The combinaison your crewmembers and yourself are wearing is a bit... special.
For example, they're almost never allowed to take it off, as it give them a quasi-optimal protection against the void of space as well as the unknown atmosphere of a foreign planet.
Also, the "helmet" used by our brave explorers isn't actually made of plexiglas, or glass, or any matter that could potentially break : it's actually a bubble.
Every time a depressurization of the ship occurs, or if a crewmember happens to be thrown into space, or enter the atmosphere of an unscanned planet, the bubble of the Omnivest™ will automatically deploy itself to ensure its wearer's survival at the best of its capacity.
Each Omnivest™ is able to endure temperatures ranging from hundreds of Celcius degrees to well bellow the freezing point, but the bubble do have a flaw : even though it's nearly impossible to break or pop it, the bubble itself doesn't really protect its user agaisnt potential physical injuries.
Basically, if someone decided to punch you, the fist would not be stopped by the bubble (because if that broke the bubble, it would potentially expose you to the atmosphere or absence of atmosphere of the place), but it would be the cleanest fist to ever break your jaw !
(Illustration made by the great, the cosmic, the one and only Mistexpi)
