It was the thirteenth scheduled lunar space exploration mission, scheduled for liftoff at the thirteenth minute after the thirteenth hour. The Lunar landing was scheduled for the thirteenth day of the month. All it lacked was a Friday to be a paraskevidekatriaphobe’s worst nightmare. Unfortunately, no one at NASA was superstitious.
Or, perhaps, fortunately. If anyone had stopped or made changes to the schedule of Apollo 13, the world may have missed one of the greatest adventures in space exploration history.
Problems Began Before LaunchApollo 13, the third planned Lunar-landing mission, was scheduled for launch on April 11, 1970. There were problems even before the launch. Just days before, Astronaut Thomas K. Mattingly was replaced by Jack Swigert when it was learned he may have been exposed to German measles, and did not have the antibodies necessary to be immune (Mattingly never contracted the disease.). Shortly before launch, a technician noticed a higher pressure on a helium tank than expected. Nothing was done about it besides keeping a close watch. A vent for liquid oxygen would not close at first and required several recyclings before it would shut.
The launch, itself, went according to plan, if an hour late. Shortly afterward, though, the center engine of the second stage cut off more than two minutes early. In order to compensate, controllers burned the other four engines an additional 34. Also the third stage engine was fired for an extra 9 seconds during its orbital insertion burn. Fortunately, this all resulted in a mere 1.2 feet per second greater speed than planned.
Smooth Flight - No One WatchingThe first part of the flight went fairly smooth. As Apollo 13 entered the Lunar corridor, the Command Service Module separated from the third stage and maneuvered around to extract the Lunar Module. Once this was completed, the third stage was driven on a collision course with the moon. This was done as an experiment and the resultant impact was to be measured by equipment left behind by Apollo 12. The Command Service and Lunar Modules were then on "free return" trajectory, which, in the case of complete engine loss, would slingshot them around the moon and on course back to Earth.
The evening of April 13 (EST), the crew of Apollo 13 had just finished a television broadcast explaining their mission and about life aboard the ship. Commander Jim Lovell closed the broadcast with this message, "This is the crew of Apollo 13. Wish everybody there a nice evening and a, we're just about to close out our inspection of Aquarius and get back to a pleasant evening in Odyssey. Goodnight." Unknown to the astronauts, the television networks had decided that traveling to the moon was such a routine occurrence; none of this was broadcast over the air. No one was watching, though soon the entire world would be hanging on their every word.
Routine Task Goes AwryAfter completing the broadcast, flight control sent another message, "13, we got one more item for you when you get a chance. We'd like you to err, stir up your cryo tanks. In addition err, have a shaft and trunnion, for a look at the comet Bennett if you need it."
Astronaut Jack Swigert replied, "OK, stand by."
Moments later, the technicians in flight control heard a disturbing message from Apollo 13. Jack Swigert said, "OK Houston, we've had a problem here."