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At a Glance

Why do we need Hope?

Mars is a cold, dry, desert, with a carbon dioxide-filled atmosphere 100 times thinner than Earth’s. But it wasn’t always like that. We know liquid water once flowed on its surface, supported by an atmosphere that may have been favorable to life.

But then something happened. About 4 billion years ago—right around the time life arose on Earth—Mars lost its magnetic field. On Earth, our magnetic field shields us from the solar wind, the constant stream of charged particles coming from the Sun. Without a magnetic field for protection, the solar wind stripped away much of Mars’ atmosphere, eventually transforming the planet into its current state. This discovery was made by NASA’s MAVEN spacecraft, which continues to study the planet.

Hope will build on MAVEN’s findings by building a complete picture of the Martian atmosphere, and studying how Mars’ climate changes over time. This will give scientists deeper insight into how Mars changed over time, and whether the planet could have once supported life. It will also help us understand how our own planet’s climate is changing, and what the consequences of those changes are.

Hope also demonstrates the importance of international collaboration in space exploration. The mission is managed by the United Arab Emirates (UAE), with participation from scientists and engineers at U.S. universities. Japan will launch the spacecraft. Space exploration brings us all together, and when more nations participate and collaborate, everyone wins.

How Hope will explore Mars

Mars then and now

NASA’s Goddard Space Flight Center

Mars then and now
This conceptual image depicts the early Martian environment (right)—believed to contain liquid water and a thicker atmosphere—versus the cold, dry environment seen at Mars today (left).

Hope will launch in summer 2020 and arrive at Mars in early 2021. Its orbit around Mars will be roughly 22,000 by 44,000 kilometers—much higher than NASA’s MAVEN, which has a tight, 4,500-by-150-kilometer orbit optimized for relaying communications between rovers on the surface and Earth.  

From its high perch, Hope will study Mars’ upper atmosphere, watching traces of hydrogen and oxygen—remnants from Mars’ wetter days—leak into space. The spacecraft will also study how the planet’s upper and lower atmospheres interact with each other, while a high-resolution digital camera will capture stunning views of the planet.

Hope’s primary science mission is scheduled to last for 2 years. The mission could be extended for another 2 years after that.

Mars aurorae 

Humans can’t see ultraviolet light, but some animals can, possibly including dogs and cats. Mars has daytime ultraviolet aurora, caused by solar wind hitting hydrogen molecules leaking into space. That means if you brought your dog or cat to Mars, it might be able to see direct evidence of Mars’ atmosphere leaking into space!

What you can do to support Hope

You can help us support the exploration of Mars and other worlds by sharing the passion, beauty, and joy of space exploration. Visit our Mars page to learn about The Planetary Society’s top priorities for Mars exploration.

Three ways you can be a space advocate

You can also follow the mission directly: 

This page was written by Planetary Society staff writers based on research provided by Andrew Jones. It is regularly updated.

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