Mars colonization

from Wikipedia, the free encyclopedia
Artistic impression of the colonization of Mars (Source: NASA )
Mars with visible polar caps

The term Mars colonization refers to the permanent settlement of humans on the planet Mars . The optimistic assessments of individual visionaries about the feasibility of such an undertaking are opposed by massive technical, physical and medical problems. There are currently only theories or experimental approaches to overcoming them, feasible solutions do not yet exist.

implementation

SpaceX - Vision of the arrival of the first space travelers on Mars

The vision of colonizing Mars is currently primarily pursued by the US company SpaceX , which is promoting the development of the fully reusable combination of launcher and spacecraft Starship and Super Heavy . SpaceX sees itself as a "transport service provider" and relies on collaboration with scientists and interested, relevant institutions when designing a Mars colony. Since 2016, SpaceX has named the year 2022 as the target for the first unmanned flight to Mars; however, this date proved unrealistic and was removed from the Starship description on the company website in May 2020. The vision of the future that had been published by then envisaged that material transport should first take place in order to set up an infrastructure, then two years later also manned flights. SpaceX named the Arcadia Planitia plain on the northeastern edge of the Erebus Montes mountains at about 40 ° north latitude as the target area for the first Mars flights .

In earth-based research stations of organizations such as NASA , Roskosmos and the Mars Society , it has been and is being tested how people cope in an isolated, Mars- like environment.

In order to save energy and resources, so-called Mars-to-Stay missions have been proposed. On such a mission, the first astronauts on Mars are supposed to stay there indefinitely.

Conditions in comparison with the earth

Similarities with the earth

Mars is a relatively Earth-like planet :

  • The length of the Martian day (called “ Sol ”) is very similar to that of the Earth day. A sol lasts 24 hours, 39 minutes and 35.244 seconds.
  • Mars has a surface area that corresponds to 28.4% of that of the earth, and is therefore only slightly smaller than the land area of the earth (29.2% of the earth's surface).
  • Its axis of rotation is inclined by 25.19 ° to the poles of the planet's ecliptic . The corresponding value of the earth is 23.4 °. As a result, Mars has seasons like Earth, although they are almost twice as long, as a Martian year is about 1.88 Earth years.
  • Mars has an atmosphere. Although this is very thin (approx. 0.6% of the earth's atmosphere), it still offers a certain protection from cosmic and solar radiation . It has also been used successfully for atmospheric braking of spacecraft.

Differences to earth

  • The strength of the planetary magnetic field is only about a hundredth of the earth's magnetic field and therefore offers very little protection against cosmic radiation. After just three years on the surface, the maximum values for astronauts according to NASA's safety guidelines would be reached. It is unclear whether and when Mars could develop a new magnetic field.
  • The air pressure on Mars is only about 6 mbar (0.6% of the earth's atmosphere), which is well below the Armstrong limit (61.8 mbar) at which people can live without pressure suits . The very thin atmosphere consists mainly of carbon dioxide. Therefore, habitable structures with pressure vessels, similar to those in a spaceship, would have to be built on Mars. Achieving an earth-like composition of the air and adjusting the pressure by means of terraforming is considered difficult, as the solar wind would constantly remove the upper layers. The thin atmosphere also offers significantly less protection against small asteroids.
  • The surface gravity on Mars is 38% of that on Earth.
  • Because Mars is farther from the Sun , the amount of solar energy reaching the upper atmosphere is less than half the amount reaching the Earth's upper atmosphere or the surface of the Moon. However, the solar energy reaching the surface of Mars is not hindered by a dense atmosphere like that on Earth.
  • With an average surface temperature of −23 ° C near the equator and a low of −140 ° C in the area of ​​the polar caps, Mars is significantly colder than Earth. The lowest temperature recorded on earth is −93.2 ° C, and this is in Antarctica . In addition, because of the more eccentric orbit, temperatures vary more than on Earth.
  • Due to the further distance to the sun, the Martian year is 668.6  Sol, about twice as long as the Earth year.

transport

Traffic between Earth and Mars

Travel time to Mars depending on date and take-off speed, 2019–2023

Due to the large and strongly fluctuating distance between Earth and Mars, traveling to Mars would be very complex. Using today's technology, a spaceship takes approximately six to ten months to travel. According to the Earth-Mars sidereal period, the optimal start window occurs every 779 days, i.e. about every 26 months.

To reach Mars, you need less energy per unit of mass ( Delta-V ) than to all other planets except Venus . A trip to Mars on a Hohmannbahn with today's technologies takes about nine months. Other trajectories that reduce the travel time to seven or six months in space are possible, but require higher amounts of energy and fuel and are already standard for unmanned Mars missions. Shortening travel times to less than six months requires a greater change in speed and an exponentially increasing amount of fuel. This cannot be achieved with chemical missiles. Research projects for new propulsion technologies such as VASIMR or nuclear rocket propulsion aim to shorten interplanetary flight times. Another possibility is constantly accelerating technologies such as solar sails or ion propulsion .

