The First Astrowitches

<br> "Two young witches stow away on a space mission in an effort to contact a witches' space exploring expedition that has not been heard from in a long time." --summary/blurb from multiple library records and online dealers <br><br> "Another story about Witchard, a good boy witch in the fourth grade. Here he has an adventure in space with a new female buddy named Witcheena, who's cut from the same cloth." --listing in "For Children/Mummies, Ghouls and Other Scary Stuff" by Suzanne Curley, <i>Newsday</i> 1985-10-27 p55

Evidently this is a sequel to The Resident Witch (1970) and The Witch Who Saved Halloween (1971), which feature a girl witch named Witcheena and boy witch named Witchard. See the capsule review by Suzanne Curley (below, quoted in full).