White Star is deal of the day at RPGNow/DTRPG

While I don't think it's particularly good.it's a decent sketch of an OSR Sci-Fi game and is on sale for $4.99 at RPGNow and DTRPG

Machinations of the Space Princess is the best OSR Sci-Fi game IMHO, and Starships & Spacemen isn't bad, though I would give the nod to White Star over it.

White Star now available from Barrel Rider Games

Whether a noble Star Knight protecting the universe from galactic tyranny, a hot shot pilot in the cockpit of the fastest stunt fighter in space, or an enigmatic Alien Mystic, classic science fiction adventure awaits you with White Star: White Box Science Fiction Roleplaying.
Based on Swords & Wizardry WhiteBox, White Star brings all the simple elegance  of WhiteBox out of the dungeon and into the stars! This complete roleplaying game includes seven new classes as well as rules for advanced technology, laser weaponry, space combat, and so much more!

Honestly, I think this has to be perhaps the most tortuous use of "White Box", but Barrel Rider puts out some good stuff. $9.99 for 132 pages in PDF, with a print option coming soon.