Where is my von Braun wheel?

Completion: 75%

3462 words • Essay first planted on: March 25, 2025 • Last updated on April 17, 2025

In 1962. There — that answers the clickbaity title right away.

NASA had viable designs for rotating wheel space stations that could have given astronauts artificial gravity. Then, the Apollo program effectively killed them.

While NASA’s lunar focus delivered the historic moonshot, it dismantled a promising engineering effort at Langley Research Center that might have revolutionized human spaceflight. That decision set us on a half-century trajectory of small, zero-gravity stations that continue to plague astronauts with muscle atrophy, bone loss, and vision problems.

Had NASA maintained its parallel pursuit of artificial gravity, we might now have permanent orbital settlements supporting deep space missions rather than the limited outposts we’ve settled for. This historical pivot point matters today as commercial space companies contemplate artificial gravity again, potentially correcting a costly detour in humanity’s path to becoming a spacefaring civilisation.

James Webb, the former NASA admin immortalised by the JWST, standing underneath a prototype of a von Braun Wheel

The need for artificial gravity

Early space visionaries, such as Werner von Braun, strongly believed that settling the solar system required developing technologies to generate artificial gravity within orbiting habitats as — rephrasing Heinlein — space is a harsh mistress. Modern-day astronauts exercise a few hours each day to overcome microgravity’s effects on the body. von Braun was convinced that rotating wheel space stations prevented such physiological problems and were thus ‘as inevitable as the rising sun’”. In these systems, humans live along the periphery of a wheel, within which they experience gravity due to the wheel’s rotation. Popularised by von Braun in his 1949 sci-fi novel, Project Mars, and the 1956 Disney piece, the concept actually traces back to Herman Potočnik’s 1929 book The Problem of Space Travel. Its legacy is perhaps why many felt that an operational spinning station was, at best, a couple decades away.

Potocnik Concept art of a rotating space station.

von Braun explaining the layout of his wheel-shaped station

The difficulty of building large stations

This elegant solution to generate artificial gravity, however, comes with a major engineering challenge. Much like a ferris wheel, the wheel’s rotation could disorient astronauts if spun too fast. If the wheel spins slowly then its physics dictates it must be quite large. For example, one of von Braun’s designs called for a massive 75 metre diameter wheel that generated lunar gravity if spun at 3 rpm and Earth-like gravity at 5 rpm — this range is considered reasonable for astronauts.

However, the physics of rockets presents a different obstacle as it must be slender, like an arrow, to escape Earth’s gravity well and reach orbit. This defines the main upstream engineering challenge: how can we fit enormous space structures into slender rockets? For context, even Starship’s upper-stage, which is about 9 metres wide and 22 metres tall cannot fit von Braun’s conceptual station in a straightforward manner.

Architects of the International Space Station (ISS), the largest space structure ever built, tackled a similar packing problem using multiple smaller spacecraft which connect, like space Ikea, into a structure greater than its parts. Such in-space assembly involves spacecraft either gently crashing into each other at specific connection points (a manoeuvre called rendezvous and docking) as well as astronauts and space cranes supporting finer assembly tasks. While this works great in theory, the ISS’s assembly needed over 40 rocket launches spanning several years (and even more launches for cargo resupply and repairs). More damning is the typical ISS crew size of 7, which is a little over twice that of the first ever space station, Salyut, from 1972. Clearly 50 years of space station development does not indicate that such modular in-orbit assembly will scale to von Braun’s anticipated 80 humans or, more relevant today, Starship’s 100 any time soon. Civilisation-scale megastructures like the Stanford Torus and O’Neill cylinders appear even more outlandish to discuss today than when they were first proposed in the 70s.

From this vantage point, it is quite clear that the architectural bottleneck is a technology running through all operational space stations so far: their use of small ‘tin can’ modular spacecraft as the centrepiece for assembly, which is a legacy of Apollo. This, in my opinion, is unfit for building large space stations at scale or speed. But how did we get here? To understand this, we need to look into the pre-Apollo era space technology development programs and the consequence of Apollo’s announcement on them.

