Did NASA's Viking landers accidentally kill life on Mars? Why one scientist thinks so

Viking 2 lander at Utopia Planitia – an unexpected rockfest. Viking 2 landed some 4,600 miles from its twin, Viking 1.

In 1975, NASA's Viking 1 spacecraft entered orbit around Mars, carrying a mission to unlock the secrets of the Red Planet. Soon, it released twin landers that drifted toward the Martian surface and eventually made history as the first American spacecraft to touch down on the world.

For over six years, Viking 1 continued to orbit Mars' Chryse Planitia region while its landers collected soil samples using robotic arms and onboard laboratories, marking a groundbreaking chapter in humanity's exploration of the Martian environment.