By Conor White

The Curiosity rover is no longer alone on Mars.

NASA's InSight lander successfully touched down on the Red Planet Monday afternoon, but spectators will have months to wait before any results arrive.

"It's a 26-month mission," said Sarah Lewin, an associate editor at said. The first results from InSight's experiments are expected sometime in the spring.

InSight marks NASA's first mission to Mars since Curiosity began its journey in 2011. The launch was originally scheduled for 2016 before officials discovered a leak in the rocket's vacuum chamber. As a result, InSight missed its launch window. The delay and necessary repairs added almost $154 million to the mission's price tag, bringing it to a total cost of $814 million.

And even those years of planning didn't guarantee a success.

"Mars missions have like a 40 percent success rate across the world," Lewin said. "NASA is a little bit higher, so there was a definite chance it wouldn't work."

Now that it has safely landed, the probe will be responsible for drilling into Mars ー largely to determine the planet's composition. The robot will also monitor the planet for "Marsquakes."

"We've put a lot of things on Mars that are either orbiters, which are looking down on it, or rovers like Curiosity exploring the surface, but we really don't know what's going on inside," Lewin said.