More on The Path Not Taken

I’m still not trying to claim omniscience by saying that had NASA taken this alternative route (building a set of very small RLV demonstrators/X-Vehicles first instead of Shuttle) that everything would have been perfect. But I figured it would be worth thinking a bit about some of the potential implications.

What if the public’s first impression of the difficulty of reusing rocket engines was the RL-10 instead of the SSME? Instead of hundreds of engineers tearing the engine down after each and every flight (as was the case at first with the SSME), there’d have been a little bit of post flight inspection (with the engine still fully assembled), with overhauls only once every 20-50 flights.

What if the public’s first impression of TPS wasn’t the brittle ceramic tiles on our high cross-range, high ballistic coefficient shuttle, but was a more robust metallic TPS or ceramic cloth TPS on a low ballistic coefficient vehicle?

What if the public’s first impression of an orbital RLV was a vehicle that could be launched from any airport in the world that could handle a 747, instead of something that required thousands of workers, massive crawlers and launch towers, and was only considered safe to launch over the open ocean?

What if the public’s first impression of an RLV being serviced between flights was in a standard aircraft hangar, and if their first impression of RLV stages being stacked was a simple overhead gantry crane in said hangar, instead of the massive Vertical Assembly Building?

What if the public’s first impression of the manufacturing of an orbital RLVs was that they cost about the same as a medium sized passenger jet, and were expected to fly hundreds of times before being retired, instead of costing an order of magnitude more, and only flying just barely over once per year per airframe?

What if the public’s first impression of the economics of an RLV was that they were cheap enough that private firms like FedEx and PanAm could buy and operate multiple tail numbers for intercontinental package and personnel delivery, instead of being so expensive that only NASA could afford to own and operate them?

What if rocket vehicles were actually flying enough that maintenance costs, and hardware lifetime started becoming as important as the same for early jet engines? What improvements to robustness and reusability would we have seen over the past 30 years?

What if a smaller, simpler vehicle had been ready in time to refuel Skylab so it wouldn’t have been allowed to deorbit? What if people’s first experience with a space station were based on vehicles that could fly once per day per vehicle, instead of once per year per vehicle? A station where new crew or scientists or tourists could visit every day, with new experiments coming up and down just like on a ground based lab?

What would have happened to the orbital launch market if all of the sudden Boeing or McDonnell Douglas, or whoever was selling launch vehicles as fast as they could make them? How much money and how many competing designs would’ve sprung up in short order? Especially if developing an orbital RLV was seen as being not vastly more difficult than designing a commercial passenger jet?

It’s an interesting thought, isn’t it?

The other interesting thought is the realization that such small RLVs are still doable today, and in fact can probably be developed for less thanks to all the advances over a lifetime. Just a thought.

The following two tabs change content below.
Jonathan Goff

Jonathan Goff

President/CEO at Altius Space Machines
Jonathan Goff is a space technologist, inventor, and serial space entrepreneur who created the Selenian Boondocks blog. Jon was a co-founder of Masten Space Systems, and is the founder and CEO of Altius Space Machines, a space robotics startup in Broomfield, CO. His family includes his wife, Tiffany, and five boys: Jarom (deceased), Jonathan, James, Peter, and Andrew. Jon has a BS in Manufacturing Engineering (1999) and an MS in Mechanical Engineering (2007) from Brigham Young University, and served an LDS proselytizing mission in Olongapo, Philippines from 2000-2002.
This entry was posted in Launch Vehicles, NASA. Bookmark the permalink.

21 Responses to More on The Path Not Taken

  1. Anonymous says:

    All good questions. And rather than ask what if this or that had happened, most of them could, and should, be asked now about our current situation.

    But as long as we’re waxing philosophical, then how about this: What if Congress provided NASA with a ten percent budget increase, but specified that thereafter, ten percent of every budget should be focused on developing near term (i.e. < 5 year time frame) technological breakthroughs? This funding could be put towards the retirement of technical risks associated with any spacecraft system proposed by commercial interests so long as the requesting entity also committed to bringing the system to full commercial viability within ten years if it is shown to be feasible. Yeah, it’ll never happen, but what fun would a what-if game be if you restrained yourself to reality?

  2. Jon Goff says:

    Anonymous,
    Funny how something that was probably technologically feasible 30 years ago is probably still technologically feasible… 🙂 I really hope someone is able to take steps in that direction. If we last long enough at Masten, and do well enough with suborbital vehicles, we have some ideas for moving on to orbital vehicles, but that’ll be a long time yet. A mini-“Space Plane” or “Frequent Flyer” though is totally within the realm of what someone could do. The only problem is raising enough money for a project like that. If the thing works, it’d be in a great shape to create several evolutionary terrestrial markets (personel and fast package delivery), while also drastically changing the whole earth-to-orbit equation. The single biggest challenge though is putting together the money for something like that. Sure it’s nearterm feasible, but it’s still going to cost $100-250M depending on how you go about it. That’s a lot of money, and with the bad name NASA has given to RLVs, and the bad reputation commercial space has on overpromising…it’s still going to be a challenge even today.

