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Why is almost every spacecraft design in reality and sci-fi “pointed” like airplanes and sea ships, as if it’s only going to move in one direction on one plane?

Why is almost every spacecraft design in reality and sci-fi “pointed” like airplanes and sea ships, as if it’s only going to move in one direction on one plane? I’m guessing it’s because of the need to go through our atmosphere first. Wouldn’t an omnidirectional saucer-like shape (or spherical for larger ships) be more practical in 3D vacuum?

frabert 6y ago
Because that's what the public expects a thing that flies fast to look like. Also the Rule of cool applies here.
- 4gotunameagain 6y ago
  In actual engineering, the "rule of cool" only applies when two options appear to be exactly similar on all other aspects. Which is almost never.
- Razengan 6y ago
  Even then the Independence Day saucers and Borg cubes and spherical ships win out in the cool factor.
elygre 6y ago
I can think of two: * There would often be a need to separate human areas from more energy rich areas. A pointed solution often allows for this separation. * Current engine design has a "rear end" of some sort, which then implies "pointing"
phreeza 6y ago
If you are going fast enough, my understanding is that the interstellar medium is actually not that empty and such a shape might make sense again. At least that is the reason given in the Revelation Space saga.
- yetihehe 6y ago
  We don't yet need to go through interstellar medium. Currently vehicles which need to go through atmosphere are pointy. Vehicles which do not are not pointy (all current satellites).
  - phreeza 6y ago
    The question specifically included sci-fi.
    - detritus 6y ago
      and, critically, 'fast enough'.
gmueckl 6y ago
Sci-fi shows need designs that are "readable" by the viewer in split secons. That means unique, distinguishable silhouettes that also tell you at a glance where everything is moving in a shot. Pointy designs make that work excellently. As for the real world: there are plenty designs that are not pointy and flying: every satellite, the ISS, the lunar lander... however, all the designs that interact with earth's atmosphere have to respect aerodynamics. Thus, just about every ascent vehicle becomes pointy. Landers are different. The Soyuz return module doesn't look particularly pointy, for instance.
- the8472 6y ago
  almost every satellite. https://en.wikipedia.org/wiki/Gravity_Field_and_Steady-State_Ocean_Circulation_Explorer https://en.wikipedia.org/wiki/Gravity_Field_and_Steady-State...
the8472 6y ago
> Why is almost every spacecraft design in reality and sci-fi “pointed” like airplanes and sea ships, as if it’s only going to move in one direction on one plane? Because they have directional main engines. That does not strictly necessitate them to be pointy on the opposite end, but it at least requires some design that can distribute the force through the ship's body with the minimal amount of structural mass. E.g. an axial design that only has to withstand compressive forces, not shear forces. A bigger issue is the lack surface area for cooling. Not even The Expanse gets that one right.
- rriepe 6y ago
  Mass Effect is the only sci-fi I've come across that touches on the issue of building up heat in ships in space.
  - the8472 6y ago
    Banner of the Stars addressed it by cooling peak loads via disposable coolant instead of solely relying on radiative cooling. It became a limiting factor during a large-scale fleet battle.
  - pomian 6y ago
    Saturn Run, is a really interesting and fun book - by John Sandford. I highly recommend it, as a successful modern science fiction book. That topic is really well covered, with engineers solving all sorts of problems, including that one.
- skrebbel 6y ago
  > A bigger issue is the lack surface area for cooling. Not even The Expanse gets that one right. Care to elaborate? What's "lack surface area" and how does the Expanse get it wrong?
  - PeterisP 6y ago
    Whatever you do with internally generated energy, you either get it out or it accumulates, overheating you. You need 3-10 m^2 of radiators for every kW of power you use. If your ship is powered (I mean internal power, not engine exhaust) by a 1MW reactor, then you need radiators close to the scale of a football field pushing out waste heat, no matter what tech that reactor uses.
hyko 6y ago
They’re not? Obviously many of the spacecraft we’re used to spend a fair bit of time in the atmosphere, but even real manned spacecraft have come in different shapes and sizes (usually variations on spheres and/or cones).
bluGill 6y ago
In SciFi many ships have a military purpose and should be designed around the guns and the engines. Everything else used cramed in where there is space.

frabert 6y ago

Because that's what the public expects a thing that flies fast to look like. Also the Rule of cool applies here.

