[09-06-07 –  Satellite Today] The National Polar-orbiting Operational Environmental Satellite System (NPOESS) passed a major milestone last month, prime contractor Northrop Grumman announced Sept. 6.

The Cross-track Infrared Sounder (CrIS), a next-generation atmospheric sounding instrument for improved weather forecasting, is a key sensor for the environmental satellite. The metal composite structure successfully passed a frame proof test, which marks the conclusion of an extended analysis and design effort underway since October 2006.

A frame proof test is a vibration test that simulates the loads the sensor will experience during system test and launch. The CrIS passed the test without any change to mechanical or dynamic signatures.

The next step in the sensor’s development is final subsystem testing, system-level re-integration of the CrIS sensor, followed by electromagnetic interference, vibration and thermal vacuum testing. The flight unit is scheduled to be delivered by May 2008 for integration on the NPOESS Preparatory Project (NPP) spacecraft, the company said.

CrIS is one of four sensors that will be a part of the NPP risk reduction mission, and one of nine sensors currently manifested for the operational NPOESS system. CrIS will play a primary role in providing the global soundings required for numerical weather forecasting and other atmospheric variables needed for climate monitoring and prediction.