Here is the full list of all 15 Reentry - there are An Orbital Simulator achievements.
Docked with Agena
Flying in formation with another Gemini spacecraft.
Successfully completed the Gemini Academy Exam
Successfully completed the Mercury Academy Exam
Successfully completed the Apollo Academy Exam
Successfully completed the Lunar Module Academy Exam
Awarded to the astronaut who solves a problem using SCE to AUX in a MOCR session.
Awarded to the astronaut who performs a successful atmospheric entry without exceeding maximum G-loads.