Landsat data continuity mission awaits liftoff

Launched by NASA in partnership with the U.S. Geological Survey, the Landsat Data Continuity Mission (LDCM) will add a new chapter to an enduring program. Since 1972, Landsat has enabled people around the globe to observe our planet's land masses. The enhanced images that will be provided by improved Landsat data come at a time when such information is vitally important.

"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 in Greenbelt, Md.

LDCM will be lofted into orbit aboard a two-stage United Launch Alliance Atlas V rocket. The five-year mission will begin with a launch from Space Launch Complex 3 at Vandenberg Air Force Base in California. 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.

Six Landsat satellites have successfully launched since the first made its debut in 1972. Jointly managed by NASA and the U.S. Geological Survey, the Landsat program has provided continuous views of Earth's surface for more than four decades. Landsat 7, the most recent in the series, launched in April 1999.

The Landsat Data Continuity Mission builds on this foundation and brings with it two advanced science instruments that will deliver more data -- and clearer images -- than ever before. The Operational Land Imager (OLI) is designed to measure visible, near infrared, and short wave infrared wavelengths, while the Thermal Infrared Sensor (TIRS) monitors temperatures on Earth's surface. Using what scientists call a "push-broom" approach, these detectors will record a constant stream of data as the spacecraft passes 438 miles overhead in a near-circular, near-polar orbit.

"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."

During each satellite pass, OLI and TIRS will observe and collect image data for a 185-kilometer-wide swath of land. As Earth rotates beneath the satellite's orbit, subsequent seams of land will come into view, providing a complete picture of the planet's surface every 16 days.

To keep Landsat over water during the critical period of liftoff and ascent, managers selected Vandenberg Air Force Base as the mission's launch site. LDCM will be the first NASA mission launched at Space Launch Complex 3 since the agency's Terra satellite launched more than a dozen years ago. But despite a few changes, the launch team hasn't encountered any difficulties during launch preparations, said Omar Baez, senior launch director in NASA's Launch Services Program based at Kennedy Space Center in Florida.

"They're operating out of a new control center since we launched back then," Baez said. "But it's still the Atlas V, still the Atlas V crew. There are folks we've worked with for years. It's like coming home."

The rocket's booster and Centaur stages were erected at the pad in October 2012. The LDCM spacecraft arrived at Vandenberg in December and underwent final prelaunch tests and closeouts before it was installed atop the rocket Jan. 25.

With launch only a few days away, LDCM/Landsat 8 will soon begin sending home data to be used for years to come.

"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."