Keith Henson has some concerns that high volume flight rates for the SpaceX BFR could be a problem for the atmosphere if it was used for many thousands of flights to place massive amounts of space-based solar power to replace the usage of oil and other fossil fuels.
SpaceX BFR has cheap orbital launch costs and can reach the moon. But it needs refueling on the moon in order to bring lunar material. The Nuclear turbo rocket can do it all without refueling.
Space based solar power satellites could replace fossil fuels. This would require both lower cost and higher volume than SpaceX could deliver. The cost to GEO can’t go to over $200 per kilogram and the required traffic level is 15 million tons per year to LEO. (12 million to GEO.)
Bucknell’s air-breathing nuclear thermal rocket could bring the cost to orbit down to $50-100 per kilogram and have high reusability to enable the high traffic volume with a few hundred rockets to build space based solar to replace human oil usage.
Space based solar power satellites could replace fossil fuels. This would require both low cost launch and very high volume. The cost to GEO can’t go to over $200 per kilogram and the required traffic level is 15 million tons per year to LEO. (12 million to GEO.)
Bucknells turbo air-breathing thermal rocket could deliver even lower cost and higher volume than what Henson has described. SpaceX BFR could as well but there is a question about atmospheric effect of very high volume BFR flight.
The main advantage of orbital space based solar is you get 5 times as much sun as the best deserts and 15 times for places like Japan and the UK.
Henson’s space based solar plans solve energy concerns without subsidies and make a lot of money. Low energy cost makes everyone better off.
Initial target cost is 3 cents per kWh to undercut coal, 2 cents per kWh or less to replace oil. The Bucknell turbo rockets could bring costs below 1 cent per kWh
Henson uses a method of designing to cost. Design to cost is a management strategy and supporting methodologies to achieve an affordable product by treating target cost as an independent design parameter that needs to be achieved during the development of a product
Synthetic Oil from electricity. Hydrogen in a barrel of oil takes ~20 MWh. At two cents, $40 per bbl.
Capital $10 per bbl based on this plant below
Potential cost for space based power satellites?
For low maintenance and zero fuel cost, the levelized Cost of Electricity is capital cost of 80,000
That is $2400 per kW for the target of three cents per kWh
$2400 per kW is split
$200 per kW for the rectenna,
$900 per kw for the power satellite parts.
That leaves $1300 per kw for transport.
At 6.5kg per kW, that’s $200 per kg.
At 2000 km, the stack unfolds to make a propulsion power satellite.