NASA's $850-million mission to Mars is about to launch — here are 13 incredible facts you probably didn't know about the red planet

InSight is slated to lift off on Saturday, which is one day after International Space Day, on May 4. But it's just one of dozens of robotic and satellite missions that humanity has rocketed to Mars over the decades.

These spacecraft have beamed back dazzling photos, inspired sci-fi movies like "The Martian", and even helped give Elon Musk, the founder of SpaceX, the idea to colonize the red planet with the Big Falcon Rocket.

While scientists readily admit they have much to learn about Mars, including the planet's internal structure (a mystery InSight will try to solve), what we have found out so far is incredible.

Here are 13 fascinating facts about Mars and our robotic exploration of the red planet.

Volcanoes

Olympus Mons is more than twice as high as Hawaii's Mauna Loa, the tallest mountain on Earth from top to bottom.

Canyons

Compared to the Grand Canyon on Earth, Valles Marineris on Mars is nearly five times deeper, about four times longer, and 20 times wider.

Mars quakes

The red planet doesn't have plate tectonics, which is what causes most quakes on Earth. But rising plumes of magma could trigger Mars quakes, as could meteorite impacts and the contraction of the world due to cooling. InSight will listen for them with its seismometer.

Oases

If aliens existed on Mars, they might have lived in oasis-like pools. These pools would have been habitable for life, just as they are on Earth.

Tsunamis

Martian oceans also had tsunamis like those on Earth. The tallest may have reached as high as 400 feet, just slightly shorter than the London Eye.

Ice Caps

Like Earth, Mars has ice caps at its poles. The northern cap is up to 2 miles deep, is a mix of water and carbon dioxide, and covers an area slightly larger than Texas.

Temperature

The average surface temperature on Mars is -81˚F, 138 degrees chillier than on Earth. But on a mid-summer day at the red planet's equator, temperatures can peak at a balmy 95˚F.

Oceans

Billions of years ago, Mars had oceans and flowing water. But adding them up would give you just 1.5% of all water on Earth today.

Surface Area

Mars has almost as much surface as Earth has land — but that doesn’t account for the 71% of Earth that’s covered in water.

Atmosphere

The Martian atmosphere is 61 times thinner than Earth’s, andit consists almost entirely of carbon dioxide, which makes up just 0.04% of Earth’s atmosphere.

Sunsets

On Earth, sunsets are a brilliant mix of reds, pinks, oranges, yellows, and other colors. But on Mars they're blue. Because air is dozens of times less dense on the surface of Mars than it is on our planet, white sunlight refracts less — leading to fewer colors (primarily blues).

Launch rate

Missions to Mars have become much rarer — after 23 launches in the 1960s and 1970s, we’ve launched just 10 in the newmillennium (so far).

Missions

Getting to Mars is hard: About a third of the missions launched have failed.

This story has been updated. It was originally published on June 1, 2017.

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