At 12:12 PM 2/10/2003 -0800, Michael Wallis wrote:
Agreed ... Consider what is and what we need. The shuttle takes about three months to be rebuilt and ready for launch by an army of about 10,000 people (down from 25,000). That's about 4 MILLION man-hours! When we can turn a vehilce in 40 man-hrs (5 peole x 8 hrs) we have something usable. When it can be 4 man-hrs we have something that will fulfill the type of flight rate needed to make travel to space economical for the average person.
It takes more than 4 man-hours to turn around a 747! I don't think it's possible to get there for a launch vehicle due to the necessity to load inert gas and two different propellants, instead of just kerosene. 40 man-hours would be a very good turn around time, IMO, since a launch vehicle will probably require more inspections between flights than an aircraft, due to the higher stresses encountered. Achieving such a turnaround time would also eliminate ablative TPS systems from contention, requiring either re-radiative TPS (metal or ceramic tiles) or the transpiration cooled TPS previously discussed. The inspection situation is *much* worse for an SSTO, because an SSTO must push the limits to much farther in order to achieve a profitable payload fraction. I suspect that you could achieve excellent cost reductions by pulling turnaround time into the low thousands of hours (consider the competition!). I think you are setting the bar far too high by looking for forty hours in a first generation reusable launch vehicle.
-p
Mars or Bust!
www.marssociety.com
_______________________________________________
ERPS-list mailing list
[EMAIL PROTECTED]
http://lists.erps.org/mailman/listinfo/erps-list
