Factual error: The astronauts land on an asteroid said to orbit a binary star 655 million miles from Earth. This is impossible, as that distance would place them well within our solar system. In fact, they'd be inside the orbit of Saturn, where of course there aren't (nor could there be) any extraneous suns. The nearest star to our system is, in fact, trillions (not millions) of miles away.
Factual error: The scientists, having carefully charted their course to Earth, state that it is an 11 million mile trip from their planet. Not likely. Mars is our nearest planetary neighbor, and it's over 34 million miles away at its closest orbital approach. There are no planets any nearer to Earth than Mars. This is one of the very few cases where Rod Serling simply failed to do his astronomy homework.
Factual error: Decker is flying a Nieuport 28, which entered service in early 1918. However, the date is supposed to be March 5, 1917. Furthermore, the Nieuport was a French-built aircraft that was flown by the French and Americans but not the Royal Flying Corps.
Factual error: Corey is in solitary confinement on an asteroid. However, asteroids are neither large enough nor stable enough to hold an atmosphere. In addition, the distance from earth stated in the episode wouldn't be much further than the moon; there are no asteroids in a stable, regular orbit around the the moon or the earth, nor around the sun anywhere that close to earth.
Factual error: At the end of the episode, Major General George Harper looks out the window, puzzled. As he looks out the window, we see a palm tree in front of the building that is facing the window. Reims, France, is in northern France, where it is too cold to support that kind of tree.