Saturday, July 16, 2011

GPS IIF-2 Launch

The newest next generation GPS satellite lifted-off today at 2:41 AM EDT.  Aboard the Delta 4, the satellite was in it’s proper orbit within 3 1/2 hours.
The satellite will undergo a checkout period prior to being set healthy.  Typically this takes a few weeks.
Here’s a shot from Universe Today:
GPS IIF-2 - Launch

Technical Data


SVN: 63
PRN: 1
Orbit/Slot: D/2A
2SOPs NANU: 2011047
The orbit slot is one of three bifurcated slots.  Per Richard Langley and CANSPACE:
The D2 slot is one of three orbital slots that are expandable into fore (F) and aft (A) slots. SVN46/PRN11 is currently in slot D2F. The other two bifurcated slots are B1 and F2.

Launch Info

In previous GPS satellite launches aboard less powerful boosters, it took a day or more to get to the proper orbit, using an additional Apogee Kick Motor (AKM) attached to the satellite itself to propel it to it’s destination in Medium Earth Orbit (MEO).  Now, with more powerful boosters, satellites are directly placed into their correct slots. From Spaceflight Now:
T+plus 100 minutes. Unlike the previous generations that rode on smaller rocket Delta 2 rockets, the dozen next-generation GPS 2F craft will be delivered into orbit atop the Delta 4 and Atlas 5 fleets of boosters in the Air Force's Evolved Expendable Launch Vehicle program.
The Delta 2's, although highly reliable, weren't powerful enough to inject the GPS satellites directly into the orbiting constellation. The three-stage vehicles released the craft into a highly elliptical orbit stretching from 100 miles at its closest point with Earth to some 11,000 miles at its highest point, which is the altitude where the GPS network resides. The newly-launched satellites were themselves fitted with a solid-fuel kick motor that ignited a few days into flight and finished the job of propelling the craft into a circular orbit.
United Launch Alliance's powerful Delta 4 and Atlas 5 rockets will haul the GPS 2F satellites directly to their desired destinations, bypassing the circuitous route of the past. So instead of taking days to reach the GPS orbit, the new 2F-2 satellite will get there in three-and-a-half hours today.
More articles:
Spaceflight Now
Universe Today

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