— The last of the current generation of civilian
polar-orbiting environmental satellites was mated with its Delta 2 rocket and completed prelaunch checkout Jan.
18 in
preparation for a Feb. 4 liftoff from Vandenberg Air Force Base,
, according to officials from NASA and the National Oceanic and Atmospheric Administration (NOAA).

The NOAA N-Prime spacecraft, which had to be rebuilt after a high-profile factory-floor mishap in 2003, will continue the Polar Operational Environmental Satellite (POES) constellation’s legacy of weather forecasting, climate modeling and international cooperation, Gary Davis, director of NOAA’s Office of System Development, told reporters in a Jan. 22 conference call.

Built by Lockheed Martin Space Systems of Sunnyvale, Calif., for NASA on behalf of NOAA, N-Prime is the 16th and final of the current generation of POES spacecraft. Since the first satellite in the series was launched in 1978, 14 of 15 satellites were successful, with one failing shortly after launch. Of the successful satellites, the average lifetime has been 3.7 years, said Wayne McIntyre, NASA’s program manager for the polar-orbiting environmental satellites.

The N-Prime satellite is designed to operate for a minimum of two years, but NOAA is hoping to keep it in service at least until January 2013 when the first next-generation National Polar-orbiting Operational Environmental Satellite System (NPOESS) satellite is due to launch. If NPOESS, being developed jointly with the U.S. Air Force, is not ready to go by then, a precursor spacecraft known as the NPOESS Preparatory Project, targeted for a June 2010 launch, would be able to take over some of N-Prime’s duties, Davis said.

NOAA maintains two POES satellites in near-polar orbits roughly
900 kilometers
high, which ensures that each part of the Earth is observed at least four times per day. N-Prime has six weather and climate instruments that will take vertical profiles of atmospheric temperature and humidity while measuring radiation, atmospheric ozone, aerosol distribution and sea-surface temperature. The satellite also has a search-and-rescue antenna that has been part of an international network that is credited with saving 24,500 lives around the world since 1982,
said. N-Prime boasts an upgraded data collection system, capable of downlinking commands to ground receivers to modify their performance.

The N-Prime satellite made headlines in recent years as a result of a pair of mishaps suffered during handling at Lockheed Martin’s
plant. In September 2003, the satellite was badly damaged when it fell nearly a meter onto a concrete floor. The cause of the accident was 24 missing bolts needed to secure the spacecraft to a large stand called a turn-over cart, which is used to rotate satellites from a vertical to a horizontal position.

The chassis and two of the satellite’s six instruments were damaged in the accident, resulting in $135 million in cost growth, part of which was absorbed by Lockheed Martin. McIntyre said NASA comprehensively reviewed the accident and made significant improvements to the facility and work-force training procedures.

“The result since then in rebuilding it shows that we attacked the right areas,” McIntyre said.

Then in 2007, Lockheed Martin employees were moving the spacecraft when its search-and-rescue antenna broke loose from a nylon tether and banged into the Advanced Microwave Sounding Unit A1 instrument. After months of computer modeling by NASA and NOAA showed the satellite suffered no internal damage, N-Prime was cleared for launch. That incident created no cost growth or launch delay because the contractor and government were able to find the replacement parts that were needed, and N-Prime in any case was scheduled to be stored in a warehouse for more than a year before shipping to the launch site, Davis said.