Smithsonian.com

A digital rendering of Curiosity, set to land on Mars early Monday morning. Photo via NASA/JPL-Caltech

Science enthusiasts and space geeks around the world are eagerly awaiting the landing of NASA’s rover Curiosity on Mars, planned for Monday morning at 1:31 am Eastern time. The Mars Science Laboratory, set to replace Opportunity and Spirit, is our most advanced rover yet, and NASA scientists hope that it will help us learn about the Martian climate and geology, collect data for a potential future manned mission and perhaps even find evidence that life could have existed on the the red planet in the past.

“The overarching goal is to assess the potential for past or present habitability on the surface,” says Smithsonian geologist John Grant, who is serving as a participating scientist on the Curiosity team. “Can we find a place on Mars where the conditions may have been habitable, and is the evidence that allows us to determine this actually preserved?”

One of the mission’s biggest challenges, though, is simply landing Curiosity safely on Mars. Over the course of seven minutes, from when it hits the top of Mars’ atmosphere to when it comes to rest on the surface, the one-ton craft must decelerate from 13,000 to 1.7 miles per hour. This feat will be achieved though a highly choreographed routine—as the craft descends, a supersonic parachute will slow it down; then, three rockets will shoot upward to form a “sky crane,” from which the rover will be lowered at a controlled speed via nylon cords. NASA’s short video on the challenge, Seven Minutes of Terror, below, is a must-watch:

After Curiosity touches down, the fun part starts: The vehicle will embark on a two-year-long mission to explore Mars’ surface in unprecedented detail. The craft is nearly 10 feet long (roughly the size of a small car), significantly bigger than previous rovers, and its larger wheels will allow it to roll over obstacles as large as 30 inches in height. It includes three cameras—a main camera for video and stills, a secondary lens for microscopic images of rock and soil samples, and a special lens for capturing images of the initial descent. Additionally, navigation cameras are mounted on the central mast and on all four corners of the rover to help it avoid hazards.

The craft also includes a number of new tools for analyzing soil and rock samples in terms of chemical composition. A robotic arm with several spectrometers will analyze the mineral content of rocks, and a gas chromatograph will determine the gas mixture of Mars’ atmosphere on a molecular level. The ChemCam, used for remote analysis of samples, can vaporize a piece of rock from more than 20 feet away by shooting a targeted laser pulse, then analyzes the content of the rock by collecting the light emitted from it.

“With Opportunity and Spirit, we could look around, approach the rocks, put our instruments on them and say something about their chemistry,” Grant says. “With Curiosity, we can still do all that, but now we have a whole analytical lab on board, so we can take the next steps, and find out other info that could point to whether this [planet] might have been habitable or not.”

After landing, the craft will undergo a series of equipment checks, and then begin exploring its landing site: Gale Crater. Of particular interest is a mountain at the center of the crater known as Mount Sharp, made up of a series of sediment layers that scientists believe could help us understand Mars’ evolution from a planet with liquid water—and possibly organic compounds—to a largely barren environment.

“These layered sediments, just like sedimentary rocks here on Earth, record the environmental conditions of when they were deposited,” Grant says. “So what we hope to have is effectively a book that can be read from the bottom up, and as we go chapter by chapter, layer by layer, we can understand what happened to those conditions, how and why they changed and eventually how we ended up at the Mars we see today.”

Grant is currently heading to NASA’s Jet Propulsion Laboratory in California to be with the rest of the mission’s team for Monday’s landing. Because signals from Curiosity take 14 minutes to travel all the way from Mars to Earth, the scientists are forced to effectively watch a “taped delay” version of the landing—something that makes the event particularly stressful for the control team.

“As you’re seeing the data about the spacecraft coming in for a landing, the landing has already happened. It’s kind of like watching the Olympics at night: somebody’s already won that race, but you don’t know who,” he says. “It’s very tense and very nerve-wracking—but it’s also very exciting.”