During the journey, the astronauts are exposed to radiation from which they must be protected. Cosmic rays and solar wind cause DNA damage that the cancer increase risk, but the effect of long-term space flights in interplanetary space on the human body is unknown. NASA scientists, who generally measure the risk of radiation in terms of cancer risk, put the probability of dying of cancer caused by a thousand-day mission to Mars at 1 to 19%. However, it should be noted here that this probability represents an additional risk. This, combined with the base 20% chance that a 40-year-old non-smoker will die of cancer, could result in a 39% risk of developing fatal cancer. In women, the likelihood of developing cancer is probably increased due to the greater proportion of the total weight of glandular tissue.

Landing on Mars

Mars has only 38% of the gravitational pull of the Earth, and the density of the atmosphere is only about 1 percent compared to Earth. The relatively strong gravity and adverse aerodynamic effects make it considerably more difficult to land a larger spacecraft with thrusters, as was done on the Apollo moon landings. Heavy lander projects will require different braking and landing systems used in previous manned lunar or unmanned missions to Mars.

Transports on Mars

Mars rovers with radionuclide batteries (RTGs) as an energy source are the first means of transport, although their operation would not be particularly efficient due to the payloads to be carried. Hydrazine as a fuel could represent an alternative, depending on how it can be synthesized on Mars, there would also be other options. These rovers should - if possible - contain residential modules, as research trips lasting several days are desirable. When building several colonies, these could be connected by magnetic levitation trains , which, due to the lower atmospheric pressure, could reach much higher speeds than on Earth. For the same reason, however, separate life support systems would be required which could keep the occupants alive for longer periods of time even in emergencies such as loss of pressure and derailment.

Since there is an atmosphere, the suitability of aircraft such as airships or airplanes should be investigated. Experiments on Earth have shown that balloons with sufficient volume can fly and lift loads even at very low pressure. In a thinner atmosphere, an airplane would have to fly faster to get the same lift.

On Mars itself you would have to use adapted space suits , because the suits designed for weightlessness are very heavy and rigid. As an alternative, suits similar to diving suits could be used, which would have to be very tight-fitting to ensure the necessary internal pressure. If equipped with heating elements and a compressed air helmet, such suits probably allow the necessary freedom of movement for field missions under gravity. Currently under development, however, are rigid, armor- like spacesuits with plastic joints.

care

Mars (image from Viking 1 , 1980)

In the case of permanent settlement, the supply of food and breathing air must be made possible independently of the constant supply from the earth by means of in-situ resource utilization or extraterrestrial resource utilization . Water treatment is important . One consequence is the medium-term development of a closed biological system in which the colonists grow or produce their own food. One possibility would be to use hydrogen from Earth and carbon dioxide from Mars to produce water. One ton of hydrogen could produce two tons of methane and about four and a half tons of water. However, NASA analyzes show that around 2% of the Martian soil consists of thermally releasable water, which can also be used for the local production of industrial water. Genetic modifications, which enable the fauna and flora to better adapt to the new environment, are also discussed .

communication

Contact with the earth would be comparatively difficult, since the transmission time of the signal varies with distance between 3 minutes and 6 seconds with favorable opposition (smallest distance) and 22 minutes and 18 seconds with unfavorable conjunction (greatest distance). Within a dialogue, i.e. a conversation between a station on Earth and the station on Mars, there are pauses of at least 6 minutes and 12 seconds to 44 minutes and 36 seconds between the messages, combined with a significantly lower transmission rate.

Time calculation

A Martian day ( sol ) is 39 minutes and 35.244 seconds longer than an earth day and a Martian year with 668.5907 sols is about twice as long as the earth year. This makes their own calendars and clocks necessary for the Martian settlers. Some experts have already dealt with this problem. This includes the space engineer and political scientist Thomas Gangale . He published a Martian calendar in 1985, which he named after his son Darius Darischen calendar . Some authors took up this idea and published variants of the Daric calendar in the following years. Other authors like Robert Zubrin reconsidered the idea and brought out their own designs. The latter also sets up a concept for Martian clocks.

What all these calendars have in common, however, is that they are solar calendars . In contrast to the Earth's moon, the Martian moons Deimos and Phobos are rather unsuitable as timepieces, as they can be seen relatively quickly on the one hand and not particularly well on the other.

radiation

Mars has no global magnetic field that is comparable to the Earth's magnetic field . Combined with a thin atmosphere, this allows a significant amount of ionizing radiation to reach the Martian surface. The Mars Odyssey spacecraft carried an instrument, the Mars Radiation Environment Experiment (MARIE), to measure the dangers to humans. MARIE has found that the radiation in orbit over Mars is 2.5 times higher than at the International Space Station . Average doses were about 22 millirads per day (220 micrograys per day or 0.08 gray per year). A three-year exposure at such a level would be close to the limit currently set by NASA. The level on the surface of Mars would be a little lower and would vary greatly in different places, depending on the altitude and the strength of the local magnetic field.

