Jupiter’s moon Europa: a place to live in tomorrow?

“For some reason, when contemporary sci-fi writers send people to Mars or the Moon, they focus on human relationships, while Mars or the Moon itself is no longer a matter of science fiction for them. They consider a flight to the nearest star to be the most groundbreaking project. But, in my opinion, it is fantasy pure and simple,” planetary scientist Anatolii Vidmachenko says when I ask him which of the science fiction may soon become a science fact. Mr. Vid­machenko reads a lot, particularly the books of this genre, but he cannot single out one that especially impressed him in the last while.

Mr. Vidmachenko, a professor and a doctor of sciences (physics and mathematics), works as chief research associate at the department of the physics of substellar and planetary systems of the Main Astronomical Observatory of Ukraine’s National Academy of Sciences. We talked about real, albeit remote, scenarios of the human colonization of such celestial bodies as Mars, the Moon, and Europa (natural satellite of Jupiter), as well as about the “asteroid taxi.”

We spoke on the eve of Mars’ perihelic opposition on July 27. There is nothing bellicose in the name – at this period the Sun, Earth, and the “red planet” form a straight line during the course of their orbits, and the distance between Earth and Mars becomes minimal. This occurs once in 15 years on the average. It is the most convenient time to launch space missions to Mars, for this will reduce the spacecraft’s flight path by several dozens of millions of kilometers. This May, too, NASA launched the InSight landing module accompanied by CubeSat nanosatellites MarCO-A and MarCO-B (“Purely Ukrainian names!” Mr. Vidmachenko jokes) which will explore the ground and seismic activity on that planet. The module is expected to land on Mars on November 26, 2018, and the accompanying satellites will fly on. There are a lot of things to explore. The only problem is that Ukraine may end up short of planetary scientists due to the scanty funding of research. The following interview with Anatolii Vidmachenko is about this and other, more space-related, things.

PLANETARY SCIENTIST ANATOLII VIDMACHENKO STANDS NEXT TO THE PAVILION FOR THE CELESTRON-40 TELESCOPE AT THE MAIN ASTRONOMICAL OBSERVATORY OF THE NATIONAL ACADEMY OF SCIENCES OF UKRAINE. CELESTRON-40 IS USED FOR WATCHING STARS WITH EXOPLANETS, ECLIPSING BINARY STARS, AND DISC STARS / Photo by Artem SLIPACHUK, The Day

“VOLCANOES ON MARS MAY BEGIN TO ERUPT IN THE NEAR FUTURE”

The CubeSat nanosatellites, now flying to Mars, will explore its soil and seismic activity. What arouses the greatest interest of scientists in this matter?

“There are about two and a half dozen volcanoes on Mars – the ones we are accustomed to, cone-shaped, where something erupts on top and lava flows down. It was believed previously that they are very old. But it turned out that the age of the rock on the slopes of the four highest of them, which was supposed to be billions of years, was in fact not more than a billion. This means that, in geological terms, a huge high-temperature mass flowed from there very recently. And this aroused interest in studying the planet’s seismicity – for if there are seismic tremors, these volcanoes can still erupt. One of the models shows that these volcanoes ‘slept’ for several hundred million years, then they ‘were fed up’ with this and decided to get up. And they may begin to erupt again in the near future – at least some of these two and a half dozen. These eruptions are preceded by seismic activity – Mars-quakes. Therefore, one of the main objectives is to see whether or not Mars is seismically active.

“Before this there was only a small instrument on one spacecraft, which allowed finding out whether there were any Mars-quakes.”

Speaking of the colonization of Mars, can seismic activity be a complicating factor?

“To prevent it from being a complicating factor, one should not land on these volcanoes. There are two and a half dozen of them, but there is also the remaining territory. The diameter of Mars is only half that of Earth, so you can find a place to live. The only trouble is rather a high radiation – it is almost twice as high as in the orbits of manned stations. Besides, the astronauts who orbit Earth are also protected by our planet’s magnetic field. There is no protection at all on Mars, for it has almost no magnetic field.

