HUMANS IN SPACE

Flying to the dream, or when we can expect cities on Mars

Flying to the dream, or when we can expect cities on Mars

The news from the red planet comes one by one. The first helicopter flight, the first artificial oxygen, the first rover to search for life, the entry of China and the United Arab Emirates into the club of Martian powers… It seems that the first human visit to the distant and exciting Mars is not far away. But how close are we really to our dream? Let’s discuss in detail.

The Mars Chronicles :
Mars is the most studied planet after Earth. It is currently being explored by eight artificial satellites (including the first Chinese and Arab satellites launched recently), one fixed probe on the surface and three rovers. These are China’s first Zhuzhong rover and two US rovers, including Perseverance, the heaviest Mars rover ever launched and the first specifically designed to search for signs of life. Recently, even a helicopter has taken to the local yellowish skies. And when you consider the Mars probes that have already been in service, the numbers become even more impressive.

But interplanetary robots are not enough for humanity. It seriously intends to leave its footprints in the dusty footprints of the not-so-distant red planet. Such a goal has been directly and repeatedly declared, for example by the leadership of NASA (although no specific timeframe is given).

We can assume that the first manned expeditions would be followed by bases with replacement crews, followed by colonies with permanent populations and then – who knows? – and the transformation of the red planet into a green planet. But what are the realistic plans here and what are unfounded dreams?

A round-trip ticket :
Let’s start with the question of whether a manned expedition to Mars is even possible. It’s not as simple as we’d like it to be.

The biggest danger of such a trip is radiation. Outer space is permeated by streams of charged particles emanating from the Sun and coming from the vast expanse of the galaxy. Residents of the International Space Station are exposed to 0.6 millisieverts per day. This is 200 times greater than the natural background and is equivalent to about five to six fluorography sessions. Therefore, two years is considered to be the limit for how long it is possible to stay in orbit without health risks.

In addition, the ISS crew is fairly well protected from exposure to the Earth’s magnetic field (except when passing over the South Atlantic Magnetic Anomaly). Those going to the Moon or Mars have no such protection. While lunar missions lasted a week or two, a one-way trip to the Red Planet must take six months.

It will not be possible to hide from radiation behind thick walls: spacecraft come at a price for every pound. Nor will it be possible to create a miniature copy of a geomagnetic shield on the spacecraft: where magnetic lines enter the shell there will be pockets of deadly secondary radiation. In other words, beyond low Earth orbit, humans will simply be left alone with radiation.

How serious is this danger for Mars scientists? The results of studies on this subject are mixed. Donald Hessler’s group at the Southwest Research Institute in the United States has reached more or less optimistic conclusions. According to their calculations, a man who spends 500 days on the surface of Mars and 360 days on the road will receive a dose of about one sievert (this figure takes into account the effect of different types of radiation on different organs and tissues of our body). According to current regulations in Russia, this is the maximum dose that a person can receive in a lifetime.

However, such a cruise would not be suicidal. The conclusions of Anatoly Grigoriev’s group from the Institute of Medical and Biological Problems at the Russian Academy of Sciences, however, are radically different: a three-year trip beyond the Earth’s magnetic shield will cost a person half of his brain neurons, the researchers warn.

Only new, more thorough research will show which of the experts is right. Even the very possibility of reaching Mars and surviving may be in doubt.

At the bottom of a well :
Interplanetary space and its widespread radiation are not the only obstacles for those who want to spend a weekend on Mars. The least of their problems will be getting off the red planet.

Gravity on Mars is 2.3 times stronger than on the Moon and only 2.6 times weaker than on Earth. At the same time, travellers on the red planet would not have spaceports filled to the brim with launchers. They would have to carry a stockpile of fuel and oxidisers. And this is where the limited payload capacity of rockets that can be launched from Earth comes into play. The record for the number of rockets flown today is held by the Falcon Heavy, with a payload of 64 tonnes, while heavier systems are still under development.

The launch (from Earth) of the first vehicle capable of leaving Mars is scheduled for 2026. It will not take the crew from the red planet, but only soil samples, and it will not deliver them to Earth, but only to Mars’ orbit. There, the precious cargo will be picked up by another probe launched separately from Earth and carrying its own fuel. That’s how difficult it is for current technology to escape the gravitational pull of a small but real planet.

Sun, air and water :
Suppose, however, that humanity manages to establish flights to and from the Mars Passenger Station. Could we establish a base there and provide energy, oxygen, water and food?

If one is careful, yes. The energy would come from solar panels. Oxygen could be obtained from carbon dioxide, which makes up 96 percent of the Martian atmosphere. The MOXIE instrument aboard Perseverance recently broke down local carbon dioxide (CO2) into carbon monoxide (CO) and oxygen (O2). The oxygen produced by this toaster-sized device in one hour would be enough for a person to breathe for 20 minutes. Of course, a populated base would require a completely different capacity. However, this was the first experiment in using extraterrestrial raw materials to create a practical product.

