In starbound I have a path down to the core, but it is very difficult to use my second jump to alleviate fall damage. Can I use water or a certain block to eliminate this, such as slime blocks in Minecraft?
Use Gravity Bubble tech/ability to instantly remove all velocity from a safe distance from the ground. You can then start falling again, with the fall distance reset to zero, which means no damage when you touch the ground.
Beware of trying to use Bouncy tech because if you don’t have enough space around you for the bouncy orb to appear, you will fall and receive damage. Only use it in wide drops, and even then consider Gravity Bubble for more safety.