X-20 vs Mercury?

The X-20 Dyna Soar was planned to be the Air Force/NACA’s follow up to the X-15. It was a reusable spaceplane capable of orbital flight. The Mercury spacecraft/concept was basically taken from the AF’s Man In Space Soonest program, renamed Mercury, and given to NASA. Dyna Soar was cancelled just after construction of the first plane had begun.

What I’m wondering is how different our space programs, then and now, would be/have been if the X-20 was allowed to continue?

It’s not so much X-20 vs. Mercury that would have made a big difference, but the evolutionary approach to the space program favored by then-administrator of NASA James Webb versus Kennedy’s all-out man on the moon program. But once the lunar program was committed, that defined the whole NASA strategy for the foreseeable future.

It’s hard to know how Webb’s approach would have played out but my guess would be that manned space flight might still be limited to earth orbit as indeed it is today, but advanced vehicles like those envisioned for SLS might already exist. Unmanned robotic missions might have made a lot more progress, so although mankind may not have set foot on the moon, a lot more real science would have been done. We might even have had a rover exploring Europa by now.

The X-plane path would have led to a more sustainable program and was prematurely aborted, precise as wolfpup says.

You can put the history of the US space program in context by imagining that Karl Benz got Germany to commit to building a 6-second dragster in 1890… and then all but abandoned the idea of cars.

There’s no way to know that. For all we know, the X-plane path would have led to defunding and stagnation for decades. After all, the Space Shuttle was built, and it basically led to two decades of stagnation as it was a white elephant that consumed all the manned space flight funds and never achieved its original program goals.

It may be that a big ‘race’ with the Soviets was the only way we were ever going to raise the funds necessarily to move substantially forward in space, even if the Saturn V/Apollo hardware was an eventual dead end.

“Dyna Soar?” Grand Bull Moose winner of the Awkward Codename contest. Back in the day, the only dinosaurs anybody knew about were great, big lumbering behemoths.

Why, Chuck Yeager would be even more awesome than he already is.

Neil Armstrong is remembered as the first man in space not as the first man on the moon?

I suspect that had there been no moon race, then we might have seen a moon landing in the late 1980’s, but with perhaps a fully permanent base there today.

Uh-huh, except for the litany of problems associated with spaceplanes, such as having to carry the entire mass of lifting area and all of the thermal protection systems to protect it. In fact, while the general perception is that spaceplane-type launch vehicles are somehow more efficient by virtue of being vaguely like aircraft, the reailty is that such concepts are carrying an entire aircraft into orbit and then protecting it against the conditions of reentry in order to use the gliding abilities only for the final few minutes of final descent. Capsule-type reentry provides the highest operational margins and best control. The driving consideration for both the X-20 ‘DynaSoar’ (worst name for an advanced spacecraft ever) and the STS ‘Shuttle’ was the desire for a high crossrange requirement for a polar-launch once-around-and-return trajectory, which may have made sense circa 1957 when the most advanced flight computer was a human being, but makes absoultely no sense today, or even by the time of the Apollo program.


Wow, that acronym just MISSes…

Yep, that’s what they called it, “MISS”. At the time, it was probably a Top Secret program, so a misleading project name makes sense. The atom bomb project really didn’t have much to do with Manhattan, did it?

That’s probably true. I wasn’t trying to make the point that X-20 was the way to go, but only that Webb was right about having a broader strategic vision than the dead-end of an all-out effort to achieve a lunar landing. The right thing to do would have been whatever made the most sense in terms of technology development for the long term. Mercury may have been the right start, but once the lunar program was announced everything got warped to that single objective. Gemini was just an intermediate step to Apollo, with an emphasis on docking maneuvers which were so essential to the lunar mission.

X-20 was designed the way it was because of its military mission objectives – it was almost a kind of space-faring fighter/bomber.

Actually, it did. The first headquarters of the project was at 270 Broadway in Manhattan, which housed the North Atlantic Division of the Army Corps of Engineers; also in Manhattan was the Madison Square Area Engineers Office on Fifth Avenue and research offices at Columbia University. Uranium was accumulated and stored in various places along New York harbor and Staten Island. The famous facility in the hills near Black Oak Ridge in Tennessee didn’t start getting established until the fall of 1942.

