Curiosity rover survives ‘7 minutes of terror,’ lands in Mars

Curiosity rover survives ‘7 minutes of terror,’ lands in Mars

By Alan Boyle, Science editor, NBC News

PASADENA, Calif. — After eight years of planning and eight months of interplanetary travel, NASA's Mars Science Laboratory pulled off a touchdown of Super Bowl proportions, all by itself. It even sent pictures from the goal line.

The spacecraft plunged through Mars' atmosphere, fired up a rocket-powered platform and lowered the car-sized, 1-ton Curiosity rover to its landing spot in 96-mile-wide (154-kilometer-wide) Gale Crater. Then the platform flew off to its own crash landing, while Curiosity sent out a text message basically saying, "I made it!"

That message was relayed by the orbiting Mars Odyssey satellite back to Earth. A radio telescope in Australia picked up the message and sent it here to NASA's Jet Propulsion Laboratory. When the blips of data appeared on the screens at JPL's mission control, the room erupted in cheers and hugs.

Because of the light-travel time between Mars and Earth, throngs of scientists and engineers — along with millions who were monitoring the action via television and the Internet — celebrated Curiosity's landing 14 minutes after it actually occurred.

Even the engineers who drew up the unprecedented plan for the landing admitted that it looked crazy. But the plan actually worked.

Minutes after the news of the landing broke, commentator Allen Chen brought more good news: "We have thumbnails!" Odyssey delivered two pictures showing the view from hazard avoidance cameras mounted on the rover.

The touchdown marked a $2.5 billion triumph for what Doug McCuistion, director of the Mars Exploration Program at NASA Headquarters, called "the Super Bowl of planetary exploration." Curiosity's primary mission is scheduled to last one full Martian year, or almost two Earth years — but scientists hope the nuclear-powered rover will keep going for years longer than that.

Curiosity is the biggest and most capable robotic laboratory ever sent to another celestial body: Its 10 scientific instruments are designed to study the chemistry of Mars' rocks, soil and atmosphere and determine whether the Red Planet had the right stuff to be habitable in ancient times.

The rover's prime target is a 3-mile-high (5-kilometer-high) mountain inside the crater, known as Aeolis Mons or Mount Sharp. The mountain's layers of rock could preserve billions of years' worth of geological history, shedding light on the planet's transition from its warmer, wetter past to its current cold, dry climate.

Some scientists think Curiosity could even detect the signs of present-day life, although NASA doesn't go that far.

RISKY DESCENT

The final phase of the Mars Science Laboratory's journey from Earth to Mars relied on technologies that had never been tried before in outer space — which is why it was called the "seven minutes of terror."

Seven minutes before landing, Mars Science Laboratory threw off its cruise stage and began its plunge through the planet's atmosphere at a speed of 13,200 mph (5,900 meters per second). It jettisoned two solid-tungsten weights, shifting the spacecraft's balance to become more like a wing. Small thrusters fired to put the craft through a series of "S" turns to adjust the trajectory.

The heat shield weathered temperatures ranging up to 3,800 degrees Fahrenheit (2,100 degrees Celsius). At an altitude of about 7 miles (11 kilometers), the spacecraft deployed its parachute, even while it was traveling at supersonic speeds.

First the heat shield dropped away. Then the parachute and the back shell flew off, leaving behind the rover and its rocket-powered "sky crane."

The sky crane handled the final phase of the slowdown by firing eight retro rockets. It descended to a height of about 65 feet (20 meters) and lowered the rover to the surface on the end of three cables. When the rover hit the ground, the cables were cut loose, and the sky crane blasted itself away from the landing site.

Adam Steltzner, the engineer in charge of drawing up the landing plan, said 79 explosive devices had to go off in just the right sequence — otherwise, the landing would have almost certainly failed.

NASA went with the seemingly crazy system because the 1-ton Curiosity is the heaviest payload ever delivered to the Martian surface. That weight is too heavy for the airbag-cushioned system that was used for previous Mars rovers, and too unstable to put on a lander with legs, Steltzner said.

Before the landing, Steltzner said he and his team were "rationally confident" and "emotionally terrified."

RUNNING A RELAY

When Curiosity touched down, it was out of Earth's direct line of sight, so three orbiting probes — NASA's Mars Odyssey and Mars Reconnaissance Orbiter, as well as the European Space Agency's Mars Express — monitored the data being sent out by the spacecraft. However, only Odyssey was capable of relaying the data back immediately, using what's called a "bent pipe" communication mode.

The telemetry was picked up by a radio telescope in Canberra, Australia, that's part of NASA's Deep Space Network, and relayed to the Jet Propulsion Laboratory. Mission controllers had broken out their jars of good-luck peanuts and anxiously awaited the arrival of the signal at the appointed time, 10:31 p.m. PT Sunday (1:31 a.m. ET Monday).

TV cameras monitored the action as the data came in — allowing the whole world to see the wave of relief and celebration roll through the room. More than a dozen VIPs were among those watching from JPL's campus in Pasadena.

The guest list included Black Eyed Peas musician Will.I.Am and actors Nichelle Nichols (Lt. Uhura on the original "Star Trek"), Morgan Freeman (from "Deep Impact" and "Through the Wormhole"), Wil Wheaton (Wesley Crusher on "Star Trek: Next Generation") and June Lockhart (from "Lost in Space" and "Lassie).

"What jollies!" Lockhart, 87, exclaimed during a quick visit to the JPL newsroom.