Andrew Case wrote:
> It seems to me that the figure of merit is total man-hours per launch,
> regardless of where in the processing flow they appear. This is what
> scales the cost per launch (neglecting materials costs). Cutting labor
> for fixed flight rate or increasing flight rate for fixed amount of
> labor both improve man hours/flight. Obviously this neglects a bunch of
> important issues, but as a BOTE analysis principle it seems to me that
> it's the right approach.
Not really. Figure of merit is hours of service on the vehicle. If
your vehicle generates $10,000 / hr revenue (very low) and you need to
put 20 people on it to turn it in 1 hour, your labour cost is $1,000
vs $9000 profit. You don't save anything by only putting 5 people on it
and taking 4 hours. You'd lower your per hour cost but lose $30,000
because you'd take 5 x 4 hrs vs 20 x 1 hr. With high flight rate, fuel
price becomes your major cost factor, not crew size.
> Water cooling seems to me the way to go. You'll be fueling anyway, so
> the same guy who hooks up the Fuel and Ox lines can do the TPS water.
> The water will take a lot less time, it can be completed in the slack
> time while the fuel/Ox handler is waiting for the tanks to fill.
Yes, but you'd have to carry water ( = heavy) plus tanks, lines,
valves, sensors and heaters. That's a lot of weight vs some extra HTP
and running the engines at "idle".
> You'd
> also want containerized payload so the payload swap would be a simple
> matter of pulling the old pallet and installing the new one.
That's the plan.
> It seems
> to me the four man hours of on-pad effort is possible, but once you
> take into account the time to install the payload on the pallet and
> time in the hanger for periodic maintenance, a total of four man hours
> per flight seems out of reach, especially if you have a pilot (which I
> think is a good idea for various reasons).
The prep time only has an effect on turn time if it isn't done and has
to be fixed or completed on the vehicle. Turn time is the time it
takes to turn the vehicle and get it in the air again, earning
revenue. While there are costs involved in preping the cargo, that
time is not a function of the turn. It's overhead - which is why
airline costs are based on a multiplier of fuel cost not crew costs.
Michael
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Michael Wallis KF6SPF (408) 396-9037 [EMAIL PROTECTED]
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