the world celebrated the 40th anniversary of the historic Apollo 13th mission this week. this mission was meant to be the third mission to the moon but was aborted when an oxygen tank of the module exploded during their path to the moon. the astronauts could not returned immediately since their rocket had already been fired towards the moon. they had to wait for three days for them to go round the moon and fire back towards the earth. the moon landing part of the mission was aborted. during these three days, they had to cope with the extreme of all conditions. low temp, little supply of oxygen and food. the best mathematicians in the world were flown into NASA to help the astronaut navigate their way round the moon and back to earth.