Exploration of Mars

Mars is the fourth nearest planet to the sun. The "bright red" color of the planet is responsible for its association with the Roman God of war. It is known by different names in different cultures for example. "Mangal" in Hindu culture, "Her Desher" in Egyptian culture, etc.

The bright "rusty" red color of Mars is attributed to the rich iron oxide deposits in its regolith (i.e. the loose deposits that cover the Martian surface). It is basically a terrestrial planet (i.e. made of rocks and minerals).

The "red planet" has some of the highest mountains and deepest valleys in the solar system. The Olympus Mons, is the tallest planetary mountain that has been yet discovered in the entire solar system, having a height of roughly 22 km above the sea level and Valles Marineris, also known as the "Grand Canyon" of Mars, is one of the largest system of canyons, that has been discovered in the solar system, having a length of around 4000 km, a width of around 200 km and depth of around 7 km. Olympus Mons also happens to be one of the largest volcanoes yet discovered in the entire solar system.

Observations conducted by various Mars missions have revealed the presence of channels, valleys, and gullies across the Martian surface. This points to the possibility that liquid water might have flown across the surface of mars in the past. Also, the surface of Mars is found to be covered with multitudes of large craters, with the largest one is known as Hellas Planitia, having a diameter of around 2300 km.

Observations have also revealed vast ice caps in the polar regions of Mars. These ice caps are found to remain frozen all year round.

The temperature in Mars, owing to its vast distance from the Sun, remains considerably low, with an average temperature of around -60°C.

Its atmosphere is rich in carbon dioxide and is on an average roughly a hundred times less dense than that of earth. The Martian atmosphere however supports weather, clouds, and winds. The lower density of the Martian atmosphere is attributed to the fact that, unlike earth, it does not have an intrinsic global magnetic field, as is revealed by scientific observations. So, the solar winds directly interact with the Martian atmosphere thereby 'stripping away' the lighter gaseous molecules. The weak gravitational pull of Mars could not prevent these light gas molecules from escaping into space. These are the causes that are believed to have resulted in the considerably 'thin' Martian atmosphere as we see it today.

One particular feature of the Martian climate is the infamous "dust storms". These storms are the largest of its kind in the entire solar system and is capable of blanketing the entire planet and lasts for several months. These dust storms are believed to be the result of radiative heating of the Martian surface by sunlight.

Mars has two natural satellites, named Deimos and Phobos. They are made of a mixture carbon-rich rocks and ice particles and are irregular in shape. Like our moon, the surface of these satellites are pockmarked too with craters believed to be formed by meteoritic impacts.

Why Has There Been So Many Mars Missions in Recent Times?

There has been an increase in the number of Mars missions being conducted in recent times by different countries. Only a few of them have achieved success, but yet there has been no dearth of interest, among the nations  in sending more and more satellites and rovers to Mars, despite the fact that sending a mission to Mars requires an expenditure of millions of  dollars  in the technology associated with it and a mission failure will imply a considerable economic loss for a nation. The question which may, therefore, arise in our minds is why we keep attempting Mars missions. What is the cost to benefit ratio behind it?

One of the reasons is that different observations have pointed out to the possibility of the existence of life-sustaining conditions in Mars in the past. The motivation of most of these missions is therefore  to find conclusive proof of the existence of life on Mars in the past which in turn can help us find answers to crucial questions regarding the origin of life in the solar system and whether human beings can survive in Mars. This off-course does not mean that other planets in the solar system and the exoplanets do not have any possibility of containing life. In fact, there are speculations regarding existence of microbial life forms in the subsurface oceans of Europa, one of the moons of Jupiter, Enceladus, one of the Moons of Saturn etc. Why then are we so inquisitive about Mars in particular. The answer is the proximity of the planet to earth, which makes it at least feasible, albeit with high expenses to send probes to Mars. As a matter of fact, after every 26 months, there is a time window during which the alignment of Earth and Mars are suitable to have a probe reach Mars from earth in little longer than eight months.

The other reason why so many countries are interested in sending probes to Mars is the strategic interests associated with a successful interplanetary mission, which includes display of the nation's technical prowess and geopolitical leadership capabilities.

India's motive behind its first interplanetary mission, namely the Mars Orbiter Mission (MOM), which is also incidentally hailed as the first successful maiden attempt made by any nation to reach the "Red Planet", is no different. The objectives behind India's interplanetary mission is perhaps best expressed by a comment made by Prof. Vikram Sarabhai, the father of India's space program:

"There are some who question the relevance of space activities in a developing nation. To us, there is no ambiguity of purpose. We do not have the fantasy of competing with the economically advanced nations in the exploration of the Moon or the planets or manned spaceflight. But we are convinced that if we are to play a meaningful role nationally, and in the community of nations, we must be second to none in the application of advanced technologies to the real problems of man and society, which we find in our country. And we should note that the application of sophisticated technologies and methods of analysis to our problems is not to be confused with embarking on grandiose schemes, whose primary impact is for show rather than for progress measured in hard economic and social terms."

