The Male Gaze

[Chris2Balls [:B]]

Ripley is in the escape pod, relieved, and decides to undress into her underwear, to prepare to go into her cryogenic bed thing.
I guess this is the first scene of privacy in Alien, which becomes intimacy in a way with our presence as spectators: it's the first time we see a relaxed Ripley, who isn't acting tough in the presence of men, it's the real her. It is of course consequently voyeuristic.
There is quite a blatant ass shot at 0:53. 1:12 onwards it's definitely got her sex in clear view.
Now, why is it filmed like this? Why is Ripley in a skimpy outfit?
I think, first of all, it's to highlight a fragility. A sensuous fragility, because her underwear reveals her body, and it emphasises on how vulnerable she is in opposition to the covered, stern, tough and unreachable Ripley of before. She's now within reach of the Alien, she is now very near us in the shots. The Alien is a very phallic character, an aggressor. Ripley is female. Putting forth shots of her sex and backside to me reminisces the implied rape/torture/mutilation carried out on the other woman by the Alien, and just how little there is between her and it.
I guess you could say at this point in the film there really is a relation that's built between us and her. We're in that closet with her, feeling the stress, the adrenaline, the tension.

She then gets into a spacesuit, and becomes the bold, confident and strong Ripley again.

As a side note, I think Alien is mostly about male libido.