On the priorities of space expansion

On June 11, a fundraising campaign for the creation of a mission project for a manned overflight of Mars and Venus was successfully completed . For some time I wanted to write about where and why it is better to fly, but, since I am very critical of flight missions, I postponed the publication so that criticism would not inadvertently interfere with a generally useful idea. Well, now, having joined the congratulations and wishing all the best to the project development team, you can speculate without interference which object will be the most popular for manned space expansion?

How discoveries changed goals

On the left - Mars, as the Hubble telescope sees it, on the right - as astronomers of the late XIX century saw Mars

The answer to the question “where to fly” was simple for science fiction writers of the early to mid-20th century - any goal was attractive due to a lack of knowledge. The mysterious reverse side of the moon, covered with eternal clouds Venus, Mars with its channels - it was necessary to fly everywhere. But scientific discoveries were bitter. There was no atmosphere, natives, or anything interesting on the moon other than regolith and volcanic rocks. Venus, which was represented as the past of the Earth, was not inhabited by prehistoric women, and under the clouds was a real hell with a temperature of 500 ° and a pressure of 100 atmospheres. Mars, which was supposed to be an ancient wise civilization, struggling with a lack of water and oxygen, or, in extreme cases, its ruins, turned out to be dead, and even the sphinx with pyramids discovered by probes in Kydonia turned out to be, like channels, an optical illusion. And it’s hard to answer something to the person who calls the lunar program, in which people landed six times on another celestial body with the offensive word “flag-stick”. Indeed, people left the moon and for forty years have not been motivated to return.

In the twenty-first century, the situation is not much better. We learned a lot thanks to automatic missions, but in the world of those who work in the industry or are just interested in space, there is no consensus on the goal of the next "giant leap" of mankind. In disputes and discussions, several of the most promising objects are upheld:

• Moon. For the lunar base stands , for example, the new director of the European Space Agency Johan-Dietrich Werner. No matter how useful the ISS, it is not eternal, and at the May conference, Werner proposed the idea of ​​a base on the far side of the moon.
• Mars. This is the ultimate goal in today's plans of NASA, and they consider missions to the moon and asteroids only as preparatory stages. In addition to the state space agency, Mars considers Robert Zubrin's Martian Society as its main goal, and also declares its desire to send people to Mars one way Mars One (but they may turn out to be crooks)
• Flight missions. In 2013, millionaire and space tourist Dennis Tito introduced the Inspiration Mars project, a 500-day take-off mission to Mars in 2018. Now, in 2015, it is already clear that this project will not fly anywhere - there is still no money, and there is no time left for preparation. But new ideas are being put forward now and will appear in the future.
• Orbital stations. In fact, the only project that is successfully working now is the ISS, which has been flying for 15 years, and people have been working continuously on it, visiting expeditions fly to the Chinese Tiangong. In addition to the Earth’s orbit, station ideas were proposed at the points of Lagrange and in the orbit of the Moon.

Let's try to consider these options in more detail.

Curse of the mission

The so-called flight mission is that the ship, starting from a low Earth orbit, flies past the target without reaching its orbit. Sometimes you can manage to visit several objects, changing the orbit by gravitational maneuvers at the target planets. Usually, the planets adjacent to the Earth - Mars, Venus, are chosen as targets. Such projects were created in the USSR and the USA , in 2013 Tito made a lot of noise, and now cosmonautics enthusiasts from Russia want to develop a project for such a mission.


In the project of the flight mission of 2021-2023, it is proposed to use a ship based on the European ATV truck

But any flight mission has a huge problem, the means of solution of which must be presented by the development team. In simple terms, a flight mission is sitting for months in the difficult and dangerous conditions of a small ship for several hours flying past the target planet. What can a person do under such conditions? Take a picture of the planet from orbit and press a few buttons, including scientific instruments? But automatic machines that weigh less, do not need food, water, oxygen and hygiene products, can fly for years in sleep mode, they literally have iron nerves, and their death is not a tragedy.


