Humans have been fascinated by Mars since it was first observed as a celestial object in the sky. In the 1960s, attempts to uncover the planet's secrets about planetary growth and evolution and the possibility of extraterrestrial life began. So far, only unmanned spacecraft have visited Mars, but this might change soon as NASA aims to send the first humans to Mars by the 2030s, preceded by several missions aimed at advancing exploration.
Why Mars?
In the past hundred years, all the information gathered about Mars suggests that the planet was once suitable for sustaining life forms and may still harbor microbial life. Mars is the fourth planet from the sun, positioned after Earth and is slightly larger than half the size of Earth with a gravitational force that is only 38% of Earth's. Mars takes longer to orbit the sun than Earth but rotates on its axis at a similar pace, thus a year on Mars lasts 687 Earth days while a day is just 40 minutes longer than Earth. Despite its smaller size, Mars has a land area comparable to the total surface area of Earth's continents, providing an equal amount of potentially habitable space.
What is stopping us?
Sadly, Mars is now encased in a thin atmosphere composed mostly of carbon dioxide and is inhospitable to life as we know it. The atmosphere also sporadically releases methane gas, and the soil contains toxic elements that are detrimental to life. Although water exists on Mars, it is confined to the icy polar caps or possibly hidden beneath the surface.
Currently, as scientists examine Mars, they observe features that unmistakably indicate the presence of flowing liquids in the past. These features include branching streams, river valleys, basins, and deltas which suggest that the planet might have once had an immense ocean covering its northern hemisphere. Additionally, evidence of rainfall, lakes, and rivers that shaped the terrain is also apparent, indicating that Mars once had a thick atmosphere capable of retaining liquid water at its temperatures and pressures.
At some point in its history, Mars underwent a significant transformation and evolved from a planet similar to Earth to the arid and desolate world we observe today. The mystery lies in what caused this change, what happened to the liquids and atmosphere, and where they disappeared to. Studying Mars provides scientists with a better understanding of the drastic climate changes that can affect planets and helps search for biosignatures which could indicate the presence of life in the past or even today. The more we learn about Mars, the more prepared we will be for the possibility of future human habitation.
What's next?
Approximately every 26 months, Earth and Mars are positioned in a way that reduces the cost and travel time of interplanetary missions, allowing spacecraft to reach Mars in about half a year. During these conjunctions, Earth's space agencies typically launch probes. During this time, three nations, the United States, the United Arab Emirates, and China, are sending spacecraft to Mars.
The ongoing robotic missions are preparatory steps towards sending humans to Mars in the future. NASA aims to land the first humans on the Red Planet in the 2030s and is working on designing a space capsule, Orion, which will be capable of transporting people to the moon and beyond.
Private spaceflight organizations such as SpaceX are also joining the exploration of Mars. The CEO of SpaceX, Elon Musk, has frequently expressed the belief that the survival of humanity depends on becoming a multi-planetary species and has outlined a plan to establish a settlement of one million people on Mars by the end of the century.
In the near future, it is possible that humanity will finally discover whether Mars ever supported life and if there is a potential future for our species on another planet.
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