Abhi Mangipudi is one of our fabulous Guides at Sydney Observatory. During his evening tours he is often asked about travel to Mars. And this got him thinking about the future…
“The time was fast approaching when Earth, like all mothers, must say farewell to her children” – Arthur C. Clarke
As Mars begins to disappear from our night time sky, and with the recent successful landing of the InSight mission, I couldn’t help but think about the possibility of manned interplanetary travel soon becoming a reality. Elon Musk, CEO of SpaceX, boldly announced at the International Astronautical Congress in 2017 – a conference I was fortunate enough to attend – that we will place the first footprint on Mars as soon as 2024. NASA and Boeing follow behind, claiming they will send humans to Mars in the 2030s.
Two significant astronomical events involving Mars happened in 2018. The first being Mars at opposition on the 27th of July, alongside a spectacular total lunar eclipse, and the second coming only a few days later, on the 31st of July, when Mars reached its closest approach to Earth since 2003. It was at a distance of a mere 57.6 million kilometres. Further, with the recent success of Ridley Scott’s film The Martian, it becomes more apparent that Mars is a growing interest in the public sphere.
This leads to the many questions I receive on my night tours at Sydney Observatory about Mars: How long does it take to get there? Why Mars? Is it safe for humans? Will they come back?
When Wernher von Braun laid the foundations for the Saturn V (the rocket that sent astronauts to the Moon during the 1960s and ‘70s), his goal was not to reach the Moon at all. No no, he designed the Saturn V keeping in mind the goal of sending humans to Mars, and released a technical document in 1953 called Das Marsprojekt outlining the logistics of a manned expedition to Mars. What is shocking to see is that the ideas outlined in this document are still incorporated into plans today, in our quest to conquer the red planet.
But here, my goal is to travel further into the future, beyond the first human footprint, beyond a colony, beyond even the first Martian city, all the way to terraforming Mars.
What is terraforming? The Oxford dictionary tells us that terraforming is the process of “transforming (a planet) so as to resemble the Earth, especially so that it can support human life”. The atmosphere on Earth contains roughly 78% Nitrogen, 21.5% Oxygen and 0.5% other gases. The atmosphere of Mars, in stark contrast, contains almost 100% Carbon Dioxide, and the atmospheric pressure is only 1% of that on Earth. Long story short, we need to increase the atmospheric pressure and find ways to add massive amounts of Nitrogen and Oxygen to the atmosphere.
So how do we terraform? No idea … yet.
Geographic evidence found by previous rovers sent to Mars indicate that water once flowed as a liquid across the surface in the form of rivers, lakes and even oceans. Scientists speculate that solar flares stripped Mars of its atmosphere, removing its ability to sustain water in its liquid form. Eventually it became the barren wasteland that we see today. That water still exists, now in frozen form at the poles and under the surface.
One way to terraform might be to kick start a self-sustaining greenhouse effect by adding methane and water vapour to the atmosphere. These gases would capture more heat from the Sun, decrease its planetary albedo (or reflectivity) and slowly start warming the planet. This is exactly what happens on Earth when we release copious amounts of carbon compounds into the atmosphere – but we already have the ideal temperature! Carl Sagan in his book Cosmos described the creation of a self-replicating black material that would grow and cover the polar ice caps on Mars, slowly melting them and releasing that water.
Michio Kaku in his book The Future of Humanity described orbiting satellites that could direct beams of sunlight down at the poles to heat them up. Elon Musk has suggested detonating thermonuclear weapons above the poles to also slowly heat them, but we might shelve that idea for now. If the ice caps melted, there would be enough liquid water to create an ocean around five to ten metres deep. All of these processes, however, are hugely inefficient, extremely expensive and all consequences are not fully known.
Once enough water is released, and the climate warms enough, the large amount of carbon dioxide that remains trapped in frozen form would be vapourised. It would then be possible to develop agriculture and cultivate the first Martian crops. Plants love carbon dioxide, and this combined with sunlight and water gives oxygen and sugar – a process called photosynthesis. This bloom of plants would lead to a feedback loop, whereby more plants consume more carbon dioxide and produce more oxygen. Even our own planet didn’t naturally contain vast amounts of oxygen, the only reason the Earth has oxygen is because of cyanobacteria
Further into the future, we may develop a device which could land on distant planets and, at the push of a button, explode like a bomb and spread highly engineered compounds around the surface to grow jungles and oceans within a few days or weeks.
Do we need to terraform? Some scientists suggest that terraforming will be rendered unnecessary with the development of bio genetics and enhancements to the human body. Instead of attempting to convert entire planets to this overly specific mix of nitrogen and oxygen, why not enhance the human body to survive the harshness of deserts, the deep blue, the cold Antarctic, the vacuum of space and everything in between?
But should we terraform? To a certain extent, we ought to exercise caution and not be excessively invested in the idea of terraforming. When future humans travel to distant planets and find basic life forms going through their evolutionary paces, would it be ethical for us to terraform the planet and deny them of their natural evolution, or worse yet, destroy all life on the planet for our own selfish gain? The jury is still out, but a brief examination of human history suggests what’s most likely to happen. Every time the Homo Sapien was introduced to a new continent, it almost always followed with the mass extinction of various species of animal life. Either way, terraforming Mars is one of the few options we have if we are to build a long-term, self-sustaining colony and to place us on the path to becoming a star-faring civilisation.