Rocket nozzle assembly with separable nozzle extension
Rocket nozzle assembly having a separable outboard nozzle extension for transitioning from a vacuum-optimized to an atmospheric-optimized configuration. The nozzle assembly includes an inboard divergent nozzle section attached at an interface with a detachable outboard divergent nozzle extension. The nozzle and extension are removably attached via a connector, such as a clamp and strap. An actuator causes the connector to release and thereby allow the extension to separate from the nozzle in flight. The nozzle assembly may be used with a reusable second stage rocket that lands on the ground or an ocean platform. The nozzle extension may be replaced in between flights.
1 . A rocket nozzle assembly comprising:
a nozzle removably coupled with a nozzle extension via a connector extending annularly about an interface of the nozzle and the nozzle extension, the nozzle extending from a first inboard end to a first outboard end, the first outboard end having a larger diameter than the first inboard end, the nozzle extension extending from a second inboard end to a second outboard end, the second outboard end having a larger diameter than the second inboard end, and the second inboard end removably coupled with the first outboard end; and
one or more actuators, each actuator comprising:
a first portion attached to a first end of the connector;
a second portion attached to a second, opposing end of the connector; and
an explosive bolt configured to releasably secure the first portion with the second portion, the explosive bolt having an elongated structure configured to extend linearly and tangentially along the interface from the first portion to the second portion, the elongated structure comprising a pyrotechnic charge configured to fracture and break the elongated structure to thereby release the second inboard end from the first outboard end.
2 . The rocket nozzle assembly of claim 1 , wherein the elongated structure of the explosive bolt comprises a longitudinal shaft and the pyrotechnic charge is configured to detonate to fracture the longitudinal shaft.
3 . The rocket nozzle assembly of claim 1 , wherein the pyrotechnic charge of the explosive bolt comprises an explosive shaped charge.
4 . The rocket nozzle assembly of claim 1 , wherein the elongated structure of the explosive bolt is configured to break into two or more parts after detonation.
5 . The rocket nozzle assembly of claim 1 , wherein the elongated structure of the explosive bolt comprises a structurally weakened portion.
6 . The rocket nozzle assembly of claim 5 , wherein the structurally weakened portion comprises a thinner width relative to another portion of the elongated structure.
7 . The rocket nozzle assembly of claim 5 , wherein the structurally weakened portion is scored.
8 . The rocket nozzle assembly of claim 5 , wherein the elongated structure is configured to fracture and split at the structurally weakened portion.
9 . The rocket nozzle assembly of claim 1 , wherein the explosive bolt is configured to be remotely activated.
10 . The rocket nozzle assembly of claim 1 , wherein the first portion is a first mount coupled to the first end of the connector, and wherein the second portion is a second mount coupled to the second, opposing end of the connector.
11 . The rocket nozzle assembly of claim 1 , wherein the first portion comprises a first cavity for receiving a first end of the explosive bolt, and wherein the second portion comprises a second cavity for receiving a second, opposite end of the explosive bolt.
12 . The rocket nozzle assembly of claim 1 , wherein the connector comprises a split strap comprising a first strap segment and a second strap segment.
13 . The rocket nozzle assembly of claim 12 , wherein the first portion is configured to couple to the first strap segment, and wherein the second portion is configured to couple to the second strap segment.
14 . The rocket nozzle assembly of claim 12 , wherein the one or more actuators comprises two actuators, with each actuator releasably securing together opposing ends of the first strap segment and the second strap segment.
15 . The rocket nozzle assembly of claim 1 , wherein the connector comprises a split clamp body.
16 . The rocket nozzle assembly of claim 1 , wherein the one or more actuators comprises a first actuator and a second actuator positioned on opposite sides of the interface.
17 . A method comprising:
operating a rocket engine of a rocket in a vacuum thrust mode, wherein the rocket engine comprises at least one nozzle assembly having a nozzle with an outboard end and a nozzle extension having an inboard end removably attached to the outboard end of the nozzle at an interface;
detonating a pyrotechnic device at an elongated structure of an explosive bolt extending tangentially along the interface to release a connector extending annularly about the at least one nozzle assembly to cause the nozzle extension to detach from the nozzle; and
operating the rocket engine in an atmospheric thrust mode using the nozzle without the nozzle extension.
18 . The method of claim 17 , wherein detonating the pyrotechnic device fractures the elongated structure securing the connector around the at least one nozzle assembly.
19 . The method of claim 17 , wherein detonating the pyrotechnic device comprises detonating a shaped explosive charge to fracture the elongated structure of the explosive bolt securing the connector around the at least one nozzle assembly.
20 . The method of claim 17 , further comprising releasing a clamp band from the interface of the nozzle and the nozzle extension.