’s 20 year history has helped us to develop a far better understanding of the land surface features on our home planet, as well as how man has acted to modify those features. It has resulted in the creation of an unsurpassed “digital photo album” of Earth that will be repeatedly opened and reviewed by generations to come.”
Landsat 7 joined Landsat 5 in global observations in 1999. For four years the two earth observing satellites provided extensive, frequent coverage. “In May of 2003, Landsat 7 developed problems with the scan line corrector on the ETM+ sensor, stated Landsat Program manager Tracy Zeiler. “Since then, in addition to degraded Landsat 7 data, scientists have returned to relying on Landsat 5 observations. Landsat 5 has proven, again, to be a remarkably reliable source of information.”
The “workhorse” satellite continues to perform. While Landsat 5 continues to operate, Landsat Program managers are working on a replacement vehicle. The expected end-of -life, based on fuel reserves, is projected for early 2009. Until then, the NASA/USGS Landsat 5 will continue to provide records of a changing world.
