Since the 1970s a fleet of orbiters, landers and rovers has explored Mars, with notable surface explorers including Sojourner, Spirit, Opportunity, Curiosity and Perseverance, returning images and data that transformed our understanding of the Red Planet
Observations from missions
Robotic missions have mapped Mars’s surface, analysed rocks and soils, measured atmospheric properties and returned high‑resolution imagery. Rovers have driven across diverse terrains, drilled and sampled targets, and transmitted long time‑series datasets that reveal past water activity, present climate processes and geological context for landing sites.
Why it looks blue
Robotic explorers are effective because they can operate in harsh conditions humans cannot yet endure, carry specialised instruments for in‑situ science and be tasked to investigate specific hypotheses remotely, enabling systematic study of Martian geology, chemistry and habitability while minimizing risk and cost compared with crewed missions.
Recent evidence and imagery
Recent missions have delivered landmark results: orbital reconnaissance guided rover traverses to ancient lakebeds and delta deposits, Curiosity characterised past habitable environments, Perseverance collected and cached samples for future return and deployed instruments like helicopter scouts to extend exploration reach and contextual imaging.
Implications for science
Robotic exploration yields direct measurements that constrain Mars’s climate and geologic history, inform search strategies for biosignatures and test technologies—such as entry, descent and landing systems and in‑situ resource experiments—that are essential prerequisites for safe and successful human missions.
Takeaway
Decades of robotic exploration have made Mars the best‑studied planet after Earth, providing the scientific foundation, operational experience and technological demonstrations needed to plan future sample‑return campaigns and eventual human exploration.