Where are the RAD Rockets and how do they work?
The conical backshell (part of the aeroshell) above the lander contains the three RAD solid rocket motors. Each of the three RAD rockets are powerful enough to lift a small truck, providing about a ton of force for nearly 4 seconds. They are activated by the computer in the lander. Electrical wires that run up the bridle close circuits in the backshell ignite the three rockets at the same instant. While the main RAD rockets can not be turned off once started, the lander and rover cut loose from inside their airbag cocoon at “just the right time” while the rockets fire. This separation has an additional benefit of launching the backshell and parachute up and away from the airbag-enshrouded lander. A cable cutter (a small pyrotechnic guillotine) inside of one of the lander petals does the job of releasing the lander when the vertical velocity has dropped to near zero through the rocket firings and the lander is around 10-15 meters (33-40 feet) above the ground.
