Capsule

The astronaut 'Guy Taylor" is suffering from severe Hypoxia (Oxygen starvation). Three of the main symptoms of this are confusion, disorientation and acute behavioral change. Brain function can become impaired making it difficult to pay attention, making irrational decisions with poor judgment. After consultation the production team decided to go with these traits of the illness for the character from the moment he wakes up after blacking out. Taking him out of the environment he would normally have complete control of during his test pilot days and throwing him into an environment with little to no oxygen and see his character change from the consummate professional to someone barely holding it together on to the edge of his life.Hypoxia can also cause severe headaches and hallucinations, seeing and believing things are real that aren't there.

The images of Earth outside the windows of the Capsule used no CGI and were in fact a front projected 90 minute 4k video of one complete orbit of Earth shot from space.

The Capsule used was genuinely very small and claustrophobic. Edmund Kingsley playing 'Guy Taylor' could reach both walls of the Capsule without stretching his arms out fully. The Capsule contained seven key shooting hatches. The Director used lengthy takes of up to seventeen minutes to enhance the tension and claustrophobia and between takes, Edmund would frequently stay in the Capsule.

The rocket used to propel 'Hermes' into orbit is the Black Knight. These were British rockets being tested as vehicle for re-entry studies. Essentially designed as an Intercontinental Balistic Missile, it was manufactured by Saunders-Roe on the Isle of Wight, had its engines tested at High Down Rocket Test Site 1956 - 1959 and launched at Woomera in Australia. 22 vehicles were fired between 1958 and 1965.

The Soviet flag over the headquarters building was actually green since the local authority wouldn't allow the filmmakers to use a real Soviet flag. It was complete with a yellow 'Hammer & Sickle'. When filming was complete, the crew attempted to remove the flag but the flagpole rope snapped meaning the flagged remained flying over the building for a week before it was eventually recovered.