A pre-Apollo solution: unitised stations

From 1959 till 1962, NASA Langley explored various architectures to accelerate towards von Braun’s vision. A former Director of Aeronautical Research at NASA Langley, Larry Loftin, saw crewed stations as essential to crewed exploration of our Moon and planets following the success of Project Mercury. In keeping with this, he instigated a conference in 1959 to explore ideas at Langley, two of which were taken to the prototype stage. These early concepts are notable not only for their ambition in directly pursuing von Braun’s vision but also for what now feels like a very counterintuitive way of realising large stations as “unitised” structures i.e., a single structure that eliminates or reduces the need for in-orbit assembly. An approach at odds with that used to assemble the ISS in-orbit, as described above.

The first unitised station idea explored inflating large tyre tubes (obviously made by Goodyear!) into wheel-shaped space stations — this is what James Webb, the then NASA Administrator, is standing under in the opening image of this essay; the image below shows engineers walking within this tube.

source: https://archive.org/details/1962-L-00312

Made from soft materials, like rubber and nylon, there were concerns that collisions with micrometeorites could puncture the station with fatal outcomes. So, a six-month contract was awarded in 1961 to North American Aviation to look into hexagonal space stations, one of Rene Berglund’s many station concepts, made from six hinge-connected rigid pipes. A 15-foot prototype of this system was developed, based on the table-top concept shown below.

A deployable hexagonal space station *source*: https://archive.org/details/1962-L-08732

The deployable hexagonal space station. *source*: https://archive.org/details/1962-L-08730

This design also folded neatly into a rocket for launch to later automatically deploy in-orbit; the rigidity of its habitable elements also ensured better protection to micrometeorite collisions than Goodyear’s rubber donut. Further, three inflatable tubes connected the habitats to a central hub via air-lock doors, which could be sealed in case of rupture. Loftin’s Langley team estimated that either system could be realised for $100 million (approximately a billion dollars in 2025) but, over time, the hexagonal station emerged as the most promising concept in Langley’s Manned Space Laboratory Research Group.

Space station R&D was one of the more active areas at Langley as NASA was unclear about the appropriate path to the moon and an orbiting station seemed like an appropriate precursor to crewed lunar and solar system exploration. Apollo would change everything — in May 1961, President Kennedy’s landmark speech committed America to a lunar landing instead of the original plan to merely orbit the moon.

The Apollo Applications Program: A Pivot Point

Apollo effectively sidelined the space station projects over the next few years. The methodical approach of Loftin’s team to develop von Braun stations as a staging point for lunar missions was bypassed for more direct paths to the Moon. However, by 1963, the vision shrank dramatically to align with Apollo’s more modest technologies: zero-gravity spacecraft for crews of three rather than the 36 envisioned for the rotating hexagon. The result was the Manned Orbiting Research Laboratory program to conduct biomedical, scientific, and engineering experiments on a minimum size laboratory with one crew member staying in it for one year and three other crew members on board for shorter periods on a rotating schedule. Like the rotating wheel space station program, Manned Orbiting Research Laboratory was threatened by cuts but survived into 1965 only through Langley’s persistent lobbying, which positioned larger stations as “the next logical step” after Apollo.

Elsewhere, a parallel challenge was emerging within NASA’s Marshall Space Flight Center where the Saturn rockets were being developed. Its head, Wernher von Braun, knew that his rocket team would face layoffs sooner than other centers actively involved in aspects of the first Moon landing that were downstream of launch. Its cause was an accelerated Saturn development plan by George Mueller, NASA’s Associate Administrator and head of Office of Manned Space Flight, who championed the revolutionary “all-up testing”. This is a risky approach where all stages of a rocket are flight-tested at once as opposed to doing so over multiple dedicated flights. Mueller had previously seen this approach yield success in the Minuteman ICBM program, where missiles flew with all stages active on their very first test. An identical gamble on much larger space rockets paid off when Apollo 8, in December 1968, orbited the Moon on just the third ever launch of a Saturn V.

