I'm stuck on a planet with no wood trees and no resources that are easy to exploit, and I want to get off of it as quickly as possible. What do I need to do to get my spaceship enough fuel to go to another planet?
As of 1.0 stable, only the purple colored Crystal Erchius and Liquid Erchius Fuel (requires upgraded Matter Manipulator) found on the surface and in the caverns on Moons (requires Breathing EPP to visit) can be used to fuel your spaceship. Note that travelling between planets in the same system does not require fuel.
Liquid Erchius Fuel can also be bought from the Infinity Express store on the Outpost, but at 5 pixels per unit it is rather expensive and should only be used as a last resort.