Abstract: An explosively driven latch-and-seal device for latching and sealing the ends of two telescoping members, such as a fixed nozzle section 14 and an extendible nozzle section 16 of a rocket engine. The forward end of the extendible nozzle 16 is formed with an axially extending flange 24. The rear end of the fixed nozzle 14 is formed with a radially extending projection 18 which has a recess 20 in its outer surface adjacent to the extendible nozzle flange 24. An explosively expandable tube (EET) 30 containing a mild detonating fuse (MDF) 32 is placed in contact with the flange 24 in such position with relation to the recess 20 that, when the MDF 32 is detonated, it expands to force the flange section in contact with it into the recess 20. A seal is formed between the deformed section of the flange 24 and the wall of the recess 20.