But Mueller also understood the success’s deleterious effect on von Braun’s team. But Mueller was also a space station advocate, like Loftin and von Braun, so he established a Saturn-Apollo Applications Program Office in 1965 as a step to addressing the latter’s staffing concerns while also preempting post-Apollo planning hurdles. This program would eventually fuse with Langley’s early space station work; in 1967, the Manned Orbiting Research Laboratory concept was revisited as an Earth-orbiting station that could also support a crewed Mars trip. In parallel, von Braun’s center looked into two Earth-orbiting stations: one for astronomy and another for meteorology. Such studies went ahead only because of the interests of the two centers’ directors but lacked support from NASA Headquarters, who didn’t see these studies’ alignment to Apollo.

This is evident from how follow-on budgets played out for Apollo Applications. Mueller had hoped to secure $450 million in 1967 and over $1 billion in FY 1968. Reality proved far harsher as the Bureau of the Budget slashed the FY 1967 request to a mere $42 million and the FY 1968 budget brought similar disappointments. Initial discussions between NASA and the Bureau of the Budget reduced the request from $626 million to $454 million. President Johnson endorsed this figure with an argument that would become familiar in subsequent years: “We have no alternative unless we wish to abandon the manned space capability we have created.” But even with presidential support, Congress cut the authorization to $347 million, and NASA Administrator James Webb further reduced it by transferring funds to other activities. Mueller’s Apollo Applications was finally left with only $253 million (which is a pretty tidy sum of $2.4 billion in 2025). These severe budget constraints were paving the way to ensuring that no ambitious post-Apollo missions would happen.

Nonetheless these studies progressed. They looked into “wet” stations — a spent rocket stage that would first serve as a propulsive stage and then be converted into living quarters in orbit — and “dry” ones — a space station built on the ground and launched within a rocket. Mueller was convinced that the less complex dry station would be successful but required a Saturn V which James Webb was unwilling to spare. Webb had fought tooth and nail to convince Congress and the Bureau of the Budget to fund at least 15 Saturn V vehicles to achieve Apollo’s eventual goal. His reluctance to share a rocket is, of course, understandable as Mueller’s request was well before Apollo 8’s success. This unexpected early achievement made it increasingly possible for a Saturn V to be spared for an Apollo Applications mission. So, ambitious ideas for 75-100 person rotating wheel stations, called the Space Base, briefly sprouted in 1968 but eventually Skylab — America’s first space station — would launch in 1973 on the last ever Saturn V launch.

While significant in its own right, Skylab fell far short of the grand rotating wheel stations previously envisioned while using only a fraction of the Saturn V’s lifting power. Post-Apollo, NASA’s funding shrank considerably, and the Space Shuttle became the “logical successor” to Apollo, with Skylab serving as a limited station based on Apollo technologies. It was clear that NASA would no longer pursue parallel programs but would pursue sequential/incremental programs instead. The Soviet Union, meanwhile, having cooled their interest in lunar landings, launched Salyut, the first long-term space station program. This was followed by the 1980s Mir stations, which were conceptually similar to the Manned Orbiting Research Laboratory.

The early ambitions displayed in Langley’s inflatable torus and North American’s hexagonal station now seem like relics of a more optimistic era – one where large crews would live comfortably in rotating structures that generated artificial gravity. The initial plans for these architectures were designed for repeatability and scale which could’ve led to greater scientific output than all stations so far while offering a deeper understanding of the impact of artificial gravity on human health — something unstudied to date.

This is probably a good time to note that I am quite critical of Apollo and it is also in fashion to NASA-bash right now. But, I do actually maintain the view that just like it’s better to have loved and lost than to not have loved at all, it’s also better to have Apollo’d and stopped than to never have Apollo’d at all.

If one thinks of 1960s NASA as a presidential project to “put man on the Moon” then it easy to see it like one sees SpaceX — an organisation that excels at solving complex engineering challenges when given a focus, whether it was Apollo’s lunar landings or the Space Shuttle’s reusable orbiter development. More recently, this capability is perhaps best exemplified by JPL’s remarkable track record with Mars missions: their evolution from early Viking landers to the sophisticated Curiosity and Perseverance rovers demonstrates an ability to build on experience and consistently execute challenging interplanetary missions.

