Last updated October 3, 2017 at 8:55 am
Mars has captivated generations of explorers and storytellers. 100 years ago, the mistaken observation of “canals” on the planet’s surface inspired stories of an advanced Martian civilisation, such as H. G. Wells’ War of the Worlds. As the world entered the space age, Mars became a prime target for exploration, and we dreamed of setting foot on Martian soil and building cities and homes on a new world. Today, movies like The Martian draw huge crowds to the box office, and it seems that NASA and Elon Musk are determined to turn this dream into reality.
- Related videos: Mars on the Horizon series, including interview with the author of The Martian, Andy Weir
Since 1997, humanity has had a continuous robotic presence at Mars. For 20 years, not a single day has gone by that we have not had a craft on the ground or in orbit studying the planet and leading the way to human exploration.
Mars Pathfinder (USA)
Pathfinder landed on Mars on 4th July 1997. As part of NASA’s Discovery Program, Pathfinder was designed to be a fast and cheap way to explore Mars. Although it carried instruments to analyse the Martian atmosphere, climate, and geology, its primary goal was to demonstrate new technologies, such as the airbag landing system, that would be used on future missions.
One of the technologies Pathfinder demonstrated was a rover called Sojourner, which Pathfinder carried on one of its solar panels. Sojourner drove a short distance and studied rocks and soil around the lander. Pathfinder and Sojourner operated for nearly three months before Pathfinder succumbed to the freezing Martian conditions and contact with the lander and rover was lost.
Sojourner analyses a rock, photographed by the Pathfinder lander. Image credit: NASA
Mars Global Surveyor (USA)
Hot on the heels of Pathfinder, the Mars Global Surveyor (MGS) arrived in orbit on 12th September 1997. MGS was tasked with mapping the entire planet. As well as studying Martian geology, monitoring the climate and weather, and analysing Mars’s magnetic field, MGS was used to identify landing sites for future rovers and landers, and to relay communications from other ground and orbital missions. MGS operated until a fault cut off communications in 2006.
MGS showing gullies in a crater wall possibly formed by liquid water. Image credit: Malin Space Science Systems, MGS, JPL, NASA
Mars Odyssey (USA)
Mars Odyssey arrived in orbit around Mars on 24th October 2001 and is still operational today, making it the longest serving spacecraft in orbit around a planet other than Earth. Odyssey is equipped with sensors to detect evidence of water and ice, past or present, and to study the planet’s geology and levels of radiation. Odyssey’s radiation measurements are crucial to planning human exploration missions. Like MGS, Odyssey acts as a communications relay for rovers and landers on the surface.
Artist’s impression of Mars Odyssey. Image credit: NASA/JPL-Caltech
Mars Express (Europe)
Mars Express consisted of an orbiter and a lander called Beagle 2. The orbiter successfully entered Mars orbit on Christmas day 2003, having previously released the lander. Unfortunately, Beagle 2 failed to establish communications after landing and it was presumed that the landing sequence had failed and Beagle 2 had crashed into the surface of Mars. In 2015, imagery from the Mars Reconnaissance Orbiter showed that Beagle 2 had landed successfully but one of its solar panels had failed to open, preventing the radio antenna from being deployed and cutting off communication with the craft. Had it worked, Beagle 2 would have used it sensors to search for evidence of life in the Martian soil.
The orbiter is still active and continues to map the geology of Mars using radar and high resolution imaging, as well as studying the circulation and composition of the atmosphere.
Artist’s impression of Beagle 2 on Mars. Image credit: ESA.
Mars Exploration Rovers (USA)
The Mars Exploration Rovers are better known by their individual names, Spirit and Opportunity. The rovers are robotic geologists designed to study rocks and soils for evidence of water activity on the ancient Martian surface.
The rovers landed at widely separated locations in January 2004 using the airbag landing system demonstrated by Pathfinder. Spirit landed first and started taking measurements. Spirit was extremely successful, despite being the most troubled of the two rovers. An early communications glitch was fixed, but Spirit began to have trouble with a malfunctioning front wheel. In 2006, the front wheel stopped working entirely and Spirit had to drag the wheel through the Martian soil. In May 2009, Spirit became stuck in soft soil and mission control was unable to free the rover. Spirit became a stationary science station, analysing what rocks and soil it could reach, and making weather observations. Communications with Spirit were lost in March 2010 and, after unsuccessful attempts to re-establish a link, the mission was declared over.
