NASA and United Launch Alliance conducted a countdown dress rehearsal over the weekend, setting the stage for the planned launch Saturday of an Atlas V rocket and the Mars Science Laboratory.
The 19-story rocket and America's next Mars explorer are scheduled to blast off from Launch Complex 41 at Cape Canaveral Air Force Station at 10:02 a.m. Saturday -- a day later than initially planned.
The launch slipped to give engineers and technicians time to remove and replace a faulty flight termination system battery. The system would enable range safety officers to deliberately destroy the Atlas V rocket if it veered out of control and threatened people in towns and cities surrounding the launch site.
The dress rehearsal was a training exercise that gave the NASA-ULA launch team an opportunity to go through a mock countdown just as if it were launch day. It is considered a key milestone in any Atlas V launch campaign.
A spare flight termination system battery is being activated at the launch base and will be installed and tested later this week. The activation process takes several days to complete.
The launch window on Saturday will extend through 11:45 a.m. If bad weather or technical problems prompt a minor delay in the countdown, NASA and ULA would have launch opportunities every five minutes between 10:02 a.m. and 11:45 a.m. The launch must be precisely timed to put the rocket on course for an eight-month interplanetary cruise to Mars.
Earth and Mars will be aligned properly for the flight between Friday and Dec. 18. A launch on any day during that time will lead to an arrival at Mars on Aug. 5, 2012. A delay past Dec. 18 would force NASA to push the launch back two years until Earth and Mars once again get in optimal alignment for the flight.
ABOUT THE IMAGE: Click to enlarge the NASA image of the Atlas V rocket being prepared for launch Saturday of Launch Complex 41 at Cape Canaveral Air Force Station. Photo credit: NASA/Dimitri Gerondidakis