Goodbye, Landsat 5
This post contributed by Liza Lester, ESA communications officer
Four hundred miles above the Earth’s surface, a satellite slides into lonely oblivion. After collecting and broadcasting earthly imagery for a remarkable quarter century past its expected 3-year lifespan, Landsat 5 is failing.
Over the years, US Geological Survey engineers have contrived quite a few patches and work-arounds for malfunctions on board their distant charge, but the latest blow to the satellite’s communications capability may be fatal. On November 18th, its handlers announced a 90-day suspension of operations while they consider heroic measures to resuscitate the aging equipment.
The Landsat “thematic mapper” has been a popular tool for ecological research. This year, ecologists in California tracked the waxing and waning of kelp forests through the eyes of the satellite (covered last week in Ecotone). Landsat aided design of a study of fire frequency following depredations of mountain pine beetles in the Lodgepole pine forests of Yellowstone. It mapped the greenery of Hawaii’s Big Island for an assessment of the total carbon held in the mass of the island’s plants. A quick and dirty search of Ecological Society journals returns more than ten reports, since October alone, incorporating Landsat data.
The program gained utility after the USGS made the 30-year image archive freely available online, in 2008. Congress privatized the Landsat program, originally run by the National Oceanic and Atmospheric Administration, in 1984, the year of number 5’s launch. The USGS took over operations a decade ago.
Kelp biologist Dan Reed said that the image analysis of coastal kelp forests carried out by his collaborators Kyle Cavanaugh and David Siegel for their November paper in Ecology would have been prohibitively expensive a decade ago, at $600 per scene (considered the new, cheap price at the time, after re-governmentization of the program dropped prices from a high of $4400).
Landsat 5 is survived by younger sibling Landsat 7, in orbit since 1999. An equipment failure on the 7th Landsat incarnation has, however, limited its imaging capacity since 2003. Scientists eagerly await the launch of Landsat 8, a.k.a the Landsat Data Continuity Mission, in early 2013.
Tune in again in February to hear if reports of Landsat 5’s mortality have been exaggerated.
Picture credit: anonymous NASA conceptual artist’s rendering of Landsat 5, launched to orbit on March 1, 1984.
Beetle Infestation in Rocky Mountain National Park
Sensor: L5 TM
[click for big picture]