Table of Contents
MN GIS/LIS Consortium
From the Chair
Member Portal Upgrade
2012 Spring Workshops
New State GIO
State Govt IT Consolidation
Driftwatch Crop Registry
GLO Field Notes Online
Altered Watercourse Project
Emergency Prep. Blog Update
New Ramsey Co Map Site
Dakota Co Transport Plan
State Monuments on Google Earth
National Elevation Assessment
Landsat 40th Anniversary
GISSO Job Fair Report
Future Trends in GIS Mgmt
40th Anniversary of Landsat
Adapted from USGS News Releases and fact sheets
July 23, 2012 marked the 40th anniversary of the launch of Landsat 1. The U.S. Geological Survey (USGS) and the National Aeronautics and Space Administration (NASA) planned a number of activities to recognize and celebrate continuous Landsat data flow across four decades.
Since 1972, Landsat satellites have continuously acquired space-based images of the Earth’s land surface, coastal shallows, and coral reefs. The Landsat Program, a joint effort of the USGS and NASA, was established to routinely gather land imagery from space. Landsat satellites have provided worldwide science and resource-management communities with an archive of space-based land remotely sensed data—a valuable resource for people who work in agriculture, geology, forestry, education, regional planning, mapping, and global change research. Today, Landsat 5 (launched in 1984) and Landsat 7 (launched in 1999) continue to capture hundreds of images of the Earth’s surface each day.
Landsat 5 has orbited Earth over 150,000 times since it was launched, making it the longest-operating Earth observing satellite of its kind. During this time, two data collection instruments onboard Landsat 5 – the thematic mapper (TM) and the multi-spectral scanner (MSS) – have transmitted over five million images of land conditions to U.S. and international ground stations.
In November 2011 an electronic malfunction in the TM transmitter forced a suspension of routine imaging. Now, after months of trying without success to restore daily TM image transmissions, USGS flight engineers will attempt only a few additional image acquisitions over specific sensor-calibration sites as the TM transmitter nears complete failure.
On a positive note, the MSS instrument onboard Landsat 5 was recently powered back on in a test mode after more than a decade of silence. “The resurrection of the MSS a decade after it was last powered up and 25 years beyond its nominal lifespan is welcome news indeed,” said USGS Director Marcia McNutt. “While not a complete replacement for the loss of the Thematic Mapper, it does provide some insurance for ensuring Landsat data continuity should Landsat 7 fail prior to Landsat 8 achieving orbit next year.”
Landsat 7, the other active Landsat spacecraft operated by the USGS, continues to collect images worldwide, as it has done since 1999. In 2003, Landsat 7 experienced a hardware failure that causes a 22% loss of data in every image. The problem was caused by failure of the Scan Line Corrector (SLC), which compensates for the forward motion of the satellite to align forward and reverse scans necessary to create an image. Efforts to recover the SLC were unsuccessful. In the intervening nine years, many techniques have been developed to partially compensate for the data loss and leverage the remaining data for scientific analysis and resource monitoring.
The next Landsat, the Landsat Data Continuity Mission (LDCM or Landsat 8), is scheduled for launch in January 2013. Following launch, it will become Landsat 8 and is expected to extend the Landsat record for at least another five years.
For 40 years Landsat satellites have been acquiring images of the land cover of the planet. The satellites have provided spectacular views of mountains, valleys, coastal areas, islands, volcanic fields, forests, and patterns on the landscape. By highlighting some of those features and creatively crafting the colors, the USGS developed a series of "Earth as Art" perspectives that reveal the artistic side of Landsat.
A recent Landsat fact sheet provides information about the Landsat Program and the USGS Earth Resources and Observation Science (EROS) Center webpage contains additional resources regarding remote sensing and earth science activities.