Tuesday October 9, 2012
Volume CXXXV Issue 6
Delta IV: triumph and terror Elizabeth Worsham Staff Writer
On Oct. 4, the united Launch Alliance launched a Delta IV rocket from SLC37 at Cape Canaveral, delivering an important payload to orbit, although not without complications. The GPS IIF-3 is the third of 12 Block IIF navigation satellites made by Boeing. These satellites will replace and improve the current Block IIA satellites, which have been in use since the 1990s. The improvements include doubling the accuracy of navigation signals and providing the L5 signal for civil aviation and a military signal known as M-code, which is more resistant to jamming. The satellites are designed for 12 years of operation, after which, they will be replaced by the Block IIIA network that has 500 times the transmitting power. Delta 361 lifted off at 8:10 a.m. Thursday morning, propelled for the first 95 seconds by two strap-on solid-fuel boosters, and the RS-68 main engine. After 4 minutes, the rocket entered
its second stage, and problems began. The first burn of three was supposed to last 8 minutes, but burned about a halfminute longer because of unexpected, reduced thrust. The second burn then persisted for about a minute overtime, bringing the spacecraft to an altitude of 11,001 nm where the payload was released. Although the complications did not affect the success of the mission, Pratt & Whitney, the builder of the upper stage engine, and ULA will thoroughly investigate the problem before the next launch. Thursday’s launch also marked the 21st flight of the Delta IV rocket, which is approaching its 10-year anniversary next month. The Delta IV flew its maiden voyage in November 2002, when it delivered a satellite for a French telecommunications company, Eutelsat. This will also be the last flight for Delta IV in 2012, with the next launch scheduled for midJanuary.
Photos by Richard Weakley