    As for the other idea, it isn’t crazy, but alas you’re probably right–completely unrealistic.

    ~Jon

  3. Eric M. Collins says:

    MSS and Armadillo Aerospace are two very convincing existence proofs for efficient research and development carried out by a small team. I wish both of you the best of luck at successfully carrying out your development programs.

    As for near term RLV’s, I’m kinda hoping that Benson’s Dream Chaser will end up being a strong contender for that point-to-point personnel/cargo market. If it can be built, flown, and establish a market in the next five to ten years, it could go a long way towards reversing the recent trend towards non-reusable vehicles based on the missile/capsule design for LEO transport. (Perhaps I have a personal bias, but returning to earth in a pilot-controlled winged vehicle just seems much more dignified.)

    Sorry about posting as anonymous before.

  4. Anonymous says:

    I wouldn’t send my cat to ride on a vehicle propelled by RL10s.

    Also, who is MacDonald Douglas?

  5. Jon Goff says:

    Anonymous,
    I wouldn’t send my cat to ride on a vehicle propelled by RL10s.

    Any particular reason you can cite? The engines have overall been quite reliable, and due to their expander cycle nature tend to be relatively easy to reuse. What’s your beef with them?

    Also, who is MacDonald Douglas?

    Alas, a typo on my part. McDonnell Dougless was an aerospace company that got bought out by Boeing in the 90s. Since I was talking about a counterfactual based in the 70s or 80s, I figured I’d mention them separately. Though I’m not sure if McDonnel and Douglas Aircraft had merged yet at that point. Before my time and all that.

    ~Jon

  6. Big D says:

    Stupid question that’s been bugging me for a year…

    Is there any reason you couldn’t build a rocket (at least, the body) out of polymer goop? Does it just not meet the stress and heat requirements for a giant blowtorch? It seems like that would offer an opportunity to crank out everything except the engine at a silly fast rate, with a lot less human labor involved–and people are what makes space expensive.

  7. Jon Goff says:

    Big D,
    A lot of rockets these days have components made of composites (which are more or less “polymer goo” with strings), but pure plastics aren’t used very often. Plastics manufacturing isn’t cheap either unless you’re making a lot of them. Even if you could say blowmold a propellant tank, it would still cost just as much or more than a metal one until you were making them by the thousands…

    ~Jon

  8. Anonymous says:

    Any particular reason you can cite?

    Here’s three: Delta 269, Atlas Centaur 70 and Atlas Centaur 71. I’ve also spent a lot of time working with P&W on RL10 engine build issues and have not been all that impressed with their understanding of how the damn thing works.

    RL10 has been, historically, a reliable engine, but the harder they push it, the more it bites them. With that track record, I’d want engine-out capability.

    On the polymer goop business, many large solid rocket motor cases are made of composites, which start out pretty goopy (or at least tacky) but they are filament wound, which is just about as costly as making them out of isogrid. Any way you slice it, when you are only making a few tanks, the tooling costs are going to eat you alive.

  9. Anonymous says:

    Clarification: SRM cases aren’t made out of isogrid, as I mistakenly implied. But the thrust of my argument is unaffected.

  10. Jon Goff says:

    Anonymous,
    RL10 has been, historically, a reliable engine, but the harder they push it, the more it bites them. With that track record, I’d want engine-out capability.

    For something like was being discussed in this post, there would be multiple RL-10s, so there’d be quite a bit of engine-out capability. Engine-out capability isn’t quite as critical for HTHL spaceplanes as it is for VTVL rockets, but is always a good idea no matter how reliable you think your engines are. Having only a single, non-redundant engine, especially in life-critical situations just boggles me.

    Sure, if you have to build an expendable vehicle, and if you don’t want to go with engine-out, one engine per stage is the next best thing, but it’s still playing a form of Russian roulette.

    ~Jon

  11. Anonymous says:

    Starting each concept embodied in the ’70s rocket system with a solid X-program before actually using them would’ve been a huge improvement, no question. Capabilities would’ve been understood (no space-plane) and they would’ve been much more reliable by the time they reached much use. But I think you’re being too optimistic in a few spots:

    1) NASA has had much lower-cost alternatives for small-payload, unmanned missions forever. But manned flight and big payloads (Hubble) are what attract attention.

    2) It’s necessary for reasons of both capability and pride for NASA to be able to handle heavy payloads. Indeed, isn’t a good lifesytem already a nontrivial payload?