Occasional solar proton events (SPEs) produce much higher doses. MARIE observed some SPEs that could not be viewed by sensors near Earth due to the fact that SPEs are unidirectional, making it difficult to warn astronauts on Mars early enough.

In 2003, NASA Lyndon B. Johnson Space Center opened a facility, the NASA Space Radiation Laboratory (NSRL), at Brookhaven National Laboratory that uses particle accelerators to simulate space radiation . The facility will study the effect of the particles on living organisms along with shielding techniques. There is some evidence that at this low level cosmic rays are not quite as dangerous as previously thought, and that with radiation, hormesis occurs. The agreement between those who have studied the subject is that the level of radiation that appears during the flight to Mars and on the surface of Mars is a problem. However, this problem does not prevent a trip with the latest technology.

The following precautions are possible:

  • Bury: A possible colony is first built on the surface and then covered by Martian soil. This method would not only protect against radiation, but also against small meteorites that can get through the atmosphere to the Martian floor.
  • Armoring the building: Using existing resources or materials that you have brought with you, you can achieve an absorbent reinforcement of the ceiling.
  • Shielding with water: Water has radiation-absorbing properties. The water tanks (cooling water, waste water, drinking water) can be arranged flat over the common rooms.
  • Shielding with artificial magnets : If the energy supply is sufficient, large electromagnetic fields could be used as a substitute for the missing Martian magnetic field to deflect fast charge carriers.
  • Through natural formations: It is known that there are strong regional differences in the magnetic field on the Martian surface . If a colony was established in such an area of ​​relatively strong field strength, it could be protected by these natural fields.

power supply

An efficient energy supply for heating and food production is essential for a colony. The following approaches are discussed:

Solar

The use of solar panels and solar cells to generate energy has been of great help in previous space missions, especially with mission targets within the asteroid belt . The stability against external forces could mostly be neglected. It will be different on Mars, however, because it has a gravitational force that makes the structure necessary to be more stable. The solar constant (590 W / m² for a mean distance from Sun to Mars) is about half as high as on earth. That is why twice the solar area is required compared to earth for the same output. On the other hand, the storms that occur globally and last for a long time (months) would impair the production of solar energy. For this reason, an energy storage concept would also have to be worked out when using solar energy. In addition, these storms would cover the solar cells with dust, which could reduce performance by up to 40% as long as the cells are not cleaned. The experience that has been made with solar power plants in desert areas clearly shows that this problem can only be permanently solved with appropriate automation technology. The manual effort of cleaning so many panels again and again at appropriate intervals would be too great.

Nuclear

There are two main options for using nuclear energy:

The radioisotope generator (RTG)
is a well-proven device for providing energy over a long period of time in space travel. Its greatest disadvantage, however, is the low power output, which decreases over time due to the half-life of the radioactive isotopes. However, since it can be assumed that a colony has a high energy requirement that increases over time, new RTGs would have to be continuously integrated into the energy network. However, the efficiency per unit of mass (use of around 8% of the emitted energy) is not very high, while the costs of around 75 million US dollars per RTG should not be underestimated.
The nuclear reactor
A nuclear reactor carried along could put the problem into perspective, depending on the energy utilization. The Soviet Union has already had experience with orbital reactors (see RORSAT ); However, a colony needs a much higher energy yield and efficiency per unit of mass, because otherwise the RTGs, which are less problematic in terms of safety, would be the preferred choice.

NASA is currently (as of 2011) working on the use of Stirling engines and alkali metals in RTGs, which could increase efficiency to 15–20% and thus make use more efficient.

Habitability

The temperatures on the surface of Mars near the equator are similar to those in the coldest places in Antarctica; z. For example, temperatures at Viking 1's landing site fluctuated between −89 and −31 ° C over the course of a day.

Since the beginning of the 21st century, various research projects have been carried out beyond theory with the aim of simulating life on Mars. The Mars Society started its Mars Analog Research Station Program in 2000 , which today consists of two stations, the Flashline Mars Arctic Research Station in the Canadian Arctic and the Mars Desert Research Station in Utah . Topic research projects have also been carried out by the state, such as B. Mars-500 by Roscosmos and the European Space Agency .

The NASA-funded Hawaii Space Exploration Analog and Simulation study aims to determine factors that may affect group dynamics on future Mars missions. The one-year simulation started in August 2015.

It is completely unexplained how the gravitational conditions of Mars affect life forms whose evolution took place on Earth in the long term . In particular, it is not known whether humans would retain their ability to reproduce .

