Draw a pencil line 36 inches above the floor. Use a paint roller to paint the lower half of the room medium blue and the top half light blue. After the paint dries, hang a border with pictures of planets around the room at chair rail height. Soak the pre-pasted border in water. Lay it right-side down on a flat surface and fold the ends to meet in the middle. Allow the border to "rest" for a five minutes to strengthen the glue. Unfold the border and hang it so the top of the border is 1/2 inch above the pencil line.
Use a roller blind kit to make roller blinds from crisp blue and white striped fabric. These kits have an adhesive on the front. Cut the fabric to fit the shade, remove the paper over the adhesive and smooth the fabric onto the shade. Hang the shades in the windows for a modern looking window treatment.
Make cornices from 6-inch moulding. Cut the ends of the moulding at a 45-degree angle with a miter box and saw. Cut 4-inch-long sides in the same way. Place the angles on the sides against the angles on the front to make a shape like the front of a box. Nail the sides to the front. Cover the cornices with silver leaf and hang them over the top of the roller shades to hide the hardware and give the windows a finished look.
Have a lamp shop turn a reproduction retro space toy into a lamp or use a lamp kit to do it yourself.
Hang metal shelves or wooden shelves covered with silver leaf on the wall. Lightweight shelves are designed to be hung from nails. Drive the nails into the walls with a hammer at the desired height. Display a collection of real or reproduction retro space toys on the shelves.
Make a comforter cover from black fabric with a Milky Way print. Cut two rectangles of fabric 2 inches wider and 6 inches longer than the comforter. You may have to sew two lengths of fabric together to make the pieces wide enough. Lay one piece on the floor right-side up and the other on top of it, right-side down. Pin the fabric together around the edges and sew the top and bottom together with a 1/2-inch seam allowance. Leave the top edge open. Turn the cover right-side out and make a 2-inch hem on the open side. Sew 1-inch squares of hook and loop tape every 3 inches along the opening to close the cover. Add pillow shams made from the same striped fabric used to make the roller shades. Use a sham pattern or make the shams the same way you made the comforter cover.