Day 3 - Downsizing a Little
At the 2017 IAC in Adelaide, Australia, the plan downsized a bit, and we discovered some intriguing details. The presentation is here. The summary version: “MCT” is now officially, if temporarily, “BFR.” To keep this site safe for work, we’ll call that “Big Falcon Rocket.” Instead of a 12 meter diameter, twice the size of the Saturn V, and 300 tons to LEO, it’s a 9 meter diameter, a little larger than Saturn V, and 150 tons to LEO. Of course, with orbital refilling, that’s also 150 tons to Mars. Total engine count is reduced from 42 to 31, still of two types.
It’s still a two-stage vehicle, with a booster and upper stage “ship.” In addition to the crewed ship, there’s also a tanker and cargo version. The ship now has small delta wings with split flaperons for roll and pitch control during reentry, and still lands vertically. For Mars missions, there will be some heat shield ablation, requiring maintenance after some number of missions. There will be 40 cabins, with initial plans calling for them to be double (perhaps triple) occupancy.
The first major surprise of the presentation is that SpaceX will design BFR to completely replace its Falcon 9, Falcon Heavy, Dragon, and Dragon 2. Putting all the company’s resources towards BFR means the new vehicle eventually pays for itself with satellite launches and Earth-vicinity operations. The Moon is back on the table, since a refilled BFR “ship” can land on the Moon and return to Earth. Musk also identified suborbital trips as something SpaceX is interested in. Most likely, this is because SpaceX has numbers indicating there’s a market that can generate positive cash flow without distracting from the main mission.
The second major surprise was that the 2022 date mentioned last year hasn’t changed, although Musk did admit it was “aspirational.” The current plan is two cargo ships to Mars in 2022, followed by two more in 2024—along with two crewed ships.
And that brings up the biggest surprise, which we’ll want to spend some time talking about. SpaceX intends to send those ships to Mars before there’s propellant available to get them home. Musk’s thinking is that 600 tons of cargo on 4 ships ought to be enough to make the risk manageable, since there will also be two ships with full life support.
We’ll see. Next step: making a list.