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THREE countries are launching satellites headed for Mars this week.

The United States, China and the United Arab Emirates are each sending unmanned spacecraft to the planet. Their missions involved searching for life there and to scout out the place for future astronauts.

It's not a coincidence that the launches are at the same time - there's a one month window in which Mars and Earth are in ideal alignment on the same side of the sun, which makes travel time shorter and means less fuel needs to be used.

This window only opens once every 26 months.

Each spacecraft will travel millions of miles on their journey, and get to Mars next February.

The US is sending a six-wheeled rover, called Perseverance, which is the size of a car, to collect rock sample that will return to Earth for analysis in about a decade.

The UAE's spacecraft is called Amal, and China's rover will take part in a mission named Tianwen.

Scientists want to know what Mars was like billions of years ago when it had rivers, lakes and oceans that may have allowed simple, tiny organisms to flourish before the planet morphed into the barren, wintry desert world it is today.

The United States has successfully landed spacecraft on Mars eight times. The United Arab Emirates and China are hoping they can do the same and start exploring the planet.