This question already has an answer here:

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?

enter image description here 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?


marked as duplicate by JCRM, Nathan Tuggy, Organic Marble, Steve Linton, DrSheldon Dec 20 '18 at 0:28

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

  • $\begingroup$ Partial dupe of Why are the bottom of most stages flat? $\endgroup$ – Russell Borogove Dec 19 '18 at 21:05
  • $\begingroup$ To what end do you want a "Kármán rocket"? As soon as it's out of fuel, it's gonna reenter. $\endgroup$ – Russell Borogove Dec 19 '18 at 21:14
  • $\begingroup$ @RussellBorogove low altitude recon of another planet in theory you could get closer then ever and throttle up to escape orbit. $\endgroup$ – Muze Dec 20 '18 at 1:32
  • $\begingroup$ Bring a bigger telescope instead. $\endgroup$ – Russell Borogove Dec 20 '18 at 1:33
  • $\begingroup$ @RussellBorogove what data can be gathered from orbiting inside an atmosphere of a planet at the Kármán line compared to leo? $\endgroup$ – Muze Dec 20 '18 at 1:37

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.


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.


Not the answer you're looking for? Browse other questions tagged or ask your own question.