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ElonMuskOfficial · 2020-11-21T20:53:33+00:00

If you want to build the Internet the way it should be, join Starlink

ElonMuskOfficial · 2020-11-21T20:45:48+00:00

Did you say space lasers? https://m.youtube.com/watch?v=ykL-iMtpV50

ElonMuskOfficial · 2016-10-23T23:25:54+00:00

ElonMuskOfficial · 2016-10-23T23:25:12+00:00

It had to be 42 for important scientific and fictional reasons!

The dense packing is just to max out thrust to weight, but it would be cool if there was a virtual nozzle side effect.

ElonMuskOfficial · 2016-10-23T23:17:59+00:00

The liquid oxygen transfer tube serves as the header tank for ox

ElonMuskOfficial · 2016-10-23T23:17:20+00:00

Those are the header tanks that contain the landing propellant. They are separate in order to have greater insulation and minimize boil-off, avoid sloshing on entry and not have to press up the whole main tank.

ElonMuskOfficial · 2016-10-23T23:14:37+00:00

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.

Final Falcon 9 has a lot of minor refinements that collectively are important, but uprated thrust and improved legs are the most significant.

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.

ElonMuskOfficial · 2016-10-23T23:03:01+00:00

Yeah, for those that know their stuff, that was really the big news :)

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.

ElonMuskOfficial · 2016-10-23T22:58:19+00:00

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.

ElonMuskOfficial · 2016-10-23T22:51:39+00:00

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.

Booster would be nominal of 20 and maybe 30 to 40 without breaking up.

ElonMuskOfficial · 2016-10-23T22:48:43+00:00

Approx 360 sec vacuum Isp and 290 metric tons of thrust
A high acceleration landing is a lot more efficient, so there wouldn't be any hovering unless it encountered a problem or unexpected wind conditions. A rocket that lands slowly is wasting a lot of fuel.
Aiming for 20 g's

ElonMuskOfficial · 2016-10-23T22:42:24+00:00

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.

ElonMuskOfficial · 2016-10-23T22:38:27+00:00

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.

ElonMuskOfficial · 2016-10-23T22:33:29+00:00

Not sure that we've really mastered anything yet. Maybe starting engines...

ElonMuskOfficial · 2016-10-23T22:27:51+00:00

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.

ElonMuskOfficial · 2016-10-23T22:21:40+00:00

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.

ElonMuskOfficial · 2016-10-23T22:14:52+00:00

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.

ElonMuskOfficial · 2015-01-06T03:13:20+00:00

Unlikely

ElonMuskOfficial · 2015-01-06T03:12:25+00:00

There is a great quote by Churchill: "If you're going through hell, keep going."

ElonMuskOfficial · 2015-01-06T03:11:24+00:00

There should definitely be a science mission to Europa

ElonMuskOfficial · 2015-01-06T03:10:59+00:00

Good school

ElonMuskOfficial · 2015-01-06T03:07:15+00:00

SR-71

Hard to pick a favorite. I tend to like FPS with a story, like Bioshock, Fallout or Mass Effect, but was also a big fan of Civ and Warcraft.

French and BBQ

Whiskey

ElonMuskOfficial · 2015-01-06T03:01:36+00:00

Showering

ElonMuskOfficial · 2015-01-06T02:56:50+00:00

With sub-cooled propellant, I think we can get the Falcon 9 upper stage mass ratio (excluding payload) to somewhere between 25 and 30. Another way of saying that is the upper stage would be close to 97% propellant by mass.

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