Here are some examples:

* The Mars rovers: Spirit, Opportunity, Curiosity, and Perseverance are all robotic rovers that have landed on Mars and explored its surface for extended periods.

* The Mars landers: Viking 1 and 2, Phoenix, InSight, and others have landed on Mars to conduct scientific experiments.

* Orbiters: Multiple spacecraft, including the Mars Reconnaissance Orbiter, Mars Odyssey, and the Mars Express, have orbited Mars to study the planet from above.

Therefore, while humans haven't been to Mars, we have sent numerous robotic explorers to the planet, which have successfully collected data and provided invaluable insights into its geology, climate, and potential for past or present life.