Patent GB-997276-A (GB)
Title: Improvements in or relating to rocket engines or thrustors
IPC: G21D5/02
Filed: 1963-12-09
Abstract: 997,276. Rocket propulsion unit. THOMPSON RAMO WOOLDRIDGE Inc. Dec. 9, 1963 [Dec. 7, 1962], No. 48566/63. Heading F1J. [Also in Division G6] A rocket engine comprises a radio-isotope heat source, a housing surrounding the heat source and providing a passage for flow of propellant fluid past the heat source to be heated thereby, the housing having a propellant fluid inlet to one end of the passage and a nozzle adapted to receive the heated propellant fluid from the outlet end of the passage. In one embodiment propellant from a tank 11 passes through ducts 31, 33 to a rocket motor 25 having a propulsion nozzle 24, the rocket motor being secured to the tank by a frame assembly 12 comprising a plurality of longitudinal members 13, 14, 15, 16 and hoop members 18, 19, 21, 22, a collar 23 forming part of the frame being disposed around the throat of the nozzle 24. A series of radiation shields 26, 27, 28, 29 is disposed between the propellant tank and the rocket motor. The rocket motor is shown in Fig. 3 and comprises an inner shell 45 and a concentric outer shell 42 which define therebetween an annular passage through which propellant flows from the inlet end 43 to the propulsion nozzle 44, being heated as it does so by radiation from radio-isotope material contained in capsules 51, 52, 53, 54 disposed within the inner shell 45. A radiation shield 41 is disposed around the outer shell 42 in spaced relation thereto. The propellant fluid may be liquid hydrogen H 2 , ammonia NH 3 , hydrazine N 2 H 4  or water H 2 0. The radio-isotope material may be cerium dioxide (Ce-144 O 2 ), curium (Cm-242 or Cm-244) or plutonium (Pu-238) or compounds thereof. The rocket motor shown in Figs. 4 and 5 has means for controlling the temperature which comprises a radiation shield in the form of a clam shell comprising two semicylindrical segments 61, 62 pivotally mounted on shafts 63, 64. The shafts 63, 64 have pinions 68, 69 secured thereto, the pinions engaging racks 71, 72 formed in a frame member 73 which is connected to a temperature responsive capsule 74 mounted on a collar 75 which is disposed around the propellant fluid line 76. The degree of opening or closing of the radiation shield segments 61, 62 will thus be controlled so as to maintain safe operating temperature. In a further embodiment, Fig. 7, the radiation shield is in the form of a series of louvres 97 the degree of opening or closing of which is controlled by means of a bimetallic thermostatic actuator 102 which is secured at one end to the propellant fluid line 103 and at the outer end to a ring gear 101. Angular movement of the ring gear is arranged to vary the position of the louvres 97 from the closed position shown in broken lines to the open position shown in full lines. In Fig. 9 the propellant fluid flows into a ring manifold 113 and flows from there through openings 115 into the first pass 116 of a multiple pass heat exchanger. The fluid then passes in succession through the passes and then through a porous tungsten cylinder 123 which is disposed around the radio-isotope material contained within capsule 122. The heated propellant fluid discharges from the chamber 126 through the nozzle 125.