Only found deep in terrestrial environments, lava pockets continually drip their molten slag. Lava Droplets can be collected simply by letting them hit you, or by using vibrations to empty out a lava pocket and then drilling into it.
Care should be taken around lava as it will both damage and raise your heat if it falls on you; which can lead to further damage if you are close to overheating.
Can be found at:Edit
Terrestrial Planet: 140-250 depth (only in volcanic or temperate environments)
Can be obtained by manuvering under a dripping lava pocket.
Remember, you will recieve damage from each droplet and your heat will rise, so it is advisable to prepare many repair items. In this case, it is recommended to use Titanium Ore and Iron Ore to recover HP and Topaz Crystals to recover fuel.