Exploring the Red Planet with Robots

We’ve been exploring the Red Planet robotically for almost half a century. Take a look back with us at the landers, rovers, and helicopter that have explored Mars, and some of what we’ve learned from them.  

Viking Lander 1 & 2

“Almost everything about Viking was the first time we had ever tried it,” planetary science and exploration curator Matt Shindell said. “NASA had never landed on another planet. They had never built a miniature laboratory. No one had ever built a computer that could withstand any of the stresses that Viking was under. The engineers had to design things that were never done before.” 

The landers were the first craft to operate on Mars for extended periods. They provided images, weather information, and other data for over four years (Lander 1) and six years (Lander 2). They also performed experiments to search for evidence of life. The results were mostly negative, but remain inconclusive.

Learn More About the History Making Lander 

Pathfinder & Sojourner

The Sojourner rover landed with the Pathfinder lander and rolled off to rove on Mars. Sojourner marked the first time we “roved” Mars, rather than exploring in one spot with a lander.  

Pathfinder had a TV camera and scientific instruments to gather scientific data on the Martian atmosphere and weather, as well as solar cells to provide power and communications. The lander operated for over 90 days, during which it relayed 2.3 gigabits of data including that gathered by the rover Sojourner.   

The mission gave breakthrough data about Mars. Dr. Ellen Stofan explained, “We had known from orbital data that Mars had these huge channels carved into it that we thought were carved by water, but Pathfinder and the Sojourner Rover really gave us the first evidence that the rocks at the surface showed a lot of signs of having been laid down and modified by water. That gives you the knowledge that it wasn’t just an instant in time of water, that the water had to have persisted for tens of millions of years, if not hundreds of millions of years.”

View the Mars Pathfinder Lander Prototype 

View the Test Vehicle for Sojourner 

Learn More AboutSojourner and Pathfinder 

Spirit & Opportunity

Spirit and Opportunity, twin rovers, were the next robots we sent to explore Mars.  

An important factor in selecting Mars Exploration Rover landing sites was the search for evidence of water on Mars at some time in the planet's past because water is thought to be essential for the development of life.  

Spirit was sent to the floor of a 140-kilometer (90-mile) wide crater named Gusev, because geologists thought it might once have contained a large lake. 

Spirit’s roving route involved climbing Husband Hill. The top of Husband Hill gave Spirit a panoramic view of the surrounding plains, which were often swept by swirling columns of wind and dust called dust devils. Consisting of a mix of ancient rocks altered by interaction with water, the Columbia Hills seem older than the lava covered plains. Scientists aren't sure whether the rocks were created by an impact, volcanism, or some other process. But their complexity and altered condition point to a time when Mars was geologically active and wetter. 

Spirit spent much of its second year on Mars exploring Home Plate, an area within a basin surrounded by the Columbia Hills. The rover found that Home Plate is likely an eroded volcanic structure that may have formed when hot lava erupted through wet rocks. 

Opportunity was sent to Meridiani Planum, a smooth area near the Martian equator. Based on infrared measurements made from orbit, scientists thought the surface had an abundance of hematite, an iron-rich mineral that often forms where water is present. The area also had outcrops of light-colored rocks that might have formed from sediments, rather than lava. From its landing site in Eagle Crater, Opportunity traveled to Victoria Crater, about 10 kilometers (6 miles) away. 

Opportunity found many tiny sphere-shaped nodules, dubbed "blueberries," that were rich in hematite and were probably formed by water below the surface. 

Opportunity discovered that the area's light-colored rocks have wavy layers that cut across each other in sets, a feature geologists call cross-bedding. On Earth these ripples in rock form when shallow flowing water deposits fine sediments that are then covered by wind-blown sediments during dry periods. So the rocks found by Opportunity result from repeated deposition by wind and water. Scientists studying the chemistry of the rocks in Eagle Crater also found evidence that this water was highly acidic. 

Phoenix

The Phoenix Mars Lander set down in the arctic region of Mars in 2008. Its mission was to study the history of polar ice deposits and their impact on the Martian climate, and whether this region could ever have supported life. It operated for five months, collecting data on soil properties, and sending back over 25,000 images of polar terrain, rocks, and soil. 

Curiosity

Curiosity piloted a new way to land on Mars. Weighing in at over 900 kilograms (2,000 pounds), Curiosity could not use the conventional airbag system that facilitated the landing of previous Mars rovers. Instead, an innovative technology called the "Sky Crane" performed a powered descent with Curiosity suspended beneath it. When computers detected that the rover was touching the ground, the connection was severed and the Sky Crane intentionally crashed a safe distance from Curiosity. The Sky Crane landing system offered a precise way to land a heavy rover. 

After landing in 2012, Curiosity began a multi-year mission to explore the Gale Crater, which was thought to host an ancient lake, and to climb Mt. Sharp in its center. Curiosity brought to the red planet’s surface a formidable life sciences laboratory that may well help resolve beyond serious question whether or not life ever existed on Mars. This rover is the first full-scale astrobiology mission to Mars since the Viking landers of 1976. Having followed the water, and found evidence of it, Curiosity now seeks to answer if Mars could have supported—or might still support—life. 

View of Model of Curiosity 

InSight

InSight distinguished itself from other landers by studying what is going on beneath the surface of Mars. Part of the tools it carried with it were a seismometer to search for and study Mars quakes, and heat probes with the ability to study up to 16 feet under the surface.   

Listen to a Podcast and Learn More About InSight 

Perseverance & Ingenuity 

Perseverance is the latest rover to land on Mars and it brought with it a small helicopter called Ingenuity.

Perseverance is seeking signs of ancient life and collect rock samples that may later be returned to Earth. Landing in Jezero Crater, “Percy” is exploring ancient lake and delta deposits to determine what the ancient lake was like and whether there are any preserved biosignatures related to life on Mars. 

Ingenuity performed the first powered, controlled flight on another planet. While Mars has lower gravity at about one-third that of Earth, its atmosphere is only one percent as dense, which makes the helicopter’s task of getting off the ground much more difficult. While flying, Ingenuity can survey the Martian landscape.  

Learn More About Perseverance and Ingenuity