In the Inspiration Mars mission, I would have to look at the night side of Mars, which is even sadder

Why send people at all if the machines are easier, cheaper, and better cope with the task? The team of developers of the flight mission should come up with some kind of high and important task, for which people are needed, and their risk and inconvenience will be justified in some way. Moreover, those ideas that have been put forward do not stand up to criticism:

• Obtaining new scientific information . In a few hours of flying past a target, people will not be able to get more scientific information than a robot. In addition, the robot can be transferred to the orbit of the planet, and it will be there for years.
• Studying the effects on people of a long space flight . This is best done in Earth’s orbit, from where you can always return within a few hours. If necessary, you can fly over the radiation belts, receiving the same dose of radiation as in interplanetary flight, but without the risk of dying due to a broken equipment halfway to Venus.
• Prestige . It is not worth hoping that the flight mission will be justified by the prestige “we were at Mars”. A few hours near Mars is not a colony, and not even a landing. In my opinion, the concept of "flying seventeen months for two hours at Mars" looks pathetic and subtly reminiscent of jokes about mowing grass in a gas mask.

Orbital Station Road

Station "Salyut-7"

Orbital stations appeared a relatively long time ago - "Salyut-1" went into space in the spring of 1971. It was created as an asymmetric response to the lunar program of the United States, but the idea survived the competitor and was very useful. It was orbital stations that allowed people to be in space not for days, but for months. There are many physical, biological, medical and other experiments at orbital stations. More recently, private orbital station projects. But from the point of view of space expansion, the orbital station is a transshipment point, not the ultimate goal. Space is empty, and, unlike the planet, the orbital station cannot use local resources. Therefore, now enthusiasts of orbital stations cannot answer the question of why an orbital station is needed beyond the low Earth orbit. Perhaps that is why there are no bright and visible projects of new orbital stations. Yes, sometimes they talk about the station in one of the points of Lagrange, but, again, it is usually considered as a transshipment point on the way to the Moon.

Two finalists

As a result, we have two finalists left - Luna and Mars. Over the past months, I have gradually come to the conclusion that the moon should become the goal of the twenty-first century. Let robots ride Mars, but even landing there, in my opinion, is irrational. But it’s worth trying to build a base on the Moon, at least visited, and I’ll try to argue my opinion.

The first argument. Flight time

Distance to the Moon on the scale of the speed of light.

The moon can be reached in three days. It takes about six months to fly to Mars. This simple fact at our current level of technology is the most important. Emergency evacuation is possible from the Moon, but not from Mars. Of the 9 manned flights to the moon, one ( Apollo 13 ) encountered a deadly accident, but the capabilities of the lunar module were enough to maintain the life of astronauts at the time of their return. A similar accident on the way to Mars is certain death. A technique is never 100% reliable.
The distance to the moon is about one light second. You can easily keep in touch in real time and synchronize the operation of scientific instruments. The distance to Mars ranges from 3 to 22 light minutes. If you want to “call” Mars, then your interlocutor will answer you in the best case after 6 minutes, and in the worst case after 40. The only option for acceptable communication is email. And every 26 months for about two weeks, when the Sun is between the Earth and Mars, communication is generally impossible.
In addition to communication, the duration of flight time makes qualitatively different requirements for ships. For two weeks of the Earth-Moon-Earth flight, there are enough non-renewable supplies of water, food, oxygen and electricity. A flight to Mars can not do without a closed life support system, which is much more complicated.

The second argument. Nothing happens for free

Look at the map of characteristic velocity (delta-V) that you need to spend to move between the bodies of the solar system: The



white triangle means the possibility of aerodynamic drag on the atmosphere. At the circuit level, everything seems simple, and the margin of characteristic speed seems comparable for the road to the moon and Mars. However, aerodynamic braking is not free. The aerodynamic shield and landing system has a mass. And not the fact that the landing system for Mars, using "free" braking about the atmosphere, will be easier than the landing system on the moon. For example, the landing step for soft landing of the 900 kg Curiosity rover weighed 2.4 tons. A lunar landing station with the same initial mass will allow landing about 1.5 tons to the surface, which is enough for a similar rover and landing stage.