    3) Fat chance of a small, cheap manned lifter. All you can hope for is a non-Shuttle (e.g., Saturn VI-kinda-thing).

    4) Is RL-10 really all THAT much cheaper/faster to scale? I mean, by the time you’re talking about enough little lifters harnessed up to lift big stuff, is it really all that cheap to buy or turn around vs Saturn or a scaled up Atlas?

    5) Forget daily flights back then. I don’t see where the demand comes from. Even rocket payloads are time-consuming and labor-intensive. Dreaming they’ll come doesn’t mean it’ll happen.

    6) Yeah, yeah, Skylab could’ve been saved. And it would’ve been alot cheaper and seen more flights than Shuttle did (though it probably still would’ve seen bugs and seen long downtimes awaiting committee reports). Alot more could’ve been done within NASA’s budget.

  12. Jon Goff says:

    Anonymous,
    Regarding the manned flight parts of questions/statements 1 & 2, I think that you’re overestimating how big a spaceplane would need to be to be useful for hauling people. Capsules tend to give one a false intuition for how heavy those things need to be. For an RLV, you already have the OMS/RCS engines, and the TPS, and the landing system. In a system like what I described, you don’t need a launch escape tower (though an ejection seat *might* be worthwhile–but manually bailing out might also work). For adding people, you only need to add the weight of a pressure shell (not that heavy), presumably some sort of docking mechanism (so the people can go somewhere–alas this is probably one the heaviest parts for a manned spaceplane), and some short duration life support. This doesn’t have to be all that heavy.

    I wouldn’t be surprised if you could fly 2-4 people on a spaceplane that could only haul 2000-4000lb of cargo.

    4) The “all RL-10” design only makes sense if you keep it to a reasonable size. Sure, if you put unreasonable constraints on how big the thing needs to be, you’ll come to different conclusions. But you haven’t really done that convincing of a job of explaining why NASA’s first RLV would need to be big.

    Mind you, in my proposed counterfactual, I mentioned keeping the Saturn IB flying, while possibly doing small incremental upgrades to reduce operating costs. If you absolutely have to launch something big, use the Saturn IB, and send the people up in one or two of the smaller RLVs.

    5)Well, providing new “payloads” may be difficult, but passengers and cargo, consumables, and propellant are a lot more common. With a vehicle flying every day like this, some of them could be people coming up and down for the station. Some of it could have been providing propellants to a propellant depot. Some of it could be food, or supplies, or raw materials, etc. Not everything that flies on an orbital vehicle has to be some clean-room assembled multi-billion dollar “payload”.

    ~Jon

  13. Mr. X says:

    Since I was talking about a counterfactual based in the 70s or 80s, I figured I’d mention them separately. Though I’m not sure if McDonnel and Douglas Aircraft had merged yet at that point.

    McDonnell bought Douglas Aircraft in 1967, primarily because Douglas was late to the jetliner party with their DC-8 in the mid 50’s and had yet to reach the break-even point on DC-8 sales. It didn’t help that Donald Douglas Jr. had forced out people like Ed Heinemann and Arthur Raymond who had made the company so successful in the past.

    Just a little bit of trivia, but it must have been ironic in 1967 to see the Mercury and Gemini capsules under the same corporate name as the Delta and S-IVB when the two firms had been rivals just a few years prior.

  14. Anonymous says:

    But you haven’t really done that convincing of a job of explaining why
    NASA’s first RLV would need to be big.

    NASA has long had the option to develop a maximally cheap manned space system. They’ve never chosen it. It’s clearly not a NASA priority. There was the thinking that the Shuttle would eventually get cheap, by lots of launches, but they didn’t do anything to make it happen. It’s been over a decade since the failure of Shuttle cheapness hopes were obvious to anybody not mired in a pro-Shuttle culture. Again, no cheap manned lifter alternatives have been seriously proposed.

    The idea that that culture would be different strikes me as unrealistic. Given the primitive orbital assembly possibilities of the era, it’s not hard to see why, either.

    With a vehicle flying every day like this, …

    You still haven’t pointed out an actual potential source of demand for daily space flight. Yeah, I know NASA kept dreaming about daily Shuttle launches – I’m sure somebody, somewhere still does. But where would the demand have come for daily manned space launches in the ’80s or ’90s even in the unlikely event there was a cheap manned platform? You need to explain that. It wouldn’t’ve come from NASA or the govt. Unless they opened their platforms up to entrepreneurs on easy terms, it wouldn’t happen. And how did Dennis Tito get to orbit again? How did NASA treat him in the space station? Another cultural unlikelihood there. And don’t confuse manned and unmanned space travel. Two totally separate markets.