Opportunity is still operational, still driving and doing science nearly 14 years after landing. Having driven a total distance of nearly 45 km, Opportunity holds the record for the longest distance driven on another planet.
Artist’s impression of Spirit/Opportunity on Mars. Image credit: NASA/JPL/Cornell University, Maas Digital LLC
Mars Reconnaissance Orbiter (USA)
The Mars Reconnaissance Orbiter (MRO) arrived at Mars in March 2006. When it arrived, MGS, Mars Express, Odyssey, Spirit and Opportunity were all operational, marking a record six different craft operating simultaneously around a planet other than Earth.
MRO is equipped with sensors to study the landforms, geology, ice, and weather of Mars in greater detail than the craft that preceded it. As well as providing weather and landing site information for future missions, MRO is designed to support other Mars missions as a high-capacity communications relay satellite. MRO is able to transmit more data back to Earth than all previous interplanetary missions combined.
Artist’s impression of MRO skimming the Martian atmosphere to slow down into orbit. Image credit: NASA/JPL/Corby Waste
The Phoenix lander was a relatively cheap and simple craft designed to search for water ice and environments suitable for microbial life at the Martian north pole. Phoenix landed in May 2008 and had completed its mission by August. It found evidence of water ice just below the surface of the soil, and a range of salts that may make conditions in the area suitable for microbial life by lowering the melting point of ice and providing useful chemicals.
Artist’s impression of Phoenix landing at Mars’s north pole. Image credit: NASA/JPL-Calech/University of Arizona
The Curiosity rover is the current star of the show. Curiosity landed on Mars in a spectacular fashion in 2012, winched down to the surface from a rocket-powered flying sky-crane. This car-sized, plutonium-powered rover carries on from the work done by Spirit and Opportunity by studying the geology of Mars to determine if conditions were ever suitable for microbial life to evolve. Curiosity’s results show that liquid water was present on the surface of Mars for millions years, possibly long enough for basic life forms to get started.
Curiosity uses a camera on its robotic arm to take a selfie. Image credit: NASA/JPL-Caltech/MSSS
- Related article: NASA’s Curiosity – Roving the Red Planet
Mangalyaan or Mars Orbiter Mission (MOM) is an Indian probe that reached Mars orbit in September 2014. MOM is India’s first interplanetary mission and makes the Indian Space Research Organization the first to reach Mars on its first attempt.
MOM is also notable for being extremely cheap by the standards of interplanetary space missions, costing around US$71 million. Significantly less than the US$108 million production cost of The Martian movie!
The mission is primarily a technology demonstrator to allow the Indian Space Research Organization to learn how to design, plan, and operate an interplanetary mission. MOM also carries instruments to contribute to the study of Mars’s geology and atmosphere.
Artist’s rendering of MOM at Mars. Image credit: Nesnad/Wikimedia
Mars Atmosphere and Volatile EvolutioN Mission (MAVEN) is a NASA probe that reached Mars orbit in September 2014 and is designed to study how the planet’s atmosphere and water were lost over time. MAVEN has already determined that the solar wind blows the atmosphere into space, stripping the atmosphere of CO2. This turned Mars from a relatively warm planet with liquid water, to a cold and arid desert.
Artist’s rendering of MAVEN in orbit around Mars. Image credit: NASA/GSFC
ExoMars Trace Gas Orbiter (Europe/Russia)
Launched in 2016, the ExoMars Trace Gas Orbiter (TGO) is designed to study methane and other trace gases in the Martian atmosphere that could be the result of biological activity in the soil. TGO also carried the Schiaparelli lander, which was intended to be a landing technology demonstrator, but crashed into the surface of Mars, possibly due to parachute and engine problems.
Model of the Schiaparelli lander at ESOC in Darmstadt, Germany. Image credit: Gerbil/Wikimedia
As organisations, both government and private, drive towards the human exploration and eventual colonisation of Mars, the number of ground and orbitals missions studying the planet is going to increase.
In May 2018, NASA will launch InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) to investigate the interior of Mars and find out how did terrestrial planets form.
2020 is set to be a busy year for Mars missions. China, Japan, and the United Arab Emirates are all aiming for their first successful Mars mission. Following on from the success of Curiosity, the USA will launch their Mars 2020 Rover, while the European Space Agency will ramp up their ExoMars program. India are also going to build on their success with a second, more advanced Mangalyaan mission.
If all goes to plan, humans won’t be far behind.
Check out the proposed SpaceX interplanetary transport system below. Elon Musk will give up an update on his Mars base plans at the upcoming International Astronautical Congress.