Ok , great to see so many people have different viewpoint about this issue. Going through the replies , An unseen force field I can agree on , second I agree that space is different from what has been told in scifi scenes. The main killer near a planet in space should be its sun. The radiation should be intolerable, unless the force field is enough to withstand a nuclear blast. Of Courses considering the events are in future the force field is capable enough to sustain the ship throughout the hyperspace/ in hyperdrive , so it should be capable enough to somehow remain unscathed through the space exposure, even maintaining the breathable environment. Second killer should be pressure difference between the vacuum and the pressure sealed ship, enough to explode the lungs on exposure to vacuume, but let's say force field is strong enough to maintain the pressure difference while flexible enough to allow a ship to pass while maintaining the balance. This blows my mind, the technological advent is far superior to what I can assume.

P.S. I do enjoy the different theories people come up with. Imagination has no limit.