* Astronomy

Blobrana · L

RE: Landsat 5

Blobrana · L

The U.S. Geological Survey has announced that the Landsat 5 satellite is back in operation.
USGS and NASA engineers were able to make adjustments to operating procedures for the solar array drive mechanism that now allows the solar array to provide enough power for the mission to resume normal operations. Consequently, acquisition operations have begun over the conterminous U.S. and the international stations will be brought on line in the coming weeks.

The solar array drive mechanism began exhibiting problems in late November 2005. 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. As a precaution, imaging operations were suspended until the problem was identified and potential solutions were evaluated and tested.

"This is good news for the global science and operational communities. The Landsat Program has a well-established record of over 30 years of earth observations. The latest developments allow the Landsat user community to continue to rely on Landsat imagery. I am optimistic about the 'fix' applied to the solar array problem and the future operations of Landsat 5. At the same time, we are moving aggressively to develop a Landsat Data Continuity Mission that will provide Landsat data continuity" - Mr. Jay Feuquay, Land Remote Sensing Program Coordinator for the USGS.

Landsat 5, launched in March 1984, has performed far beyond its three-year design lifetime and has continued to collect global land surface coverage. Over 620,000 images, illustrating events from the Chernobyl disaster to Hurricane Katrina, have proven invaluable for identifying the impact of natural and human-induced changes. Landsat 5 and Landsat 7 together provided full global coverage of the Earth’s surface.

The Landsat Program is the longest running civilian program providing vital images of the Earth’s surface from space. The first Landsat satellite was launched in 1972 and since then, Landsat satellites have been providing a constant stream of moderate-resolution images. In 1999, the Landsat Program took a giant leap forward technologically with the launch of Landsat 7. The instruments on the Landsat satellites have acquired millions of images of the surface of the planet, providing a unique resource for scientists who study agriculture, geology, forestry, regional planning, education, mapping and global change research.

The Landsat Program has been a joint initiative of USGS and NASA to gather Earth resource data using a series of satellites including Landsats 5 and 7. NASA is responsible for developing and launching the spacecrafts, while the USGS is responsible for flight operations, maintenance, and management of all data reception, processing, archiving, product generation, and distribution. The primary objective of the Landsat Program is to ensure a consistent, calibrated collection of Earth imagery that can be used to scientifically measure change over decades and beyond, and support the operational agencies. Landsat’s global survey mission is to repeatedly capture images of the Earth’s land mass, coastal boundaries, and coral reefs; and to ensure the data acquired are of maximum utility in supporting the objectives of monitoring changes in the Earth’s land surface and associated environment.

Source

Blobrana · L

On November 26, 2005, the back-up solar array drive on the Landsat 5 satellite began exhibiting unusual behaviour.
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 last January. As a result of this current situation, imaging operations will be suspended for at least the next two weeks or until attempts to solve the problem have been resolved.

Landsat 5, launched in March 1984, has performed far beyond its three-year design lifetime and has continued to collect global land surface coverage. Over 125,000 images, from the Chernobyl disaster to Hurricane Katrina, have proven invaluable for identifying the impact of natural and human-induced changes. Landsat 5 and Landsat 7 together provided full global coverage of the Earth’s surface every eight days.

The Landsat Program is the longest running program providing vital images of the Earth’s surface from space. The first Landsat satellite was launched in 1972 and since then, Landsat satellites have been providing a constant stream of moderate-resolution images.
In 1999, the Landsat Program took a giant leap forward technologically with the launch of Landsat 7. The instruments on the Landsat satellites have acquired millions of images of the surface of the planet, providing a unique resource for scientists who study agriculture, geology, forestry, regional planning, education, mapping and global change research.

The Landsat Program is a joint initiative of USGS and NASA to gather Earth resource data using a series of satellites including Landsats 5 and 7. NASA is responsible for developing and launching the spacecrafts, while the USGS is responsible for flight operations, maintenance, and management of all data reception, processing, archiving, product generation, and distribution.
The primary objective of the Landsat Program is to ensure a consistent, calibrated collection of Earth imagery that can be used to scientifically measure change over decades and beyond. Landsat’s global survey mission is to repeatedly capture images of the Earth’s land mass, coastal boundaries, and coral reefs; and to ensure the data acquired are of maximum utility in supporting the scientific objectives of monitoring changes in the Earth’s land surface and associated environment.

Read More (PDF)