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NASA launches new Earth observation satellite

Jenny Winder, News Writer
12 February 2013, 12:02

Sen—NASA's latest Earth observation satellite, the Landsat Data Continuity Mission (LDCM), launched into orbit on February 11.

The satellite was blasted into orbit aboard a United Launch Alliance Atlas V rocket from Space Launch Complex 3 at Vandenberg Air Force Base in California.

The mission, which is scheduled to last for five years, is a collaboration between NASA and the U.S. Geological Survey (USGS).

The Landsat program has provided continuous views of Earth's surface since 1972.

The earliest satellites captured images in visible-light and near-infrared frequencies, with a resolution of 80 meters. Landsats 4 and 5 (which fell silent on January 6) reached 30-meter resolution. Landsat 6 failed during launch, whilst Landsat 7 has been operating for 13 years and has provided 15-meter resolution images. Landsat 7 is now partially blind and has only limited fuel.

"With increasing population, and with advances in technology, our land cover and land use are currently changing at a rate unprecedented in human history," said Jim Irons, LDCM project scientist at NASA's Goddard Space Flight Center.

The size of an SUV and weighing 6,133 pounds (2,782 kilograms) Landsat 8's payload consists of two science instruments with moderate resolution of 15 to 100 meters, depending on spectral frequency. The Operational Land Imager (OLI) with over 7,000 detectors per spectral band has been designed to measure visible, near infrared, and short wave infrared wavelengths.

The OLI  will also take measurements in two new bands, one to observe high altitude cirrus clouds and one to observe water quality in lakes and shallow coastal oceans as well as aerosols.

The Thermal InfraRed Sensor (TIRS) with detectors sensitive to two thermal infrared wavelength bands is able to separate the temperature of the Earth's surface from that of the atmosphere.

These detectors will record a constant stream of data of a 185 kilometre swathe of Earth as the spacecraft passes 438 miles overhead in a near-circular, near-polar orbit, providing a complete picture of the planet's surface every 16 days.

ULA Atlas V rocket carrying the Landsat Data Continuity Mission (LDCM) spacecraft

United Launch Alliance's Atlas V rocket blasts off from Vandenberg Air Force Base, California on February 11, 2013, carrying the Landsat Data Continuity Mission (LDCM) spacecraft. Image credit: United Launch Alliance

"All earlier Landsat sensors, on Landsats 1 through 7, were called 'whisk-broom sensors.' Each one of these sensors used a mirror that oscillated back and forth," Irons said. "In contrast, both of the sensors on the Landsat Data Continuity Mission, OLI and TIRS, instead of using an oscillating mirror, they will use long arrays of detectors across the focal plane of each instrument."

Once in orbit, after three months of extensive testing, the LDCM satellite will be renamed Landsat 8 and operational control will then be transferred to USGS. Although the mission is planned to last 5 years, the satellite carries sufficient fuel for 10 years of operations.

Over a decade's worth of Landsat data has been made freely available since 2008. "The data is used by thousands of users all over the world for things like land resource monitoring, crop health identification, crop yield calculations, monitoring urban sprawl, urban planning - the data is used all over the place," said Del Jenstrom, deputy project manager for the mission.

"And to me, that's very rewarding, to work with such a great team of people on a mission that really does affect people's lives."

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