“An astronaut can be exposed to a lethal dose of radiation in the seven or eight months of flying to Mars, when the probability of his survival is 50 to 50 even if solar activity is as low as it is now and there are practically no ejections on the Sun. And if some people have landed on the planet, they must immediately dig into the ground or hide in a cave. The flight to Mars is planned for 2022 [Mars One project. – Author], when solar activity will be at its highest. In such periods, astronauts tend to refrain even from flying around Earth. So it is better to do this either before 2022 or after 2025.”

HOW MICROORGANISMS CAN “TAME” MARS

You once said in an interview that Mars is covered with very harmful and very powdery dust

“It is the so-called perchlorates. These chloric compounds are really very dangerous for breathing and very small-sized. While our dust, say, on the table is hundreds of microns, and some particles can even be a millimeter in size, the size of perchlotates is less than a micron, i.e., a thousandth part of a millimeter. Accordingly, they penetrate into all cracks and clog all kinds of filters. Only completely airtight stations can work on Mars. If a station has wheels, the latter usually have some fissures which these perchlorates will fill up. And while some of the Mars rovers initially had six wheels, later models were fitted with three or two only. Incidentally, some of these vehicles have been working on Mars for about ten years.”

Speaking with journalists about the colonization of Mars, you once said favorable conditions could be created there by way of terraformation, “Earth-shaping.” How can it look like? How long will it last?

“We must wait for two hundred thousand years or so (laughs). Indeed, it is quite a long process. Our team is now toying with the idea of disseminating microorganisms in Mars’ atmosphere, which could feed on carbon dioxide and discharge as much oxygen as possible. We believe that several dozens or hundreds of nanosatellites filled with special biomaterial, i.e. microorganisms that consume carbon dioxide, can work there for several dozens or hundreds of years, and, as a result, it will become warmer on Mars, water will begin to flood over some bottom lands, and atmospheric pressure will go up. For in the first several hundred million years the pressure on Mars was 0.4 bars, whereas it was 1 bar on Earth [now the pressure near Mars’ surface is 160 times lower than on Earth. – Author]. This means it is possible to try to raise it again.

“Viking spacecrafts searched for life on Mars’ surface from the mid-1970s onwards. We wished they would at least dig deep enough to reach ice. As it turned out later, they were very close to this. Their scoops could dig five to seven centimeters deep, while, as it is known now, frozen water lies at a depth of more than 15-20 centimeters. If they had reached water, the strategy of future explorations could have been essentially changed at that very time. Instead, everybody searched for water there from the late 1970s until the early 2000s. Now that water has been found, it is necessary again to search for life [incidentally, there is ice at Martian poles, and it became known in late July that there are under-ice lakes with liquid water on the planet. – Author]. In 2009 or so, designers began to develop spacecrafts that can search for any kind of life, at least microbes.”

THE MOON’S VOLCANOES AND MINERAL RESOURCES

I read that Ukrainian scientists are taking part in international Moon exploration projects which can be a steppingstone for more advanced explorations on Mars.

“What is interesting in this case is the work of China. They decided: yes, Mars is good, but one must learn just to survive in conditions other than those on Earth. So they showed a very nice residential and research complex in Antarctica and said they would first test this kind of system on the Moon and then would take it to Mars. In other words, they are willing to participate in Mars-related projects, launch spacecrafts to and explore the planet at a short distance, but they postpone colonization for a later time.

“A number of scientists have examined ongoing changes on the lunar surface at the Main Astronomical Observatory and the National Karazin University of Kharkiv. Those who worked at Karazin University’s Astronomy Research Institute mostly applied spectrophotometric and spectropolarimetric methods. And, for example, Vitalii Kysliuk explored the Moon’s figure at our observatory.

“Besides, we have made several suggestions on how to watch the Moon change the tilt of its rotation axis by astronomical methods, installing a telescope in circumpolar areas or near the equator. We repeated the work of the 1960s, employing a new method, and showed that what used to take dozens of years to research something can only take a year now.

