Mars is the fourth planet from the Sun – a dusty, cold, desert world with a very thin atmosphere. Mars is also a dynamic planet with seasons, polar ice caps, canyons, extinct volcanoes, and evidence that it was even more active in the past.
Mars is one of the most explored bodies in our solar system, and it's the only planet where we've sent rovers to roam the alien landscape. Two NASA rovers and one lander are currently exploring the surface of Mars (and a Chinese lander is set to land later this year). An international fleet of eight orbiters are studying the Red Planet from above.
These robotic explorers have found lots of evidence that Mars was much wetter and warmer, with a thicker atmosphere, billions of years ago.
NASA's next-generation Perseverance rover – the largest, most advanced rover NASA has sent to another world – touched down on Mars on Feb. 18, 2021, after a 203-day journey traversing 293 million miles (472 million kilometers). Confirmation of the successful touchdown was announced in mission control at NASA’s Jet Propulsion Laboratory (JPL) at 3:55 p.m. EST (12:55 p.m. PST).
Perseverance is one of three spacecraft that arrived at Mars in 2021. The Hope orbiter from the United Arab Emirates arrived on Feb. 9, 2021. China’s Tianwen-1 mission arrived on Feb. 10, 2021, and includes an orbiter, a lander, and a rover. Europa and India also have spacecraft studying Mars from orbit.
Go farther. Explore Mars In Depth ›
If the Sun were as tall as a typical front door, Earth would be the size of a dime, and Mars would be about as big as an aspirin tablet.
Mars orbits our Sun, a star. Mars is the fourth planet from the Sun at an average distance of about 228 million km (142 million miles) or 1.52 AU.
One day on Mars takes a little over 24 hours. Mars makes a complete orbit around the Sun (a year in Martian time) in 687 Earth days.
Mars is a rocky planet. Its solid surface has been altered by volcanoes, impacts, winds, crustal movement and chemical reactions.
Bring a Spacesuit
Mars has a thin atmosphere made up mostly of carbon dioxide (CO2), argon (Ar), nitrogen (N2), and a small amount of oxygen and water vapor.
Mars has two moons named Phobos and Deimos.
There are no rings around Mars.
Several missions have visited this planet, from flybys and orbiters to rovers on the surface.The first true Mars mission success was the Mariner 4 flyby in 1965.
Tough Place for Life
At this time, Mars' surface cannot support life as we know it. Current missions are determining Mars' past and future potential for life.
Mars is known as the Red Planet because iron minerals in the Martian soil oxidize, or rust, causing the soil and atmosphere to look red.
Robots Blaze the Trail for Humans on Mars
Perseverance aims to help future astronauts brave that inhospitable landscape. The mission’s main science goal is to look for signs of ancient life. It also will be the first spacecraft to collect samples of the Martian surface, caching them in tubes that could be returned to Earth on a future mission – the vehicle also includes technology that paves the way for human exploration of Mars.
Robotic explorers, like Perseverance, have long served as pathfinders to get humans into space, to the Moon and, eventually, the surface of the Red Planet.
- NASA's Perseverance Will Blaze a Trail – for Humans
- NASA's Moon to Mars Strategy
- Artemis 1: The first in a series of increasingly complex missions that will enable human exploration of the Moon and Mars.
No other planet has captured our collective imagination quite like Mars.
In the late 1800s when people first observed the canal-like features on Mars' surface, many speculated that an intelligent alien species resided there. This led to numerous stories about Martians, some of whom invade Earth, like in the 1938 radio drama, "The War of the Worlds." According to an enduring urban legend, many listeners believed the story to be real news coverage of an invasion, causing widespread panic.
Countless stories since have taken place on Mars or explored the possibilities of its Martian inhabitants. Movies like "Total Recall" (1990 and 2012) take us to a terraformed Mars and a struggling colony running out of air. A Martian colony and Earth have a prickly relationship in "The Expanse" television series and novels.
And in the 2014 novel and its 2015 movie adaptation, "The Martian," botanist Mark Watney is stranded alone on the planet and struggles to survive until a rescue mission can retrieve him.Kid-Friendly Mars Resources