Author: MaryAnn Chory, Don Adkins, Mustufa Bahrain, Michael Wehner

Northrop Grumman Space Technology (NGST), based in Southern California is the system prime contractor for the National Polar-orbiting Operational Environmental Satellite System (NPOESS), a low-earth orbiting system that will be the enabler to providing higher quality weather products with greater timeliness than today's systems. In accomplishing this mission Northrop Grumman is utilizing a multi-mission spacecraft that performs both the afternoon as well as the late afternoon low earth polar orbits in a common spacecraft design. This spacecraft leverages products and capabilities from the NASA EOS Aqua and Aura spacecraft while integrating newer generation capabilities such as FireWire for accommodating more advanced sensor payloads and much higher data rates than current weather systems with delivery of weather products to users within 28 minutes.

The first NPOESS satellite will be launched in 2013 for a constellation that will operate well into the following decade. This poster will provide an overview of the NPOESS spacecraft capabilities for the present as well as future growth.

The larger variant NPOESS bus maximizes the available envelope afforded by today's modern EELV launch vehicles to host existing manifested payloads while affording extra “deck space” for upgrades to existing payloads or new payloads of opportunity as they become available. The structure is designed for low earth orbiting weather missions and employs a highly stable optical bench for hosting of payloads.

To accommodate current as well as emerging technologies the spacecraft utilizes an advanced open command and data handling architecture employing a “plug-and-play” databus approach for electrical interfaces. Evolving to a standard data bus approach allows both the spacecraft and payloads to design to a single well established interface with low risk similar to the approach employed by computer manufacturers and hardware peripherals. Employing this approach enables new payloads to be added with relative ease versus legacy programs in which electrical and software interfaces were more “craft-like” in nature. If new interfaces emerge in the coming decade the NPOESS bus has been designed with forethought to accept these new interfaces with minimal impact into the onboard NPOESS data handling system.

To deliver all classes of weather data users the NPOESS satellite delivers high quality high rate weather data to a worldwide network of SafetyNet™ receptors that receive NPOESS payload sensor data several times per orbit and enable delivery of processed weather environmental data to users within 30 minutes. This system also broadcasts data in real-time to users within the satellites field of view for both large users with large receiving dishes as well as smaller mobile users. Also flying on NPOESS are legacy payloads such as the Advanced Data Collection System (ADCS) which collects data globally transmitted from mobile transmitters in whales, tropical forests and ocean buoys as well as the Search and Rescue System (SARSAT) payload which receives distress signals from mobile transmitters on boats, aviation or expeditions.

This presentation will provide an overview of the current requirements and capabilities for the NPOESS mission as well as flexibility to evolve over time as new payloads become available to provide valuable weather data to the global user community.