[0x08] Making Life Multi-planetary

Cargo/Cabin

BFR Cargo/Carbin Area | BFR 货舱/客舱

The cargo area has a pressurized volume of 825 cubic meters greater than the pressurized area of an A380. BFR is capable of carrying a tremendous amount of payload In a Mars transit configuration, since you would be taking three months in a really good scenario but maybe as much as six months, you probably want a cabin, not just a seat.

货物区有一个825立方米的加压密封舱（pressurized area），比A380的还要大。BFR能够为火星运输（in a Mars transit configuration）提供超大量的负载，因为你最快也要3个月才能到达，实际行程可能长达半年。因此，你需要的是一个客舱而非仅仅一个座位。

The Mars transit configuration consists of 40 cabins. You could conceivably have five or six people per cabin if you really wanted to crowd people in, but I think mostly we would expect to see two to three people per cabin, or about a hundred people per flight to Mars. And then there is a central storage area and galley and a solar storm shelter, entertainment area, and I think probably a good situation for at least BFR version one.

火星输送结构设置了40个客舱。可想而知（conceivably），如果要输送尽可能多的乘客（crowd people in），每个客舱需要容纳5-6人。但我预计（expect to）每个客舱多半（mostly）只会安排2-3人，也就是说一个班次（flight）大约输送100人上火星。飞船上有中央仓库，厨房（galley），太阳风防护区（solar storm shelter），娱乐区（entertainment area），所以至少在首个版本的BFR上乘客会有比较舒适的环境。

BFR Main Body | BFR 主干

In the center body of the vehicle, this is where the propellant is located —— sub-cooled methane and oxygen. As you chill the methane and oxygen below its liquid point you get a fairly meaningful density increase. You get on the order of 10 to 12 percent density increase, which makes quite a big difference for the propellant load. We expect to carry 240 tons of methane (CH4) and 860 tons of oxygen. In the fuel tank are header tanks; when you come in for landing. your orientation may change quite significantly, but you cannot have the propellant just sloshing around all over in the main tanks, you have to have the header tanks that can feed the main engines with precision. That is what you see immersed in the fuel tank on figure 7.

火箭的中部放置着推进剂 —— 超低温甲烷（methane）和液氧。通过把甲烷和氧气降温压缩液化（chill below its liquid point），总体密度得到了大约（on the order of）10%-12%的显著提升（meaningful density increase），这样就能装下更多推进剂。BFR预计可以携带240吨液体甲烷和860吨液氧。燃料罐（fuel tank）中藏着头罐（header tanks）。当BFR将要着陆时要掉头（orientation may change quite significantly），但是不能让主燃料罐里的推进剂晃得到处都是（slosh around all over），这时候就需要点燃头罐给主引擎做微调（feed the main engine with precision）。图7中可以看到浸泡在燃料罐里的头罐。

BFR Engines | BFR 引擎

The ship engine section consists of four vacuum Raptor engines and two sea-level engines. All six engines are capable of gimbaling The engines with the high expansion ratio have a relatively smaller gimbal range and slower gimbal rate. The two center engines have a very high gimbal range and can gimbal very quickly. And you can land the ship with either one of the two center engines. When you come in for a landing, it will light both engines but if one of the center engines fails at any point, it will be able to land successfully with the other engine. Within each engine there is a great deal of redundancy as we want the landing risk to be as close to zero as possible. The sea-level engines are about 330 ISP at sea level. The upper stage engine is 375 ISP. Over time there is potential to increase that specific impulse by 5 to 10 seconds and also increase the chamber pressure by 50 bar or so.

飞船发动机由四枚真空暴龙引擎和两枚海平面（sea-level）引擎构成。所有6枚引擎都可以随意改变方向（gimbaling）。高扩张比（expansion ratio）的引擎具有较小的变向幅度（gimbal range），并且可以快速完成变向。BFR可以使用两台中心引擎之一来完成着陆操作。当BFR开始着陆时，它会同时开启两台引擎，一旦其中任何一台失效（fail at any point），仍然可以凭借另一台顺利着陆。每台引擎都有极强的容错性（a great deal of redundancy），因为我们希望能把着陆风险降为0。在海平面上，海平面引擎具有330比冲，上层引擎具有375比冲（ISP, Impulse SPecific）。未来有望将比冲值提高5-10秒，并且将燃烧室压力（chamber pressure）提升50毫米汞柱左右（or so）。