While other space agencies have struggled with Mars landings (like ESA’s Beagle 2 and their joint effort with Russia on Schiaparelli), JPL has developed a repeatable expertise that makes the extraordinary seem routine albeit at high cost. Their technologists pioneered a Martian landing technology that is now used to land SpaceX’s rockets. So, the issue isn’t NASA’s engineering capability — it’s about ensuring these formidable technical skills are directed toward the right long-term priorities for space development and are done cost-effectively with shorter development cycles. And it’s about greeting a regulatory environment that allows more players to join such efforts from all over the world by making ITAR a thing of the past.

So will I ever get my Von Braun Wheel?

Possibly. The commercial potential for rotating space stations is gaining attention once again. Jed McCaleb of Vast, one of the fast-moving commercial players, echoes von Braun that space stations would be useful for Mars transport as they’d be ‘much nicer to live on than inside Starship’ and artificial gravity stations are essential for humans living in space beyond a year. Starship’s Mars transport could range from months to years, depending on when it launches.

At the moment, Vast is developing smaller 0-g Haven stations and their 2035 plan is for an artificial gravity station in the shape of a long spinning stick station; think of it as a two-bladed fan. This is a step in the right direction but the limiting feature of their design is that any gravity will only be at the very ends of the sticks. Also, their stations continue to build on the modular Apollo-era technologies, which I think is questionable. One way to understand my skepticism is by looking at the plot below, which shows the average station volume per astronaut alongside its crew capacity. Vast’s 2035 plans will likely be less comfortable than the ISS if one uses this metric of volume per astronaut; it’s also well short of the von Braun and Space Base station concepts of the 60s. However, this occupancy metric is also worthy of questioning as artificial gravity stations should make use of area per person — like we do on Earth — and not volume. Yet, all space station documentation has focused purely on volume. Further, this metric also tells us why the Stanford Torus and O’Neill Cylinders are megastructures that might be too distracting for now as they are too far removed from other artificial gravity stations. There are probably a number of other concept reasonable stations in this design space that should be explored (Note that I have omitted several ideas in this plot as it is not meant to be exhaustive).

Space Station Comparison: Volume per Astronaut vs Crew Capacity

Langley’s earlier work concluded rigid hexagonal stations were superior on account of the delicate nature of the inflatable fabric; this would require little new engineering research and is something that could be pursued in a 0-g scenario. At the same time, there is also need for research on inflatable soft goods. We’re mostly accustomed to living within rigid structures on Earth and so do not often think of lightweight, expandable living spaces made from textiles as a viable alternative. However, the inflatable toruses investigated by Langley were of minimal mechanical complexity and simplified construction. In the vacuum of space, textile-based structures could provide vast habitable areas with superior radiation shielding and thermal management. This insight is not particularly new as the Bigelow Expandable Module (BEAM), a small inflatable module currently on the ISS, has proven stronger than the metallic modules to micrometeorites and orbital debris collisions while being just as safe from radiation. BEAM was a commercial effort resulting from an early stage NASA program, TransHAB, in the 1990s. But, at 16 m³, new efforts are needed into discovering and developing new high-strength soft materials to enable a 6000 m³ von Braun wheel. Now would be a good time to explore making even larger versions of such systems that converge toward artificial gravity stations.

Then there is the matter of closing the business case for any station. Almost all space station companies today believe they offer a platform to scale in-space manufacturing for startups like Varda and Space Forge. These companies are leveraging microgravity to produce better pharmaceuticals and semiconductors. This means there is no immediate need for artificial gravity, allowing station manufacturers to first focus purely on deploying larger unitised volumes rapidly. Artificial gravity can be addressed later in the roadmap; however, working with a station geometry that can later adapt to artificial gravity will better streamline subsequent efforts to support long-duration stays and interplanetary travel. This is a huge issue with the ISS design — it can’t just become a spinning station that offers some artificial gravity.

That said, it is completely likely that there is no near-term return on investment on a space station. This is a bitter pill we must swallow while seeing their development as an opportunity to expand on existing industrial capacity that pushes the frontiers of the possible. That is precisely the legacy of Apollo to its credit.

For the first time since the Saturn rockets, we have a launcher– Starship – that offers an opportunity to once again develop unitised large space structures that extend beyond the concepts in Langley’s archives. Pursuing rotating space stations would weave perfectly into the new tapestry for space exploration being stitched by Starship; the successor to the Saturn V needs engineering as ambitious as Langley’s in the 1960s.