tl;dr Glitch in or with Crew Transfers allows for cloning kerbonauts. /tl;dr I set out to do a simple science hogging mission around Mün. Mk2 3 crew pod with a jr science lab tacked on to the manoeuvre stage. I stuck to my plan and kept out three heroes in the command module until in a stable orbit @ 30k around Mün, and then transferred Jeb & Bob (Bill (Anders) is a personal hero of mine so he was left in command). Using Crew Transfer to simplify the crew tranfers. Ran some EVA's (with Bill) and some other science stuff and then it was time for more EVA's to collect data from the modules. For some reason, that I think is a bug/glitch, I was able to do the EVA with Jeb, who was in the science lab. After collecting the data I had him store his data in the command module and then board it, and this is where the odd things start. I now had Bill and Jeb in the command module and Bob and Jeb in the science module ... Which created a bit of an ethical dilemma, since I only had resources to land the command pod back on Kerbin, with space for 3 kerbonauts, and now I had 4 kerbonauts to care for. In the end I managed to rendezvous with my KISS (Kerbin Inadequate Space Station) and deposit one unit of Jeb there, before landing safely. So now I have two Jebs after a transporter accident, anyone knows if he has a second name?