Abstract: An energy absorber comprises at least one layer of energy absorbing material, each layer having a plurality of cells within the respective layer of energy absorbing material, wherein each layer of energy absorbing material deforms when a force applied to the at least one layer of energy absorbing material reaches a threshold force level; a fluid filling the plurality of cells in each respective layer of energy absorbing material; and a skin covering external surfaces of each respective layer of energy absorbing material to contain the fluid within the cells of the respective layer of energy absorbing material until the force applied to the energy absorbing material causes the respective layer to deform; wherein the threshold force level for each layer of energy absorbing material is based on a viscosity of the fluid in the cells of the respective layer and on a crush strength of the respective layer of energy absorbing material.

Abstract: Systems and methods for underwater descent rate reduction are provided. In one embodiment, a method for underwater descent rate reduction for an underwater delivery vehicle is provided. The method comprises: opening a first valve based on a first hydrostatic pressure to permit water to flow into a first chamber of a hydrostatic pressure driven piston assembly; developing a pressure differential across a piston head separating the first chamber from a second chamber of the hydrostatic pressure driven piston assembly; pushing the piston head into the second chamber to extend a piston rod from the hydrostatic pressure driven piston assembly; and pivoting a deflecting flap downward into a direction of vehicle descent as the piston rod extends.

Abstract: Systems and methods for underwater descent rate reduction are provided. In one embodiment, a method for underwater descent rate reduction for an underwater delivery vehicle is provided. The method comprises: opening a first valve based on a first hydrostatic pressure to permit water to flow into a first chamber of a hydrostatic pressure driven piston assembly; developing a pressure differential across a piston head separating the first chamber from a second chamber of the hydrostatic pressure driven piston assembly; pushing the piston head into the second chamber to extend a piston rod from the hydrostatic pressure driven piston assembly; and pivoting a deflecting flap downward into a direction of vehicle descent as the piston rod extends.

Abstract: An energy absorber comprises at least one layer of energy absorbing material, each layer having a plurality of cells within the respective layer of energy absorbing material, wherein each layer of energy absorbing material deforms when a force applied to the at least one layer of energy absorbing material reaches a threshold force level; a fluid filling the plurality of cells in each respective layer of energy absorbing material; and a skin covering external surfaces of each respective layer of energy absorbing material to contain the fluid within the cells of the respective layer of energy absorbing material until the force applied to the energy absorbing material causes the respective layer to deform; wherein the threshold force level for each layer of energy absorbing material is based on a viscosity of the fluid in the cells of the respective layer and on a crush strength of the respective layer of energy absorbing material.