Mars has fascinated humankind for millennia, so it’s not surprising that we attempted to visit Mars as soon as were technologically able to do so–and we haven’t stopped visiting since. Since 1960, only three years after the launch of Sputnik, we began our quest to go to the Red Planet.
In total, 43 missions have been designed and launched, but only 23 have been successful. While NASA has conducted the largest number of missions, India’s space agency recently sent its very first orbiter to Mars.
There are over 2,000 operational satellites orbiting Earth at any given moment, and it will be awhile before Mars has anywhere close to that many. It is, however, the only planet in our solar system inhabited only by robots, many, many robots. Until humans step foot on Mars, robotic spacecraft will continue to be the primary way that we explore our planetary neighbor.
While many attempts have been made to visit, almost half have been successful. Out of the 23 successful missions, seven are still currently operating on or around Mars.
Here’s a list of the 23 missions that made the cut:
1) Mariner 4 (1964)-NASA:
Mariner 4 was NASA’s second attempt at a Mars mission and the first successful one. Mariner 4 flew by the planet and sent back the first images of the Martian surface that any human had ever seen. Scientists were flabbergasted by the images depicting Mars as a desolate, heavily-cratered world, and not at all the habitable place they had hoped to see.
2) Mariner 6 (1969)-NASA:
Mariner 6 was a flyby mission, and its job was to sample the Martian atmosphere as well as to map the polar and equatorial regions of Mars. Mariner 6 sent back hundreds of photos and helped prove technology for future missions.
3) Mariner 7 (1969)-NASA:
Mariner 7 flew in conjunction with Mariner 6 and helped map about 20% of the entire Martian surface.
4) Mariner 9 (1971)-NASA:
Mariner 9 was the first unscrewed spacecraft to orbit another planet. It sent back the highest resolution images of Mars at the time and mapped 70% of the surface at a surprisingly low altitude of 930 miles.
5) Mars 2 (1971)-RUSSIA:
Almost immediately after the Mariner 9 craft entered Mars’ orbit, the Soviet Union followed suit with their Mars 2 orbiter. This mission had a paired lander that failed and thus became the first human-made object to impact the surface of another planet.
6) Mars 3 (1971)-RUSSIA:
The Mars 3 orbiter was the twin spacecraft of Mars 2, that launched nine days afterward and operated for 20 orbits. The lander became the first to attain a soft–landing on the Martian surface.
7) Viking 1, Orbiter (1975)-NASA:
The Viking 1 orbiter had several instruments onboard to analyze the atmosphere and examine the surface. It is still currently in orbit around the planet to prevent contamination of the surface from any possible Earth-based microbes possibly still on the spacecraft.
8) Viking 1, Lander (1975)-NASA:
The Viking 1 lander was a monumental success. It became the first lander to transmit a clear image from the surface of Mars. The Viking 1 landing site, Chryse Planitia, was surrounded by basaltic rock, indicating past volcanic activity. The lander carried an experiment designed to search for life. Until the Opportunity rover, Viking 1 held the record for longest operating Mars mission at 2,245 sols.
9) Viking 2 Orbiter (1975)-NASA:
The Viking 2 Orbiter successfully completed 706 orbits around Mars and returned over 16,000 images.
10) Viking 2 Lander (1975)-NASA:
The partner to the orbiter, the Viking 2 lander touched down in Utopia Planitia and operated for 1,281 sols. Just like its sister mission, Viking 2 carried an experiment to detect life. Several of its instruments sent back positive results of life that were contradicted by other instruments. Ultimately, scientists determined the results were false positives.
11) Phobos 2(1988)-RUSSIA:
The Soviets continued their Mars exploration program with Phobos 2. Named after the Martian moon it was designed to explore, Phobos 2 entered orbit around Mars and took 37 images of its namesake. Due to the high resolution of the instruments on board, this mission provided scientists with the first mineralogical maps of Mars and Phobos.
12) Mars Global Surveyor (1996)-NASA:
The Mars Global Surveyor operated just shy of a decade. The purpose of the mission was to obtain a complete global map to help identify potential future landing spots. After examining the high-resolution images sent back by the spacecraft, scientists were able to confirm that Mars’ weather creates active landforms, such as dunes, that are similar to landforms on Earth.
13) Mars Pathfinder (1996)-NASA:
The Pathfinder mission was the first successful landing since the Viking missions. It utilized a novel landing mechanism that involved the deployment of giant airbags. When the airbags deployed, the spacecraft bounced around on the surface until it came to a slow stop, allowing it to safely deploy the rover inside.
14) Sojourner (1996)-NASA:
This shoe-box sized rover was loaded with scientific instruments. Its mission was supposed to operate for only seven sols, but successfully explored the surface for over three months instead.
15) Mars Odyssey (2001)-NASA:
The Mars Odyssey orbiter is currently operating in orbit around Mars. Its mission is to study water content on the Martian surface as well as to serve as a communications relay between Earth and rovers on the Martian surface.
16) Mars Express (2003)-ESA:
This currently operational orbiter was the European Space Agency’s first mission to Mars. It carried an extensive suite of scientific instruments and produced a wealth of data about the planet’s atmosphere and geological makeup. It very discovered frozen water ice on the south polar ice cap.
17) Mars Exploration Rover, Spirit (2003)-NASA:
The MER-A rover, Spirit operated on the surface for six years in Gusev Crater. The sister to the MER-B, Spirit was originally planned as a 90-day mission. NASA lost contact with Spirit in 2010, and the mission was officially terminated in 2011.
18) Mars Exploration Rover, Opportunity (2003)-NASA:
The MER-B has been operational and conducting science for over 11 years. Opportunity currently holds the record for longest-running Mars mission ever. It is now exploring Endeavor Crater.
19) Mars Reconnaissance Orbiter (2005)-NASA:
MRO is a workhorse, observing active geology on the surface, imaging the planet in high resolution, and serving as a communication relay between the two operational rovers and NASA’s Deep Space Network at JPL.
20) Phoenix Lander (2007)-NASA:
The Phoenix Lander was the first to touch down in a polar region on Mars. Phoenix was designed to study the history of the ice in the north polar cap as well as help scientists understand possible habitability on the planet.
21) Mars Science Laboratory (2011)-NASA:
MSL, or more commonly known as the Curiosity Rover, has been actively working on Mars for four years. Curiosity is by far the most advanced rover ever built. Curiosity is currently making her way up the slopes of Mt. Sharp in Gale Crater, an ancient Martian lakebed.
22) Mars Orbiter Mission (2013)-ISRO:
New to the Martian operating team is India’s MOM spacecraft. India is the fourth space agency to send a mission to Mars. They were wildly successful when sent MOM into orbit on their first attempt. MOM is a proof-of-concept mission as well as a scientific mission.
23) Maven (2013)-NASA:
The Mars Atmosphere Volatiles Evolution mission is NASA’s most recent orbiter designed primarily to study the Martian atmosphere. Scientists are trying to understand why and how Mars lost its atmosphere. MAVEN has already provided scientists with valuable data to help answer these questions, and will continue to do so until the mission is complete.
ExoMars (2016)-ESA: The European Space Agency launched a brand new rover to Mars on March 15th, 2016. The Exobiology on Mars mission is designed to detect biosignatures of Martian life. There are two components to this mission: an orbiter and a lander. The location of biosignatures found on Mars will inform ESA’s choice of a landing site for their ExoMars rover in 2018.
Mars 2020 Rover (2020)-NASA: This new and improved rover is scheduled to launch in 2020 and will land on the surface around seven months later. The 2020 rover will search for signs of organics in the Martian soil as well as conduct experiments at its landing site in preparation for a future manned mission.