Why have your fabric in blocks at all? Make a big rocket ship out of the appropriate colored fabrics, scrappy style. I mean, make the fabric out of appropriate scraps, cut out a big rocket ship. Use it in the center of your quilt. Then use your rocket ship fabric as the border around it. Fill in with any thing that hits your fancy - appliqued planets, shuttles, Mars Rovers, etc.
Lots of ways to use your fabric and showcase the rockets.