Orville

Comment Threads

• David L commented on Bread and Circuses (circumlunar version)
  Read Gasdive's comment. You're not comparing to anything. So what if you use twice the fuel. So the fuel costs go from $250K to $500K. If the cost of the booster and engine come down by a million or 5 it's a total win if at the end of the day you're putting a similar mass/weight into orbit. Again, my point was that for ICBM launches a very major goal is for a 10 minute or less window from command to launch to being miles from the site. That is what drives much of the design of the main booster...
• gasdive (he, him, ia) commented on Bread and Circuses (circumlunar version)
  The other goal of ICBM design is a fuel that's stable sitting in the tanks of the missile for years on end, that lights up reliably when you light the blue touch paper and stand well clear. Super cryogenic oxygen isn't one of those fuels....
• gasdive (he, him, ia) commented on Bread and Circuses (circumlunar version)
  Interestingly the webcomic Freefall has just started a sub plot involving Chlorine Trifluoride. http://freefall.purrsia.com/ff3100/fc03030.htm...
• David L commented on Bread and Circuses (circumlunar version)
  goal of ICBM design is a fuel that's stable Yep. There are just dozens of conflicting goals here. One group wants a way to deliver a big bang to somewhere else on the planet on little notice but with a "be prepared to go" for years. The other wants to put mass into orbit (typically) around the earth with long lead times and dates of varrying flexibility. While the devices that meet those goals may intersect at times depending on various constraints, there's no rule in physics that says what is best for one is best for the other. Way...
• Nojay commented on Bread and Circuses (circumlunar version)
  When I say "expensive" I mean in terms of the extra fuel it costs to get the rocket to 10,000 feet (or 3km in real units). At the moment a modern launcher runs about 1.6 to 1 or better in terms of launchpad thrust to launchpad weight at takeoff. A slower rocket will have to carry lots more fuel to get to 10,000 feet because it's always, always fighting 9.86m/s/s while it's getting there and the longer it takes the more fuel it has to have on the pad which makes it heavier which... As an extreme case imagine a...