Earth Landing System and Parachutes
what goes up must come down
The HAPP Earth Landing System (ELS) serves exactly the same function as the one on the Apollo Command Module: To ensure the craft lands without damage to itself or objects on the ground. The HAPP utilizes three large parachutes, each 1.5 meters / 60 inches in diameter, any one of which is sufficient to guarantee survival of the camera payload.
The HAPP deploys its chutes with a highly engineered cold gas mortar system. Major components are shown in the photo above. When triggered by the onboard computer, a CO2 cartridge is ruptured using a black powder charge and steel ram. The gas vents through a custom CNC-machined manifold and into the carbon fiber mortars.
Once the pressure reaches a critical level inside the mortars, the end caps are blown off as small nylon retaining pins finally yield to the stress. The parachutes are ejected at approximately 120 kph / 75 mph.
The entire ELS system, including parachutes and CO2 slug, weighs only 1006 grams. This achievement is the result of extensive calculations and testing to ensure reliable performance with minimum mass.
The parachutes are attached to structural components that are strong enough to withstand the shock of chute inflation, yet light enough to keep the system mass low. These tether arms were CNC-machined from 7075-T6 high strength aluminum alloy using a design that was optimized through multiple iterations of finite element modeling and 3D-printed prototypes.
Check out the blog for more details on the ELS development process, including slow motion videos of the mortars in action.