NASA to athletic Mars rover: ‘Stick the landing’


PASADENA, Calif. — It’s NASA’s most ambitious and expensive Mars mission yet — and it begins with the red planet arrival late Sunday of the smartest interplanetary rover ever built. Also the most athletic.

Like an Olympic gymnast, it needs to “stick the landing.”

It won’t be easy. The complicated touchdown NASA designed for the Curiosity rover is so risky it’s been described as “seven minutes of terror” — the time it takes to go from 13,000 mph to a complete stop.

Scientists and engineers will be waiting anxiously 154 million miles away as the spacecraft plunges through Mars’ thin atmosphere, and in a new twist, attempts to slowly lower the rover to the bottom of a crater with cables.

By the time Earthlings receive first word of its fate, it will have planted six wheels on the ground — or tumbled itself into a metal graveyard.

If it succeeds, a video camera aboard the rover will have captured the most dramatic minutes for the first filming of a landing on another planet.

“It would be a major technological step forward if it works. It’s a big gamble,” said American University space policy analyst Howard McCurdy.

The future direction of Mars exploration is hanging on the outcome of this $2.5 billion science project to determine whether the environment was once suitable for microbes to live. Previous missions have found ice and signs that water once flowed. Curiosity will drill into rocks and soil in search of carbon and other elements.

Named for the Roman god of war, Mars is unforgiving with a hostile history of swallowing man-made spacecraft. It’s tough to fly there and even tougher to touch down. More than half of humanity’s attempts to land on Mars have ended in disaster. Only the U.S. has tasted success, but there’s no guarantee this time.

“You’ve done everything that you can think of to ensure mission success, but Mars can still throw you a curve,” said former NASA Mars czar Scott Hubbard who now teaches at Stanford University.

The Mini Cooper-sized spacecraft traveled 8 months to reach Mars. In a sort of celestial acrobatics, Curiosity will twist, turn and perform other maneuvers throughout the seven-minute thrill ride to the surface.

During its fiery plunge, Curiosity will brake by executing a series of S-curves — similar to how the space shuttle re-entered Earth’s atmosphere. At 900 mph, it will unfurl its huge parachute. It then will shed the heat shield that took the brunt of the atmospheric friction and switch on its ground-sensing radar.

A mile from the surface, Curiosity will jettison the parachute and fire up its rocket-powered backpack to slow it down until it hovers. Cables will unspool from the backpack and slowly lower the rover — at less than 2 mph. The cables keep the rocket engines from getting too close and kicking up dust.

Once the rover senses touchdown, the cords will be cut.

Even if the intricate choreography goes according to script, a freak dust storm, sudden gust of wind or other problem can mar the landing.

“The degree of difficulty is above a 10,” said Adam Steltzner, an engineer at NASA’s Jet Propulsion Laboratory, which manages the mission.

It takes 14 minutes for radio signals on Mars to travel to Earth. The lag means Curiosity will already be alive or dead by the time mission control finds out.

The rover’s landing target is Gale Crater near the Martian equator. It’s an ancient depression about the size of Connecticut and Rhode Island combined with a 3-mile-high mountain rising from the center of the crater floor.

Curiosity will explore whether the crater ever had the right environment for microorganisms to take hold.