The plan calls for flying 10,000 spaceships to create a one million people colony on Mars. Fascinating concept no doubt. Each spaceship should carry 100 passengers. To launch such a spaceship the size of the rocket which would be needed exceeds anything that has been built so far. To demonstrate the scale a comparison of rockets was shown.
Wonder why there is no Space Shuttle in the table? Perhaps to somebody's surprise, the answer is because the Space Shuttle is not actually a rocket. However, the table is missing one rocket which deserves inclusion at least because it would be the closest by performance to the proposed Mars rocket. Energia launch rocket which was a vehicle to carry to orbit Soviet space shuttle Buran. Unlike the US space shuttle however, Energia was a true rocket capable of delivering any payload to orbit, and not only a shuttle.
Musk has long said that he founded SpaceX in 2002 chiefly to help humanity colonize Mars. Becoming a multiplanet species would serve as an insurance policy, minimizing the risk of humanity's extinction should something terrible happen on Earth, he has said.
Musk reiterated that argument during the IAC presentation Tuesday. But he also put forth another reason why settling Mars is worth the trouble and the risk.
"It would be an incredible adventure; it would be the most inspiring thing that I can possibly imagine," he said. "Life needs to be more than just solving problems every day. You need to wake up and be excited about the future, and be inspired and want to live."
Can't say better!