a large, bowl shaped cavity (dent) in the ground or on surface of the moon or a planet
crater
causing difficulty; hard to do or deal with; uncomfortable
awkward
a device for controlling the passage of fluid or air through a pipe, duct, etc (or something else)
valves
large and heavy or solid
massive
an opening of restricted size allowing for passage from one area to another
hatch
the mechanism for bringing about ignition in an internal combustion engine, typically activated by a key or switch (what turns the engine/motor on)
ignition
allow something to move, act, or flow freely
released
possessing great and impressive power or strength, especially on account of size
mighty
be carried slowly by a current of air or water
drift
a roughly circular line, route, or movement that starts and finishes at the same place
circuit
the height of an object or point in relation to sea level or ground level; great height
altitude
