Rocket Fuel is a necessary resource if you wish to run your Spaceship. To make Rocket Fuel, you'll want to process Crude Oil through a Refinery. (You may also use Buildcraft Fuel -- they are currently interchangeable)
Once you have Rocket Fuel, you're going to want to either pipe it or manually carry it (via a Filled Fuel Canister) to a Fuel Loader attached to your Rocket Launch Pad. When the fuel has been placed in the Fuel Loader and then loaded into the Spaceship you'll be ready to launch. If you don't have a Fuel Loader or cannot power one readily, you may also manually load fuel into the Spaceship by pressing 'F' while in the Spaceship and dragging the canister into the fuel slot.
There was a griefer that edited this, I fixed it but I don't remember the crafting recipe but I will fix that later too soon