There should be no problem with water either. There is plenty of water ice on cold Mars, even at latitudes equivalent to the Mediterranean on Earth. What’s more, in some places the ice is only a few centimetres from the surface, so it can be picked up with just a shovel. By the way, there is also liquid water on Mars, albeit under a layer of ice a kilometre and a half thick near the south pole. It’s unlikely that anyone would think of running a water pipeline to this subglacial lake.

As for food, the colonists will have to provide an artificial habitat for plants, supplying them not only with air, light and water, but also with soil. By the way, it doesn’t work to just mix Martian soil with your own faeces, as the hero of the movie “The Martian” did. The soil on the surface of the red planet is heavily coated with toxic perchlorates, which have to be got rid of chemically. However, it is possible to take a “clean” base of soil from greater depths. Especially since the inhabited base itself is also best built in the form of an underground bunker to protect against cosmic rays. After all, unlike Earth, Mars has no shield in the form of a magnetic field and its atmosphere is thin.

Another question is what this entertainment will cost humanity and whether taxpayers will be prepared to pay for it.

The apple trees will blossom.

What about the most daring projects that do not require humans to adapt to Mars, but Mars to adapt to humans? In science fiction, the process (of transforming the planet into the shape of Mars) is called the resonant word “terraforming”.

Today’s Mars is not a very hospitable place. The atmospheric pressure is only 0.6% of Earth’s and the average temperature is minus 63 degrees Celsius. Not to mention that there is virtually no oxygen in the atmosphere.

In this context, it has been proposed to melt the water and carbon dioxide ice on Mars (e.g. by thermonuclear bombardment). The extra carbon dioxide and water vapour would make the red planet’s atmosphere denser and cause a greenhouse effect that would heat up its surface. This could revive the ancient Martian sea, enthusiasts believe. The next step is to release cyanobacteria into the water, which absorb carbon dioxide and produce oxygen during photosynthesis (which is how oxygen was formed in the Earth’s atmosphere billions of years ago).

But detailed calculations by Bruce Jakosky of the University of Colorado at Boulder and Christopher Edwards of Northern Arizona University shatter these fantasies. Scientists have calculated that the known reserves of carbon dioxide and water ice on the Red Planet are several times smaller than what would be required for such an undertaking. In fact, the old atmosphere on Mars is not so much frozen as it has moved out into space. The solar wind, which for billions of years has been licking the gas envelope from the planet’s unprotected magnetic field, is to blame. Mars has already lost too much to revive a dense atmosphere and liquid water without “importing” them on a planetary scale.

If there is a way to green the red planet, it will require technology from the day after tomorrow. So far, humanity has not even “terraformed” the Earth’s deserts, with normal air, nearby oceans and generally all available resources. And perhaps it’s for the best: we’re not yet very good at calculating the consequences of such experiments.

Why do you earthlings need a foreign country?

To sum up. The prospects for a manned expedition to Mars are doubtful. It would require knowledge and technology that we don’t yet have, and it’s hard to say when they will appear. But if such flights become possible, the prospect of establishing a manned base is real enough (if not economically, then technically). Turning Mars into a second Earth is likely to remain science fiction for at least a century.

Now let’s ask the eloquent question: why would humans (and not unmanned probes) fly to the Red Planet in the first place?

Science doesn’t need to. In the harsh environment of space, a fragile and vulnerable human being is an obstacle. It’s hard to even speculate what it might cost to take an astronaut to Mars and back alive and well. But there is no doubt that many research robots could be sent there for the same money.

The economy doesn’t need it. It is ridiculous to expect that something 56 million miles from Earth can be mined or produced to cover the cost of transportation. Of course, the exploration of Mars would involve a massive investment in technology, which would certainly help invent many things useful for a whole earthly life. This was once the case with the lunar programme. The cosmic origins of Teflon and Velcro are a myth, but there are real “lunar inventions”. But wouldn’t investment in medical science or, for example, methods of recycling rubbish bring great practical benefits?

It is not necessary for the safety of our species. We sometimes hear that Mars is our backup home in case something happens to Earth. But what would have to happen to our planet to make it even less cosy than Mars, without air or liquid water but with toxic soil and radiation? And if humanity has to penetrate a deep hole with a closed ecology, it will be much easier to do so at home.

In fact, the only purpose of going to Mars is to realise a beautiful dream. That’s no small thing. The pursuit of the dream (and, of course, political prestige) has already led Earth’s Homo sapiens mammals first to Earth’s orbit and then to the Moon. Perhaps it will continue to lead us through the universe, against all odds and arguments.

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