# starship-design: Calculations involving self-powered relativistic spaceflight

```Hello Andrew,

>Now that I finally got some more time, I had a proper look at your page,
>and there's one or two things I want to ask you :)

I'd hope so :)

>What does exp mean - it follows an integration a couple of times.. is
>something to do with e^x?

Yes, Exp[x] equals e^x where e approximates 2.71828

>How would you go about calulating the Fuel Factor for a conventional
>rocket?

I believe Hydrogen and Oxigen are a possible fuel, I'm not sure if that
means that H2O is the reaction product, but that doesn't matter much. My
guess is that you're only interested in orders of magnitude.
Per mole of H2O gass as reaction product, about 2.5E5 Joule is freed. That
makes about 1.3E7 Joule per kg. So that's a fuel factor of (3E8)^2/1.3E7=6.7E9

Don't use any final velocities over 1/10,000 of the lightspeed!

>Anti-Proton catalysed fission: seeing as how it releases 16 neutrons
>instead of 2, I don't suppose I can just multiply the energy released by 8
>to work out the fuel factor?

I'd need to know the complete reaction (including the amount of antimatter)
to comment on that. (You need to know the total energy released per kg of
fuel.)
BTW. Keep in mind that my model assumes 100% efficiency, which makes it
only useful to find a lower limit for the fuel use or rough guess for the
actual fuel use.

>And lastly: do you know of any links to anything to do with plasma engines
>in general?