Mars Gas Hopper

 Link to SBIR Proposal Summary

The Mars Gas Hopper, or "gashopper," is a novel concept for propulsion of a robust Mars surface hopper vehicle which utilizes indigenous CO2 propellant to provide Mars exploration with greatly enhanced mobility. The gashopper will acquire CO2 gas from the Martian atmosphere, and store it in liquid form at a pressure of about 10 bar. When enough CO2 is stored to make a substantial ballistic trajectory hop to another Mars site of interest, the CO2 propellant tank will be moderately heated to raise it to 70 bar. The propellant is then run through a hot pellet bed to form high temperature gas that is expanded through a nozzle to produce thrust. The gashopper uses its CO2 propulsion system for major liftoff, attitude control, and landing propulsive burn(s), as required. Unlike chemical rockets, the gashopper’s exhaust will not contaminate the landing site with organics or water. The gashopper has a potential flight range of 10 to 100 kilometers. It can fly over terrain impassible to rovers, imaging as it flies, land to reconnoiter a remote location, and then fly again. Thus, it offers unique capabilities for Mars surface exploration.

Firing the hot graphite rod engine on the test stand. The visible CO2 exhaust shows we have utilized nearly all the heat capacity of the bed – hot exhaust is completely invisible.

The protoflight version of the gashopper chained to the floor for tethered static tests.

The protoflight version of the gas hopper undergoing flight/hover test. The initial mass of the hopper is 51 lbs, and the engine thrust is rated 40 lbf. A 20 lbf. assist from a counter balance allowed flight and provided upward guidance to avoid upsetting the gashopper.

The balloon assisted gashopper flight.

Left: CO2 gashopper before liftoff. Fully loaded, the gashopper weighs 51 lbs, and requires a little help from a helium weather balloon providing 20lbs of lift.

Center: Liftoff!

The gashopper ascends rapidly on about 50 lbs thrust. Right: The CO2 gashopper reached an estimated 40 meter apogee, then started downward towards a planned DC-X style landing.