SpaceX CEO Elon Musk did an Ask Me Anything session on Reddit on Sunday afternoon about his Interplanetary Transport System (ITS) and plans to colonize Mars. Musk also provided an update on upgraded Falcon 9 Block 5 booster which SpaceX expects to launch for the first time next year.
Below are some key excerpts. You can find the full session here.
El-Psy-Kangaroo asked for details about SpaceX’s Mars missions.
“We are still far from figuring this out in detail, but the current plan is:
- Send Dragon scouting missions, initially just to make sure we know how to land without adding a crater and then to figure out the best way to get water for the CH4/O2 Sabatier Reaction.
- “Heart of Gold spaceship flies to Mars loaded only with equipment to build the propellant plant.
- “First crewed mission with equipment to build rudimentary base and complete the propellant plant.
- “Try to double the number of flights with each Earth-Mars orbital rendezvous, which is every 26 months, until the city can grow by itself.””
Ulysius asked about plans for permanent habitation on Mars.
“Initially, glass panes with carbon fiber frames to build geodesic domes on the surface, plus a lot of miner/tunneling droids. With the latter, you can build out a huge amount of pressurized space for industrial operations and leave the glass domes for green living space.”
__Rocket__ asked if the ITS has enough delta v to fly between Mars and Earth between the every 26 months launch windows with a reduced cargo load.
MINDMOLESTER asked what technologies SpaceX would have to develop to make ITS a success.
“It used to be developing a new metal alloy that is extremely resistant to oxidation for the hot oxygen-rich turbopump, which is operating at insane pressure to feed a 300 bar main chamber. Anything that can burn, will burn. We seem to have that under control, as the Raptor turbopump didn’t show erosion in the test firings, but there is still room for optimization.
“Biggest question right now is sealing the carbon fiber tanks against cryo propellant with hot autogenous pressurization. The oxygen tank also has an oxidation risk problem as it is pressurized with pure, hot oxygen. Will almost certainly need to apply an inert layer of some kind. Hopefully, something that can be sprayed. If need be, will use thin sheets of invar welded together on the inside.”
Everyday Astronaut asked about how ITS would do entry, descent and landings back on Earth.
“Good question — that wasn’t shown at IAC. The spaceship and tanker would have split body flaps for pitch and roll. Probably just use the attitude control thrusters for yaw.”
nalyd8991 asked for more details on the carbon composite development tank for the ITS.
“The flight tank will actually be slightly longer than the development tank shown, but the same diameter.
“That was built with latest and greatest carbon fiber prepreg. In theory, it should hold cryogenic propellant without leaking and without a sealing linker. Early tests are promising.
“Will take it up to 2/3 of burst pressure on an ocean barge in the coming weeks.”
theZcuber asked about how different ITS will be when configured for crew smaller than 100.
“Probably just pack the pressurized space with cargo. Early missions will be heavily weighted towards cargo. First crewed mission would have about a dozen people, as the goal will be to build out and troubleshoot the propellant plant and Mars Base Alpha power system.”
Zucal asked for details on the interior of ITS.
“I think we need a new name. ITS just isn’t working. I’m using BFR and BFS for the rocket and spaceship, which is fine internally, but…
“Will aim to release details of the habitation section when we have actual live mockups. Maybe in a year or two.”
FoxhoundBat asked about upgraded Falcon 9 performance.
“Actually, I think the F9 boosters could be used almost indefinitely, so long as there is scheduled maintenance and careful inspections. Falcon 9 Block 5 — the final version in the series — is the one that has the most performance and is designed for easy reuse, so it just makes sense to focus on that long term and retire the earlier versions. Block 5 starts production in about 3 months and initial flight is in 6 to 8 months, so there isn’t much point in ground testing Block 3 or 4 much beyond a few reflights.