Nothing about launching a rocket into space is easy. But the easiest part is now over for the Mars Science Lab, or MSL, with its liftoff on an Atlas rocket behind it.

If it works, Deputy Project Manager Ashwin Vasavada said, the implications are enormous. “I think the best way to say why we’re so excited about this mission is that it sets us up for the future of finally answering that age-old question of does life exist on other planets.”

From now until August 6, the vehicle will travel more than 350 million miles through the void of space. On that date, if you were a Martian looking up, you might see MSL streaking across the sky about 3 p.m., Mars time.

As it descends, a rover named Curiosity will be lowered to the surface. It won’t be easy. This will be nail-biting time and hold-your-breath moments for the mission scientists and engineers.

In the past, NASA’s rovers have used airbags to land and bounce across the surface until coming to stop. But Curiosity, at 2,000 pounds, is too big. The Cadillac of rovers, it’s the size of a car. “We’re choosing to make the rovers bigger and bigger, said Jessica Samuels, a surface systems engineer. “Because we want to cover more ground.”

Because of its size, engineers at NASA’s Jet Propulsion Laboratory in California had to design a whole new landing system. Curiosity will be lowered by tethers from its descent stage. Once it’s on the ground, the cables will be severed, the descent stage will fly off, and the six-wheeled rover will be on its own. “So when we land,” Samuels said, “we’ll be ready to go, wheels out, ready to hit the surface.”

If all this works, Curiosity will be the most sophisticated vehicle ever to operate on the Red Planet. “This rover for the time gives us the ability to take a whole geological laboratory to Mars and then feed it samples of Martian rock,” Vasavada said.

Armed with a drill on the end of a robotic arm, Curiosity can bore into rock, scoop up samples and place them in its onboard laboratory. Because Mars has no ozone layer to protect it, scientists believe the surface is sterile. “On Mars,” said Chief Engineer Rob Manning, “if life exists as single-cell organisms, or if it ever existed, we believe it will be under the ground or inside rocks.”

The suite of instruments can tell scientists what kinds of minerals are in the rock and their chemistry, including perhaps the presence of organic material. That would be the Holy Grail of Martian exploration, Vasavada said. “Now if we discover organic material on Mars, then it gets very exciting. The chances of it may be low, but the payoff is huge. Organic materials are required for life as we know it.”

But just the presence of the building blocks wouldn’t mean that life exists. “If you go to the driest desert on Earth, can you find life on your samples if you do a year robotic study? Probably not. It’s actually quite difficult. Life has to stick up and make itself seen,” Manning said.

The sophisticated descent system also gives the science team a shot at a pinpoint landing. The touchdown spot is the Gale Crater, inside of which sits a three-mile-high layered mountain. Each layer, the mission scientists believe, can tell them the history of Mars, when it was wet and more Earthlike, and when it began to change. “So the goal is to go back in time to these environments and figure out if they really, truly could have supported life,” Vasavada said.

And if water ever flowed on Mars, the scientists believe, it might have pooled in the crater. It won’t be there any longer, but evidence could be just below the surface.  From Curiosity’s cameras, the mission team will select targets, then send commands telling the rover where to go and what to sample.

The $2.5 billion mission comes with high risk but the potential for high reward. Finding evidence that life could have existed would easily validate the price tag and likely reinvigorate a desire to hasten Mars exploration.