[AR] Re: Amateurs and HSF

  • From: Henry Spencer <hspencer@xxxxxxxxxxxxx>
  • To: Arocket List <arocket@xxxxxxxxxxxxx>
  • Date: Sun, 24 Jul 2022 01:55:26 -0400 (EDT)

On Sat, 23 Jul 2022, Matthew JL wrote:

...with the slow ramp-up of more powerful and technologically capable liquid engines (I am optimistic about the future of Half Cat and derivatives even in the face of regulatory challenges), it seems like inevitably someone's going to build an engine that warrants putting a person on top of it.

Armadillo Aerospace was building engines (and experimental vehicles) with an eye on that twenty years ago, in fact. And yes, they were an amateur group in the beginning: "I'm running this endeavour like a rich hobbyist rather than a poor aerospace company." -- John Carmack, 2002. (Although they gradually started paying people as revenue started coming in and the workload got higher.) They came close, and might have succeeded if they hadn't hit stubborn supply-chain problems with their chosen oxidizer (peroxide).

So let's look ahead in the hobby another 10-15 years and imagine what that might look like.  Capsule-and-booster as tradition warrants (and Copenhagen Suborbitals is doing)?  A spaceplane in the vein of the X-15 or SS1/SS2? 

John Carmack thought back then, and last I heard still did, that a one-piece rocket with vertical takeoff and landing was the right way to go. Adding either separation events or wings adds a lot of complexity; making either one pay for itself is harder than it looks. The less mechanical and aerodynamic complexity, the better. (In particular, designing supersonic airplanes, especially ones with a large Mach-number range, is *hard*. If Burt Rutan had trouble with it -- he did -- so will you. A design concept that can mostly ignore the atmosphere is a big simplification.)

That said, there is undoubtedly more than one way to do it...

What will bridge the gap between the amateur space now and something as ludicrous as homebuilt spacecraft?

Actually, homebuilt spacecraft have been a reality for over 60 years -- see the amateur-radio satellites, starting with OSCAR 1 in 1961.

A homebuilt space *vehicle* would be a much bigger job, yes. Probably the key requirement for bridging *that* gap is non-technical: somebody on the team has to be at least a little bit rich, or have a patron who is. Armadillo cost John about half a million a year for most of its decade-plus life. It could have been done for less, perhaps much less, but even with all-volunteer labor, there are a good many things that require cash up front if you want to get results in a reasonable amount of time. And most of the volunteers will gradually lose interest and leave if the project never seems to get anywhere.

(Even an amateur project needs a realistic budget plan -- one in which required outlays don't exceed likely financial resources. "Realistic" means no step in the middle saying "and then a miracle happens". Even rough estimates can tell you when you're being unrealistic -- it's not going to cost *less* than you think...)

Don't forget the Regulatory Affairs aspect. Quoth FAA regs, 14CFR1.1 (emphasis added): "'Amateur rocket' means an *unmanned* rocket that...". As soon as it's manned, it loses its amateur status and (in principle) you have to cope with the full regulatory process. This can be onerous even if you manage to negotiate simplifications, e.g. via "alternative means of compliance providing an equivalent level of safety" clauses. And don't underestimate the effort required, or the fact that it's not fun -- it wasn't an accident that the Regulatory Affairs guy at Armadillo was the first one to start getting paid...

Henry

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