If you'd be interested in Sound Effects, but are not willing to make a large commitment, there are many individual parts that need sound effects someone could tackle. For example:
- The weird chittering of a specific alien.
- The ambiance of Luke's hospital room.
- The musical growling of the protoWampas
- The sounds of each individual space flight scene.
So the job can be just as big or as small as you're interested in.