“In addition, resources on the surface of Earth are running out, but they are available in outer space. The first source is the Moon. There are also a few asteroids flying not so far from Earth, and they can also be used to good advantage. Moreover, in some of them the deposits of metals – iron and nickel – exceed those in the half of Earth’s mines. And these asteroids are not so big. You can pull and work with them here. But it is also possible, instead of pulling over the whole rock, to fly there, extract what you want, and get the readymade material right on the spot. For example, you can make there and bring home several container-loads of microchips.”

Can there still be any seismic activity on the Moon?

“There is some volcanic activity there. When Apollo spaceships were flying to the Moon [there were six missions from 1968 until 1975. – Author], they left some seismometers there. These devices recorded that, in addition to the usual volcanic activity, when the crust quakes, there is also the so-called impact activity – a space meteoroid hits the surface with a bang. Incidentally, seismic activity on the Moon’s far side, which we can’t see, is several times higher than on the side we can see.

MARS, AUGUST 5, 2015, ON THE EARTH CALENDAR. NASA’S CURIOSITY MARS ROVER IS TAKING A SELFIE IN THE BUCKSKIN AREA. IN MARCH 2018, THIS MARTIAN LABORATORY “MARKED” 2,000 SOLAR DAYS OF WORKING ON THE “RED PLANET.” CURIOSITY’S NUMEROUS SELFIES, WHICH HAVE HIT THE HEADLINES ALL OVER THE WORLD, HELP SCIENTISTS WATCH THE ROVER’S CONDITION / Photo from the website NASA.GOV

“In most of the lunar volcanoes lava flowed out into crust cracks and spread about, hardening on the surface. In 1999, a volcano was found on our satellite, which is a cone about six kilometers high with the Compton-Belkovich Crater. Lava could flow out of it about 800 million years ago, i.e. very recently in geological terms. Interestingly, what flowed out contained radioactive element thorium – a huge quantity of it was found on this volcano’s slopes.”

IN SEARCH OF LIFE ON EUROPA

You and a colleague of yours spoke at the international scientific conference “Astronomical School of Young Scientists” in May about the possibility of colonizing Jupiter’s moon Europa. One of the advantages is water under a thick layer of ice. At the same time, it is difficult to reach Europa. Could you say more in detail about the advantages of this celestial body for colonization? What explorations of it are being carried out now?

“It was known long ago that there is a 10 to 12 kilometers deep ice layer on Europa and still deeper, from a few dozen to, maybe, hundreds of kilometers, there is water. However, ice may thaw in some places, which forms a small-size lens with water at a certain depth. As salt freezes in ice, melt water will be unsalted and practically potable. Therefore, it is possible to drill just in this place and get water. Gravitation is there in fact the same as on the Moon – one sixth of that on Earth. Hence, a floating island can theoretically be made in this water lens. You can extract some oxygen and nitrogen out of it, while ammonia is already available there, – so you can live. Jupiter shines above you through the ice, and the Sun glows far away.

“And it turned out in 2012 that Europa has not only water, but also fissures through which it is ejected into the surrounding space – geysers. This means water is in fact on the surface. If you search for life at 12-kilometer intervals, you’ll have to drill very much. But if there are such geysers, you just fly by, quickly grab a few kilograms of this water, pack it into a container, and examine whether there is life on Europa.”

“LYING LOW” ON MERCURY

If people wished to live somewhere else, which celestial body should they begin with?

“Three colleagues of mine and I spoke at the ‘Astronomical School of Young Scientists’ about where to search for life and which territories to choose for living in. The first conclusion is: man must not be exposed to asteroid-related danger and must live on Earth only. It is necessary to carry out the so-called repopulation. For example, we choose a few asteroids. There are about 5,000 asteroids now, which periodically come close to Earth. We have selected several dozen asteroids two to three kilometers in diameter, which have water, iron, silicon, and other mineral resources. Some of them fly circles and others have elongated orbits and periodically fly near Earth or near the chosen asteroids that fly circles. Accordingly, we land on such an asteroid, bury ourselves under its surface, disengage oxygen from water, and colonize this celestial body. When we launch a couple of dozen of such stations, we will have dozens of what may be called fixed-route taxis for communication with Earth.

