Why study Mars?

Mercury, Venus, Earth and Mars are known as the terrestrial planets; this means that they are all made of rocks and metals. Unlike Mercury, both Venus and Mars also have an atmosphere, albeit much more dense (Venus) or much less dense (Mars) than the Earth. The three planets formed in similar conditions, and they evolved similarly during the early solar system. Nowadays they are significantly different, and so at some point in the past their evolutions have diverged though Mars remains the most similar planet to Earth in the solar system.

Mars can tell us about the history of the Earth, by understanding how the planet has evolved over billions of years. The surface of the Earth has been recycled through plate tectonics and eroded by water and wind; whereas Mars has no plate tectonics, and the weak atmosphere has allowed the ancient bedrock to be preserved on (or just under) the surface.

Mars can also tell us about how life evolved both in the solar system and in the broader universe in general. The conditions on early Mars may have been sufficient to support life: if so, traces of ancient life may still be present, waiting to be discovered. If not, we can understand why not, and apply that knowledge to our understanding of the universe.

How do we study Mars?

Through observations from Earth-based telescopes and those flying or orbiting around the Earth. Examples include:

• The NASA Infrared Telescope Facility (IRTF) a telescope at the top of Mauna Kea in Hawaii.
• The Stratospheric Observatory for Infrared Astronomy (SOFIA), a Boeing 747 jumbo jet modified to host a telescope.
• The Hubble Space Telescope, in orbit around the Earth.
• The James Webb Space Telescope (JWST), approximately 1.5 million km from the Earth. This is around 4 times further from the Earth than the Moon.

By analysing Martian meteorites

These are lumps of rock that have been ejected from the Martian surface, travelled through the solar system, and eventually hit the Earth and have been collected by scientists.

By sending spacecraft into orbit around Mars

At present, there are orbiters from NASA (USA), ESA (Europe), ISRO (India), Roscosmos (Russia), UAESA (United Arab Emirates) and CNSA (China) in orbit.

By sending rovers and landers to the Martian surface

Curiosity, InSight, Perserverance/Ingenuity and Tianwen-1/Zhurong and currently operating on the surface of Mars.