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OTV-3 mission badge (Credit ULA)
The next rocket launch from Cape Canaveral Air Force Station is scheduled to take place tomorrow, 11th December, at 1:03 EST (18:03 GMT). The Atlas V rocket will be launching the USAF secret space plane into orbit for the third mission: OTV-3 from Space Launch Complex 41 (SLC-41).
The projected weather conditions suggest that there is only a 30% chance of launching with lightning, cumulus cloud, disturbed weather, and thick cloud all being concerns for violation.
The launch window is quite long tomorrow opening at 1:03pm EST it extends 5 hours until 6:03pm. Hopefully within that time span there will be a window of opportunity for the weather to clear and the mission to get underway.
The launch has been dogged with delays mainly due to the problems encountered on the last Delta IV mission. The reduced engine performance of the Delta Rocket affected the Atlas as they use common components. Originally slated to launch in October this date has slipped a few times awaiting the results of the Delta IV investigation. The ULA investigation into the anomaly states “Although the investigation into the flight data anomaly continues, all credible crossover implications from the Delta anomaly for the OTV-3 Atlas vehicle and engine system have been thoroughly addressed and mitigated, culminating in the flight clearance decision for the OTV-3 launch”. This gave the green light to mission planners to schedule the Atlas V for launch.
Continue reading for the mission profile and images…
Atlas V OTV-3 rocket exploded view (credit ULA)
The Atlas V will fly in the 501 configuration with a single Atlas V main booster, single Centaur upper stage and a 5 metre diameter payload fairing. There will not be any Solid Rocket Boosters for this flight. The overall height of the Atlas V rocket on the launch pad will be just shy of 200 feet.
The payload is the USAF’s X-37B OTV space plane. This secret spacecraft has been designed to orbit the earth for extended periods of time and then perform an automated re-entry and land at Vandenberg Air Force Base in California. Built by Boeing the mission parameters for OTV-3 remain undisclosed, but include space experimentation, risk reduction and concept of operations development for long duration and reusable space vehicle technologies.
OTV on runway at Vandenberg (Credit Boeing)
The launch preparations start today with the Atlas V moving from the Vertical Integration Facility where the rocket has been assembled and checked for flight readiness. The rocket is mounted on a Mobile Launch Platform which will roll out to the launch pad on twin railway tracks. The MLP is trailed to the launch pad by a series of specially designed rail carts which provide the services needed to keep the rocket and spacecraft monitored and controlled whilst mobile. The trip is only about 400 yards, but takes around about an hour to complete.
Once on the launch pad the the MLP is locked in place in a process known as MLP Hard Down. When this is complete the Rocket is connected to services on the launch pad. This includes the communications, conditioning, and fuel lines. When this is complete the rocket will be ready for tanking and final countdown.
About 5 hours prior to launch the rocket starts the fuelling process. This will continue for about 3 hours when the fuel tanks are full. At this point the fuelling enters a topping off process which continues until launch.
As the countdown proceeds there will be a pause at T-4 minutes when a planned hold is entered. This hold allows the engineers to and flight controllers to go through a series of checks to ensure the flight readiness of the Atlas V, the Centaur upper stage, and the X-37B spacecraft. After a readiness poll of all the stations the hold will be released and the terminal countdown entered.
At T-2.7 seconds the rocket engine will be lit and after a few seconds when the engine builds up power the hold-downs will be released and the Atlas V will streak into the skies.
Atlas 5 - OTV-2 Launch
