1964 in Hanover, so-called "post rockets" developed by the "hobby" rocket engineer Gerhard Zucker (1908-1985) were to be launched in Braunlage (Harz) on May 7, 1964 to carry appropriate "rocket mail". The second rocket launched exploded at a height of 4 meters, seriously injuring three of the spectators who were only 35 meters away, two of whom died shortly afterwards. A court case was initiated against Zucker for involuntary manslaughter and bodily injury, accusing him of violating regulations for private rocket operation. The case was eventually dismissed. However, as a consequence, private rocket launches were banned in the FRG.

A Hanover post office had prepared a special postmark for the rocket launches and already stamped it on covers that were to be carried by the postal rockets. However, the postmark was withdrawn 3 weeks before the event, for what reason is unknown.

Prepared cover for one of the rocket flights, but not flown. Withdrawn black special postmark Hanover. Green private stamp for the stamp exhibition "Jumelage Philatélique". Green sticker "Rocket Perpignan". Red cachet “ZUCKER rocket with spa management participation Braunlage / H.". Recipient's address pasted over with written note: "Special postmark approved by OPD Hanover withdrawn by BPM Bonn three weeks before issue. No longer applied"