Each craft had to hit the atmosphere right , deploy its parachute , turn on retrorockets and inflate airbags just before touchdown 每架探測器必須以正確的角度進入大氣,展開降落傘,點燃制動火箭,并在著陸瞬間為安全氣囊充氣。
A retrorocket (short for retrograde rocket) is a rocket engine providing thrust opposing the motion of a vehicle, thereby causing it to decelerate. They have mostly been used in spacecraft.