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I wonder why nobody ever proposed a space launch system like Starship. Methane as a fuel and all the theory behind are well known, so why?

Is it solely because of IT progress that made returning the stages possible?

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    $\begingroup$ Just to clarify, you are specifically asking about Methane as a fuel source? Because if not, there are similar proposals--for example the Sea Dragon--which never got anywhere for a variety of reasons $\endgroup$
    – Dragongeek
    Mar 23, 2021 at 19:10
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    $\begingroup$ @Dragongeek no, about the whole system, which many consider "revolutionary" and "impossible". $\endgroup$
    – Anixx
    Mar 23, 2021 at 19:11
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    $\begingroup$ @Anixx Has anyone besides industry competitors claimed the system is "impossible"? $\endgroup$ Mar 23, 2021 at 19:30
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    $\begingroup$ en.wikipedia.org/wiki/McDonnell_Douglas_DC-X $\endgroup$
    – Polygnome
    Mar 24, 2021 at 7:57
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    $\begingroup$ OP WHAT? Nothing about starship is new in the slightest. Everything implemented in it has been proposed before $\endgroup$
    – Hobbamok
    Mar 24, 2021 at 9:32

5 Answers 5

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I wonder why nobody ever proposed a space launch system like Starship.

What exactly do you mean by "like Starship"? Systems like Starship have been proposed before, although differing in the details, going back to Von Braun's mid-1950s Mars expedition concepts. Starship is ambitious in several ways, but it's more evolutionary than revolutionary.

Starship is fundamentally a large, two-stage-to-orbit launcher with full reusability of both stages.

It's about 60-70% larger by liftoff mass than the largest successfully flown orbital launcher (the Saturn V), but much, much larger rockets have been seriously proposed (e.g. Sea Dragon).

Two-stage-to-orbit with full reusability of both stages was seriously considered for the US space shuttle program (as described in The Space Shuttle Decision), but the budget didn't allow for development of a fully reusable booster. The fully reusable shuttle concepts relied on winged, horizontal landing rather than vertical propulsive landing, but the pros and cons of the two approaches are endlessly debatable. Propulsive vertical landing has been demonstrated and proven at smaller scales (Surveyor, Apollo LM, several Mars landers, DC-X, Falcon 9).

Large methane rocket engines and full-flow staged-combustion engines haven't been flown before, but both concepts have had development work done previously.

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    $\begingroup$ A lot of projects of the past indeed proposed full reusability via airstrip landing or parachutes. It seems though the vertical landing is the only option, compatible with travel to other planets. $\endgroup$
    – Anixx
    Mar 23, 2021 at 19:58
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    $\begingroup$ As I see it, the most "revolutionary" aspects of Starship are 1: they're not relying on some super-advanced technology that will cost billions to develop, and 2: they're actually executing on it, in a field where the established players were comfortable with the status quo. Much the same goes for another business of Elon's: Tesla isn't taking advantage of some revolutionary advance that has just enabled electric cars, it's just executing on something the established car makers didn't care to do and in fact were actively resisting. $\endgroup$ Mar 23, 2021 at 21:17
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    $\begingroup$ @RussellBorogove I would say the dramatic success of SpaceX is that they didn't try to go high tech. $\endgroup$ Mar 24, 2021 at 1:45
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    $\begingroup$ @LorenPechtel or did so in a very constrained way. The Raptor is pushing the boundaries of the state of the art, and they're using some high-end robotic welding machines. However, those machines are welding stainless steel with pretty bog-standard techniques, and they didn't even start on that until they were sure that Raptor would do the job. $\endgroup$ Mar 24, 2021 at 2:10
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    $\begingroup$ Their engine is hi-tech, their material are hi-tech, their code is hi-tech (they use C++ and Javascript!), their sensors (MEMS) are high tech and did not exist like 20 years ago. But nothing is completely innovative, automated landing? done by CCCP in a time where computer where big as rooms. VTVL (vertical take off and landing)? explored and demonstrated in the 1960 (apollo landing!) and multiple other rocket later. Even blue origin had Goddard before spacex's grasshopper. What spacex did was to manage to concrete those idea in a product in a economical way, an incredible feat by itself $\endgroup$
    – Lesto
    Mar 24, 2021 at 14:44
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Fundamentally, it's because of economics. There simply wasn't any demand for a large rocket between today and the space race.

Let's analyze what (I think) makes the Starship concept special:

  • Size: Starship is one of the biggest (if not the biggest) rockets ever constructed.
  • Reusability: One of Starship's core design goals is to be reusable comparable to airplanes
  • Budget: Being cheap and simple is at the core of Starship's philosophy ("the best part is no part")
  • Mars compatibility: Starship is intended to be refuelable via ISRU on Mars

Now, let's go over why nobody's seriously suggested something like Starship before (although there are exceptions, which I'll get to later).

