Multiple Problems Delay Next GPS Satellite Launch -- Block IIR-M1
Multiple Problems Delay Next GPS Satellite Launch
Ref: http://www.space.com/missionlaunches/sfn_delta2_gpsdelay_050510.html
By Justin Ray
posted: 10 May 2005
10:45 a.m. ET
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:
o A mis-installed capacitor on a navigation payload under assembly.
o Screws were discovered not properly torqued in a navigation
payload. Inspections performed on GPS 2R-M1 showed its screws were
torqued.
o 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.
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