It's been over 20 years since NASA first landed the Pathfinder mission and Sojourner rover on the surface of Mars, a massive achievement that has changed the way we view our solar system and greatly expanded our understanding of a long, long list of things.
In all, NASA has managed to land successfully on Mars eight times - the Viking 1 and 2 missions, Pathfinder, Spirit, Opportunity, Phoenix, Curiosity, and InSight. While that might make it seem like success on Mars may get stale, it's still a huge deal to land anything successfully on a moving target that's more than 33 million miles away at its closest point.
And all that success hasn't blunted NASA's ambitions, either. With a ninth landing planned for 2021, the latest mission includes a rather unexpected element that, if it works, would be yet another first for NASA: flying a helicopter on Mars.