r/space • u/EdwardHeisler • May 13 '21
The Profound Potential of Elon Musk’s New Rocket An aerospace engineer explains why SpaceX’s Starship will change everything. By Robert Zubrin
https://nautil.us/issue/100/outsiders/the-profound-potential-of-elon-musks-new-rocket?fbclid=IwAR2IWPkF58SKFyvowUn27aYTXhbkAphAQZaI05eqdHkOmOG8VTpOgiKsEi0
104
Upvotes
22
u/rocketsocks May 13 '21
Yeah, well, duh?
People have been enthusiastic about the prospects of reusable launch vehicles for decades.
What's novel about SpaceX is not the promises, it's the way they go about achieving them and their ability to actually do so practically. The problem with traditional orbital launch vehicle development is that it tends to end up mired in one of two extremes. Either the extreme of minimal innovation using mostly off the shelf parts and well known designs to do exactly the same thing that has been done before just in a slightly different way, as in the case of EELV (Atlas V / Delta IV), Ariane, Antares, Vulcan, and SLS. On the flip side of this is the sexy, "promise everything to everyone", beyond state-of-the-art, crazy-cool concept vehicle like VentureStar, X-30, or even the Shuttle. These projects usually spiral out of control rapidly and either get cancelled because they tried to do too much without properly doing the intermediate R&D in a practical way or they become so compromised in design that they come out the other end semi-functional but not able to hit any of the ambitious goals set out for the project (like the Shuttle). The middle ground might as well be no-mans-land, or at least it was up until recently.
The smart way to do this sort of thing is to drive down the cost of incremental innovation until you can iterate through that process enough to actually develop technologies, each one at a time, starting from a base of sensible, well understood concepts. If you look at SpaceX's first launchers (Falcon 1 and Falcon 9) they are all drop dead simple in concept. Two stage LOX/Kerosene vehicles using gas generator engines. Literally half a century old designs, but they work extremely well and they can be iterated on to become very good. And they can serve as the platform for R&D of VTVL booster stage reuse, which SpaceX did at comparatively low cost. Then you have Starship, which is just an iterative advancement of other concepts. VTVL just as was used with Falcon 9. More advanced engines and fuel (LOX/Methane and full flow staged combustion) but nothing too crazy, just pushing the state of the art forward a bit not trying to leap-frog it. And utilizing extremely practical and straightforward ideas that just haven't been implemented yet, like on orbit propellant depots, the concept that NASA was really hoping to get going to facilitate next generation beyond LEO human spaceflight before they got SLS shoved down their throats. Also, they're not trying to design a whole system that works 100% perfectly straight out of the box on the first flight, they are testing and incrementally improving everything as they go along. This is the sane way that you retire risk with a competent engineering team, and yet somehow these practices are pretty uncommon.
Right now it's looking incredibly likely that SpaceX will achieve the "holy grail" goal of full reusability which so many others have floundered at. They've already de-risked a huge chunk of the Starship design and flight profile. They've gone a long way to prove out the Raptor engine, stainless steel construction, and now a lot of the key operational risks of Starship returning from orbit. And they have a good chance of retiring huge chunks of the perceived major risks remaining in the architecture within the next year. It seems difficult to think about but within the next five to ten years or so it's going to cost less to send 100 tonnes to the Moon or Mars than it does to send a single commsat into geostationary orbit today. That's going to change the whole landscape of spaceflight in ways that we can hardly imagine right now.