This article was originally featured on The Drive.
When the spaceplane’s landing gear struck the runway on July 21, 2011, it marked the end of the line for the Space Shuttle. An incredible accomplishment in its own right, the shuttle project was a child of the optimistic post-Apollo era. Funding complications, high maintenance costs, and design limitations eventually morphed it into a bloated program that never truly explored its full potential, though. But take a look at its early concepts and you’ll see how the project was intended for even greater heights than it actually attained.
Nearly a decade before the first Space Shuttle took flight, aerospace giant Rockwell—with influence from NASA’s legendary engineering titan Maxime Faget—sketched out stunning design studies that envisioned a sleek shuttle orbiter capable of landing back on Earth like an aircraft, along with a truly monstrous booster stage that could be retrieved in the same manner. This, Rockwell believed, would allow costs to stay low while still maintaining a fair amount of capability. It generated a ton of data—and beautiful concept imagery—in order to convince NASA that the ambitious plan had merit.
These concepts aren’t as outlandish as other attempts at a shuttle design—think Chrysler’s single stage to orbit behemoth. Had there been just a bit more technological advancement and a little less meddling from the Air Force, there’s no saying Rockwell’s shuttle and booster plan couldn’t have happened. Unfortunately, however, the idea was doomed from the beginning.
Post-Apollo expectation vs. budget reality
After the moon landings began in 1969, the question of what we could do next was on everybody’s minds. The possibilities appeared endless. Going to the far reaches of our solar system, creating a permanent moonbase, and more all felt like distinct realities. Within the United States government, though, the will to fund these programs was drying up. By the late 1960s, the Nixon Administration and Congress gradually whittled away at budgets for potential groundbreaking projects. Soon, only the cheapest options, a low-orbit space station and an associated resupply vehicle, were on the table.
This development eventually gave birth to the International Space Station and the Space Shuttle we all know and love. True, the 184-foot-long, stub-winged aircraft we wound up with let the U.S. lay the only reasonable claim to ever owning a space fleet. But before that final specification was officially laid down, several aerospace organizations, including Rockwell and even internal teams at NASA, presented different, more impressive designs to the government for consideration.
The idea was to get the cost per launch and cost per pound sent into orbit as low as possible. The economics had to work. There were a few ways to do that. You could develop inexpensive vehicles that were disposable (i.e. destroyed after every launch), expensive vehicles that could be re-used several times, or a hybrid between the two ideas.
The Space Shuttle we wound up with was a hybrid and, due to a set of unavoidable constraints, not a very good one. The orbiter itself was reusable and only the relatively cheap liquid fuel tank would be totally destroyed as a part of the launch process; however, in order to secure funding, the project had to use existing, known-quantity technology. The result was low upfront costs but high ongoing maintenance costs. Furthermore, only 24 of the disposable fuel tanks for the orbiter could be produced per year. This put unfortunate limits on a vital mathematical reality: With a relatively fixed price for the program, more launches would mean less cost per launch.
This straightforward calculus is how Rockwell, who eventually became the prime contractor for the final Space Shuttle, defined its early designs. It proposed a highly reusable system that would enable a large number of launches. There would be a steep initial cost—advanced materials and manufacturing techniques to utilize some incredible new substances would have to be developed—however, if it could eventually make this system reliable and affordable, then it would be a winner among the cheaper disposable proposals.
Here’s where things start to get cool. Just like what SpaceX does today, Rockwell wanted to recover the booster stage that carries the orbiter payload out of Earth’s dense lower atmosphere. To do this, it wouldn’t have boosters autonomously return to launch pads like they do today; that would’ve been a lot to ask of computers from the 1970s. Instead, the booster stage itself would have wings. After releasing the smaller orbiter it carried on its back, it would be manually piloted back down to a runway by an onboard crew, and then landed like a plane.
The orbiter would work the same way the Space Shuttle eventually did. Unlike the Space Shuttle, the exterior of Rockwell’s orbiter wasn’t defined by thousands of unique silica ceramic tiles to defend it against the heat of re-entry. Instead, it would be made of more exotic, aircraft-adjacent materials. It also would have deployable jets to increase its cross-range flight distance, a payload of 9,070 kilograms (about 20,000 pounds), and a total cargo volume of 18.3 meters by 4.6 meters in diameter (60 feet by 15.1 feet in diameter.) The Space Shuttle could carry the same volume of cargo, but its payload was much greater at 27,500 kilograms (approximately 60,000 pounds).
