A preliminary design for a nuclear engine is presented. The engine is based
on the nuclear heating of a gas composed of H-2 and (242)mAm as a nuclear
fuel. This engine has an initial volume of 0.135 m(3) and at 64 MPa the cri
tical mass is 0.228 kg. The simplicity Am-242m Of the engine design might c
ompensate for the use of rare nuclear fuel, such as Am-242m. (C) 1999 Elsev
ier Science Ltd. All rights reserved.