Ad Astra was a science fiction fanzine published in the United States by Mark Reinsberg.
It ran five issues from May 1939 to November 1940. Two pages of the unfinished sixth issue appeared later in the fanzine Midwest Marky.
Contributors included Forrest J Ackerman (Voice of the Imagi-Nation), John W. Campbell Jr., Leslie A. Croutch, Hugo Gernsback, Jack Darrow, Jack Erman, Larry B. Farsaci (The Golden Atom), Joseph Gilbert (The Southern Star), J. Harvey Haggard, W. Lawrence Hamling, Charles D. Hornig (The Fantasy Fan), Erle Korshak, Henry Kuttner, Robert W. Lowndes, Robert A. Madle (Fantascience Digest), Gerald W. Meader, Richard I. Meyer, Raymond A. Palmer (The Comet), Clifford D. Simak, E.E. "Doc" Smith, Harry Warner, Jr. (Spaceways, Horizons), Art Widner (FanFare, YHOS), Jack Williamson, and Donald Wollheim (The Phantagraph).
Julian S. Krupa was the art editor, and provided the cover art for four of the five issues, and some interior artwork.