Mars is by far the most-studied object in the Solar System beyond the Earth and Moon. But there is a myth that the planet is jinxed. While it's true that several high-profile missions have failed, a much greater number have succeeded and many are still actively sending back pictures and data from the planet.
Because Mars takes nearly twice as long as Earth to orbit the Sun, there is a short window of opportunity every two years when missions can be launched economically. In 2020, for example, three missions were launched within an 11-day period, from the US, China and the UAE. In addition, some missions to more distant planets have also passed Mars on their way, using what's known as gravitational slingshot to steal a little of Mars's orbital momentum to boost them on their way.
This is the first interplanetary probe from the Arab world. It is designed to study the climate of Mars in detail, and involves an orbiting craft named Hope (Al Amal in Arabic). The craft and its experiments were designed in the UAE in conjunction with US laboratories and built in the US. It was launched on a Japanese rocket.
The experiments will focus on gaps in our knowledge about the climate of Mars, such as establishing why the planet has lost hydrogen and oxygen into space. Although it is often thought that Mars is too small to hold onto a thick atmosphere, the planet’s size in itself is not sufficient to explain the loss of what was clearly once a more extensive atmosphere. The prevalence of dust devils is also of interest.
The craft is due to reach the planet in February 2021.
Tianwen-1, launched by the China National Space Administration, consists of an orbiter, lander and rover. The mission has ambitious aims to find evidence for life on Mars, either past or present, by means of studying the martian soil for biosignatures, and investigating distribution of water ice and the atmospheric composition. It will also prepare the way for a Chinese sample-return mission in the 2030s.
The orbiter should arrive in February 2021 and the planned landing site is in Utopia Planitia in April 2021.
NASA’s Perseverance rover is based on the successful Curiosity rover which is still operational in Gale crater. It should land in Jezero crater in February 2021. One of its experiments is a ground-penetrating radar which could detect underground ice and brine at a depth of up to 10 metres. Another is aimed at producing oxygen from the carbon dioxide atmosphere, as a test of the technology looking forward to future crewed missions. In addition, there will be a solar-powered drone to scout out the best route for the rover and test the technology.
This European Space Agency mission was due to be launched in July 2020, but has now been put back for launch in 2022 and arrival in 2023. One part of the ExoMars mission, the Trace Gas Orbiter, is already in orbit around Mars and is returning valuable data about the atmospheric composition. The second part will consist os a Russian lander named Kazachok, which will deliver the ESA rover Rosalind Franklin to the surface. Its primary mission is to search for biosignatures. Rosalind Franklin was built in the UK.
The first spacecraft to be sent to Mars were in the very early years of the Space Age. The Soviet Union tried to launch two missions in October 1960, just three years after their first Sputnik, but both failed on the launch pad. The first one to actually survive into orbit was Mars 1, launched in November 1962. Communications were lost with the probe when it was about halfway there, but it probably did fly past Mars in June 1963.
Following that, the USA launched two missions, Mariners 3 and 4, in November 1964. Mariner 3 failed but Mariner 4 made it all the way and managed to take a series of 21 images across a swathe of the martian surface. These historic images and the measurements made by Mariner 4 transformed our view of Mars, revealing craters for the first time and demolishing forever the famous canals. The pictures are very basic by modern standards, but electronic imaging technology in the 1960s was restricted to video cameras using bulky glass vacuum tubes rather than today’s tiny CCD chips which we all have in our phones.
Two subsequent Mariner missions, 6 and 7 in 1969, also returned series of photos showing more craters from swathes of the surface.
The next onslaught on Mars came in 1971. The USSR made a bold attempt with Mars 2 and Mars 3. Each craft had an orbiter and a lander, as do many of the subsequent missions. Mars 3 became the first spacecraft to land on Mars, but the planned rover failed to deploy. This is one case where Mars itself played a part in the failure, as a planet-wide dust storm was raging at the time. This also affected the first pictures from NASA’s Mariner 9, which was the first successful Mars orbiter. Its pictures showed a blank planet for many weeks. Eventually the storm subsided and details started to emerge.
Although many images had been returned by Mariners 4, 6 and 7, by chance none of them had included some of the most dramatic surface features on Mars – the great volcanoes and the gigantic canyons carved by a wet period in Mars’s ancient past. The largest of these is now named Valles Marineris – Mariner Valleys – after Mariner 9.
The next window of opportunity in 1973 saw four probes from the USSR, all of which reached Mars but failed to complete their missions.
In 1976 came a welcome success from the US with the two Viking probes, each with an orbiter and a lander. A wealth of data came back from these two craft, with the Viking 1 lander in particular continuing to operate for over six years from the surface of Mars. The landers carried scrapers to deliver soil samples into experiment bays. One of these gave a signal that could have been due to a biological signature, but this was subsequently discounted by NASA.
After a long gap during which Mars was left in peace, in 1988 the USSR sent two probes to the martian moon Phobos, both of which failed. It was not until 1996 that the US had another success, with Mars Global Surveyor, which returned detailed images and data for over seven years. And in the same year, NASA’s Pathfinder mission successfully landed and deployed the first successful rover, named Sojourner. This tiny device, not much bigger than a toy radio-controlled car, sent back pictures and analysis of the soil using an x-ray spectrometer.
Since 1998, every launch window has seen missions to Mars, with varying degrees of success. That year saw two failures for NASA, one of which is still remembered as probably the most notorious and embarrassing reason for a failure. Mars Climate Orbiter was planned to orbit the planet and to study its atmosphere in great detail. However, due to a mix-up in software units, in which one set of thrust figures was given in pound-force-seconds and another in newton-seconds, the craft failed to enter orbit and probably crashed onto the surface. Three months later, Mars Polar Lander crashed, probably due to an engine failure.
Since the start of the 21st century, most missions have been successful, all or in part. NASA’s Odyssey orbiter, launched in 2001 (as befits its name) continues to send back data and images, as does ESA’s Mars Express. The latter was used as a launcher for the UK Beagle 2 lander, which did reach the surface but failed to open its solar panels fully so did not communicate with Earth. However, Mars Express continues to yield valuable data, as this recent work shows.
Twelve missions sent to Mars since 2000 have been successful and eight are still operational. The Curiosity rover is sending back amazing and detailed panoramas as it continues its planet trek across Gale crater. Three more missions are on their way, with ESA’s ExoMars due to launch in 2022 for a 2023 landing.
Last Updated: 2020-10-04 20:34:10