The third argument. No luck with the atmosphere

Dust on the solar panels of the Spirit rover

In general, the atmosphere of Mars is characterized by surprisingly inconvenient characteristics. The pressure on the surface of Mars is comparable to the pressure at an altitude of ~ 30 km above the Earth, and the atmosphere itself is 95% carbon dioxide. On the one hand, the atmosphere is too dense to ignore when taking off or landing, on the other hand, it is too thin to even walk on the surface without a spacesuit. It is difficult to use for anything useful. Yes, specially designed devices can fly in it and, for example, you can try to use it to grow plants and produce oxygen, but it is difficult. The atmosphere is not dense enough to store heat, and despite the fact that there is no extreme moon heat on Mars, the conditions are not much better. The range from -140 ° to + 20 °, alas, is quite comparable with the lunar -170 ° - + 110 °. The Martian atmosphere also allows the formation of dust storms of a planetary scale, which will interfere with the operation of solar panels and fill all the equipment with dust. On the Moon, dust is also unpleasant, it is abrasive and will require increased attention when developing the rubbing parts of mechanisms. But in general, the atmosphere of Mars does not make him prettier than the Moon, and, possibly, vice versa.

The fourth argument. About water and resources

In recent years, water has been discovered throughout the solar system from Mercury to Saturn’s moons. Regrettably, these discoveries do not spur colonization efforts at all - other conditions remain critically inconvenient. There is water on Mars and on the Moon, and there and there is a lot of it. Perhaps it is easier to get it on Mars, it reliably has ice in large and concentrated quantities, but no one has really descended into craters on the poles of the Moon, it may be no harder to get water there.


Blue - water, green - infrared brightness, red - pyroxene mineral

In terms of geology, Mars is richer than the moon. It had a long and interesting history, it is already almost reliably known that once upon a time there were literally oceans of liquid water on it. The history of the moon is poorer, there was no liquid water on its surface, and it will not be possible to find sedimentary rocks found in abundance on Mars on it. But from the point of view of colonization, the most important will be the question of the economic use of local resources. And here, it seems, the Moon is not far behind Mars. For example, in a 2014 studyIt is alleged that plants grow quite successfully in both Martian and lunar soil. Yes, of course, in the study we used soil simulators, but the surface of Mars is well known to us thanks to robots, and we brought quite a lot of soil from the Moon so that we could hope that the simulators will be accurate enough.


Map of the prevalence of iron oxide on the moon.


Different types of basalts on the moon.

The fifth argument. About science

And on the moon and on Mars, you can conduct very interesting research. On Mars, his story will be extremely interesting - how he lost water and oxygen, was there life on him, and is it now preserved? On the moon, you can conduct a wider range of studies. In addition to exploring the moon directly, telescopes can be built on it, which, working together with the earth, can create an interferometer with a giant base. It will be possible to easily examine small planets of neighboring stars and take their spectrum. Who knows, maybe stone planets with lots of water and oxygen are as common as the gas giants that we can see now? In addition, the moon can become a polygon of colonization. How to build a base? How to organize life support in it? How to use local resources? All of this can be effectively learned on the moon.


Differences in color of the surface of the moon. The image was obtained from 53 photos, processed in three spectral filters with the formation of the image in artificial, exaggerated colors

Argument Six. About prestige

It is believed that the mission to Mars will be much more prestigious than the lunar program. I disagree. The fact is that the lunar program of the twentieth century was, in fact, a jump above his head. Yes, six expeditions landed on the moon, but three of them spent only a day on the surface, and the remaining three - only three days. This is a very short time. There was only one professional geologist on the moon. Even machine guns have not yet landed at the poles, and no one has done deep drilling of lunar soil. Yes, indeed, repeating the American lunar program is uninteresting and not prestigious. But to come for a long time, to build a base, to do science in a big way - this will really be a giant leap forward.

About where, what and how to do on the moon - in the next part.
By the tag "thoughts about the future of astronautics" Reflections on the present and future of astronautics.