SpaceX CEO Elon Musk got a rock-star reception last September at the International Astronautical Congress in Mexico when he unveiled his long-promised plan to send scads of settlers to Mars. Now he’s working on a reprise, and it just might be announced at this September’s IAC meeting in Australia. Musk dropped the hint overnight when a follower asked him on Twitter to say when he’d unveil Version 2.0 of the plan, which is supposed to explain in more detail how all those Mars missions be paid for. “Maybe the upcoming IAC in Adelaide,” he replied.
