REDONDO BEACH, Calif. 30 March 2009. Northrop Grumman Corp. successfully completed the Critical Design Audit of the Space Segment for the National Polar-orbiting Operational Environmental Satellite System (NPOESS). NPOESS is the nation's next generation low Earth-orbiting weather and climate monitoring system and will provide timely and essential data to civilian and military users through 2025.

Since last March, 85 detailed technical reviews were conducted, with more than 100 customer community reviewers evaluating the depth and maturity of the Space Segment's design elements, culminating in the recent 10 day Critical Design Audit, Northrop Grumman officials say. The Space Segment consists of the spacecraft bus, science instruments, communication payloads, launch vehicle interface and systems engineering.

The NPOESS Space Segment has features that support timely delivery of data from advanced sensors. The segment handles sensor data via a command and data handling architecture that utilizes a space-qualified, high-speed chipset based on the 1394a industry standard and four 1553 data networks. This data is downlinked to a global network of SafetyNet ground stations, which provides 95 percent of weather products to users within 28 minutes of observation.

The Space Segment also features: ample physical space to mount more than 13 sensors on each spacecraft bus with robust mass and power margin; ability to produce data equal to half the Library of Congress per day; spare power and communication resources, wired in a manner similar to a house, enabling sensors to plug into an empty socket; a quiet dynamic and electromagnetic environment suitable for many types of sensors.

NPOESS' next major review is the system-wide Critical Design Review, which is scheduled for late April.

"The Space Segment design features new and innovative subsystems, but benefits from our history in building two NASA Earth Observing System satellites," says Dave Vandervoet, vice president and NPOESS program manager for Northrop Grumman Aerospace Systems, prime contractor for NPOESS. "We have great confidence that the NPOESS Space Segment will serve as a robust platform for the new generation of environmental, weather and climate sensors for this important mission."