-2

What are the reasons why planes can't go into space?

https://thehumble.co.uk/aircraft-with-forward-swept-wings/

Pondlife
  • 71,714
  • 21
  • 214
  • 410
Dilshan Hiruna
  • 1
  • What does a forward-swept aircraft wing have to do with your question? Can you define "space"? Altitude higher than the Karman line? – Ron Beyer Dec 08 '19 at 01:15
  • Closely related – Pondlife Dec 08 '19 at 01:31
  • 1
    Err... Have you forgotten the Space Shuttle? Or the Air Force's X37b? – jamesqf Dec 08 '19 at 01:54
  • They can, and have. So many of them actually. Especially into space, not orbit. You have rocket powered ones like X15 and space shuttle. Rocket carried ones like X37 and Buran, jet powered ones like Mig-31. – user3528438 Dec 08 '19 at 04:24
  • the space shuttle was just a glider, right ? – Fattie Dec 08 '19 at 17:09
  • Dilshan, note that propellor aircraft certainly could not go to space. – Fattie Dec 08 '19 at 17:09
  • Dilshan, if you're still reading and want an extremely simple one-sentence answer, it's that: "Wings, and airplane motors, only work in the air." That's it. In the same way a "boat" couldn't work in space since "keels only work in water". – Fattie Dec 08 '19 at 17:17
  • @Fattie: No, the Space Shuttle took off under power, and glided to a landing. Which is essentially what you do in most small planes - pull the power back to idle somewhere on base or final. Besides, gliders are airplanes. Launching something like the X37b (if it doesn't actually have its own engines) is no different, in principle, from getting a tow to launch your sailplane. – jamesqf Dec 08 '19 at 17:31
  • @jamesqf , I think it's a stretch to say it "took off under power". it was just an object attached to a space rocket, as it were! heh! it just had utterly no connection to "aeronautics", "airplanes" when taking off, I think! :) I think the point is for the OP, the "space shuttle" certainly didn't "fly ["in any way like an airplane"] in space". – Fattie Dec 08 '19 at 23:02
  • 1
    @Fattie: On the contrary, the Shuttle had its own engines, It used a droppable fuel tank and rocket-assisted takeoff, both of which have been used by military airplanes since WWII. Likewise, there are airplanes that can do vertical takeoffs (the Harrier, the Convair Pogo: https://en.wikipedia.org/wiki/Convair_XFY_Pogo ) and vertical climbs under power. – jamesqf Dec 10 '19 at 04:51

2 Answers2

4

Basically it's because they have engines that need atmospheric oxygen for thrust. Stick a rocket motor on it, with enough power to achieve escape velocity, and provide a self contained compressed gas source for pressurization at say 10 or 15 thousand feet cabin altitude and make the pressure hull fully air tight (airplanes normally leak quite a lot), and away you go to the stars if you like.

Of course, now you have to get back down without burning up so you need maneuvering thrusters to control attitude on re-entry, and you need some kind of heat shield...

After working all that out, voila! You end up with the Space Shuttle.

John K
  • 130,987
  • 11
  • 286
  • 467
  • Oddly enough the Buran had air-breathing jet engines. – Ron Beyer Dec 08 '19 at 02:32
  • Wasn't that for landing or something? – John K Dec 08 '19 at 02:37
  • Yeah, it was only to be used during reentry and landing. – Ron Beyer Dec 08 '19 at 02:44
  • The rest of the rocket was just there to carry the fuel needed to get the space shuttle up there. – Jan Dec 08 '19 at 10:16
  • Just for the record, I feel the "pressurized" bit is pretty irrelevant, right? A number of aircraft (military etc) are not pressurized right? The dudes have to wear spacesuits. Actually, was the Vostok and other early craft pressurized or did they have to wear suits exclusively?? – Fattie Dec 08 '19 at 17:12
  • They were pressurized but they wore space suits in case. If you run at 8 psi which most airliners run at, that gives you a 15000 ft cabin in space which most people can tolerate, more so if the oxygen content is increased. – John K Dec 08 '19 at 19:22
1

There are two major problems with trying to take an aeroplane to space.

  1. The engines are air breathing, this makes them far more efficient than rocket engines, but means they only work over a relatively narrow range of speeds and atmospheric densities.
  2. Planes are designed with wings to use aerodynamic lift, this is far more efficient than directing thrust downwards, but again a given set of wings is only effective over a relatively narrow range of speeds and atmospheric densities.

There is a big gap between the highest speed/thinnest atmosphere at which aerodynamic flight with air breathing engines is practical and the lowest speed/thickest atmosphere at which orbit is practical. So-far the only successful way to get into orbit has been to brute-force through with big multi-stage rockets.

Peter Green
  • 1,681
  • 12
  • 15