 Then at the beginning of 1942, Hoelzer built an analog computer to calculate and simulate V-2 rocket trajectories Hoelzer's team also developed the Messina telemetry system.After evacuating Peenemünde for the Alpenfestung (Alpine Fortress), Hoelzer returned to Peenemünde via motorcycle to look for portions of his PhD dissertation prior to surrendering to United States forces at the end of World War II.Hoelzer was a student of Alwin Walther.