No one under 20 years of age has experienced a day without NASA at Mars.
The Pathfinder mission, carrying the Sojourner rover, landed on Mars on this day in 1997.
In the 20 years since Pathfinder’s touchdown, eight other NASA landers and orbiters have arrived successfully, and not a day has passed without the United States having at least one active robot on, or in orbit around, the fourth rock from the Sun.
The longest operational mission is the Mars Odyssey orbiter, circling the planet’s polar regions. Taking up the post on 24 October 2001, it is expected to keep sending imagery and telemetry until 2025.
All told, there have been more than 40 missions to the red planet since 1960, from all nations.