Mars Rover: How a Self-Portrait Captured the Power of Curiosity
A crowd in New York City’s Times Square celebrated as the rover Curiosity made its way to the surface of Mars in 2012 NASA invited the world to share the triumph or catastrophe of the mission as it was happening TV cameras at NASA’s Jet Propulsion Laboratory JPL in Pasadena California beamed live images from mission control There team members wearing blue polo shirts sat at several rows of monitors Systems engineer Allen Chen was ready to narrate the coming events for both his team and audiences around the world Curiosity was almost at the end of its 345-million-mile 555-million-kilometer interplanetary voyage But the greatest challenge was ahead It had to survive a 7-minute plunge through the Martian atmosphere and land safely I worked 10 years for seven minutes to go well 2 Chen said Would Curiosity survive the drop and land on its wheels ready to roam and explore Or would it suffer the fate of previous Mars missions which had shot past the planet crashed or simply stopped communicating Since 1960 more than half of all missions to the red planet had failed We’ve got literally seven minutes to get from the top of the atmosphere to the surface of Mars going from 13,000 miles an hour to zero in perfect sequence perfect choreography perfect timing 3 engineer Tim Rivellini said in a
NASA video about the mission If any one thing doesn’t work just right it’s game over Mars Science Lab mission engineer Adam Steltzner worried that the entire mission rode on his Entry Descent and Landing EDL team the people responsible for depositing the rover safely on Mars It’s kind of an emotional time he said We’re wishing for the best We feel that we’ve done everything to deserve it and now it’s in the hands of the fates 4 As Curiosity’s capsule neared Mars the planet’s gravity drew it in Curiosity navigated downward blindly most of the way Its cameras and radar were packed inside the capsule’s darkness A NASA orbiter tracked the capsule and sent updates about the descent as radio signals to Earth Engineers could translate this heartbeat to learn the capsule’s speed altitude and path toward the surface Chen announced reassuringly Things are looking good 5 An artist’s concept of NASA’s Mars Science Laboratory’s spacecraft approaching Mars with Curiosity safely tucked inside Now more like spectators mission members monitored the unfolding drama A spacecraft takes months to travel from Earth to Mars and it takes 14 minutes or so for the signal from the spacecraft to make it to Earth that’s how far Mars is away from us 6 Steltzner explained Curiosity’s team could not guide the rover’s high-speed descent from Earth with that much delay So engineers had programmed Curiosity with
500,000 lines of computer code so it could operate on its own and steer itself to the rocky surface of the planet Now the team only needed to send the simple command Do_EDL and wait Because of the delay the spacecraft had already completed its descent when the JPL team got the signal saying the descent had started CURIOSITY’S EYES Spacecraft photographs have told Mars story to Earthlings since 1965 The Mariner spacecraft were originally designed without cameras but mission scientists thought they would be beneficial and they were added Today onboard cameras are prized Seventeen cameras are aboard Curiosity NASA selected Michael Malin to design Curiosity’s main cameras The former professor and JPL scientist has worked on spacecraft cameras since 1986 His cameras had taken literally millions of pictures from spacecraft launched to the Red Planet said geochemist Roger Wiens He seemed to know every square foot of Mars like his own backyard 7 As soon as Curiosity’s heat shield fell away one of Malin’s cameras started clicking The Mars Descent Imager snapped nearly 300 photographs making the first movie of a Mars landing The Mastcam designed by Malin is two cameras mounted 7 feet 2 m above the surface on a rotatable mast They take crisp colorful photographs that can be woven into dramatic 360-degree views Each camera sees differently one can focus narrowly while the other sees a wider perspective Mission engineer Adam Steltzner said that when images from both eyes are combined humans can relate to the distances just like as if they were there 8 With the help of the images scientists can guide the rover toward interesting rocks to investigate Curiosity has a 7-foot 2-m robotic arm that holds another Malin-designed camera called the Mars Hand Lens Imager MAHLI It does the same job as the magnifying lens that geologists on Earth wear around their necks MAHLI can photograph objects smaller than a human hair Close-up photographs showing the colors and structure of rocks can help scientists learn how they formed Michael Malin is the subject of a test photo at JPL by a Mastcam of his design
Chen’s updates were beamed around the world Curiosity’s capsule hit Mars atmosphere tearing along at 13,000 mph 20,920 kph In just over a minute friction spiked its temperature to 2,372 degrees Fahrenheit 1,300 degrees Celsius But though it glowed brightly relieved engineers learned that its heat shield had not burned away Chen announced that the capsule’s parachute had deployed to slow the plummeting craft Applause swept through the room around him The parachute weighed only about 100 pounds 45 kilograms but it could withstand 65,000 pounds 29,500 kg of force And there was more good news The capsule’s speed had fallen dramatically to 200 mph 320 kph Having served its purpose the heat shield needed to be discarded Keeping it would have made a safe landing impossible Mission engineer Steve Lee said they had to get that heat shield off It’s like a big lens cap blocking our view of the ground to the radar 9 Chen announced to applause We are in powered flight 10 Team members knew that meant the heat shield had dropped away and rockets had fired to fly Curiosity away from the parachute Radar directed the craft toward its target near the base of Mount Sharp in Gale Crater The landing was going according to plan yet an enormous challenge was just ahead NASA had used parachutes and rockets on Mars landings before but it had never used a sky crane maneuver To land the massive rover Curiosity would first hover just 65 feet 20 meters above the ground Cables would then lower the rover When its wheels rested on Mars soil explosives would fire and cut the cables freeing the rover from the sky crane which would soar off to crash far away If it went well said Steltzner we’d be lauded as brainiac brilliant guys and if it went poorly we would be obvious idiots 11
