Multiple Problems Delay Next GPS Satellite Launch

A handful of worriesspawned by problems found in the factory have prompted the Air Force to delaylaunching the next Global Positioning System satellite.

The Lockheed Martin-builtGPS 2R-M1 spacecraft was supposed to fly from Cape Canaveral this month aboarda Boeing Delta 2 rocket. But issues arose involving internal components,causing officials to put the brakes on launch plans.

The problems include:

• A mis-installed capacitor on a navigation payload under assembly.
• Screws were discovered not properly torqued in a navigation payload. Inspections performed on GPS 2R-M1 showed its screws were torqued.
• Navigation payload-manufacturer ITT determined that a Destructive Physical Analysis had not been performed for a relay used on the GPS 2R-M1 satellite's L-Band transmitter DC-DC converter.

Officialsacross the GPS program are trying to ensure the problems won't harm the GPS2R-M1 spacecraft and its $75 million mission to replace an aging satellite inthe military's navigation constellation.

"The GPS Joint ProgramOffice has worked with Lockheed Martin, and their subcontractors, to understandroot cause of the issues and extensively review the' reach-back' potential to(GPS 2R-M1)," the Air Force Space and Missile Systems Center toldSpaceflight Now.

The Air Force and LockheedMartin believe the issues have been resolved, permitting GPS 2R-M1 to resumeits launch campaign.

The satellite is expectedto be transported to launch pad 17A in late May or early June for mating atopthe Delta rocket. Although a firm launch date has not been established, the AirForce anticipates liftoff in mid-June.

This spacecraft is thefirst in the so-called "Modernized" line of GPS 2R-model satellites.The updated craft increase the power for existing signals and offer two newmilitary signals as well as a second civilian signal to benefit users aroundthe world.

The improvements willprovide greater accuracy, better resistance to interference and enhancedperformance for all users, according to the Air Force. The advancements for themilitary will provide warfighters with a more robust jam-resistant signal andenable better targeting of GPS-guided weapons in hostile environments, whilethe new civilian signal removes ionospheric errors and improves accuracy.

The GPS craft sendcontinuous navigation signals that allow users virtually anywhere on the planetto find their position in latitude, longitude and altitude and determine time.The signals are so accurate that time can be figured to less than a millionthof a second, velocity to within a fraction of a mile per hour and location towithin a matter of feet.

The GPS constellationfeatures 24 primary and several backup satellites flying into six orbitalgroupings 11,000 miles above Earth. The Air Force continues to launch newsatellites as replacements to keep the critical navigation system in goodhealth. Twenty-nine satellites are functioning in orbit today.

"The health of the GPSconstellation is excellent," the program office said.

Which location GPS 2R-M1will fill is expected to be decided Tuesday.

"The ConstellationSustainment Assessment Team is meeting May 10 to determine the orbitalslot," officials said.