Research centered on three plasma confinement designs; the stellarator headed by Lyman Spitzer at the Princeton Plasma Physics Laboratory, the toroidal pinch or Perhapsatron led by James Tuck at the Los Alamos National Laboratory and the magnetic mirror devices at the Livermore National Laboratory led by Richard F. Post. By June, 1954 a preliminary study had been completed for a full scale "Model D" stellarator that would be over  long and produce 5,000 MW of electricity at a capital cost of $209 per kilowatt. However, each concept encountered unanticipated problems, in the form of plasma instabilities that prevented the requisite temperatures and pressures from being achieved, and it eventually became clear that sustained hydrogen fusion would not be developed quickly. Strauss left AEC in 1958 and his successor did not share Strauss' enthusiasm for fusion research. Consequently, Project Sherwood was relegated from a crash program to one that concentrated on basic research.