There's an intruder on Mars. In August 2012, NASA's Curiosity rover landed on the Red Planet, for a mission to uncover more of Mar's mysteries, and like anyone on a fun adventure, the rover has been sending home plenty of news and photos.
The adventure began on August 5, when Curiosity, a roving laboratory the size of a compact car, landed right on target after a 36-week, approximately 350-million-mile (563-million-kilometer) journey aboard a spaceship. The landing required a herculean effort because the six-wheeled rover weighs nearly one ton, and the thin Martian atmosphere offers little friction to slow down a spacecraft. Curiosity had to go from 13,000 miles per hour (20,921 kilometers per hour) to zero miles per hour in seven minutes, and it did so by unfurling a parachute and then firing rockets to brake. In a Hollywood-style finish, cables delicately lowered the rover to the ground at 2 mph (3.2 kilometers per hour).
Curiosity is the heaviest piece of machinery NASA has landed on Mars—not long ago, engineers had no idea how to design a one-ton piece of equipment so that it could make a safe landing in an environment like the one on Mars. Curiosity's touchdown displayed the progress they've made, and the success of the landing gave NASA scientists confidence that they can unload equipment that astronauts may need in a future manned trip to the Red Planet.
"We have ended one phase of the mission, much to our enjoyment," mission manager Mike Watkins said after the landing, adding, "but another part has just begun."
Since landing, Curiosity has been transmitting a stream of photos of the Martian landscape. Early images depicted Martian gravel, a mountain at sunset, and most scintillating of all, the spacecraft's white-knuckle plunge through the Red Planet's atmosphere. Curiosity made headlines when it captured images of a phenomenon that is familiar to Earthlings—a partial eclipse of the sun. This is when a moon moves between a planet and the sun, blocking part of the sun from view. On Mars, this event isn't quite as rare as it is on Earth—this is because two moons zip around the Red Planet, and they're closer and faster than our lumbering moon. Scientists say there's even somewhat of an eclipse season on Mars. While past rovers have taken pictures of solar eclipses from Mars, Curiosity's camera takes high-resolution photos and so many shots that it produces a movie of sorts.
After Curiosity gazed skyward, the Mini Cooper-sized vehicle focused on the ground. In September, it tested its first rock with a laser and chemical testing kits mounted on the end of its robotic arm. The target was a pyramid-shaped dark rock, about 10 inches (25.4 centimeters) tall and 16 inches (40.6 centimeters) wide at its base. Two of the arm's chemical-sniffing devices snuggled up against the rock, allowing scientists to figure out what it was made of.
"It's just a cool-looking rock sitting out there on the plains," said Mars Science Laboratory scientist John Grotzinger. But the rock was not that unusual and seemed similar to rocks past rovers had tested before, which made it a good start for the rover's testing equipment.
The nuclear-powered Curiosity is also working on answering an ongoing question: Was there ever life on Mars? This involves determining whether the planet has the ingredients needed to develop and support life. For years, scientists have known that there is water ice on Mars, and so Curiosity is digging into the Martian surface to analyze what's there and to hunt for some of the molecular building blocks of life, including carbon.
Whether there are seeds of life or not, Curiosity isn't alone on Mars. It joins NASA's long-running Opportunity rover, which has been exploring craters in Mars' southern hemisphere since 2004. Opportunity's twin, Spirit, fell silent in 2010 after getting stuck in a sand trap. Curiosity's prime mission will last two years.
The Associated Press contributed to this story.
Dig Deeper
In its first thousand days on Mars, Curiosity traveled about 8 kilometers (5 miles). The average day, or sol, on Mars (about 24 hours and 40 minutes) sees the rover move about 100 meters (328 feet). At the start of each day, Curiosity receives a new set of instructions, which tells the rover where to travel and what experiments to carry out.
Mars is a planet with a diameter about half that of Earth. The orange surface colors, seen in some of Curiosity's pictures, come from molecules of iron and oxygen—rust. Mars has two tiny moons called Deimos and Phobos. They were probably once asteroids that were pulled into orbit around Mars. Curiosity has filmed solar eclipses when Phobos blotted out portions of the sun. These observations are data that allow scientists to learn more about the moons' orbits.
Curiosity has confirmed that the same processes that affect the other terrestrial planets affect Mars. Valleys and raised areas formed on Mars as the mantle moved. One huge system of valleys, called Valles Marineris, is long enough to stretch across the United States. Most of the northern hemisphere has smooth plains of cooled lava. Several volcanoes are higher than any mountain on Earth. The lava must have built up in the same spot for a long time, so scientists have inferred that the crust of Mars has cooled more than Earth's crust.
The thin, mostly carbon dioxide atmosphere of Mars made landing Curiosity a tremendous challenge. The air pressure is only about 1 percent of the air pressure on Earth and is not dense enough to keep the surface warm. Temperatures may reach almost 20°C (about 60°F) in the daytime and −90°C (−130°F) at night. The large differences in temperature produce fast winds that cause gigantic dust storms that sometimes cover most of the planet.
Exploring Mars presents special challenges to scientists and engineers because of the distance between Earth and Mars. Communication with Curiosity takes about 20 minutes. The rover transmits its data to larger spacecraft in orbit around Mars. Earth is visible to those spacecraft for two-thirds of every orbit. They can send much more data to Earth than Curiosity can because they have much bigger antennas.
A team of scientists and engineers determine every move that Curiosity makes. They also decide which pictures the rover takes well in advance. Each choice is based on a complex set of decisions. Analyzing the data and photographs from the rover will give the scientists more information about Mars. In 2008, scientists confirmed the presence of water in a Martian soil sample. Now, scientists want to find out whether the water ice on Mars could ever thaw into liquid water. They hope to learn which chemicals, minerals, and organic compounds might be mixed with the water ice.
QUESTION 1
QUESTION 1 OF 8
1 / 8
What is this article mainly about?
A.NASA's long-running Opportunity rover has been surveying craters in Mars' southern hemisphere since arriving on the Red Planet in 2004, while its twin rover, Spirit, fell silent in 2010 after getting stuck in a sand trap.
B.NASA's Curiosity rover, which has been exploring Mars since August 2012, is transmitting a stream of photographs and data from the Red Planet back to Earth for NASA scientists to analyze.
C.Curiosity, NASA's latest rover, made headlines after capturing a series of images depicting a partial eclipse that occurred when one of the Red Planet's moons moved between it and the sun.
D.Not long ago, NASA's scientists had no idea how they would design a one-ton piece of equipment so that it could make a safe landing in an environment like the one on the Red Planet, and the latest rover is proof of their progress.