After the propellant is used up, Sonic Wind will use two parachutes to slow down. The first parachute, just 29 inches in diameter, will create about 3000 pounds of drag at about 700mph. Another 1000-plus pounds of drag will already be acting on the now-powerless vehicle. This will decelerate the vehicle at about six-plus G's negative.
For the non-technical among us, a "G" is a unit of force equal to the force exerted by gravity on a body at rest and used to indicate the force to which the vehicle is subjected when accelerating or decelerating.
At 375mph the second chute, 7 feet in diameter, will be deployed. It will generate about 7000 pounds of drag and ten-plus G's of deceleration. The high-speed chute is on a forty-five foot tow line, and the low-speed chute is on a thirty foot line, so they will pull together. On average, Sonic Wind should slow about 150mph per second while deployment is underway.
At 100mph a rake-shaped brake will be rammed into the ice, under the vehicle and behind the center of gravity, braking and stabilizing. This brake will be similar to a bobsled's activated by compressed air on board - either air or helium bled from the pressure tank.
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