NPP Satellite Sensor Damaged in Testing
An artist's depiction of the NPOESS Prepatory Project satellite.
Credit: NASA.

WASHINGTON -- A flight-demonstration sensor for the next-generation of U.S. polar-orbiting weather satellites sustained damage during testing Oct. 11, but program officials said the mission's launch schedule should not be affected.

The sensor, dubbed the Cross-track Infrared Sounder, was damaged during acceptance testing at the Ft. Wayne, Ind., facilities of its builder, ITT Corp. The sensor is part of the payload package aboard a precursor satellite to the U.S. civil-military National Polar-orbiting Operational Environmental Satellite System, or NPOESS.

The precursor mission, a multi-agency effort known as the NPOESS Preparatory Project (NPP), is scheduled to launch in September 2009. Government and industry program officials said the mishap, which occurred during a vibration test meant to prove the instrument is tough enough to survive launch, appeared unlikely to delay NPP's liftoff.

U.S. Air Force Col. Dan Stockton, the NPOESS program director, acknowledged Oct. 19 in a brief written statement that the Cross-track Infrared Sounder had been damaged and vowed that it would be fixed.

"Any problem of this nature is serious. We have deployed resources of the [Departments of Commerce and Defense] and NASA to work with the contractor team to evaluate and fix the problem," Stockton said.

NPOESS is a joint effort of the Air Force and National Oceanic and Atmospheric Administration, with NASA as the junior partner. NASA has the lead in the NPP mission. Andrew Carson, the NASA program executive for the NPP and NPOESS programs, told Space News in an Oct. 19 e-mail that if the NPP mission does fall behind schedule, the setback with the Cross-track Infrared Sounder probably would not be to blame. He said the NPP's current launch date, a full three years later than originally planned, is driven primarily by how long it takes to complete one of the spacecraft's other instruments, the Visible Infrared Imaging Radiometer Suite.

"Delivery of the Visible Infrared Imaging Radiometer Suite is on the critical path for the launch of NPP in September 2009," Carson said in his e-mail. The Cross-track Infrared Sounder "vibration failure review team is taking a cautious, methodical approach to determine the root cause of the failure. It is too early in the investigation to say how much redesign or rework will be necessary, however it is not expected that the delivery of the... flight unit will slip beyond the delivery of" the Visible Infrared Imaging Radiometer Suite.

That instrument, being built by El Segundo, Calif.-based Raytheon Space and Airborne Systems, has been widely labeled the driving factor behind the NPOESS cost and schedule problems leading up to the decision to restructure the program.

Sally Koris, a spokeswoman for NPOESS prime contractor Northrop Grumman Space Technology of Redondo Beach, Calif., said in an Oct. 19 e-mail that the test setback is expected to have minimal impact on completion of the NPP spacecraft.

"Based on the information we have at this time, we believe there is sufficient margin in the program's schedule to accommodate analysis and repair of the sensor prior to its required delivery date to NPP," Koris wrote. "Meanwhile, a flight-like... engineering development unit will be used to test and verify mechanical and electrical interfaces between the sensor and the spacecraft."

The NPP spacecraft is being built by Boulder, Colo.-based Ball Aerospace and Technologies Corp. under contract to NASA. Northrop Grumman is overseeing development of NPP's instruments since subsequent models will fly aboard the NPOESS satellites, which are slated to start launching in 2013.

Koris said in her e-mail that the Cross-track Infrared Sounder "was undergoing a planned series of acceptance tests when it sustained structural damage in the instrument frame." She said review boards made up of government and industry personnel have been convened to investigate the incident and "determine if this is a manufacturing problem, a test configuration or test fixture problem, operator error or a design issue."

Bernice Borrelli, a spokeswoman for Rochester, N.Y.-based ITT Space Systems Division, said in an e-mail that the sensor development program "will incur a schedule movement but it will not impact the NPP schedule."

Ball Aerospace spokeswoman Roz Brown said Oct. 19 that prior to the testing incident Ball expected to take delivery of the sounder Jan. 3 and begin integrating it with the NPP spacecraft bus around Jan. 10. She said Ball Aerospace also does not expect the setback to impact NPP's launch schedule but was awaiting NASA's assessment of the situation.