I forgot to tell you: For rescue missions, use a remote-controlled* craft and make sure it's empty of personnel before launch.

*There are remote control modules available in the same place you pick your command capsules. All you have to do is make a spaceship like you normally would make it, with a command capsule and everything, but just clip on an extra remote control module. This allows the ship to either be remotely controlled with an empty capsule, or, be controlled by Kerbals in the capsule.