Personalized Big Brother Astronaut T-Shirt. Big Brother Astronaut is so cool, he's riding a skateboard on the moon. You really have to look up to him! Cute gift for any big brother with big dreams. Everyone loves our Custom T-Shirts! Wardrobe essential for looking good, 24/7. 5.0 oz., pre-shrunk 100% cotton. Seamless 1x1 rib collar. Shoulder-to-shoulder taping. Double-needle stitched sleeves, bottom hem and front neck. Note: greys are a cotton/polyester blend.