Joe Carroll is giving a talk on some long-shot “wild cards” that could have a high payoff. One of them is aerosnatch of first stages, which could simplify launch system design by eliminating the need for flyback, and has such a high payoff in performance, that he suggests we understand it better before making any decisions on heavy-lift design, because it may set an upper limit on economical launch vehicle size.
Another is recycling aluminum on orbit, as a first step toward processing true extraterrestrial materials. He points out the bizarre (and typical of a government) situation in which everyone agrees that orbital debris is a problem, but there is no budget for it anywhere in the federal government. Also discussing slings and elevators, propounding the advantages of the former over the latter. For people to an from LEO, elevators, but for a lot of payload beyond, slings are the way to go. Makes an analogy of going from ships to railroads. Rockets are the ships, slings are the railroads (the latter requires an up-front infrastructure, and is limited in destination, but very efficient once in place). Thinks that the first sling will be at 51.6 inclination, second at zero.
If aerocapture of the 1st stage is limited by size but you need a larger booster, cluster them and recover two or three.
Did the “recycling aluminum” section touch on recovering aluminum from alumina at all?
No.
How does aerosnatch work? Google is unusually useless here.
I should have written airsnatch. It parachutes in and you grab it with a long tensionable cable and hook from an aircraft. The same way they used to get film canisters from orbit in the early days (e.g., Corona) before they could transmit the data, but on a larger scale.
ULA proposed something similar for recovering just engine pods, not a whole stage.
Aerocapture might actually be a good application for electric VTOL aircraft (hybrid with gas turbine?) – much greater 3D control is possible than with an airplane or helicopter and I suspect that craft capable of directly docking/undocking with larger aircraft (or boosters) might be practical.
Perhaps send a swarm of redundant electric ducted fans in that attach themselves to the vehicle and safely land it.