From ExtremeTech
By: Jesse Murray
On September 29, Elon Musk released his revised plan for sending humans to Mars. The key to this plan is a new rocket called the BFR. It would be nine meters in diameter, 106 meters in height and have a lift off thrust of 5,400 tons. At the top of the BFR would be 40 separate cabins for passengers as well as large common areas and a galley. Musk said that about two to three people could fit in each cabin, which means there could be over 100 passengers on each trip to Mars. As Musk has stated on many occasions, an enormous rocket like this can only be affordable if it is fully reusable. Therefore, instead of building sophisticated rockets and crashing them every time they fly, Musk has focused on making his rockets fully reusable by perfecting propulsive landing.
As of the presentation, SpaceX has completed 16 successful propulsive landings in a row and expects the landings to become only more reliable and safe in the future. Another key element to getting humans to Mars at a low cost is to be able to refill the BFR with tankers while it’s in Earth’s orbit. That way, the BFR has a full tank to use on its journey to Mars, as opposed to a nearly empty tank after it has used all its fuel just to get into Earth’s orbit.
A nine-meter diameter rocket like the BFR would be extremely useful to NASA because it would mean that NASA could get objects that are up to almost nine meters in diameter into Earth’s orbit. For example, NASA could send up a new Hubble that would have ten times the surface area of the current Hubble, which would be about ten times better than a telescope. Musk stated that in about six to nine months, SpaceX will begin to build the new BFR and by 2022 SpaceX should be ready for cargo missions to Mars. Perhaps the most astounding way Musk plans to reduce the cost of these missions is to use the BFR to fly civilian passengers between any two cities on Earth in less than 1 hour at the same price as full fare economy in an aircraft.
