NASA's rover Curiosity successfully carried out a highly challenging landing on Mars early Monday, transmitting images back to Earth after traveling hundreds of millions of miles through space to explore the red planet.

Scientists praised the landing Monday.

"This is a stunning achievement. The engineering went flawlessly," said Scott Hubbard, who was the first Mars program director at NASA headquarters and is now a consulting professor at Stanford University.

The 10 science instruments aboard Curiosity are in "perfect health," and testing and calibration are under way, NASA said Monday.

Some rover team specialists are analyzing the data from the landing, while others are preparing Curiosity for exploring Gale Crater, where it landed, NASA said. On its first full day on Mars, the rover is tasked with raising its high-gain antenna, enabling it to communicate directly with Earth at higher data rates. The primary method of transmitting data is through the orbiters, because that is more energy-efficient.

When asked whether anything had gone wrong during the landing, Jennifer Trosper, a mission manager with NASA's Jet Propulsion Laboratory in California, said simply, "No."

"There's a lot ahead of us, but so far we are just ecstatic about the performance of the vehicle," she told reporters at an afternoon news conference.

She said the rover will start sending weather data Tuesday but some of the "exciting science" won't begin for about nine Mars days.

"It does take time to check out the vehicle," she said.

Social media sites were bubbling with posts from enthusiastic Earthlings on Monday. The rover even has its own Twitter account, @MarsCuriosity. It informs readers: "FYI, I aim to send bigger, color pictures from Mars later this week once I've got my head up & Mastcam active #MSL"

The $2.6 billion Curiosity made its dramatic arrival on Martian terrain in a spectacle popularly known as the "seven minutes of terror."

This jaw-dropping landing process, involving a sky crane and the world's largest supersonic parachute, allowed the spacecraft carrying Curiosity to target the landing area that scientists had meticulously chosen.

The mission control in the Jet Propulsion Laboratory burst into cheers as the rover touched down Monday morning. Team members hugged and high-fived one another as Curiosity beamed back the first pictures from the planet, while some shed tears.

At the news conference, NASA showed off some of the initial images, including one of Mount Sharp, which rises 3.4 miles above the floor of the Gale Crater, according to NASA.

"We can see more clearly these pebbles all over the ground," said Joy Crisp, a deputy project scientist with the mission. "We can see that it is very flat. ... There are no obstacles for driving [the few miles from the landing site]" to Mount Sharp.

Scientists cannot tell yet how easy it will be to scoop up the surface material, she said.

"I think the science team has a lot of work to do to figure out how were these materials put there," she said. "Was water involved? We don't know yet."

President Barack Obama weighed in on the historic moment.

"The successful landing of Curiosity -- the most sophisticated roving laboratory ever to land on another planet -- marks an unprecedented feat of technology that will stand as a point of national pride far into the future," Obama said in a statement congratulating the NASA employees who had worked on the project.

The scientific community reacted with a mixture of elation and relief.