The Red Planet, Pathfinder & Sojourner

Whenever Ancient people saw into the sky, they wondered what’s that glowing red spot in the sky? Is it another Earth with aliens? or a star?

There were a lot of hypothetical theories about that glowing red spot. Chinese astronomers named it “fire star” while Egyptian’s called it “Her dasher” a God. Fortunately, in this modern age of technology, we have answers about all the mysteries of the red planet. The glowing red spot was actually a red planet, known as Mars. NASA made a lot of attempts but failed to reach there and then started a series of missions to find the existence of life on the red planet. Rover has not discovered yet the existence of living beings. But scientists said, there could be a possibility for the existence of any organism’s remainings maybe died hundreds of years ago.

Once, doctor Jim Rice, an astrogeologist, said; “Exploration assures that humanity will continue to thrive, even if not on earth”.

Collectively Four humanoid robots were subjected to rover over the red planet. Here is the list of rovers successfully landed on Mars.

° Sojourner

° Spirit & Opportunity Twins

° Curiosity

° Perseverance

Now maybe a thought will arise into your mind that when NASA has sent perseverance rover to the red planet?

Let me tell you, Perseverance is the fifth rover traveling toward the red planet, launched on 30 July 2020. So, it’s a future scheduled rover for Martian soil.

Here we will talk about the first successful mission, the Pathfinder & sojourner mission.

Pathfinder Lander:

Pathfinder mission was the first of the other successful Mars exploration missions. They designed this mission to deliver a well-equipped technology lander & a humanoid robot “Sojourner” from Earth to Mars. 4 Dec 1996 when pathfinder’s space vehicle Delta II 7925, launched from Cape Canaveral air station Florida. After escaping from the Earth’s gravity spacecraft and pathfinder followed their trajectory toward the red planet. After a long space journey of around 33.9 million miles finally pathfinder entered Mars’s atmosphere moreover faced many challenges. Pathfinder entered directly into the Martian atmosphere and used a large (11m in diameter) parachute to diminish speed, and heat shields to overcome the burning effects due to air resistance.

One of the biggest challenges was safe landing on the Martian soil. Pathfinder was assisted with innovative airbags technology, designed to minimize the impulsive damage effects by direct hitting the Martian surface. The giant Cocoon of Airbags technique was introduced for the first time in the pathfinder mission as shown in the art figure. this technique was ultra-modern and distinctive from the conventional rocket landing system. After 7 months-long voyages, 4 July 1997 pathfinder successfully landed on Mars stony area named “Ares Vallis”. This rockiest site was selected by scientists because they could have the opportunity to study a wide variety of rocks. During landing the airbag cushioned lander bounced back like a giant beach ball to a height of about 15 meters and covered approximately 20 km of distance before coming to rest. Pathfinder lander was tele-programmed (remotely programmable), and its duty was to build two-way communication & send data directly back to the Earth. Lander’s antenna sent a congratulation signal back to earth for its victorious landing. 90 minutes after landing, scientists received a signal from the lander showed that the pathfinder has deployed its petals on the Martian surface and waiting for the sunshine to recharge itself. Another transmitted message sol1 (Martian 1st day’s message) was about the lander & rover's health including the data about temperature & the atmosphere’s density.

A broadcast signal takes about 10 minutes to travel from Earth to Mars, so the lander was programmed to communicate every 10 minutes. On the first day, there were a lot of communication issues like distortion or noise in the signal, and sentences were not complete, later on, resolved by the rover.


SOJOURNER: a humanoid intellectual robotic rover of Mars.

The first rover of Mars was a Lightweight ≈34 pounds, six-wheel, oven size robot traveled over the Martian surface to detect any existence of life. The humanoid rover Sojourner equipped with artificial intelligence (AI) technology having the capability of decision making. Sojourner was a robotic scientist because it was skillful to detect or analyze different chemical and physical samples by itself. The rover was equipped with highly developed science instruments.

Two small sizes, high quality black & white cameras were mounted in the head of the sojourner while a color camera was mounted in the back. A laser system assisted the rover to detect and range the barriers or hurdles. High tech Alpha proton X-ray spectrometer(APXS) was embedded to study structures, the arrangement of elements, and the material composition of rocks and soil by bombarding alpha particles. Sojourner was powered by a solar panel and D-cell size non-rechargeable batteries. The rover traveled over the Martian surface at a maximum speed of 2-feets per minute (1 cm per second). Sojourner’s rocker-bogie mobility system gave a great degree of stability and ability to cross barriers. In short, sojourner was an amazing creation of the '90s.

Mission overview & results:

The pathfinder mission was scheduled for only 30 days, but it lasted for 450 days and continued sending data until 27 Sep 1997. Pathfinder had sent 274.2 Megabytes of information directly back to the earth. The lander and rover sent 1750 images in total including high definition mosaics (panoramas). Chemical analysis of the landing area showed the abundance of silica in the Martian rocks. Dunes of sand were found in the area behind the landing site. The pebbles and rounded stones indicate the existence of water in the past. From different images taken in the morning and by imagery techniques they found ice clouds in the lower Martian atmosphere which evaporates daily and warms the atmosphere. Sojourner has set its alpha proton X-ray spectrometer (AXES) down into the Martian soil for 10 hours of measurements all night. Sojourner frequently used its imaging technique to detect wind direction and wind speed. Sojourner sent all these pieces of information back to the earth through the pathfinder lander communication system.

Sojourner was one of the amazing and pioneering high-tech robots that proposed a novel way of research and missions for Mars exploration.

The mission of finding life or leftovers did not stop here. NASA planned another Mars exploration mission and after 6 years they sent twin rovers to search for the mysteries of the red planet.

After reading this amazing mars exploration mission questions will arise in your mind.

Did the sojourner found something amazing or got nothing?

Martian soil and atmosphere are suitable for human beings or other living organisms?

Can Mars be a better planet than Earth or not?

All these mysteries can be explored by reading the complete series of missions. As mentioned in the start, Pathfinder was the first successful lander, designed to deliver well-equipped and high-tech instruments to the martian soil. So, pathfinder accomplished this goal in a very effective and successful manner.

Further, the mysterious theories about the existence of life are waiting for you in the next MARS EXPLORATION MISSION story. stay tuned.

The Writer