The question-and-answer session was intended as a follow-up to Musk's speech at the International Astronautical Congress in Guadalajara, Mexico, last month, in which he described plans to send up to 1 million people to Mars and turn humans into a multiplanetary species within 40 to 100 years.
His vision involves massive, reusable rocket boosters launching spaceships into a "parking orbit" where they are later refueled by propellant tankers. Eventually 1,000 spaceships carrying 100 people each would embark en masse for the Red Planet.
But there are fewer details on what they would do once they arrive. Musk has said a refueling station would be established on Mars to harvest methane fuel for the rocket so settlers could come back to Earth.