Automatic retro-rockets for landing.
Landertrons (left to right: XT-L1, XT-L2, XT-L2B) are small solid rocket motors which can be mounted on a craft and set to automatically fire in one of three modes:
SoftLanding, firing to brake a rocket's descent and prevent the rocket from breaking. Note that the engines will cut out when the craft is above the ground, so be ready for a bit of a drop!
ShortLanding, firing to arrest a spaceplane's mom