NASA's Maven Mars mission launches Monday, to help solve climate change mystery

Maven is scheduled to blast off aboard an unmanned rocket at 1:28 p.m. EST (1828 GMT) Monday.

Flight time
The journey to Mars will take 10 months, putting Maven in orbit around the red planet in September 2014. The spacecraft will circle the red planet for a full Earth year, examining the upper atmosphere. It will dip as low as 78 miles (125 kilometers) above Mars to sample the atmosphere. Its orbit will extend as high as 3,864 miles (6,218 kilometers).

Purpose
Scientists want to learn how Mars transformed from a warm, wet planet a few billion years ago to the dry, cold world of today. The atmosphere went from thick to thin. Much of the atmospheric gas may have escaped into space. The sun is the likely culprit.

Cost
The Maven mission will cost $671 million over its entire lifetime. That includes the price of the unmanned Atlas V rocket used to launch the spacecraft from Cape Canaveral Air Force Station.

Maven spacecraft
When its solar wings are extended, Maven stretches 37.5 feet (11.4 meters) - about the length of a school bus. It weighs 5,410 pounds (2,454 kilograms), the same weight as an SUV. Eight scientific instruments are on board, as well as communications relay equipment for use with Mars landers. Maven stands for Mars Atmosphere and Volatile Evolution, with a capital "N'' at the end of EvolutioN. The idea for Maven dates back 10 years. Scientists hope to keep it going well beyond its advertised working lifetime of one Earth year. The project is led for NASA by the University of Colorado's Laboratory for Atmospheric and Space Physics in Boulder.

About Mars
Mars is the most similar planet to Earth in our solar system, with the greatest prospects of habitability for future astronauts. Mars is about half the size of Earth but has about the same land area. A Martian year lasts 687 Earth days.

Mars missions
Maven is NASA's 21st mission to Mars. Fourteen of the first 20 succeeded. The 1964 Mariner 4 was the first spacecraft to fly by the red planet. Curiosity was America's most recent Mars visitor, launching in 2011 and landing in 2012.

Chugging away at Mars
Three spacecraft currently are collecting data in orbit around Mars: NASA's 2001-launched Mars Odyssey, Europe's 2003-launched Mars Express and NASA's 2005-launched Mars Reconnaissance Orbiter. Two rovers are on the surface, still working: NASA's 2003-launched Opportunity and 2011-launched Curiosity.

Future Mars shots
NASA plans to launch a robotic geologist named InSight in 2016; the lander will penetrate the Martian surface with a seismometer and heat probe. The next NASA wheeled rover will fly in 2020, collecting rock samples for potential return to Earth. A human expedition is not anticipated until the 2030s.