Multiple Problems Delay Next GPS Satellite Launch

A handful of worries spawned by problems found in the factory have prompted the Air Force to delay launching the next Global Positioning System satellite.

The Lockheed Martin-built GPS 2R-M1 spacecraft was supposed to fly from Cape Canaveral this month aboard a 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.

Officials across the GPS program are trying to ensure the problems won't harm the GPS 2R-M1 spacecraft and its $75 million mission to replace an aging satellite in the military's navigation constellation.

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

The Air Force and Lockheed Martin believe the issues have been resolved, permitting GPS 2R-M1 to resume its launch campaign.

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

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

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

The GPS craft send continuous navigation signals that allow users virtually anywhere on the planet to 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 millionth of a second, velocity to within a fraction of a mile per hour and location to within a matter of feet.

The GPS constellation features 24 primary and several backup satellites flying into six orbital groupings 11,000 miles above Earth. The Air Force continues to launch new satellites as replacements to keep the critical navigation system in good health. Twenty-nine satellites are functioning in orbit today.

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

Which location GPS 2R-M1 will fill is expected to be decided Tuesday.

"The Constellation Sustainment Assessment Team is meeting May 10 to determine the orbital slot," officials said.