    P.S.: I’m deeply unconvinced that manned travel could be cheaper at a given era than unmanned travel in ours- the recovery and refueling costs you’re waving your hands over so frantically are considerable. Not only do you need ALOT of fuel, but it needs to be chilled and handled carefully for the RL10 and all other reusable designs that had success back then. Remember, you need vastly more energy to reach orbit than fly a plane.

  15. kert says:

    once again, i posted this on a previous thread, but:
    You still haven’t pointed out an actual potential source of demand for daily space flight.
    for suborbital intercontinental hops: organ transplants. there is about 90 000 waiting list for various transplants in US, and i believe people are willing to pay for that.

  16. Monte Davis says:

    “It’s been over a decade since the failure of Shuttle cheapness hopes were obvious to anybody not mired in a pro-Shuttle culture.”

    Any reason why it wasn’t obvious by, say, 1983?

    I’m not claiming special perceptiveness, just good fortune in covering STS development through the 1970s: the divergence between what those involved said on and off the record got more striking each year.

    It wasn’t a case of cynical “let’s fool Congress/the public,” but a hope-driven “well, it could work out if there are enough launches”… with the value of “enough” increasing ever farther beyond anything plausible.

  17. Jon Goff says:

    Monte,
    I’m not claiming special perceptiveness, just good fortune in covering STS development through the 1970s: the divergence between what those involved said on and off the record got more striking each year.

    Out of curiosity, do you think my thesis here (that trying to keep the Saturn team together was one of the major drivers for overreaching with STS that lead to it becoming the disaster it is) is anywhere near legit? I was only six months old when the Shuttle first flew, so I wasn’t around when a lot of the early decisions were being made, so I don’t have a good way of knowing if my observations seem valid or not.

    ~Jon

  18. Monte Davis says:

    OK, first “Saturn team” and “Apollo team” aren’t quite synonymous. The work curve for the former peaked earlier, and there was more time for it to erode before STS activity ramped up. NASA spending started down almost 3 years before the first Moon landing, and almost 6 years before a firm STS commitment.

    Of course there was an effort to keep together Apollo’s core capabilities and, as far as possible, the best people. But I’d say even more than “keep a big team for a big job,” it was the unconscious Apollo conceptual model — the drive for another Babe Ruth “point to the fence and knock the ball out there” achievement like that of 1961-1969 — that was the real killer.

    They talked the talk — routine, robust, economical space truck yada yada. But the whole effort was geared to “version 1.0 will be an operational vehicle that will be our primary launch vehicle.” IOW, they approached the development of a radically new launch (and re-entry) system as if it were a mission with a deadline. “We’re not here to learn until we know enough to do it right; we’re here to get it done.”

    So approaches and choices that would have favored operational economy and robustness — but also reduced payload and taken longer — lost out to performance and scheduling.

    If you haven’t already, do read Tom Heppenheimer’s _The Space Shuttle Decision_, online at

    http://history.nasa.gov/SP-4221/contents.htm

  19. Anonymous says:

    I’m sorry, but ballistic and metallic TPS don’t go together… go look aft X33. It’s trajectory was very lofted to keep the heat RATES down since metallic TPS can’t take the temperatures that tiles can. The tiles on the shuttle have never catastrophically failed. Their only drawback is the number of them, and that is purely a function of the size of the vehicle. Smaller shuttle (which u like), less tiles. The shuttle, from a thermal standpoint is overdesigned. Replace those tiles with TUFI tiles and damage would go down (weight up, but I think it would be worth it). Lose the external tank and the shedding foam and …

  20. Karl Hallowell says:

    I’m sorry, but ballistic and metallic TPS don’t go together… go look aft X33. It’s trajectory was very lofted to keep the heat RATES down since metallic TPS can’t take the temperatures that tiles can. The tiles on the shuttle have never catastrophically failed. Their only drawback is the number of them, and that is purely a function of the size of the vehicle. Smaller shuttle (which u like), less tiles. The shuttle, from a thermal standpoint is overdesigned. Replace those tiles with TUFI tiles and damage would go down (weight up, but I think it would be worth it). Lose the external tank and the shedding foam and …

    And as I understand it, thermal loading decreases as the mass per crosssectional area goes down. So one possible solution is to use a light vehicle with a large crosssectional area (eg, using a drogue chute).

  21. Jon Goff says:

    Anonymous,
    I never said anything about a ballistic reentry. I was saying that a reentry vehicle with a low ballistic coefficient could’ve used different TPS. Ballistic coefficient != Ballistic reentry. You can do a lifting reentry with a low-ballistic coefficient vehicle–in fact that’s probably the best way to do things.
    ~Jon

Leave a Reply

Your email address will not be published. Required fields are marked *