His doctoral thesis was Line-of-Sight Guidance Techniques for Manned Orbital Rendezvous, earning him the nickname "Dr. Rendezvous" from fellow astronauts.
Vďaka jeho doktorandskej práci s názvom Line-of-Sight Guidance Techniques for Manned Orbital Rendezvous dostal od iných astronautov prezývku „Dr. Rendezvous“.