The Tyranny of the Rocket Equation (2012) • Hacker News Board

Re: The Tyranny of the Rocket Equation (2012)

#161

Post by ytturbed » Tue, Nov 04, 2014, 5:13 PM UTC

pjc50 wrote: post #30

ytturbed wrote: post #2

>Currently, all our human rated rocket engines use chemical reactions (combustion of a fuel and oxidizer) to produce the energy. Yes, however, for completeness: an explanation of why we must limit designs to chemical rockets ought to include an explanation of why the dozen or so fusion projects underway around the world will all fail, i.e. let's inject some rational optimism. Note that the Apollo programme began befo…

The fusion projects have been running for a long time with little success. Apollo was built on scaling tech that already worked (1940s rocketry could reach space although not achieve orbit)

To address my claim you would need an explanation of why that trend will continue, including for the several new projects. Btw, Apollo used a novel alloy.

Re: The Tyranny of the Rocket Equation (2012)

#162

Post by ytturbed » Tue, Nov 04, 2014, 5:17 PM UTC

shalmanese wrote: post #35

ytturbed wrote: post #2

>Currently, all our human rated rocket engines use chemical reactions (combustion of a fuel and oxidizer) to produce the energy. Yes, however, for completeness: an explanation of why we must limit designs to chemical rockets ought to include an explanation of why the dozen or so fusion projects underway around the world will all fail, i.e. let's inject some rational optimism. Note that the Apollo programme began befo…

Fusion devices aren't rockets and are thus, not subject to the Tyranny of the rocket equation.

I was addressing the statement 'Currently, all our human rated rocket engines use chemical reactions', and I agreed with it. But it's not good enough if you consider the lengthy design cycle of propulsion systems. We ought to be creating additional designs which assume that fusion sources of various sizes and masses will be available.

Re: The Tyranny of the Rocket Equation (2012)

#163

Post by ytturbed » Tue, Nov 04, 2014, 5:25 PM UTC

mcguire wrote: post #149

ytturbed wrote: post #2

>Currently, all our human rated rocket engines use chemical reactions (combustion of a fuel and oxidizer) to produce the energy. Yes, however, for completeness: an explanation of why we must limit designs to chemical rockets ought to include an explanation of why the dozen or so fusion projects underway around the world will all fail, i.e. let's inject some rational optimism. Note that the Apollo programme began befo…

How much does your fusion plant weigh?

We ought to design for a range of masses.