Is a Kármán Rocket Possible?

Question

Why are the rockets not razor sharp, skinnier and taper off at both ends farther to cut through air better? Would making a rocket more aerodynamic allow it to be more efficient flying as a "Kármán plane"?

In other words: I know why the rocket bottom is flat and that is not what I am asking. I want to know why rockets are so blunt? Could a rocket be designed to be more aerodynamic on the second stage for a sustaining prolong burn and flight at the Kármán line?

I added this picture to show how the rocket could be tampered at both ends.

What would a "Kármán plane" look like, a bird, or a plane?

To what end do you want a "Kármán rocket"? As soon as it's out of fuel, it's gonna reenter. — Russell Borogove, Dec 19 '18 at 21:14
@RussellBorogove low altitude recon of another planet in theory you could get closer then ever and throttle up to escape orbit. — Muze, Dec 20 '18 at 01:32
@RussellBorogove what data can be gathered from orbiting inside an atmosphere of a planet at the Kármán line compared to leo? — Muze, Dec 20 '18 at 01:37

score 3 · Accepted Answer · answered Dec 19 '18 at 21:04

Why are the rockets not razor sharp

Because then the payload fairing would spend a lot of mass for space that wasn't useful to enclose a payload.

skinnier

The skinnier the rocket, the worse its volume-to-surface-area ratio, increasing its weight for a given capability. Additionally, some rockets like SpaceX's Falcon 9 are already skinny enough that flexion of the rocket body is a problem.

and tamper off at both ends

The back end isn't tapered for a number of reasons, discussed in an earlier QA.

Would making a rocket more aerodynamic allow it to be more efficient flying as a "Kármán plane"?

Less so, if anything; a longer, skinnier rocket is less able to make use of body lift. In any case, orbital launchers don't hang out at the Kármán line; they get past it and well above it in a big hurry.

For large launchers, aerodynamic drag produces only a small performance penalty -- only on the order of 1% of the ∆v produced is lost to drag. Making them pointier would increase weight or decrease payload volume to little benefit.

Is a Kármán Rocket Possible?

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