If you think it’s a matter of distance, then you’re only partly right. Understanding the complexities of a manned Mars expedition.
It is difficult to imagine now, but only 4 years passed between the launch of the first satellite in 1957 and the beginning of manned space exploration - the flight of Yuri Gagarin in 1961. Seven years later, in 1968, Apollo 8 makes its first manned flight around the moon. And a year later, in July and November 1969, American lunar modules land twice on the surface of the Earth's satellite.
For the first time in the Sea of Tranquility (Apollo 11), the second - in the Ocean of Storms (Apollo 12). While NASA is storming the moon, the USSR is sending research probes to other planets. The first hard and soft landings on nearby planets are in the treasury of the successes of Soviet cosmonautics.
For the first time in history, the descent vehicle of our interplanetary station "Mars-3" makes a soft landing on the surface of the Red Planet. This happened on December 2, 1971. True, this landing on Mars turned out to be the only one for the national cosmonautics. In addition, it should be said that in the early sixties this year it was planned to launch a Soviet manned interplanetary spacecraft to Mars.
In those years it seemed obvious that after walking on the Moon, a person would soon walk on Mars. And he will not just walk along its dusty paths, but will ride on a whole train. Such a composition, naturally, wheeled, on a large-sized chassis and consisting of five platforms, was assumed by the Soviet Martian program. At the head of the train is the cockpit of a crew of six cosmonauts; here is also a manipulator and a drill. On the platforms - the main and reserve take-off rockets to return to the ship, which remained in orbit, and a nuclear power plant. Initially, a reconnaissance aircraft was also provided. Later, when it turned out that the atmosphere of the planet is very rarefied, this idea was abandoned. Such a research train was supposed to cross Mars from one pole to the other. It took a year to travel around the planet. It seemed that just a little more - and Mars will submit to man.
But little by little, real flights began to give way to fantastic plans, and manned astronautics closed in a ring of near-earth orbits. After the end of the Apollo program, NASA never stopped proposing missions to Mars. Even a manned flyby of Venus, planned for 1973-1974, was even considered. With the development of technology, the Soviet Martian program also changed many times.
Public organizations did not lag behind. For example, the Martian Society, founded by the American engineer and publicist Robert Zubrin in 1998, put forward its proposals for a manned flight to the Red Planet. The proposed project, called Mars Direct, was in fact an alternative to the unfulfilled Space Exploration Initiative of the George W. Bush administration. And since the appearance of Elon Musk, the realization of the hope of conquering Mars has been associated more with SpaceX than with state space agencies. But we only continue to dream of flying to Mars. What prevents us from reaching it in the same way as the Moon almost half a century ago?
On rare days and nights, we do not see our satellite in the sky. The moon accompanies our planet relentlessly in its path around the sun. To her - 384 467 km. Fly - I don't want to. How long is it to Mars? Here you cannot answer with one number. Mars, like any other planet, including the Earth, makes its independent path around our star. The distance between the two planets is constantly changing.They are closest to each other during the days of confrontation, which are repeated every 26 months. During opposition, Mars is in the earth's sky in the direction opposite to our star, that is, relatively speaking, on the continuation of the line "Sun - Earth".
But the shape of Mars' orbit is also important. It has a rather noticeable eccentricity. Simply put, it is more flattened than our planet's orbit. Therefore, when Mars is at the point of its orbit (perihelion) closest to the Sun, the distance to it is minimal: less than 60 million km. Such moments are repeated every 15-17 years and are called "great confrontations." These years, as a rule, are present in the plans for flights to Mars. This is the best time to fly. Another great confrontation will come next year. Earlier this year, SpaceX announced the first test flight of the Red Dragon spacecraft. But, as is now known, the company has postponed his flight for two years. In 2020, Mars and Earth will come close again, but not as close as the next. NASA is planning the first manned flight to Mars in 2035. This is also a year of great confrontation - the planets will approach each other by 57, 15 million km. The minimum distance between the two planets, recorded in modern time, is 55, 76 million km (August 27, 2003), and the maximum is 401, 3 million km. At this time, our planets are also on the same conventional line, but on opposite sides of the Sun.