Global Missions to Mars

The first robotic spacecrafts to Mars were sent by The United States of America, back in 1960s and 70's. They were a part of the Mariner program of NASA (National Aeronautics and Space Administration), the American Federal Space agency, whose objective was to investigate the planets Mars, Venus and Mercury. The successful missions to Mars were named Mariner 4, 6 ,7 and 9. The first three were planetary flybys, which revealed that Mars is a barren planet with no signs of life or any civilizations. This revelation practically debunked all speculations, regarding advanced Martian civilizations, that were made by the people before that time. It was Mariner 9 which was the first planetary orbiter sent by any nation that mapped about 80 % of the planet revealing its landforms.

Viking 1 lander of NASA made history in 1976, by being the first Lander to successfully touch down the surface of Mars. The Viking 1 and 2 missions not only captured close-up pictures of the Martian surface and its landforms but also conducted biological experiments on Martian soil in a small scale to find traces of life, but the results were inconclusive.

The Mars Pathfinder Lander launched by NASA in 1996 became the first lander to carry and successfully deploy a free moving rover vehicle, named Sojourner to analyze Martian rock samples.

Out of the many successful Mars Mission of NASA, the Mars Exploration Rover Missions (MER)  of 2003 deserves special mention in the fact that the two rovers deployed in this mission, namely  the Spirit and the Opportunity explored the planet more extensively than any of the previous missions. These rovers also outlived their planned mission period. Opportunity also holds the record for the longest distance travelled by any off-earth wheeled vehicle (around 46 km). The present ongoing missions of NASA includes Mars Odyssey (launched in 2001), Mars Reconnaissance Orbiter (MRO) (launched in 2005), Curiosity (launched in 2011),  Mars Atmosphere and Volatile EvolutioN (MAVEN) (launched in 2013) and Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) (launched in 2018).

In 2020 NASA plans to launch another mission called Mars 2020, which plans to put a rover named Perseverance to conduct experiments to investigate the environmental history of Mars. It will also collect and preserve samples to be brought back to earth in future for further investigation.

Besides NASA, which holds the record of  launching the maximum number of successful Mars missions till date, space agencies of other countries also have conducted successful Mars Mission some notable examples being Mars Express Mission (launched in 2003) of The European Space Agency (ESA) , Mars Orbiter Mission (MOM) (launched in 2013) of Indian Space Research Organization (ISRO) etc. These missions are still active till date.

The MOM mission of India deserves special mention not only because it happens to be the first Mars mission to successfully put an orbiter probe  (the Mangalyaan) in orbit around Mars but also because the entire mission had cost only R460 crore, which is an economical price tag by any western standards. A followup of this mission, named Mars Orbiter Mission-2 has already been announced and is expected to be launched sometime around 2024. This Mission will include a lander and rover along with an orbiter.

Buoyed by India's success in its maiden attempt, countries like UAE (HOPE Mission), China (Tianwen-1 Mission) etc.   have planned to send Mars probes in the year 2020. Plans are also underway to launch a NASA and ESA joint collaborated mission, to bring back samples collected by Mars 2020 Mission to earth, sometime around 2026.

Not only this NASA and private space agency SpaceX also have ambitious plans to send manned missions to Mars sometime around 2030.

Challenges of Conducting Mars Missions

Successful Mars exploration missions involve not only a very high degree of engineering prowess but also a fair amount of luck. It is therefore no wonder that we find such a high degree of failure rates in these missions. The challenges involved in any Mars exploration programme are enormous with the principal three amongst them being insertion of the probe into an orbit around Mars, descent of the lander and soft landing of the lander on Martian surface. Therefore, adequate tests need to be conducted in simulated environments that mimic the environmental conditions and uneven landform of Mars. All these require considerable degree of economic expenditure on the part of the government and in turn on the taxpayers.

Human Missions to Mars will face even more challenges, including risk to the lives of the astronauts taking part in the mission, stemming from the technical malfunctions as well as the unpredictable nature of Martian climate.

Conclusion

Considering the enormous challenges involved in conducting manned Mars missions it is very likely that more and more unmanned missions would likely be conducted before an attempt is made to conduct a manned mission.

Even in the unmanned missions, the challenges would be to reduce the costs involved in the mission without compromising the safety of the mission. In this respect India has been a torchbearer, by conducting so many successful unmanned space missions at very economic prices.  This has been achieved mostly by relying on indigenously developed components and technologies rather than on importing expensive foreign components. The cheap labour availability is also an added advantage for India.

If we conduct a cost to benefit analysis of all these missions, we will be amazed to find that the technological breakthroughs  that has been during these missions have enormous applications in our daily lives including  accurate weather predictions , space-based communication services  (which have revolutionized the  modern day communication systems),  space-based positioning systems , (which can pinpoint  any location on the earth's surface with a considerable degree of accuracy and is an integral part of almost all mobile phone application), among many others.

India alone has received huge military and strategic benefits, from its MOM and other space programs. These programs have demonstrated India's strategic military capabilities to the world.  

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