Saturday, January 17, 2015

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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