– could the space shuttle just fly into space like a plane, rather than being propelled vertically by rockets?
In: 48
Here’s my best ELI5 which builds off the air gets thinner piece.
Imagine you are at the bottom of a pool and start swimming up. You move upward towards the surface because there is enough stuff (water) for you to push downward on. Then why when you reach the surface, you can’t just keep swimming into the sky? Because although there is stuff (air), there is not enough for you to push down on.
It works similarly for airplanes. They can push down on air, but once there isn’t enough air, even they cannot push down on nothing.
ELI10
Picture sitting on ice with 10 friends all in a line. The 2nd person pushes on the front person. The first person goes forward and the 9 people go backward. The new 2nd person pushes off on the new first person. This person flies forward and the 8 remaining continue backward. Repeat this process until there is one person left. They have moved quite a distance.
This is how the rocket gets out of the atmosphere. It bring the fuel (people) and started exploding it (pushing them) away until it can push itself out of the atmosphere where there isn’t enough air for the plane to get out by itself.
IIRC, the orbiter itself was nothing more than a glorified glider. Sure, it had engines but those were more for steering upon reentry than having any real effect on takeoff. (Source: reading everything I could about the shuttle in the 80’s, cuz space = cool.)
No it cannot, the better question would be “why?”
Also, I must note that the shuttle has terrible aerodynamics.
Pilots train to fly the shuttle by flying a business jet with engines not just turned off, but thrusting in *reverse*.
[Amusing source and info. ](https://youtu.be/Jb4prVsXkZU)
Absolutely not. Despite the appearance the space shuttle does not function like a plane that has wings. The large wing like structure is actually a brake providing drag over a larger surface area. The space shuttle isn’t really capable of atmospheric flight, it’s just moving so ridiculously fast it covers huge distances while falling back to earth. Think of the space shuttle like a parachute, a one way trip back down, but this is far too heavy for the atmosphere to push back up.
The shuttle, no.
However, this is a proposed method for getting to space called a spaceplane. A space plane would be equipped with engines that can work in an atmosphere like a airplane, and also in space, like a rocket.
The difficulty is that transition from atmosphere to space. An airplane needs air, both to run its engines, but also to glide on, which limits how high it can fly. Above that, it’s all about orbital mechanics and rockets.
Spaceplanes are hard to get right, because wings are heavy, and beyond the technical challenge of building hybrid engines, they’re also heavier than a simple rocket.
Another way to take advantage of the efficiency of airplanes is to attach a rocket to a plane, carry it up high and release it like a missile. This is called “air launch to orbit”. It doesn’t really see much use outside of some experimental vehicles.
As you rise higher above the surface, the air density reduces. This means you need larger, more efficient wings to maintain lift – or you need bigger engines to go faster to get more lift from the same size wing.
Both of these things require more *weight* which sends you back around the same spiral of needing either bigger wings or bigger engines. You also start to reach the limits of materials – for example, the bending forces in the wing structure and wing roots grow, so you either need a stronger material or more weight to keep things strong enough.
To get into orbit, you also need to gain a vast amount of speed – for example the ISS orbits at 7660m/s or about 17,000 mph, at 400km altitude. If you attempt to gain that sort of speed inside earth’s atmosphere the drag losses become unsustainable. For reference, the SR-71 flew at 2400mph at 27km in altitude and the air friction was so severe that the entire plane is titanium.
Therefore, one way to think about it is that the vertical launch profile is the quickest way to punch through the thick air as quickly as possible and minimise the frictional losses. Then you can accelerate to orbital speeds with minimal losses once above ~100km altitude.
You know the Kármán line that (kinda) separates space from not space? that line is defined by the point where wings no longer generate lift, so you can only fly up to ~100km but then you’ll get stuck.
People on the KSP realism mod like to use planes for re-usable launches since the spaceX method (booster catching) is poorly supported. this is because a lot of your losses with a rocket are due to aerodynamics, so you can cut out a bunch of your losses by doing most of your sideways acceleration at ~80km with a ramjet, but then you still need a two stage rocket to get the rest of the way to orbit from 80km.
the reason why this isn’t popular IRL is because the engineering of such a craft would be ridiculously complicated, and you’d need to haul a ramjet that you aren’t using to and from orbit from 80km, so it’s just easier to brute force it, especially if you can re-use your first and second stage boosters already.
What WAS used IRL was an airlaunch – essentially strap the rocket to an airplane (usually an out of service bomber) and launch it from that airplane’s service ceiling instead of the ground. This was very popular for the Space planes that were being launched before we had orbital rocket capabilities (X-15 is the most famous example), but those planes were more rockets with some wings and aerodynamics attached, instead of planes with rockets on them.
A fish needs water to swim, and a plane needs air to fly.
An aquatic animal can gain enough speed to breach the surface and glide for a while, and in theory a plane could go fast enough to “breach” our atmosphere and glide into space. But the animal cannot really swim in the air without water, and a plane can’t really “fly” (the way planes do) in space without air.
That’s probably about as far as you can take the analogy.
There are other posts that explain the mechanics of flight pretty well, but I just wanted to throw in a super-simple analogy to give a reader the beginnings of the idea and get them into the mindset to understand the deeper answers.
Airplanes achieve lift using the atmosphere and jet engines provide thrust using atmospheric air. Space doesn’t have air, so they have to use something else to propel the vehicle. Hence, rocket boosters and you have to BYO fuel.
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