The aerodynamic problems we reviewed earlier in the “How to create a UFO” series only apply to atmospheric flight. But a classic UFO should also fly in space. Is this scientifically possible? Can a disk-shaped spacecraft leave the atmosphere on its own and continue its travel in a vacuum? And if so, what method should it use to produce thrust and perform orbital maneuvers? Here we examine the changing conditions of space flight, whether a “flying saucer” can traverse the atmosphere, and what technologies could make this a reality.
Is it possible for a disk-shaped vehicle to traverse the atmosphere?
In science fiction, classic UFOs fly quite easily both in the atmosphere and in space. But a real vehicle needs to comply with strict ballistic conditions to enter orbit. In order for the object to orbit the Earth, it needs to reach first space velocity – about 7.8 km/s (28,100 km/h) in low orbit. For comparison, the fastest manned airplane (the X-15 rocketplane) accelerated only to ~2.2 km/s. It is obvious that no atmospheric flying vehicle, regardless of its shape, can just “flap its wings” and reach orbital velocity – rocket thrust and enormous energy are needed. The disk-shaped vehicle could theoretically be equipped with rocket engines or boosters. For example, if you took a disk-shaped vehicle and attached a powerful reusable booster to it (similar to how spacecraft are put into orbit), it could leave the atmosphere. But here comes the issue of aerodynamics at high speeds: when flying through dense layers of the atmosphere at a speed of several kilometers per second, the shape of the disk would be subjected to colossal aerodynamic loads and heating.
A disk is not the optimal shape for atmospheric breakout. In ballistic lift (nearly vertical), the shape is not as important, but in horizontal acceleration (and achieving orbit requires horizontal acceleration), the saucer will experience severe drag. The conical or needle-shaped rockets are chosen for a reason: they minimize air resistance at supersonic speed. In contrast, a disk at supersonic speed will create shock waves across the entire wide frontal fin – the pressure and temperature there will be extreme. But this method does not provide lift, and the chance of tipping over increases.
It’s worth noting that LRV‘s lenticular concept, with its lenticular shape, could go into space with nuclear propulsion. The shape of the double-convex lens (close to a disk) was attractive because it could potentially serve as a good heat shield during re-entry. Indeed, re-entry from orbit requires reducing velocity from ~8 km/s to zero, and spacecraft capsules have a blunt, rounded shape (e.g., the shape of the Starliner or modern Crew Dragon vehicles is close to disk-shaped to create a lot of drag and dissipate energy through the air). Thus, a disk entering the atmosphere can brake quite well and remain stable (’cause with an axis of symmetry, deflections are not so critical). But launching a disk into space is a different matter. Most likely, if someday there will be a “space saucer”, it will have a combined scheme: for example, first vertical ascent on a rocket (as a multiple stage), and already in space – the separation of the disk, which will be a maneuvering vehicle.
Behavior in a vacuum
Once outside the atmosphere, the disk-shaped vehicle faces another problem: there is no air in a vacuum, consequently all lift and aerodynamic control disappear. Spaceflight obeys the laws of orbital mechanics, and is controlled only by jet propulsion. In space, a disk is just a piece of metal: the shape no longer provides any advantage or disadvantage in terms of motion. That means that reactive control systems are needed for maneuvers and stabilization: small rocket engines or impulse nozzles at the edges of the vehicle that can turn it around, correct orbit, and so on. The International Space Station, for example, has gyrodynes (jet flywheels) and attitude-correcting thrusters – similar to what the “space disk” should have.
Thus, in vacuum, the disk shape is neutral – it doesn’t help to fly, but it doesn’t hinder either (except the mass distribution affects the moments of inertia at turns). However, if the disk plans to re-enter the atmosphere, the shape becomes critical for safe entry. There is a plus here: the disk can act as a good aerodynamic braking device. As previously mentioned, the capsules have a similar geometry – a hemisphere or truncated cone. A disk entering “flat” will create a lot of resistance and decelerate a lot in the upper layers (which is desirable to avoid overheating). But entry control is also difficult – you have to make sure the disk doesn’t fall sideways. Possible solution: rotation around a vertical axis as a stabilizer (like a bullet rotating in a barrel – stabilized gyroscopically). Or the use of small gas rudders, which in a rarefied atmosphere still work.
Technical constraints and potential solutions
The main obstacles to the “space saucer” are as follows:
Necessity of tremendous speed/energy to get into orbit. This requires rocket technology. Solution: use the disk only as an orbital maneuvering or entry/exit vehicle, paired with a booster.
Aerodynamic drag and heating during atmospheric acceleration. The disk will heat up like a frying pan during supersonic flight. Protection against heat (heat-resistant materials, ablative protection) is required. Alternatively, enter orbit almost vertically (then less friction time). It is possible to use a reusable carrier: first, the saucer is raised vertically on a rocket, and then separated.
No lifting in a vacuum. Needs to turn on the thrusters for any movement. In the space, the shape may be chosen based on other considerations: convenience of equipment placement, for example. Incidentally, the disk could rotate, creating artificial gravity on the rim (like the concepts of rotating space stations), but this doesn’t work well for small diameters (hundreds of meters are needed for comfortable gravity).
Atmosphere-space docking. A vehicle that can both fly in the air and maneuver in space is a design compromise. It’s necessary to have both wings/engines for air and rockets/fuel for vacuum. This leads to more complexity and more mass. One of the solutions is to make a hybrid engine that works like a jet engine in a dense atmosphere (grabs air), and above it switches to internal oxidizers like a rocket engine. Such direct-flow air-jet engines (SCRAMJETs) could, in theory, accelerate the vehicle to orbital speeds using atmospheric oxygen for part of the trajectory. Perhaps the disk-shaped vehicle could have a central rocket engine and a circular air intake around it – in the first stage it works like a SCRAMJET, in the second stage it works like a rocket. This direction is also more conceptual, but interesting.
Why create a “flying saucer”?
Today, a saucer is not so much about classical aerodynamics as it is about active control systems and artificial intelligence that enable non-standard shaped vehicles to fly.
In the future, if power supply and control systems become even more compact and plasmodynamic and magnetohydrodynamic engines become more efficient, a flying saucer could be a new stage in the evolution of unmanned and even manned aviation and offer the following advantages:
- Symmetry of design. The disc shape has perfect axial symmetry, making it equally favorable for movement in any direction.
- High maneuverability potential. A flying saucer can theoretically perform instantaneous maneuvers, as in science fiction — sharp jerks to the side, hovering at a point, rotation around its own axis.
- Compactness and aerodynamic braking. The disk can serve as a natural aerodynamic braking shield during re-entry.
- Potential for vertical takeoff and landing (VTOL). The combination of a compact shape and the use of an air cushion or active circulation allows the saucer to operate as a vertical takeoff and landing vehicle without the complex mechanics of folding wings or propellers.
- Universality. Disk-shaped vehicles are interesting as a platform for multi-medium transportation: theoretically, the disk can be adapted for flight in the air, movement in water (like an underwater drone), and with the appropriate technologies — even for space.
Lastly, it’s worth saying: physics does not prohibit disk flight in either the atmosphere or in space. It’s a matter of engineering skill and technology. On Earth, we have already created many “impossible” flying vehicles – from tailless stealth aircraft to rocketplanes. The disk is just another challenge. Progressively, with the development of active control systems and new methods of thrust generation, we are getting closer to having the first real “flying saucers” in our skies, and perhaps someday beyond.
