Friction with Mars's tenuous atmosphere slowed the spacecraft as it descended but created temperatures up to 3,800 degrees Fahrenheit. A heat shield protected the rover inside from incineration. Meanwhile, a network of eight thrusters adjusted the trajectory toward the landing site. At an altitude of about seven miles, with Curiosity traveling at 900 miles per hour, a 50-foot-wide parachute deployed. Twenty-four seconds later, the probe ditched its heat shield and checked speed and altitude using onboard radar.