$8.90/lb to LEO (was The old "big rockets aexpensive" canard)

Don't forget that 1963 dollars are a lot bigger than current ones.
What is the inflation factor from '63 to current? 5? 10?

According to this inflation calculator, $100 in 1963 would cost $696 as of 2008 -- unless you're talking about computers and the like, of course.

Michael McNeil

>> Neither one of you is putting actual dollar numbers on the cost for specific missions.
>
> Marginal cost-per-pound to 300 n.m. orbit, averaged over a 10-year program, in January 1963 dollars:
>
> 240 launches, recoverable first-stage:
>
> Pessimistic values: $28.60
> Optimistic values: $8.90
> Most probable values $16.20
>
> http://neverworld.net/truax/Sea_Dragon_Concept_Volume_3.pdf
>
> Those estimates are hampered by ancient guidance hardware, a command module for humans which includes an escape tower, low launch rate, non-use of second-stage rocket body as scrap or tubing for orbital city, small vehicle size (only 506 ft. and 40 million pounds gross lift-off mass), smaller 1963 shipbuilding industry, smaller 1963 Panama Canal capacity, etc.
>
A million pounds is only 500 tons. 40 million is 20,000 tons. The
very high tech, high exhaust velocity Neptune
http://www.ilr.tu-berlin.de/koelle/Neptun/NEP2015.pdf puts almost that
much in LEO with a 6000 t liftoff mass. Given the ratio on exhaust
velocities, this more or less checks out. Of course for a power
satellite project you need cargo to GEO, not LEO. Assuming a high
exhaust velocity LEO to GEO transport, 250 ton would get to GEO. That
means ten launches a day. Since most of the liftoff mass is
propellant . . . rocket fuel will be coming in by tanker and we are
talking an awful big LOX plant.

> I believe Mike has cited $0.10/kg for mass-driving from Moon to EML2 (I believe O'Neill in the 70's was his source). A $10 billion lunar mass-driver, paying merely its cost-of-capital at 10%/year, would then need to launch 10 billion kg per year, just to break even. That seems like a lot. Maybe he had been referring to just the electricity costs, at some very-low cost-rate.
>
It cost 15 kWh/kg to lift from the earth to GEO. The energy ratio for
LEO would be (2.5)^2/(14.1)^2 or about 3%. 100 ton/hr takes 1.5 GW
from the earth, 45MW from the moon.

Power satellite materials demand is around a billion kg/year (million
tons) per year. 45MW at a few tons per MW is a substantial amount of
material to soft land on the lunar surface.

>> But Mike is dead on correct in saying that high delta v cost more.
>
> He is not correct in ignoring, in his analysis, the myriad relevant Earth-launch-favorable differences between Earth and Luna.

All else held constant.
>
>> Making the stages reusable is yet another problem.
>
> It seems to be pretty easy to re-use the first stage when it's a thick-walled pressure-fed rocket, and one is launching it from the ocean. Keeping some pressure in the tank helps protect it during impact. Inflating a big cheap tail-flare also helps protect it by slowing it prior to impact. This is all explained in numerical detail in the two Sea Dragon report pdf's, here:
> http://neverworld.net/truax
>
>> The best proposal I know of now is Reaction Engines Skylon.
>
> Even their optimistic cost estimates on their website put the marginal LEO payload-delivery costs higher than those of the Sea Dragon. They cite $2-5 million per launch for "low-value" payloads. "10.5 tonnes to a 460km equatorial spacestation" works out to $86.40-216.00/lb.

Don't forget that 1963 dollars are a lot bigger than current ones.
What is the inflation factor from '63 to current? 5? 10?

> They cite a 10-year development period. The Sabre engine looks complicated and expensive and time-consuming to maintain. It has 2 turbopumps (for each of two nozzles?), a circulator pump, an airplane-type air-turbine, and a lot of complex piping. There are 2 of those Sabre engines on each vehicle, so all of that complexity gets multiplied by 2.

Most of it is very close to existing jet engines. (The designers are
old RollsRoyce engineers.) The really tricky part, which they have
built samples, is the heat exchanger.
>
> If the Skylon actually ends up working, and doing it cheaply, it will be another piece of evidence that launching things from Earth is inherently easy. But the Sea Dragon already proved that on paper, using half-century-old technology and techniques.
>
From what I know of the testing program at Reaction Engines, they are
fairly deep into it. Sea Dragon never was developed at all.

But getting things to GEO isn't easy. The big problem is the
missmatch between the exhaust velocity and the mission velocity that
forces staging and high mass ratios. The only way I can make a case
for cargo rates to GEO low enough for power satellites to make sense
is to use very high exhaust velocity laser propulsion on the second
stage. That way I can put up relatively heavy loads to 4 km/sec,
which reduces the cost for the Skylon down into the $20 per kg
(suborbital).

Keith