Not smashing itself to smithereens was only one of Curiosity’s achievements in the NASA rover’s first day on Mars. It also hit the bull’s-eye and did a first bit of science.
Curiosity on its Way. From 340 kilometers away, the HiRISE camera on the Mars Reconnaissance Orbiter caught the Curiosity rover inside its entry vehicle dangling from its parachute. The chute had been ejected from the entry vehicle by an explosive charge after atmospheric drag had slowed it to Mach 2. The descent vehicle with the rover tucked inside would soon drop out to fire its retrorockets.
That’s a 10! With Mars on the other side of the solar system, Curiosity landed about only 2 kilometers (at green diamond) from the center of its 20-kilometer-long targeted landing region (blue ellipse). That is a gold-medal win for the spacecraft’s guided entry system. To safely land in the confines of Gale crater near the science target at the foot of Mount Sharp, engineers borrowed the algorithm used to guide Apollo astronauts to their ocean landing targets 40 years ago. In the first application to another planet, the onboard autonomous system decided when Curiosity, in its heat-shield-equipped entry vehicle, was getting off track as it “surfed” through the atmosphere. The system then fired jets to put it back on course. The on-target delivery shows that engineers are ready in this one respect for NASA’s ultimate goal of returning rock samples from Mars. Engineers could target an earlier rover, which had collected samples, with a second rover that could retrieve the samples and then launch them off Mars for eventual return to Earth.
Down for Sure. Within minutes of touchdown, Curiosity sent back its first, rather crude images from the floor of Gale crater. After seven previous landings on Mars, the scene was familiar enough. Looking into the sun, one of the rover’s six wheels is on the near right side (distorted by the correction applied to the original fish-eye image). A flat, wind-swept plain in the middle ground is rimmed near the top center and right by the wall of Gale crater about 20 kilometers away. And then there is the instant science. The uniform size of the small gravel at the surface suggests material carried from the crater rim by water rather than debris blown out of nearby smaller impact craters. The wheel’s failure to dent the surface on landing shows the surface to be relatively hard. Scooping up the first soil sample may have to come elsewhere.