4gotunameagain 6y ago
In actual engineering, the "rule of cool" only applies when two options appear to be exactly similar on all other aspects. Which is almost never.
Razengan 6y ago
Even then the Independence Day saucers and Borg cubes and spherical ships win out in the cool factor.

elygre 6y ago

I can think of two: * There would often be a need to separate human areas from more energy rich areas. A pointed solution often allows for this separation. * Current engine design has a "rear end" of some sort, which then implies "pointing"

phreeza 6y ago

If you are going fast enough, my understanding is that the interstellar medium is actually not that empty and such a shape might make sense again. At least that is the reason given in the Revelation Space saga.

yetihehe 6y ago
We don't yet need to go through interstellar medium. Currently vehicles which need to go through atmosphere are pointy. Vehicles which do not are not pointy (all current satellites).
- phreeza 6y ago
  The question specifically included sci-fi.
  - detritus 6y ago
    and, critically, 'fast enough'.

gmueckl 6y ago

Sci-fi shows need designs that are "readable" by the viewer in split secons. That means unique, distinguishable silhouettes that also tell you at a glance where everything is moving in a shot. Pointy designs make that work excellently. As for the real world: there are plenty designs that are not pointy and flying: every satellite, the ISS, the lunar lander... however, all the designs that interact with earth's atmosphere have to respect aerodynamics. Thus, just about every ascent vehicle becomes pointy. Landers are different. The Soyuz return module doesn't look particularly pointy, for instance.

the8472 6y ago
almost every satellite. https://en.wikipedia.org/wiki/Gravity_Field_and_Steady-State_Ocean_Circulation_Explorer https://en.wikipedia.org/wiki/Gravity_Field_and_Steady-State...

the8472 6y ago

> Why is almost every spacecraft design in reality and sci-fi “pointed” like airplanes and sea ships, as if it’s only going to move in one direction on one plane? Because they have directional main engines. That does not strictly necessitate them to be pointy on the opposite end, but it at least requires some design that can distribute the force through the ship's body with the minimal amount of structural mass. E.g. an axial design that only has to withstand compressive forces, not shear forces. A bigger issue is the lack surface area for cooling. Not even The Expanse gets that one right.

rriepe 6y ago
Mass Effect is the only sci-fi I've come across that touches on the issue of building up heat in ships in space.
- the8472 6y ago
  Banner of the Stars addressed it by cooling peak loads via disposable coolant instead of solely relying on radiative cooling. It became a limiting factor during a large-scale fleet battle.
- pomian 6y ago
  Saturn Run, is a really interesting and fun book - by John Sandford. I highly recommend it, as a successful modern science fiction book. That topic is really well covered, with engineers solving all sorts of problems, including that one.
skrebbel 6y ago
> A bigger issue is the lack surface area for cooling. Not even The Expanse gets that one right. Care to elaborate? What's "lack surface area" and how does the Expanse get it wrong?
- PeterisP 6y ago
  Whatever you do with internally generated energy, you either get it out or it accumulates, overheating you. You need 3-10 m^2 of radiators for every kW of power you use. If your ship is powered (I mean internal power, not engine exhaust) by a 1MW reactor, then you need radiators close to the scale of a football field pushing out waste heat, no matter what tech that reactor uses.

hyko 6y ago

They’re not? Obviously many of the spacecraft we’re used to spend a fair bit of time in the atmosphere, but even real manned spacecraft have come in different shapes and sizes (usually variations on spheres and/or cones).

bluGill 6y ago

In SciFi many ships have a military purpose and should be designed around the guns and the engines. Everything else used cramed in where there is space.