This first orbiter design was based heavily upon a concept done by the aforementioned aerospace genius Maxime Faget. Its straight-wing layout later proved to be impractical for reentry; however, Rockwell created it anyway, allegedly in an attempt to curry favor with NASA leadership, where Faget had a fair amount of influence. Much of the later technical art was based on the more feasible delta wing version of this craft.
So yes, the early Rockwell orbiter concept needed a little work, but on paper, it made a lot of sense. The company said that these more durable, higher-quality craft could complete as many as 100 operational missions and save on tremendous costs in the long run. There were no disposable boosters to deal with, after all, which could enable a large volume of missions. Sure, there were hurdles, but if the development process could begin, the company argued, it could iron them out. It was just a matter of getting the ball rolling on its orbiter design.
The incredible booster stage
Then there was the dreamt-up piloted booster, itself a behemoth. It had 12—yes, 12—liquid-fueled rocket engines, as well as four air-breathing turbofans. The Space Shuttle, for reference, had just three main liquid-fueled rocket engines, along with two solid boosters. In Rockwell’s early designs, the booster stage’s rockets would spit all of the fire necessary to get the two craft in orbit. Once that part of its mission was complete, its turbofans would deploy and extend its cross-range flight ability, similar to the orbiter, thus increasing the possible number of landing strips it could access once it was time to come back down to Earth.
The booster stage was bigger than a 747 and it had a gross takeoff weight of 2.7 million pounds; more than twice that of the doomed Antonov AN-225 Mriya. While this whole idea seems increasingly insane on the surface, the idea of using jet engines to power spaceplanes in Earth’s lower atmosphere wasn’t actually that unorthodox. The idea would eventually be tested on the Soviet Buran, although the prototype that underwent that testing never completed a re-entry.
As Rockwell’s project boiled down a bit, the most realistic reason to have a giant piloted booster was so that the combined craft could ferry itself from one landing strip to another (as opposed to being carried on the back of a 747 like it eventually was) and because of the aforementioned cross-range flight distance, too.
It was at least theoretically possible to have these jets on the piloted booster, and actually, without the liquid fuel for the rockets, the craft was relatively lightweight, according to its designers. Lighter than a 747 on landing, in fact. The booster would launch vertically, release the orbiter, and then re-enter the atmosphere at hypersonic speeds before gradually slowing to below Mach 1 and deploying the jets for a short, cross-range flight before landing. Materials like titanium, columbium (niobium), Inconel, and more would be utilized in its construction to make this all possible.
The jet engines actually stuck around on the shuttle concept for some time until they were eventually removed in the final design.
So what happened?
Money eventually did come to Rockwell, but not for building its piloted booster and light orbiter concept. The issue was that, following the Apollo missions dragging on into the 1970s, general interest in space programs faded and the political will to continue a lot of spending on non-military space programs just didn’t really exist anymore. In order to justify any shuttle, not just the shuttle Rockwell really wanted, it meant serious cutbacks and concessions to the Air Force, who only agreed to support the project publicly if it got its way in terms of payload.
Then there was the issue of the engines. Using only liquid-fueled rocket engines would’ve been the best option on paper; however, to cut costs, recoverable solid boosters were added. This—plus the incorporation of a disposable fuel tank system that was taken from another competing shuttle design, the Lockheed Star Clipper—meant that the more expensive, piloted booster seemed unreasonable. The disposable fuel tank and solid boosters saved too much money upfront to be ignored.
In the end, the cost of the piloted booster concept was what killed the whole plan. Today, though, it’s more than just a big what-if. Stratolaunch, an ambitious aerospace company, is using a massive, rocket-less, purely air-breathing launch vehicle in order to potentially help objects, including spaceplanes, into low-Earth orbit. Just the same, SpaceX’s recoverable, liquid-fueled boosters prove the idea can work.
Neither of these is a huge, vertically launched, 2.7-million pound monster with a dozen rocket engines and four jets to boot, but they aim to do effectively the same thing. As it turned out, Rockwell’s engineers weren’t sketching themselves into a corner after all. They just needed technology to advance a bit further.