We've learned about the space exploration of Mars and the spacecrafts that got near the planet.
There have also been space crafts that have landed on Mars and studied the planet.
The Russian space program had their Mars program:
Mars 2 was launched May 19, 1971, and crash landed on the planet.
Mars 3 was launched May 28, 1971, landed on the planet and sent back information for 14.5 seconds before it stopped working.
Mars 6 was launched August 5, 1973, and crash landed on the planet.
The US NASA space program had their Viking program:
The Viking 1 was launched August 20, 1975
The Viking 2 was launched September 9, 1975
Both of these spacecrafts had orbiters and landers. The orbiters circled the planet taking pictures, and then launched landers to the ground.
The landers then did scientific experiments on the ground to test the dirt and the air.
(from: wikipedia - viking program)
Kid Facts - Blast from the past: White Dwarf
