Getting
People Into Space
I want to
work through some ideas for getting peeps into space. First off, I'd love to
get away from rockets, but don't see that happening soon. I do see us going
with space planes and suborbital launchers.
(I love that
1N lets me do math on the fly. Spreadsheets can be intimidating, when all I
want to do is talk on the page…)
I'm going to
rough out a suborbital launcher based on spaceship one, two cylinders slung
under long straight wings, plus the orbiter between. The fuel is jet fuel for
controlled flight in atmo, LOX/LH (liquid hydrogen) for the suborbital
ballistic arc out of atmo. Go w/ 77% propellant, 66% LOX/ 11% LH, 2% for
landing gear, 2% for space frame, 10% for the orbiter, 3% for rocket engines,
3% for jet engines and fuel, 3% for everything else-
.66+.11+.02+.02+.1+.03+.03+.03 = 1.0. LN(.77/.23) = 1.2083*425sec*9.82m/s^2
=-5,042.8 m/s. Call it 5 km/s, a 100 tonne GLOM with a 10 tonne orbiter which
has another 5 km/s delta-V, one tonne payload, 9.5 km/s to reach orbit with
losses, 1/2 km/s to circularize in LEO.
This is a
hypothetical 13 tonne reusable SO space plane, costing $10K/kg or $130M. The
reusable orbiter has a ballute and parawing instead of landing gear and a heat
shield for reentry. It similarly costs $13M, and we need 10 to 20 times as
many, probably. A fleet of 3 SOSP for redundancy is $390M. Fifty orbiters would
be $650M, so 50 tonnes in LEO for $1.04B, or ($13*50+3*$130)/50tonnes =
$20.8M/tonne or $20.8K/kg in LEO, not including the costs of fuel, salaries and
other capital costs, such as operating out a small dedicated airport/spaceport
which also handles air freight and passengers for the spaceport.
Fuel @
$10/kg? Call it 77tonnes*1.1*1000kg/tonne*$10/kg = $847,000.00 per launch,
adding $847/kg. Salaries @ 100 persons, each @ $100,000 per year is $10M/yr. A
billion dollar spaceport @ $100M/yr. The 3 SOSPs and 50 orbiters for $1.04 @
$104M/yr.
Two flights
per week, 50 weeks per year? 100 flights, 100 tonnes per year into $10M + $100M
+ $104M = $214M is $214M/100 = $2.14M
per launch, plus $.847M in fuel is $2.987M per flight or tonne,
$2,987/kg. One per day reduces the cost per flight to $214M/250 +$.847M =
$1.703M and $1,703/kg.
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