SpaceX founder and CEO Elon Musk just hosted a Reddit AMA (Ask Me Anything) session, which he describes as supplemental to the speech he gave at the International Astronautical Conference in Guadalajara, Mexico last month.
There were a lot of questions about his Mars colonization plans, about ITS, how people are going to live there and so on. Musk mostly answered questions about his Mars colonization plan and technology required to get there.
About Interplanetary Transport System (ITS)
SpaceX’s ITS consists of a booster and a spaceship and is designed for a maximum acceleration of 20 Gs. However, the spaceship would be “limited to around 5 g’s nominal, but able to take peak loads 2 to 3 times higher without breaking up.”
Musk also said unless the ITS encountered any problem or unexpected wind conditions, there wouldn’t be any hovering when a user asked whether it will be able to hover over the surface of Mars.
When asked about the lineup of Falcon 9 and the big booster, Musk replied “The big booster will have an easier time of things than Falcon, as the mass ratio of the stages is lower and it will have lower density. Net result is that it won’t come in quite as hot and fast as Falcon, so Falcon should be a bounding case on the big booster.”
Another Reddit user asked about what SpaceX had next to do with ITS, Musk answered that they had originally aimed to design “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,” mentioning that their next target is to secure their tanks from oxidizing.
“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.”
Musk also said that there is a possibility of changing the name of ITS. “I’m using BFR and BFS for the rocket and spaceship, which is fine internally, but…“
Will falcon 9 be reusable?
Another asked whether it’s possible to reuse the Falcon 9 rockets currently flying. “I think the F9 boosters could be used almost indefinitely, so long as there is scheduled maintenance and careful inspections,” he replied.
Colonizing of Mars
This is one of the important factors that he didn’t cover during IAC talk that how people would actually survive once they reach on the red planet. However, this time he has a couple of details:
“Initially, glass panes with carbon fiber frames to build geodesic domes on the surface,” he wrote, “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.”
The number of flights might be doubled
Musk revealed in his Reddit timeline that he would “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.”
However, the rendezvous isn’t always necessary. When a commentator asked if they would use the rockets outside of those rendezvous windows, where payload mass wasn’t a primary factor. There might be some emergency situations or an immediate mission to or from Mars might be necessary to survive. And Elon Musk simply replied “yes.”
There are already more than 5000 comments for this Reddit AMA. And Elon Musk has covered a lot about his Mars colonization.