Exploring Mars helps scientists learn about momentous shifts in climate that can fundamentally alter planets. It also lets us look for biosignatures, signs that might reveal whether life was abundant in the planet's past—and if it still exists on Mars today.

What are they looking for on Mars?

NASA will also look for life on Mars by searching for telltale markers, or biosignatures, of current and past life. ... On Mars, searches are already underway to locate lakes or streams that may have left behind similar deposits. So far, however, the kinds of biosignatures we know how to identify are those found on Earth.

Why do we care so much about Mars?

We have learnt that Mars is like Earth's little broth- er: it shares a similar history and of all planets in our Solar System, it is the closest to our one. ... It may sound too much like a science fiction but this effort is crucial for the survival of our kind and for learning more about our own Planet Earth.