Design to cost goals power Sat solution: Raise millions of tons a year to GEO at a cost of less than $100/kg Space based solar power for a 1-2 cents a kWh, synthetic fuels made from that power for $1 a gallon (easy) Excess energy (300TW-years) to put carbon back in the ground if we need to Danger of storing 470 cubic km of CO 2 We know how to make synthetic oil
$40 billion for the lasers $60 billion for the rockets Long build up time to get the lasers installed and focusing mirrors in place, limited bootstrapping possible (does meet <$100/kg) Not impossible, but not compelling Can we improve on the ISP of the first stage and reduce front end cost? Yes!
Reaction Engines SABRE “peaking at about 2800 seconds within the atmosphere”
Skylon and Lasers Takes off from runway, 12 t to LEO
Laser stage 12 t Mass ratio 2 6 t propellant, 6 t payload LEO to GEO 4.1 km/sec Modest ISP of 600 6MW of laser, $60 million takes 24 hrs LEO-GEO First mirror is a problem
Eventually (after much buildup) 50 t laser stage, 25 t payload to GEO Skylon sub orbital, contributes 4-5 km/sec delta V 8 GW laser (8 years @ a GW/ year) contributes 9-10 km/sec
After 8 years, a Skylon flight every 15 minutes 96 flts/day, 60-100 rockets 800,000 t/year to GEO Growth with more laser Skylon life up to 500 flights Fleet size at 1.5 flights/day Other sub orbitals work too
Cost/kg to GEO Initial figured at twice the per flight depreciation of a $450 M vehicle and 6 t to GEO ~$750/kg Mature figured at twice the per flight depreciation of a $292 M vehicle and 25 t to GEO ~$46/kg Design to cost goal met <$100/kg