Early Monday morning, NASA's Curiosity rover is expected to become the seventh, and easily most ambitious, rover mankind has ever attempted to send to Mars.
Humanity's history with successfully operating rovers on Mars is mixed: NASA is the only space agency that has ever successfully operated a vehicle on Mars. Previous attempts by the Soviet Union and Great Britain either crashed or never communicated back to Earth.
NASA, on the other hand, is still operating the Opportunity rover, which landed in 2004. Its twin, Spirit, got stuck in the sand in late 2009 and ceased all communication in early 2010.
Despite NASA's successes, landing Curiosity will be no small task. It's about the size and weight of a Mini Cooper and about five times as heavy as Opportunity.
Once the Mars Science Laboratory, as the entire package has been dubbed, hits the planet's atmosphere, it'll take about seven minutes for it to land, which NASA has dubbed "Curiosity's Seven Minutes of Terror." The entire landing process will be fully automated, and is the most complicated landing ever attempted.
"We've got literally seven minutes to get from 13,000 miles an hour to zero," Tom Rivellini, an engineer with NASA's Jet Propulsion Laboratory, explains in a video about the landing process. "If any one thing doesn't work just right, it's game over."
As the lab enters the Martian atmosphere, its heat shield will reach temperatures of 1,600 degrees—once it's through, the heat shield will be cast aside, a supersonic parachute will slow the lab further, and a rocket-propelled "sky crane" will attempt to gently lower the rover onto the Martian surface.
Adam Steltzner, another engineer involved with the project, admits that "when people look at it, it looks crazy."
During those nerve-wracking minutes, scientists won't even be able to monitor Curiosity's progress—it takes 14 minutes for Curiosity to radio back to Earth.
"When we first get word that we've touched the top of the atmosphere, the vehicle has been alive, or dead, on the surface for at least seven minutes," Steltzner says.
Russia's only two attempts at landing a rover, in the early 1970s, both failed: One crash landed, and another failed within one minute of landing. Great Britain lost contact with its Beagle 2 spacecraft in 2003 before it was scheduled to enter the atmosphere.
NASA, on the other hand, has never crashed a rover while attempting to land, although the Mars Pathfinder, the first successful rover, lost communication with Earth about two months after landing in 1997.
If all goes according to plan, Curiosity's mission will be to determine whether life exists or could have ever existed on Mars. It'll be the first rover to have a fully functioning organic chemistry lab and will analyze Mars' rocky surface for any traces of life.
According to NASA, "the overarching science goal of the mission is to assess whether the landing area has ever had or still has environmental conditions favorable to microbial life, both its habitability and its preservation."
Jason Koebler is a science and technology reporter for U.S. News & World Report. You can follow him on Twitter or reach him at firstname.lastname@example.org