"Space Craft Digest" was a UFO magazine published in the 1950s in the USA by the "Pacific Lemurian Society". This publication contended that the USA should research and develop the technology used by UFOs, contending that "In the near future, someone on this planet is going to streak ahead a thousand years with one brilliant flash ... If this is not a citizen of the U.S. we may find our whole western civilization in jeopardy".
I think this publication is in the public domain under the copyright rules that apply to unregistered material published in the USA pre-1964.
I have therefore uploaded scans helpfully produced by the AFU in Sweden.
All the best,