@toonbat  
The Gameloft game says otherwise.

It might just be a high-altitude airplane pilot pressurized flight suit, like the U-2 pilots wore.

@TheMasterEraser
 
“If you’re wondering how he eats and breathes, and other science facts…”

It’s a diving suit. :P

@Kamazeustra  

 
It’s a matter of cultural familiarity. We “know” dropping an anvil on a cartoon will stun but not kill, may result in a cast but not a compound fracture with bloody bones sticking out of flesh. When it comes to the myth of Icarus, we’re told to just accept that the sun’s warmth causes the wax of the wings to soften and the feathers to fall out. And we accept it because it’s a myth.
 
That’s adapted in the pony world with the dew evaporating and the cobwebs bursting into flame. But we’ve also been told in a previous episode (Dragonshy) that the higher you go, the colder it gets. So clearly, there’s some heat source close to Cloudsdale in this episode, which we’re naturally going to assume is the sun; the same sun which has different physics: the princess raises and sets it herself.
 
Because the Pony world invites elaboration and worldbuilding in a way myths don’t, the audience wants an explanation, and is not satisfied with cartoon physics of “it just happens, okay?” So we theorize. Perhaps the air gets colder, then hotter, the higher you go. Or perhaps the sun is closer to the Pony world than it is in our world. The clouds are certainly closer to the ground, hundreds of feet and not thousands.
 
It’s a place for fertile imaginations, not for “it’s just a kids show, don’t overthink it.”

@Yet One More Idiot  
Absolutely, but I make sure to list why I’m putting a “grammar error” tag on an image so the artist has the chance to correct it. :)

@TheMasterEraser  

 
I flatly disagree. In a world built on classic cartoon physics like this: that also pulls liberally from Greek mythology for its world building, one particular Greek myth is a deal breaker?

@Kamazeustra  

 
Uh, yes we do? Just like you would if you were rewriting or expanding the story of Icarus, where either the sun did it, or the gods did it, or magic did it, or pride did it, but something made the wax melt. Of course it’s a reference to Icarus and Daedalus, but that’s no excuse for shoddy storytelling.

@Scorch215  
Except that they combusted. It was a direct reference to the story of Icarus. You don’t need to twist yourself into knots trying to explain cultural touchstones in terms of real world physics.

@Scorch215  
Mount Everest is about 5 miles high. Low Earth orbit is 100-200 miles high. The Sun is 93 million miles “high”.
 
Rarity’s wings were perfectly safe even if dried out; the only way they could’ve become hot enough to catch fire is if Rarity could fly a significant portion of the distance from Cloudsdale to Equestria’s Sun. That strongly implies Equestria’s Sun is MUCH closer, probably barely above the atmosphere.

@Background Pony Number 17  
you forget those wings were limited time and extremely delicate as they were made of dew, they ahd been in the so they effectivly dried out. not to metion if you go to the top of mount everest you will be high enough to see satallites almsot with the naked eye clearly adn the atmospher is thinner. less atmospher mens less sheiding you from the sun.
 
Generally i find if the show doesnt explain its reasonable to use our understanding of things at least loosely.

Maybe astronauts are works of science fiction in Equestria.

@Background Pony #9CB3  

 

 
It’s possible Equestria’s Sun and Moon are much closer than our own. Rarity was able to fly under her own power high enough that the Sun set fire to her gossamer wings, even though she could fly with them unharmed in Cloudsdale.

Just be honest, where’s oxygen?

Gilda mentioned “out of gas” and one other reference that might be at home in the early twentieth century.

@Darth Prime  
Rarity also meantioned Dash not looking like a Tank in her song about making the Gala dresses as well as there was a background pony who had a nuclear radiation symbol as their cutie mark as well as refrances to bullets at least once.

We have wizard costumes and no actual wizards.

[deleted]

I know it’s been said, but it bears repeating. People were dressing as space travelers, with varying degrees of scientific realism, for many years before Gagarin actually got there.

I don’t think their inter-planetary or anything, but I can see professional Pegasi flying into the highest level of atmosphere with just wingpower and a special suit or something.
 
 
It’s also fun to imagine the fist pony Astronaut to landing on the moon while NMM was there.

@iamnotabrony  

 
And then further fictionalised everything by making a movie out of it. xD
 
Maybe in Equestria, they have a similar movie - called Unicorn One!
 
lol sorry not sorry

Relevant: >>1040932

@Damaged  
To be honest, OP’s question only needs a comma after “costumes” and to remove the “but” from the start.
 
Also, having actual astronauts isn’t necessary for them to have astronaut costumes - the idea of needing to wear pressurised suits and breathing apparatus to go into space heavily predated actual space travel in the real world too.
 
For just one such example, the first actual spacesuits were designed in the 1930s, long before space travel was achieveable.
 
Meanwhile, one of the first uses of spacesuits in fictional instances of space travel appears to have been Edison’s Conquest of Mars, written in 1898.

we, those who still live IRL, had books,comics, and magazines that depicted that type of space suit nearly 75 years before we put a man in a studio to fake a moon landing.