Size: A bigger rocket is more efficient, primarily due to the square-cube law reducing non-propellant mass in the rocket the bigger it is and certain elements, such as avionics, which do not scale significantly in mass when the rocket gets larger. Large rockets have been proposed and built before (Saturn V, N1, SLS) however the rockets have always been built to suit demand. The Saturn V and the N1 were built for the space race and the SLS is being built because NASA wants to send heavier payloads to the Moon. In the past, large rocket proposals have mostly faltered against the question "But why do we need a big rocket when a smaller one will do just fine?" Only recently, with burgeoning interest in space exploration and Elon Musk's vision, has manned, beyond-orbit, spaceflight become attractive again to a wide audience, which enables the building of bigger rockets.

Reusability: Arguably, Starship is not new in this regard because it's aiming to achieved the dream that the Shuttle Program was designed for but never achieved: The spacecraft lands, the astronauts get out and high-five the next crew, which boards, and then they take off again after quickly refueling. Originally, the Space Shuttle was supposed to be just that, a shuttle but for reasons that are out of the scope of this answer, it never happened. Starship is attempting something similar, with Elon's goal of multiple reflights in a day being very ambitious. Again though, incorporating reusability in a rocket system really only makes sense when there's enough demand that the financial investment it requires makes sense compared to disposable rockets.

Budget: One of the iconic hallmarks of the Starship program is that it's being essentially welded together in a field while most other spacecraft manufacturers work in clean rooms while wearing in bunny suits. This is, in my opinion, an advantage that commercial enterprise has over government development: since SpaceX doesn't need to justify themselves to politicians and ultimately taxpayers, they can get away with a lot more. If a NASA rocket explodes, people will complain about their tax dollars being "wasted" but if SpaceX's prototype blows up... who cares? SpaceX only needs to appease their limited and hand-picked investors, which is much easier than justifying tax dollars. This institutional pressure to get it right on the first try leads to a cautious approach so that if something goes wrong, it's nobody's fault. Why haven't we seen this before? It's because successful commercial launch companies (that aren't defense contractors) are very new.

Mars compatibility: This is again, in my opinion, due to the traditionally conservative nature of space exploration. Typically, things are done in steps. For example, first, we send an orbiter, then we send a lander, and finally a rover to make sure everything will work. Building Starship with ISRU in mind is jumping over several steps and, again, not something that a government-funded program would be able to justify to a taxpayer easily.

Now, to the exceptions and what's been proposed/done before:

  • The original goals of the Space Shuttle program are remarkably similar to the goals and approach of the Starship program
  • The Sea Dragon proposal from the 1960's exemplifies the "Budget" and "Size" traits of Starship
  • Plenty of other proposed very large space vehicles like Project Orion
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    $\begingroup$ So nothing like it has been proposed, except for all the things like it that have been proposed? $\endgroup$ Mar 23, 2021 at 19:43
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    $\begingroup$ "There simply wasn't any demand for a large rocket between today and the space race" – Just compare the launch cadence of Falcon 9 and Falcon Heavy to get a feel for the difference between the market for heavy lift and superheavy lift vehicles. $\endgroup$ Mar 23, 2021 at 20:10
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    $\begingroup$ There still is no demand. At least not more demand than there was for the iPhone before it came out. Both products are pushed into existence by entrepreneurs driven by a vision. $\endgroup$ Mar 24, 2021 at 9:00
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    $\begingroup$ @Peter-ReinstateMonica the iphone seems an odd example; there were a bunch of big touchscreen phones out there running crufy old windows operating systems, and people bought and used them and would have liked something better. But perhaps you were drawing a parallel between two charismatic leaders with reality distortion fields and an uncritical cult following ;-) $\endgroup$ Mar 24, 2021 at 11:02
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    $\begingroup$ @Peter-ReinstateMonica "There still is no demand" ehh... Musk demands Mars rockets, and he has >$100B. That's one big customer/source of demand right there which didn't exist a couple years ago. $\endgroup$
    – Dragongeek
    Mar 24, 2021 at 17:23
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As other answers imply, the reason is likely not technical but economical. May be this question could attract some interesting answers at this sister site. I think it is a good example of an entrepreneur venturing into a field that has been always controlled by governments and exercising opportunities to "fail fast" and the availability of capital, both unencumbered by politics. In a sense, this is agile development at a cosmic scale.

