In order to go to space you have to download the Galacticraft mod and head to space any planet you want. Just download the Galacticraft mod and fly to the moon and back. The sun Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune. The sun can't be flown to. If you try to you will burn yourself. You clear out an area and build a launch pad and put your rocket on it and hop in and hold space to launch.