NASA has temporarily disabled a 21-year-old satellite to prevent it from re-entering the Earth’s atmosphere and crashing into the planet. The satellite, named ‘Landsat 7’, has been in operation since 1999 and it is jointly managed by NASA and the U.S. Geological Survey (USGS).
Landsat 7 has been running low on fuel, and to save the remaining fuel, it has been switched to a ‘safe hold’ mode. This mode reduces fuel consumption by limiting the satellite’s movement. The decision to put Landsat 7 in this state was taken after NASA detected a potential issue with one of the satellite’s gyroscopes, which help control its orientation in space.
The Landsat 7 satellite has been a key tool in Earth observation for over two decades. It captures images of Earth’s land surface and coastal regions, providing valuable data for a variety of scientific research and environmental monitoring projects. The data gathered by Landsat 7 has been instrumental in tracking deforestation, water usage, urban growth, and the effects of climate change.
However, the spacecraft has been dealing with a technical issue known as ‘scan line corrector failure’ since 2003. This issue has resulted in a loss of approximately 22% of each image’s data, but despite this, Landsat 7 has continued to provide useful data.
NASA and the USGS are working to address the current issue with the gyroscope and are planning to bring Landsat 7 out of safe hold mode once it is resolved. The teams are also preparing for the eventuality of Landsat 7’s retirement. Its successor, Landsat 9, has already been launched and is currently undergoing on-orbit checkouts before it begins operations later this year.
Landsat 7’s long service is a testament to the durability and reliability of such satellites. Although it is nearing the end of its operational life, the efforts to prolong its usefulness reflect the value of the data it provides. This incident also highlights the challenges of managing aging spacecraft and the importance of planning for their eventual retirement.
The Landsat program is the longest-running enterprise for the acquisition of satellite imagery of Earth. It has been providing valuable data since the launch of its first satellite in 1972. Landsat 9, the latest in the series, will continue the legacy of its predecessors, ensuring a continuous record of our planet’s changing landscapes.
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