“We believe it is possible to ‘get on’ some asteroid that is flying into the direction we need, fly up to another one and land on it. You don’t have to fly millions of kilometers – instead, you calculate a moment to fly up to your final destination on an ‘asteroid taxi’ and then you transfer, so to speak, from one asteroid to another in just a few days on a small spacecraft.

“For a longtime colonization, it’s necessary to choose asteroids that have nickel-iron ore, extractable water, and rare chemical elements. There is even gold and platinum on some. In this case you can easily live and work in their caves, extract mineral resources, and produce the goods humankind needs. ‘Taxi managers,’ life support personnel, etc., will stay there permanently, while narrow specialists needed for a given asteroid factory may well work on a rotational basis. Naturally, there should be permanent communication between stations. Two or three dozens of such space ‘fixed-route taxis’ will be enough to colonize the space from Earth, through the asteroid belt, up to Jupiter. And after living there for several years, people get back to Earth, and we examine changes in their organism and decide whether or not we can move there for good.

“The second place is the abovementioned Europa and a few more moons of Jupiter and Saturn. Europa is very close to Jupiter. Its magnetic field is too strong for us, and we may be exposed to excessive radiation. So we should reach Europa and immediately get under the ice, where there is good water – please swim and bathe (laughs). There is also Ganymede, an icy moon of Jupiter, which is farther away from that planet. There’s less radiation there and enough water. There are three or four objects around Saturn, which can also be colonized. And, quite unexpectedly, it is Venus.”

It is sultry there – more than 400 degrees Celsius on the surface

“Yes, but temperature varies from zero to +30 Celsius at the altitude of 50-60 kilometers. The pressure is one atmosphere. But atmosphere consists of carbon dioxide. On the other hand, this gas includes oxygen – so take it, break down, and isolate oxygen. Moreover, there’s also a lot of water vapor, and it’s possible to extract nitrogen. Now let us imagine: if you make a ball one kilometer in diameter, fill it with a mixture of nitrogen and oxygen or, as the Americans do in their spacecraft, helium and oxygen, the inner and outer pressure will be the same – one atmosphere. Yet the Earth-type atmosphere will be slightly lighter than the outer one. Besides, our ball has certain buoyancy. About a hundred thousand people can settle there in several tiers. Gravitational acceleration, which is 9.8 meters per second on Earth, is 8.9 there – very close. Your bones will be intact, no osteochondrosis at all (laughs). So this is an interesting object of colonization.

“And here is one more option. Scientist Oleksii Steklov has calculated depth-related temperature changes on various bodies. For example, it is quite hot on Mercury [340 Kelvin degrees. – Author]. But Mercury’s axis has no tilt and does not vary with rotation. There are a lot of craters at the poles, where the Sun never shines, and the temperature there is 90 K or much less. There is even water there, for comet nuclei, which almost completely consist of ice, used to fall in those areas. It is estimated that frozen water will suffice for millions of years there. And temperature is always from zero to +20 degrees at the depth of only three to thirty meters. So it is always warm in the polar regions – from the latitude of 70 degrees up to the poles. There’s water next to you. So you’re welcome to hide at a low depth, live, watch the Sun, and warn terrestrials if there’s been a major flare on it.”

LIGHTNING AND CHANGE OF SEASONS ON JUPITER

You have explored Jupiter and Saturn very much. Lightning occurs in Jupiter’s atmosphere much more often than on Earth. To what extent does it resemble ours?

“Lightning on Jupiter somewhat resembles the one I saw in Kyiv the other day. We have seen nothing of the sort for a long time. The Dnieper flows six kilometers or so from the observatory, and the sky is clouded there, but here something seems to be roaring in the sky all the time. This has been happening continuously. Usually, thunder booms, lightning strikes, and that’s all. But here it was roaring for almost an hour. Almost the same occurs on Jupiter – multiple-discharge lightning can ‘roar’ for 40-50 hours in a row. There are also the so-called continuous flashes. For example, the Galileo spacecraft recorded that something like lightning shone all the time at a 1,000 by 300 kilometers place, and this lasted for years.”

You were the first to record natural oscillations in the atmospheres of Jupiter and Saturn, and then you and your colleagues found seasonal changes in the atmospheres of those planets. Can these seasonal changes be compared with those on Earth?

