NASA revisits its first pioneer rover to roll on Mars 25 years ago; know all about it

Exactly 25 years ago, NASA sent a rover to Mars which proved that the red planet could be explored using wheeled robots. Launched on December 4, 1996, the rover named ‘Sojourner’ arrived on Mars when the lander it was in touched down on July 4 next year and pioneered a new era of planetary exploration. The rover, which was named after American civil rights crusader Sojourner Truth, exceeded the expectations of NASA as it lasted 83 days, twelve times more than its planned life span of just seven days.

(Locations of four NASA rovers sent on Mars so far; Image: NASA)

Objective of Sojourner

The mission Mars Pathfinder involving the Sojourner rover was just a technological demonstration of delivering a lander and a free-ranging rover to Mars in a cost-effective manner. Notably, this marked the first-ever instance when a rover rolled on the surface of another planet and the wheeled robot went to become the foundation of four more rovers that followed. According to NASA, this mission was immensely successful and both the lander and the rover sent around 2.3 billion bits of information. 

Within this information were 16,500 images by the lander, 550 images from the rover and 15 chemical analyses of rocks and soil along with extensive data on winds and other weather factors. Interestingly, it was the data from this mission that helped scientists conclude that Mars had a wet and warm past and it had a relatively thicker atmosphere. 

(Sojourner rover photographed after landing on Mars; Image: NASA)

NASA carried out the landing of the lander through an innovative method of directly entering the Martian atmosphere, assisted by a parachute to slow its descent and a system of airbags to cushion the impact. The agency says that the lander was formally named Carl Sagan Memorial Station after its landing, in honour of one of the most famous American astrophysicists Carl Sagan. After deploying the parachutes, the lander made a soft landing on an ancient flood plain in Mars’ northern hemisphere known as Ares Vallis, which is one of the rockiest parts of the planet.

NASA said that this location was chosen because engineers believed it to be a relatively safe surface to land on and one which contained a wide variety of rocks deposited during a catastrophic flood. And since the rocks were once exposed to water, the rover would not have to travel long distances for exploration. 25 years later, NASA has sent a total of four rovers-- Spirit, Opportunity, Curiosity and Perseverance-- and the last two are currently the only ones active.