Why the proposed wing for the Gemini capsule?

Crossrange; the ability to do a polar orbit once-around and return flight. With the advances in surveillance satellites and the ability to recover ejected film cartridges or return high fidelity digital images, the need for crewed surveillance missions ended and the Air Force essentially abandoned their manned space program.


I understand that a Polar orbit changes longitude with each orbit and lets you photograph the entire planet, but why the wing to land the capsule and not a parachute? Would it allow the capsule to land at a particular location that a parachute would not?

A wing allows you to land heavier and more fragile equipment than a parachute; you’d need a pretty big parachute to land something like the Space Shuttle and even then, landing would be pretty rough.

There was a plan land the Gemini capsule with a wing.

I disagree. I think that the only reason that NASA got any sort of budget to do anything at all hinged on the astronauts and the mission to the moon, which captivated the public’s imagination. To paraphrase from The Right Stuff, no buck rogers, no bucks. Yeah, if you could have secured the proper funding through the time of the space race and used it instead on an incremental program we’d have achieved more…no doubt about that (though personally I think a lot of you handwaving away what we DID achieve are missing a lot). But, the thing is, you wouldn’t have gotten that funding with an incremental project because the public wouldn’t have been behind it or willing to make the taxation sacrifices needed to make it happen. It would be like the perennial debate about high speed rail in the US…something that a lot of people say they want, and that there are strong advocates for, but just never seems to get funded to do anything substantial. Oh, I’m sure NASA would have done some things, but I can imagine programs getting started, initially funded and then at some stage getting their funding pulled for other programs. Just look at the number of Air Force projects that were initially funded but eventually pulled, even when they had working prototypes. That would, IMHO, have been the reality of the space program without something big to capture the public’s imagination…and the public’s funding.

A wing or other lifting surface allows the ability to trade lift for crossrange (e.g. distance perpendicular to the ballistic path). Since the Earth is rotating beneath the spacecraft, if you want to return to launch site from any arbitrary azimuth and altitude you need to have a certain amount of crossrange capability. The “Blue Gemini” capsule would also have a parawing which would deploy for final, low altitude approach and pop-out skids for landing on dry lakebed.

The enormous size of the STS ‘Shuttle’ delta wing was entirely driven by similar crossrange requirements for “Blue Shuttle” and resulted in a number of design compromises and low margins. The X-20 was originally designed (to a concept stage) for skip-gliding on the stratosphere without going to a truly orbital trajectory. Later, it was decided to make it fully orbital and contain some onboard propulsive capability due to heating concerns, but the problems of protecting the metallic leading edge surfaces from reentry heating ended up being one of several limiting technologies which made the ‘Dyna-Soar’ not viable.


…and within a certain amount of time. Unless the landing site is outside of your orbit’s inclination, only an arbitrarily small delta-V is enough to land wherever you want–if you wait long enough. As you said, the USAF wanted enough cross-range for a polar once-around, which rather raises the requirements.

Still, it seems like it mighta been better just to build a landing strip in Alaska or something…

Three points:
[li]"…if you wait long enough" for orbtial arguments that can take you back to a position where you could phase into a return to launch site suing “only an arbitrarily small delta-V” would mean carrying days or weeks of supplies and provisions, not to mention having some poor sop crammed in sitting position in a cockpit not much larger than a Mercury capsule. The Dyna-Soar was conceived as an operationaly system which would ascent, perform some specific set of tasks, and then return within a day or less.[/li][li]Return to landing site was desired because the intent was to service and turnaround the vehicle in short order (days or possibly even hours). This was long before the experience with the STS where we learned that those kind of turnaround times would require robustness and simplicity that are contrary to the complexity required in a high performance crewed reusable vehicle.[/li][li]Alaska is just about the last place you would ever want to land anything. When it isn’t frozen and the wind isn’t blowing at gale force, the surface becomes a soupy mess of washboard, and shipping large equipment into or out of Alaska is the kind of headache that causes logistics engineers to drink away their troubles.[/ol][/li]