ULA Delta IV (GPS 2F-1) Abort

"The Delta 4 rocket was just moments away from roaring to life and launching from Cape Canaveral's pad 37B on Monday, but a dramatic last-second abort stopped the countdown.

It was the third attempt to launch the mission carrying the first in a new generation of satellites for the Global Positioning System, and clocks were heading toward liftoff at 11:13 p.m. EDT after a smooth countdown throughout the evening.

"T-minus 15 seconds," the timer said.

"Ignitors armed," a launch team member called.

"ROFI ignition," said another engineer, referring to the radial outward firing ignitors that burn hydrogen beneath the main engine.

"T-minus 10, 9, 8, 7," the timer continued.

"Hold, hold, hold," a voice sounded.

The countdown sequencer script had aborted, automatically stopping the Delta 4 rocket from lighting its main engine and solid rocket boosters.

Well-rehearsed safing procedures began immediately to put the launch vehicle, the Complex 37 facility and GPS spacecraft into a secure configuration.

The Terminal Countdown Sequencer Rack, or TCSR, takes control at T-minus 8.5 seconds and guides activities through liftoff. Ignition of the RS-68 powerplant follows at T-minus 5.5 seconds. The engine begins to produce thrust at T-minus 3.3 seconds and then powers up to the 102 percent throttle at T-minus 1 second for a computer-controlled checkout before liftoff. The solid rocket boosters are lit at T-minus 20 milliseconds.

But Monday's attempt never actually got down to ignition. Computers detected a possible problem with the steering system on one of the twin solid rocket boosters.

The strap-on motors, which burn for 94 seconds to give the Delta a powerful kick toward space, use hydraulics to swivel their nozzles and steer the rocket during flight.

A joint statement to the press from the Air Force and United Launch Alliance said "an anomalous data signature" from the steering system triggered the countdown's abort.

"Mission managers are currently studying the situation to determine a corrective action plan," the statement says.

The earliest that launch could be attempted again is Thursday night. That day's window would extend from 11:00 to 11:19 p.m. EDT. "

-Space Flight Now
(http://spaceflightnow.com/delta/d349/status.html)

Category:

Science & Technology

Tags:

• Delta
• IV
• United
• Launch
• Alliance
• GPS
• 2F-1
• Abort
• Hold

[DudrickStudios]

I leave my house at 10 seconds to run outside. I thought an explosion might have occurred, because I always see it. But, no, they aborted.

[riDDDiculous]

This is ridiculous been driving 2 times already to see this launch...try to launch. Don't want anything bad to happen. Hopefully third times the charm :-)