Terraforming

Artist's impression of a terrage-shaped Mars

The aim of terraforming would be to transform the inhospitable Mars into a habitat that is adapted to the physiology of humans. Ideally, after this process has been completed, people should be able to stay outdoors without a pressure suit or breathing apparatus. Terraforming is not a requirement for colonization on Mars, but it could significantly improve the quality of life.

As early as 1971, Carl Sagan had the idea of ​​melting the polar ice caps and using the released gases to create a functioning atmosphere . Probably the simplest method was developed in 1991 by a team led by Christopher McKay from the NASA Ames Research Center . Factories should emit huge amounts of CFC gases into the atmosphere, thus boosting the greenhouse effect , which then leads to melting of the polar ice caps and frozen rocks. More and more complex plants could be planted successively between 500 and 1000 years. After this process, humans could probably survive without a pressure suit, but without breathing apparatus, but at the earliest after about 170,000 years.

A 2018 study by the University of Colorado Boulder challenged these concepts. The study came to the conclusion that the enclosed CO 2 resources could at best generate an atmospheric pressure similar to that of the Earth , but only a small part of it could be released. Building a noteworthy atmosphere with today's technology is only conceivable over several million years.

Fictions

literature

Movies

Computer and video games

comics

literature

  • Uwe W. Jack: A city on Mars. In: FliegerRevue , No. 06/2020, pp. 38–45

Web links

Commons : Colonization of Mars  - Collection of Images, Videos and Audio Files

Individual evidence

  1. ↑ Eric Ralph: SpaceX's first private Mars conference is focusing on the 'how' of living on the red planet. In: Teslarati. August 8, 2018, accessed May 2, 2019 .
  2. ↑ Eric Berger: SpaceX organizes inaugural conference to plan landings on Mars. In: Ars Technica. August 6, 2018, accessed May 2, 2019 .
  3. ↑ Mars. SpaceX, accessed May 2, 2019 .
  4. ↑ SpaceX is eyeing these 9 places on Mars for its first Starship rocket missions. In: Business Insider. September 3, 2019, accessed June 9, 2019 .
  5. ^ Candidate Landing Site for SpaceX Starship Near Arcadia Planitia . University of Arizona , accessed May 8, 2020.
  6. ↑ NASA checks SpaceX's potential Starship landing sites on Mars, with water in mind . Geekwire, September 1, 2019.
  7. ↑ Rainer Kayser: Is the global magnetic field returning? Astro News, July 1, 2007.
  8. ↑ NASA Probe Counts Space Rock Impacts on Mars. Retrieved May 11, 2020 .
  9. ↑ David Langkamp: VASIMR - In three months to Mars? raumfahrer.net, December 1, 2001.
  10. ↑ Can People Go to Mars? . NASA Science, February 17, 2004 (English)
  11. ↑ Michael Wapp: The planet Mars
  12. ^ Nancy Atkinson: The Mars Landing Approach: Getting Large Payloads to the Surface of the Red Planet . Universe Today, July 17, 2007
  13. ^ A b c Robert Zubrin: Company Mars. The plan to colonize the red planet. Heyne, 1997, ISBN 3-453-12608-4 .
  14. ↑ NASA: Welcome to In Situ Resource Utilization (ISRU) ( Memento from January 9, 2019 in the Internet Archive )
  15. ↑ Viorel Badescu: Mars - prospective energy and material resources. Springer, Berlin 2009, ISBN 978-3-642-03628-6 .
  16. ↑ Curiosity's SAM Instrument Finds Water and More in Surface Sample , nasa.gov, accessed January 13, 2014
  17. ↑ Thomas Gangale: The Darian Calendar for Mars (English)
  18. ↑ Michael Boden: The Martian Calendar . German Space Society
  19. ^ Space Radiobiology . BNL / NASA Radiobiology Program
  20. ↑ "Star Trek" protective shield to protect Mars travelers ( Memento from July 7, 2012 in the web archive archive.today )
  21. ↑ RM Halberle et al .: Atmospheric effects on the utility of solar power on Mars ( Memento from March 5, 2016 in the Internet Archive )
  22. ↑ Ucilia Wang: This Israeli startup makes robots that dry clean solar panels ( English ) gigaom.com. November 25, 2014. Retrieved September 6, 2019.
  23. ↑ David Williams: Mars Fact Sheet. National Space Science Data Center, September 1, 2004, accessed June 24, 2006 .
  24. ↑ Ilmenau graduate for one year in a simulated Mars station . Press release of the TU Ilmenau from August 14, 2015.
  25. ↑ Can humans have babies on Mars? It may be harder than you think. In: National Geographic . December 10, 2018, accessed May 2, 2019 .
  26. ↑ Robert Gast: Colonization of Mars: The Dream of Terraforming. Spectrum of Science , August 30, 2018, accessed October 4, 2018 .