All Spaceships have petrol engines. They run on unleaded petrol 91.
On each campervan's specification page you will find the fuel consumption of each campervan category. Fuel consumption is an estimate and will vary based on how you drive, the terrain you are driving, the average speed on the open road and urban usage.
See for more info about refuelling your Spaceship and checking the tyre pressure - always a smart thing to do when getting fuel, especially on long road trips.