ASA 100 is fine. If your cameras has a motor drive, use it. Always put your camera on a tripod if you can. If not, you could probably get away with hand holding it. Always make sure you have fresh, new batteries in your camera.
Night launches can be really spectacular, provided they are shot correctly.
The 100 ASA film will still work just fine. Don't forget the motor wind if you have one. You must have a tripod to do a time exposure shot. You need to set up a separate camera for this shot, but the effect will be worth it. This will show the flight path the shuttle takes as it climbs into orbit.