“There are seasons on Earth owing to the tilt of the terrestrial axis – 23.44 degrees. The axis of Saturn is tilted by 26.7 degrees. There are seasonal changes there as well, but you must watch them very long because the period of this planet’s revolution around the Sun is 29 something years [29.46 years. – Author]. We discovered and registered them. Jupiter’s period of revolution is 11.86 years. It took us seven years to see that there can be seasonal changes there, and we recorded a difference between summers in the southern and northern hemispheres. But the tilt of Jupiter’s axis is three degrees only. Whence is the change of seasons? We found that the magnetic and the geographic axes form an angle of 12 something degrees. For this reason, if you add these 12 to the three-degree tilt, you will have 15. And the situation will be just the reverse six terrestrial years, or Jupiter’s six months, later. This means that the geographic and the magnetic poles have the same impact as geographic inclination alone has in our case.

“As we examined the upper layers of Jupiter’s atmosphere, it turned out that 3 plus 12 degrees of tilt are enough to bring about seasonal changes. Besides, the orbit is more elongated that that of Earth. When Jupiter’s northern hemisphere is closest to the Sun, it receives 40 percent more heat than it will do six years later, when the southern hemisphere is exposed to solar rays. This alone is supposed to trigger changes in the atmosphere, and we recorded them.”

Does it mean that there are climatic differences on Jupiter too?

“Yes. But as there is no hard surface there – there is only an atmosphere [without a clear lower bound, it smoothly merges with an ocean of liquid hydrogen. – Author], – we can only see a layer of clouds in the visible segment of the spectrum. And we can see something at the altitude of 100 kilometers from the level of clouds in the spectrum’s ultraviolet segment only. In other words, we can see various atmospheric layers in different segments of the spectrum and can measure where it is warmer or colder.”

Does the number of atmospheric phenomena, particularly polar lights, vary with the season on Jupiter?

“Polar lights on Jupiter must be usually watched in the ultraviolet. It is spacecrafts or the Hubble Space Telescope that do this best of all. But this telescope is very busy – some Jupiter-related program may cut its way through once a year, and the device will be used for three or four days, and then you must wait again. Now the Juno space station is observing Jupiter’s moons. Sometimes the space next to Jupiter is also photographed.

“A few weeks ago Carnegie University astronomers watched various areas in search of what they consider the ninth trans-Neptunian planet and accidentally received an image of an area near Jupiter. It is there that they saw another 12 of its moons, so now this planet has up to 80 satellites. It is necessary now to visit that area again and carry out the needed observations. But the telescope has other goals now [the discovery was made with the help of the Blanco University in Chile. – Author]. Therefore, it is necessary to alter the goal and see again whether they were satellites or some asteroids that were flying by.”

“WE CANNOT ADMIT PhD-SEEKERS FOR THE SECOND CONSECUTIVE YEAR”

When did you take interest in astronomy?

“I first used to participate in various Olympiads in geography. At that time, in the late 1960s, Olympiads were also held in astronomy. Klim Churiumov, Nikolai Barabashov, and some other well-known specialists would visit them. In the eighth grade or so, I began to psych myself up for taking part in an astronomy Olympiad in the tenth grade. I don’t regret this so far. The only thing I am concerned about is our young people. For a third consecutive year, they work part-time at best. This is why young people are seeking odd jobs or going abroad. From 1998 until 2016, when I chaired the Department of the Physics of Planetary Systems, we admitted people every three or four years. We groomed them, and they would successfully defend dissertations. Then they began to travel abroad and, in the course of time, stay behind there. Four of those who worked here have remained behind abroad.

“Besides, it is the second consecutive year that we cannot admit people for a PhD course. For example, five people finished studies in 2017 at the Astronomy Department of Kyiv Taras Shevchenko University, where I taught comparative planetary science. As soon as they passed the last exam and defended their degree papers, they began to receive phone calls from Germany, Austria, and Australia. In the year before last, one ‘child’ went to Australia, four to Germany, and one to Poland. And nobody remained behind here because we have no right to admit them for PhD studies. We educated them and in fact made them go there. Unfortunately, this process is only gaining momentum.”