Space

How Mars rovers have evolved in 25 years of exploring the Red Planet

Each rolling robot is more agile and independent

illustration of different mars rovers on the martian surface

Much of what scientists know about Mars is thanks to a succession of rolling robot explorers, five of them illustrated here.

Cornelia Li

By Alexandra Witze

Few things are harder than hurling a robot into space — and sticking the landing. On the morning of July 4, 1997, mission controllers at the Jet Propulsion Laboratory in Pasadena, Calif., were hoping to beat the odds and land a spacecraft successfully on the Red Planet.