NASA's Mars Science Laboratory: 5 facts

LAUNCH: The mission launched from Cape Canaveral, Florida on November 26, 2011 atop a two-stage Atlas V 541 rocket by United Launch Alliance, a joint venture of Boeing and Lockheed. The journey to Mars has taken about 8.5 months, or 254 days.

LANDING: "Seven minutes of terror" is a popular Internet video featuring top NASA scientists who describe the final touchdown scheduled for August 6 at 0531 GMT.
This is the first attempt of its kind to land a heavy vehicle on Mars by using a rocket-powered sky crane.

Entry, descent and landing begins when the spacecraft reaches the top of Mars's atmosphere, traveling at a speed of 13,200 miles per hour (5,900 meters per second). Ten minutes before the spacecraft enters the atmosphere, it sheds its cruise stage, or the parts that carried propellant tanks and antennae to keep the spacecraft on course to Mars and enable communications. It then goes through a period of peak heating as it enters the Mars atmosphere. A parachute is deployed, the heat shield separates and the rocket-powered sky crane deploys nylon cords to lower the rover to the surface.

Touchdown should occur at 1.7 miles per hour.

VEHICLE: A car-sized robotic rover with six wheels, nicknamed Curiosity. It weighs about one ton (900 kilograms) and cost $2.5 billion. The concept first emerged in 2000 and was developed at NASA's Jet Propulsion Laboratory in Pasadena, CA.

TOOLKIT: Ten instrument-based science investigations are on board:

Mast camera (MASTCAM) contains two megapixel color cameras that act as the left and right eye of the rover, and are capable of returning stills, video and 3D images.

Chemistry and Camera (CHEMCAM) is a rock-zapping laser and telescope combination that can target a rock 23 feet (seven meters) away, burn it and analyze the light that emerges to identify the chemical elements inside.

Alpha Particle X-Ray Spectrometer (APXS) is on the robotic arm and can identify chemical elements in rocks and soil.

Mars Hand Lens Imager (MAHLI) is a color camera on the end of the robotic arm for use in getting closeups of the ground or wider scenes of the landscape.

Chemistry and Mineralogy (CheMin) analyzes powdered rock and soils with X-ray diffraction.

Sample Analysis at Mars (SAM) has three tools to check for carbon-based compounds that are the building blocks for life, examine the chemical state of other elements important for life and search for clues about planetary changes.Rover Environmental Monitoring Station (REMS) records daily and seasonal changes in the weather on Mars.

Radiation Assessment Detector (RAD) monitors high energy atomic and subatomic particles from the Sun that could pose a danger to astronauts if a human mission to Mars ever occurs.

Dynamic Albedo of Neutrons (DAN) can detect underground water beneath the rover at a distance of 50 centimeters (20 inches).

Mars Descent Imager (MARDI) records full-color video of the final few minutes of the rover's descent onto the Martian surface. A few images are expected back within days of the landing, but the full video may take longer.

EXPLORATION SITE: The mission aims to study the Gale Crater, a 96-mile wide crater that contains a three-mile high mountain, shaped like a broad mound so the six-wheeled rover can climb at least halfway up the site.

The vehicle is designed to function for 98 Earth weeks, or about one Martian year.