Расследование показало: уплотнительные кольца есть на обоих заглушках!
Сопловая заглушка на резьбе, кольца на графите. Передняя заглушка просто на кольцах, удерживается навинченным переходным отсеком.
Документ:
http://projectmanager.erfseds.googlepages.com/...
4. NOZZLE & FORWARD BULKHEAD INSTALLATION (BOOSTER)
Apply Dow Corning # 111 or similar grease to O-rings for the Booster nozzle an forward bulkhead (four O-rings total).
Install O-rings on Booster nozzle and forward bulkhead. Insert Booster nozzle into rear of casing until seated against insulative liner.
Slide Booster fin can/rear closure assembly onto rear of Booster motor and thread on until seated against Booster casing.
Insert Booster forward bulkhead into front of casing until seated against insulatvie liner.
Thread Booster forward closure/transition assembly into front of casing until seated firmly against casing.