Sabotage in Space: A Science Fiction, Pulp, Young Readers, Post-1930 Classic By Carey Rockwell! AAA+++

What started out as an innocent campus prank at Space Academy almost cost the Polaris unit the chance to become officers in the Solar Guard. For punishment, Tom, Roger, and Astro were assigned to spend all their spare time on guard duty in the vicinity of a new building which housed the latest hush-hush project so important to the solar universe.