If we want to avoid excessive fuel consumption, we need to go on a flight to Mars at a convenient launch window. It usually lasts only 20 days and opens about three months before the next confrontation. But you can fly to the moon almost at any time. She is always with us. In this case, not only fly, but also return.
Distance is one of the conditions that determines the flight time. But while long flights are not critical for unmanned probes, long manned missions pose a real challenge to engineers. In flight, a person needs food, water, oxygen, and various basic necessities. All this must be taken with you - therefore, the mass of the interplanetary spacecraft increases.
In addition, almost 76 hours have passed since the launch of Apollo 11 until the moment the spacecraft entered the lunar orbit. So much time, for example, takes the way from Moscow to Krasnoyarsk, if you go by train. All three days, the crew members were in the command compartment with a volume of 6.1 m³. Approximately 2 m³ for each astronaut. We slept here too, taking turns in a hanging hammock. The command module became freer only when Neil Armstrong and Edwin Aldrin went to the lunar module and landed on the moon, and Michael Collins was left alone in orbit. True, Armstrong and Aldrin shared 4.6 m³ of the crew compartment in the lunar module. But for a long flight to Mars and being on the planet, such conditions are unacceptable.
The most realistic option is to use a living module as part of the interplanetary expeditionary complex, similar to the Russian Zvezda module of the International Space Station. This option is proposed by Robert Zubrin and some other experts. It has many advantages. We already have experience with the module. It is not required to invent something new, it is enough to modernize what is already there. At the same time, its weight is 20, 29 tons. Whereas the mass of the Apollo 11 command module, without the engine compartment, was only 5.66 tons. The significant mass of individual parts of the future Martian spacecraft suggests that it will need to be assembled in orbit from several modules, launching rockets with all of its parts in turn. One rocket, such as Apollo 11, will not take him into space.
The second condition that determines flight time is technology. Recently, astronautics have been using chemical engines for space flights. They took us into space, and with their help we reached the moon. In theory, we can reach Mars in the same way.But the flight period (from 8 months to 1.5 years) imposes many risks. During this time, deterioration of the health of the crew members and technological equipment failures are possible. In this regard, the death of individual crew members or the entire expedition is not ruled out. Consequently, there are reputational and political risks for the country that sent the expedition into space and its leadership. On the whole, the tragedy in space may for some time undermine the faith of mankind in its strength.
Can you get to Mars faster? I guess, yes. Joint efforts of Roscosmos and Rosatom are developing an interplanetary tug with a nuclear electric propulsion system. Not so long ago, Sergei Kiriyenko, at that time the head of Rosatom, speaking at the Federation Council, said that such an installation would make it possible to fly to Mars in a month and a half. The difference from everything previously created is in the combination of a nuclear reactor and an electric rocket engine. Such a tug will have a docking station for a manned space complex or payload. Its creation will significantly reduce the flight time, and hence, in many cases, the mass of interplanetary complexes. As for flights to the Moon and Mars, and to any other planet or its satellite in our system.
But even reducing the flight time to one and a half months does not completely solve the problem of radiation. During flights to the Moon, astronauts only for a short time left the natural magnetosphere of the Earth, which protects us and the crews of orbital stations from cosmic radiation. They were lucky that during the flight there were no solar flares, which generate powerful fluxes of radiation that are fatal to humans outside the powerful magnetic field of our planet. In the case of a flight to Mars, relying on luck alone is too risky. The creation of an artificial magnetosphere to protect the spacecraft from cosmic radiation appears to be a promising way to combat radiation. Researches in the field of creating a portable "magnetic shield" for ships going into space are carried out by scientists from Europe. According to the results of the study, the power required to create such a shield will be several kilowatts, and the size of an artificial magnetosphere capable of protecting an inhabited ship may be only a few hundred meters. At the same time, work in this direction is only at the very beginning.
Takeoff, landing and stay on the planet
What attracts us to Mars? To many. But remember the photographs from the Red Planet taken by rovers sent to the planet, such as Curiosity and Spirit. The daytime sky of Mars has many shades. At dawn and dusk, when the Sun is near the horizon, the sky is reddish-pink, near the solar disk, its hue changes from blue to purple, and during the day it is yellow-orange. The reason for this is the presence of an atmosphere on Mars. Now remember the black sky on the moon even during the day. It is also stellar, just the photographic equipment of the lunar expeditions could not display it. Why is that? That's right, there is no atmosphere on the moon. What does this mean for flights to celestial bodies?
