The Viking program was a precursor to many Mars landing missions. It used the combination of an orbiting satellite and a lander to gather data about the conditions on Mars. The Pathfinder was a later Mars landing project. Using knowledge from the Vikings, NASA was able to make a cheaper, more efficient landing device and rover. The Viking lead to the creation of the much cheaper and more efficient Pathfinder.
The Viking program was an exploration of Mars that utilized some of the first Mars rovers and new landing technologies. NASA launched two unmanned satellites into Mars’s orbit. Each orbital spacecraft then deployed a Mars rover to the surface. The Viking 1 was launched into space on August 20, 1975. It reached Mars orbit on June 4, 1976. The rocket stayed in orbit, transmitting information and pictures of Mars back to Earth until August 17, 1980. On July 20, 1976, The Viking 1 orbital deployed its landing unit to the surface of Mars. This was the first craft to successfully reach the surface of Mars and execute its intended mission. This rover would continue to transmit pictures and atmospheric readings for six years. On November 11, 1982, NASA lost contact with the rover.
The Viking 2 was launched on September 9, 1975, one month after the Viking 1. The rocket reached Mars orbit on September 3, 1976, where it transmitted data to NASA for almost two years. It deployed its lander on September 3, 1976. The rover functioned properly until April 11, 1980, when its batteries unexpectedly died. The landers and orbitals of both Vikings were identical. Both orbitals had masses of 883kg while both landers had masses of 572kg. They used 28V Nickel-Cadmium batteries. Also, they utilized metal legs with landing pads for a smooth touchdown. The Vikings found the composition of the soil on Mars and were unsuccessful in their search for Martian life. The Viking program costs a total of one-billion US dollars.
The Mars Pathfinder was the second successful Mars mission that NASA executed. In addition to recovering more data on Mars, the Pathfinder proved that a less expensive, light weight Mars spacecraft could be built. The Pathfinder used similar technologies to the Viking ships, though it also made use of new systems like airbag equipped landing pads and programming with sensors that allowed the rover to avoid objects. NASA launched the Pathfinder on December 4, 1996. It reached the surface of Mars on July 4, 1977. One of the main differences between the Viking and the Pathfinder is that the Pathfinder had no orbiting unit. It was mostly meant to deliver the Sojourner rover to the surface while testing new landing methods. It was significantly lighter than the Vikings, having a mass of 264kg while carrying the 10.5kg Sojourner rover. The entire mission cost about 150 million US dollars. It was much cheaper and, unlike the Vikings, used on onboard computer to execute more complicated tasks and navigate rigid terrain. The Pathfinder was the first of a series of low cost, efficient Mars landings.