You'd need substantially more of them in Earth's gravity, and they're not going to save you from an explosion unless you make the crew capsule detachable.

The flip-and-land maneuver doesn't permit much "uh oh, it's gone wrong..." time to correct, either. I think they're going to have to go more in the direction of airliner-style "look, things kinda have to work" - there's no ejection seat, no parachute.