This question already has an answer here:
Scene Description in my Book: you are the squadron leader of a fighter wing in the midst of a great space battle. Your carrier ship has been destroyed and your fleet is on the retreat; they are being pursued by enemy bombers with their own fighter escort. Your squad decide to make a last stand to buy time for the fleet to get away, so they engage. The ensuing battle is fierce your fighters take out many but the enemy outnumbers you. One by one your squad HM’s (heart monitors) flat line you are the last. A blast takes out the front window and the cold grip of space fills the cockpit, you luckily put your pressurized helmet on just in time. You fight on for glory for freedom, till death takes you…
So how long would the fighter pilot survive for if the enemy doesn’t kill him first?
Environment (Important): Battle takes place away from sun so radiation will not be too much of a problem. The pilot has a pressurized helmet with air, so the air won’t just tear his lungs apart (I think). He does not have a proper space suit just a full body Flight suit with its insulation, his suit is tightly connected to his helmet (so air decompression should not kill him).
I'm thinking that he will still be killed very quickly because space is cold very cold -270.45 Celsius, -454.81 Fahrenheit but wanted to ask anyway.
If you want me to add any more details just ask.