why are we still designing rockets with the same shape (cylinder/nose cone)? Do we still not have the technology to send up boxier/flatter objects with thrusters on like the 4 corners, making for more stable landing and re take off?
In: Physics
Rockets are really mass optimized since it’s so hard to get to orbit. We can only get a fraction of the rocket’s overall mass into orbit as payload.
So you want to maximize the surface area to volume ratio of the propellant tanks. The best shape for that is a sphere. Ideally you’d have a big ole sphere with an internal bulkhead to separate the fuel & oxidizer to minimize the material mass needed for the tanks. Spheres are also strong.
Then atmospheric drag comes into play. A true sphere would have too much drag due to it’s larger frontal area. It would also be unstable during ascent. So we “stretch” the sphere into domed cylinders to get the required volume while reducing the frontal area. (This also helps with transportation logistics but that’s besides the point).
You’ll actually see quite a few upper stages and kick stages that use spherical tanks since they are used in space, where drag isn’t an issue.
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