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I have been thinking about this and sought this site to try to find an answer. I don't think it was really technical because both SpaceX and Blue Origin have achieved similar results in the same rough time period. I don't think it was economic because the resources for SpaceX and Blue Origin are smaller than what NASA could conceivably put in such an effort. I don't think it was a market issue either, because the first time SpaceX successfully landed their Falcon 9 rocket, it was obvious this would usher in a new era of cost reduction for space flight in the future.

I think it was due to billionaires.

By being billionaires, Musk and Bezos could focus on accomplishing the task at hand. They were also new at rocketry, with no organizational and cultural baggage to hold them back. NASA is hamstrung to accomplish something like this, because no one person is given the authority to execute a singular vision like this, despite the obvious benefits. Any vision would be watered down by committees and sniping power blocs that would sap resources. Also, every new POTUS thinks its fine and dandy to scramble NASA's missions every 4 or 8 years.

I think the big lesson to consider here is why couldn't an organization like NASA do this? They really should have. And they probably could have done 10+ years earlier, at least from a technology standpoint. I have nothing against billionaires, but if gov't organizations simply can't do some things that wealthy individuals can do, its a sad state of affairs. FWIW, I don't think a wealthy person in 1960 could have flown people to the moon and brought them back, so NASA used to be able to do these things, but not so much anymore.

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    $\begingroup$ "both SpaceX and Blue Origin have achieved similar results in the same rough time period": Uh... $\endgroup$ Mar 14, 2022 at 1:51
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    $\begingroup$ To expand on my previous comment: SpaceX has done ~150 orbital launches, multiple interplanetary ones, has developed multiple launch vehicles while pioneering booster reuse, is well into development of a fully-reusable system, they have developed multiple orbital spacecraft and are doing crew and cargo ISS missions, and they are constructing their own megaconstellation with nearly 2000 of their own satellites already in orbit. Blue Origin has constructed a suborbital hopper which they fly occasionally. "Results" from Blue Origin have been rather lacking. $\endgroup$ Mar 16, 2022 at 18:20
  • $\begingroup$ My point was that Blue Origin also was able to build a first stage that could be launched and also return to earth, landing upright. Since SpaceX also does that (and as you say, does it more often and better) it is not a singular accomplishment. But it is something NASA never did, or decided to never try to do. I think this is a failure on NASA's part. $\endgroup$
    – Jiminion
    Mar 18, 2022 at 18:15
  • $\begingroup$ Blue Origin flew and landed a single-stage, low suborbital vehicle. McDonnell Douglas did that much in the early 1990s. SpaceX flew and landed the booster of a medium-heavy lift orbital launch vehicle. Others besides SpaceX have developed vehicles that have actually gotten to orbit in the timeframe they've existed, Rocket Lab for instance. $\endgroup$ Mar 18, 2022 at 18:53
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The most important aspect of Starship is that it is (supposed to be) reusable. For most of rocket history it was almost impossible*.

Why?

Because of lack of good enough computers. You would need to put a pilot in it and the first few landings would end in RUD. The Space Shuttle got around this by landing as a plane.

Only after someone demonstrated it's possible to land an unmanned rocket (some time before SpaceX) did the idea of the reusable rocket move from a dream to something that can be actually done.

* There are other ways to achieve at least partial reusability that could be done sooner (parachute for engine and aerial capture), but there was no market for it (if the government is paying for a few rockets a year regardless of price, you as the supplier don't want cheaper rockets).

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    $\begingroup$ Buran was able to fly and land autonomously over 30 years ago. So I disagree with your assessment that computers were not good enough for most of space history. $\endgroup$
    – DrSheldon
    Mar 25, 2021 at 14:19
  • $\begingroup$ It could not land engines first. It landed as aircraft which was understood. $\endgroup$
    – Alpedar
    Mar 25, 2021 at 14:22
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    $\begingroup$ The DC-X landed engines first autonomously over 20 years ago. $\endgroup$
    – 16807
    Mar 25, 2021 at 16:42
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    $\begingroup$ The Surveyor spacecraft landed engines first (on the moon) in the 1960s. What you miss here is that on Earth "engines first" only works for 1st stages, that don't need to survive the heat of reentry. $\endgroup$
    – jamesqf
    Mar 25, 2021 at 17:02
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    $\begingroup$ @Alpedar I'd love to give you a nicer welcome, but this answer earns a downvote instead. Your claim that vertical landing is harder to automate than horizontal is completely unsupported and fairly dubious. In fact, landing vertically is conceptually easier because touchdown occurs at essentially zero velocity. All the automation needs is "kill rates using thrusters, vector thrust to kill horizontal velocity, throttle to achieve zero vertical velocity at touchdown". Apollo-era computers can easily do that. The hard part is making engines throttle deep enough to be able to execute this. $\endgroup$
    – TooTea
    Mar 26, 2021 at 9:49

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