There is an atmosphere on Mars. But it is very sparse. And this creates difficulties when it is required to land a spacecraft from space on the surface of the planet. It is impossible to make a soft landing using parachutes alone. The density of the atmosphere is insufficient for their use. But its density is enough to warm up the descent vehicle to critical temperatures. Therefore, various combined systems are used to land on the Red Planet.
For landing on the Red Planet, NASA is testing the so-called "Aerodynamic inflatable supersonic retarder." Outwardly similar to a "flying saucer", the device is supposed to be attached to the descent vehicles in order to ensure their braking in a rarefied atmosphere and a soft landing on the surface of Mars.
Probably for this reason, having made only one successful soft landing on the surface of Mars, the USSR reoriented itself to researching its satellite, Phobos. The flight range is the same, but the landing is incomparably easier. There is no atmosphere on the satellite of Mars. The same as on the Earth satellite. When landing on the surface of a celestial body that has no atmosphere, only rocket engines are used for braking and descent. This was the case with NASA's expeditions to the moon. But this method of landing assumes the presence on board of approximately the same amount of fuel as for starting from a celestial body. As a result, excessive consumption of fuel and an increase in mass due to its additional reserve.
But what about the purpose of the flight? Why fly to Mars? If the flight to the planet takes a long time, then it is illogical to descend to its surface only for a short time. To spend a year and a half on the road just to throw away the debris accumulated in flight, put up a flag and collect a few stones? The Apollo 11 astronauts were on the lunar surface for only 21 hours and 36 minutes. For an expedition that lasted only 8 days, this is acceptable. But for a flight to Mars, such a short time is impossible.
It is worth remembering at least that there could have been life on Mars in the distant past. The amount of potential evidence for this is growing. Perhaps it originated at the same time as ours, but then for some reason died. To fly away from the Red Planet, having reached it with such difficulty, without making new discoveries, would be unforgivable. Although, of course, the very fact of a flight to Mars will already be an incredible achievement of mankind.
The Martian expedition will face many challenges, from the search for traces of past life to the first video featuring a human. All this will require a long stay on the planet's surface. And for this it is necessary to deliver to Mars the necessary equipment, vehicles, living modules and, of course, everything that people will need far from Earth.
For short trips on the lunar surface, astronauts used rovers. But for long journeys across Mars in search of traces of life, minerals and places for future colonies, it is advisable to have transport at least such as was assumed by the Soviet flight program to Mars.
Today NASA is working on the Deep Space Habitat "Martian home" project. The multi-module structure consists of an inhabited sluice module equipped with a ramp with an inflatable domed roof, and a hygienic one, which houses a shower room, a toilet and a waste disposal system. The total volume is 56 cubic meters. It is possible to expand by docking additional habitable and laboratory modules. The Space Exploration Vehicle, which is being developed for movement on the surface, is also a kind of home on wheels. Astronauts can spend 14 days in it, which will allow them to move within a radius of several hundred kilometers from the main habitable module. By the way, the vehicle is also docked to it, which allows astronauts to move from the rover to the living module without putting on spacesuits and without going “outside”. Thus, the mass of the cargo that must be delivered to Mars will grow even more, which requires appropriate engineering solutions and financial expenditures.
The flight to the moon was "light". A short walk. But at the same time, we have not been able to repeat it for half a century. Return to the moon is only in the possible plans of NASA. Moreover, this flight is so difficult that it makes many skeptics doubt that the Americans ever flew to the moon at all.
Not only landing, but also taking off from Mars is more difficult than from the Moon. Gravity is to blame. On the moon, gravity is 16.6% of the earth's, and on Mars it is already 37%. It is quite clear that it is much more difficult to take off from the surface of the Red Planet. But we were still "lucky". If Mars were the size of Earth, then a return home mission would be even less real.After all, in fact, one would have to carry to the planet another missile the size of, for example, the Soyuz.