Jeff Bezos氏インタビュー

Geek Wire(4/13)

What we use over and over again at Blue is a particular strategy where we choose a medium-performing version of a high-performing architecture, so the BE-4 engine uses the same oxygen-rich stage combustion cycle. It’s a very high-performing rocket engine cycle – the same one that the [Russian-made] RD-180 uses, but the difference is that we operate at lower chamber pressures than the RD-180 and still can get very high performance. It adds a lot of margin when you look at things like wall compatibility and heat transfer rates and so on, to go down from that. When you get into a development effort like the space shuttle main engine or the RD-180, that’s when you are doing a high-performing version of a high-performing architecture. You are getting the last few seconds of specific impulse, and you really pay a very big price for doing the high-performing version.

If you choose a medium-performing architecture or a low-performing architecture, you get cornered into a place where you have to go for the high-performing version of the medium-performing architecture, so that’s why I go for high-performing architectures but don’t go for the last bit of performance in that architecture.


But what’s great about vertical landing is, it’s so scalable. You’re solving the “inverted pendulum” problem. The bigger the inverted pendulum gets, the higher its moment of inertia, and the easier it is to keep balance, and the easier it is to land and to reject disturbances, wind shear and so on.


I think the best way for us at Blue Origin to help other space entrepreneurs is to solve that problem of getting payloads into orbit at incredibly low cost, because that would unlock the power of thousands of entrepreneurs. That’s what we are focused on. It’s why we are doing the suborbital tourism mission. It’s why our BE-3 engine is liquid hydrogen, because we know we need liquid hydrogen for our upper stage and in-space missions later. It’s why we are using liquid natural gas [for the BE-4 engine], because our goal is to make spaceflight so cheap that the cost of the fuel actually matters.

Right now, the cost of the propellant is minimal compared to throwing the hardware away. But once we can get to a place where we are not throwing the hardware away, and we have real reusability, then we want to be using a fuel that is very low-cost. And nothing is lower-cost than liquid natural gas.