"The final piece of the puzzle for figuring out the Mars architecture is a methane engine. You need to be able to generate the propellant on the surface. Most of the fuel used in rockets today is a form of kerosene, and creating kerosene is quite complex. It’s a series of long-chain hydrocarbons. It’s much easier to create either methane or hydrogen. The problem with hydrogen is it’s a deep cryogen. It’s only a liquid very close to absolute zero. And because it’s a small molecule you have these issues where hydrogen will seep its way through a metal matrix and embrittle or destroy metal in weird ways. Hydrogen’s density is also very porous, so the tanks are enormous and it’s expensive to create and store hydrogen. It’s not a good choice as a fuel.“Methane, on the other hand, is much easier to handle. It’s liquid at around the same temperature as liquid oxygen so you can do a rocket stage with a common bulkhead and not worry about freezing one or the other solid. Methane is also the lowest-cost fossil fuel on Earth. And there needs to be a lot of energy to go to Mars.“And then on Mars, because the atmosphere is carbon dioxide and there’s a lot of water or ice in the soil, the carbon dioxide gets you CO2, the water gives you H2O. With that you create CH4 and O2, which gives you combustion. So it’s all sort of nicely worked out.“And then one of the key questions is can you get to the surface of Mars and back to Earth on a single stage. The answer is yes, if you reduce the return payload to approximately one-quarter of the outbound payload, which I thought made sense because you are going to want to transport a lot more to Mars than you’d want to transfer from Mars to Earth. For the spacecraft, the heat shield, the life support system, and the legs will have to be very, very light."
I am Elon Musk, CEO/CTO of a rocket company, AMA! ElonMuskOfficial 5 months ago Actually, we could make the 2nd stage of Falcon reusable and still have significant payload on Falcon Heavy, but I think our engineering resources are better spent moving on to the Mars system.MCT will have meaningfully higher specific impulse engines: 380 vs 345 vac Isp. For those unfamiliar, in the rocket world, that is a super gigantic difference for stages of roughly equivalent mass ratio (mass full to mass empty).
ElonMuskOfficial 5 months ago Default plan is to have a sea level and vacuum version of Raptor, much like Merlin. Since the booster and spaceship will both have multiple engines, we don't have to have fundamentally different designs.This plan might change.
At first, I was thinking we would just scale up Falcon Heavy, but it looks like it probably makes more sense just to have a single monster boost stage.
Goal is 100 metric tons of useful payload to the surface of Mars. This obviously requires a very big spaceship and booster system.
The Mars transport system will be a completely new architecture. Am hoping to present that towards the end of this year. Good thing we didn't do it sooner, as we have learned a huge amount from Falcon and Dragon.
Thrust to weight is optimizing for a surprisingly low thrust level, even when accounting for the added mass of plumbing and structure for many engines. Looks like a little over 230 metric tons (~500 klbf) of thrust per engine, but we will have a lot of them
“We’re looking at our Mars transporter being around 15 million pounds of thrust,”
http://www.askmen.com/entertainment/right-stuff/elon-musk-interview.htmlQuote from: Musk“We’re looking at our Mars transporter being around 15 million pounds of thrust,”(I think this is around 2014? Can someone else date this for me? The date is important because MCT/BFR/Raptor have clearly being evolving since Musk first started talking about them...)
No near term plans to IPO @SpaceX. Only possible in very long term when Mars Colonial Transporter is flying regularly.
But if humanity wishes to become a multi-planet species, then we must figure out how to move millions of people to Mars.
Millions of people needed for Mars colony, so 80k+ would just be the number moving to Mars per year http://news.yahoo.com/huge-mars-colony-eyed-spacex-founder-elon-musk-120626263.html …
I mean, if you do a densified liquid methalox rocket with on-orbit refueling, so like you load the spacecraft into orbit and then you send a whole bunch of refueling missions to fill up the tanks and you have the Mars colonial fleet - essentially - that gets built up during the time between Earth-Mars synchronizations, which occur every 26 months, then the fleet all departs at the optimal transfer point.
Raptor directly contributes to the rapid advancement of oxygen-rich and full-flow staged combustion and additive manufacturing technologies for the United States—enhancing U.S. industrial capability. Further, the engine enhances state-of-the-art, high-performing EELV-class propulsive capabilities for future flight engine systems to support commercial and NSS applications in accordance with Fiscal Year 2015 National Defense Authorization Act (FY15 NDAA), Section 1604. The flexibility of the Raptor design enables the technology to be applied to existing EELV-certified launch vehicles.
Flugzeuge fliegen 20,30 Jahre. Ich glaube nicht, daß es möglich ist, das so lange zu machen, aber zumindest 100mal ist unser Ziel hier.
Tom Mueller @lrocket 28 Dec 2015@Robotbeat @grinich @elonmusk When we convert to LOX/Methane for Mars rocket then frost will keep both tanks clean
Tom Mueller @lrocket 28 Dec 2015@Robotbeat @grinich @elonmusk Yes, I can confirm MUCH less soot with methane
@SpaceJosh @Robotbeat @grinich Kero much worse under any condition than CH4. For CH4 sooting dependent on OF and slightly on pressure