[ExI] Mining the Sky SL Talk I gave today

spike spike66 at att.net
Mon Apr 26 15:13:53 UTC 2010


> ...On Behalf Of samantha
> Subject: Re: [ExI] Mining the Sky SL Talk I gave today
> spike wrote:
> >  
> >...  
> > The professional rocket scientist could have a lot of 
> specifics on the 
> > orbit mechanics and the propulsion tech, but this is stuff 
> one needs 
> > to master anyways in this game, and it isn't hard.
> > 
> Do you have some sources or sites you would recommend to 
> sufficiently master what I would need of these things?  I 
> would love to know enough to know roughly whether a 
> particular mission was doable, what was involved and likely 
> cost.  Not enough of course to be a pro or fool one
>   but enough to be able to do more than cheer and blow smoke.
> Are there some nice online tools to play with?
> - samantha

That PERMANENT site you gave has some excellent stuff on there.  It has been
several years since I went poking around on the web for this kinda stuff, so
my sources are out of date, but I will take it as an assignment to find and
update.  In the mean time, you need to understand the Hohmann Transfer.
Here's a good calculator if you already know the concepts:


Or if you want to back up and take a running start, check this:


and make sure you know the hell outta this critical concept.  We will be
using Hohmann transfer orbits for the foreseeable.  If you see a writer that
assumes some magic propulsion source that gets you there faster, you can
figure out how much extra propellant it would take, and how bad an idea it

You have heard since you were a kid how it takes 8 months to get to Mars,
with little regard to what tricky tech you have.  Hohmann explains why.  AC
Clarke chose to invent suspended animation to get his guys out to Jupiter
rather than piss off his loyal fans by suggesting a way around the Hohmann
transfer orbit.

Question Samantha, are you hot with spreadsheets?  Excel is our friend.



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