Today saw the successful launch of an Atlas V with the X-37B space plane payload on mission OTV-3. The Atlas V roared into life bang on the opening of the first window of opportunity to launch today. It was a text-book launch after a number of scheduling delays.
The launch was dogged by pre-flight issues none of which were specifically related to the craft itself. First there was the problem with a previous Delta IV launch that uses common components. An investigation into the cause of the Delta IV problem ruled out any possibility of a recurrence on the Atlas V clearing the way for todays launch.
As the launch date approached there were some serious concerns about the weather coming in to play and even 2 hours before the launch window opened the weather officer was only predicting a 30% chance of favourable conditions. As things played out the weather cleared and the weather never went red.
Continue reading for the full launch report…
The Atlas V was assembled in the Vertical Integration Facility about 1/4 mile from Launch Pad 41. The rocket was rolled out to the launch pad on top of the Mobile Launch Platform yesterday and secured to the pad. There it was hooked up to the propellant fuel lines and the control and monitoring lines. After a systems checkout it was ready for todays launch.
Starting at around 6am EST this morning the countdown commenced. Todays launch schedule included two planned holds: one at T-2 hours; and one at T-4 minutes. The first few hours of the countdown involved checking out the ground and flight systems including the infamous, but essential, Flight Termination System. The FTS is activated when a rocket experiences an anomaly and needs to be destroyed.
Everything went smoothly down to the T-2 hours hold when the countdown was paused for 30 minutes. During this time no issues were present so nothing needed to be worked on. After coming out of the hold both the Atlas V and Centaur plumbing and fuel tanks were chilled down prior to commencement of the fuelling. Everything was going to plan apart from the weather. Although the launch criteria were never broken there were heavy clouds covering the area.
As fuelling continued though patches of blue started to appear, then the clouds thinned out a bit. It looked like the weather was not going to be a problem after all… This became more apparent as the countdown continued to the T-4 minute hold. So far we had had a smooth by-the-book launch countdown. All concerns evaporated when the weather officer had confirmed that the weather was GO through the first launch window.
As the clock ticked away we heard the Launch Controller polling each station and the reply came back “ready”. All that was left was permission from the Launch Director, which was promptly given. The Atlas V OTV-3 was ready for launch. The final seconds of the T-4 hold ticked away and then all of a sudden we were at T-4 and counting.
Once again as the countdown clock ticked away everything went to plan. The rocket switched to internal power, the fuel top-off was completed and the feeds secured. The FTS was activated. The skies were blue!!!
After 80 seconds into the flight the rocket had accelerated to and passed MACH-1 breaking the speed of sound. A few short moments later came Max Q with the rocket now punching through the area of Maximum Dynamic Pressure. This is where the airframe is under maximum mechanical stress. After the initial liftoff this is the second most critical part of the launch sequence.
Just over 3 minutes 30 seconds into the flight and the pressures have now reduced to such an extent that the payload fairing can be jettisoned, this was closely followed by the Centaur Forward Load Reactor. The CFLR is a structural component that ensures the payload fairing is centered correctly on the rocket and helps with load bearing during MAX Q. This has now exposed both the Centaur and the X-37B space plane ready for separation
At 4 minutes 20 seconds the main Atlas V booster has nearly completed its task of hauling the Centaur Second Stage and the X-37B space plane towards orbit. Soon came the Booster Engine Cutoff: BECO, followed six seconds later by first and second stage separation.
Ten seconds after separation the Centaur main engine starts and burns for about 13 minutes before it shuts down for the first time and we enter a news blackout. Despite the initial weather concerns this was a text book launch and another successful mission completed for the Atlas V rocket.
The Post-Launch press release from ULA states:
United Launch Alliance Successfully Launches Third X-37B
Orbital Test Vehicle for the Air Force
First Spacecraft to Launch on an Atlas, Return to Earth and Launch Again
Cape Canaveral Air Force Station, Fla., (Dec. 11, 2012) – A United Launch Alliance (ULA) Atlas V rocket successfully launched the third Orbital Test Vehicle (OTV-3) for the Air Force’s Rapid Capabilities Office (AFRCO) at 1:03 p.m. EST today from Space Launch Complex-41. The OTV, also known as the X-37B, supports space experimentation, risk reduction, and concept of operations development for long duration and reusable space vehicle technologies. The first two OTV missions also were successfully launched by ULA respectively on April 22, 2010 and March 5, 2011.
“The ULA team is proud to have played a critical role in successfully launching these three important Orbital Test Vehicle missions for the Air Force RCO,” said Jim Sponnick, ULA vice president, Mission Operations. “This is a unique spacecraft since it is the first to launch on an Atlas V, return to Earth landing at Vandenberg Air Force Base in California, and then fly again on this mission.”
This launch completes the most aggressive campaign in the history of the Evolved Expendable Launch Vehicle (EELV) program with 10 missions launched during 2012, including eight launches from Cape Canaveral Air Force Station in Florida and two from Vandenberg Air Force Station in California.
This mission was launched aboard an Atlas V EELV 501 configuration vehicle, which includes a 5-meter diameter payload fairing. The Atlas booster for this mission was powered by the RD AMROSS RD-180 engine and the Centaur upper stage was powered by a single Pratt & Whitney Rocketdyne (PWR) RL10A-4 engine.
“I sincerely congratulate our OTV customer on today’s successful launch as well as our integrated team of mission partners that successfully accomplished ten critical one-at-a-time launches in 2012,” said Sponnick.
The EELV program was established by the United States Air Force to provide assured access to space for Department of Defense and other government payloads. The commercially developed EELV Program supports the full range of government mission requirements, while delivering on schedule and providing significant cost savings over the heritage launch systems.