In which film, did the orange astronaut suit appear for the first time in cinema?

No need to look up at the stars. The answer is rather towards the Moon.

It is indeed in the movie Destination Moon, released in America in 1950, that the first orange astronaut suit made its very first appearance. It is also the first film in Technicolor that deals with space exploration.
The man behind the porthole thick orange protective layer is none other than actor John Archer, who plays Jim Barnes, an aviation tycoon who is helping to build the rocket that will take his squad to the moon and back.

Considered the very first hard sci-fi movie, it played a huge role in turning moon traveling into a possibility and not just a fantasy for the general audience.

A few years after its release, Hergé took inspiration from this pioneering work for his comics albums Destination Moon (1953) and Explorers On The Moon (1953).

Classy orange in space! © IMDB