The special thing about Proxima b is that it is a rock planet that revolves around its star in the so-called habitable zone, where there is potential water and life.
It is the year 2100. Four astronauts set foot on the stony ground of a wonderful world in the twilight. A landscape of jagged rocks looms in the distance, the only sound is the sound of the sea and a giant red sphere glows above the foursome.
After a seven-year journey, the first astronauts arrived on the planet Proxima b.
The special thing about Proxima b is that it is a rock planet that revolves around its star in the so-called habitable zone, where there is potential water and life.© Nature / Giphy
When Proxima b was discovered in 2016 with the help of the La Silla observatory in Chile, astronomers were cheering around the world.
Moreover, the planet revolves around the neighbor of the sun, the dwarf star Proxima Centauri, which is located at a distance of only 4.25 light years.
Although that amounts to 271,000 times the distance from the earth to the sun, in cosmic terms it is so close that it is not even a crazy idea to travel to the planet. And before today's babies are old, that idea can even become reality.
Proxima b was found with the La Silla telescope in Chile.© Petr Horálek / ESO
In 2093: Astronauts on the road for seven years
When the four astronauts embark on the space capsule packed and collapsed, they look forward enormously to what is to come. The two women and two men are the first to leave for a different solar system.
As soon as the spaceship leaves the earthly gravitational field, the foursome must assemble the large, inflatable modules with sports facilities, living space and vegetable garden.
The capsule is packed with freeze-dried food and water, but that is not nearly enough to keep the crew alive for seven years. That is why the space pioneers also have to get their own food and water.
In the garden they are going to grow crops in racks with artificial light and with their own excrement as fertilizer. Urine is reused as drinking water.
Swaying star indicates planet
The light from Proxima b (blue sphere) is so weak that telescopes cannot see it, but the planet is shaking its star (yellow sphere). The small fluctuations in the light waves (dotted line) of Proxima Centauri were already discovered by the Finnish astronomer Mikko Tuomi in 2013, but to be sure, he observed the star for two months in 2016 from the La Silla observatory in Chile .
Even though the planet only weighs a fraction of its star, it pulls it a bit.
As the star approaches, the light waves are shorter.
As the star moves away, the light waves become longer. The change in the light waves shows that a planet revolves around the star.
A large part of the day is filled with training and taking care of the crops. But the journey to Proxima b is long and although the new anti-matter rocket is racing through the solar system with a staggering 180,000 km / s, life is irrevocably a routine and being together is becoming increasingly difficult for astronauts.
When they approach their goal, the boredom - despite their daily tasks and an electronic library with books, films and games - can no longer be sustained.
Present: NASA is working on anti-matter missile
Whether the astronauts can actually go to Proxima b depends on whether researchers will be able to build an anti-matter missile. But if that works out, then a vessel can be on the planet in seven years.
Antimatter missiles are still science fiction, but the concept is so realistic that the engineers at NASA's Institute for Advanced Concepts are already thinking about it.
Faster with anti-matter missiles
With just a few grams of antimatter, a rocket can reach Proxima b, and the travel time is shortened to seven years. This is how the rocket engine works:
1. Tank provides antimatter
From the fuel tank, positrons are gradually sent into the rocket's engine.
2. Hydrogen is heated
Hydrogen runs to the engine from a tank through a parallel tube and is heated there.
3. Collision creates radiation
In the engine, the positrons collide with the hydrogen. The two destroy each other, releasing gamma rays.
4. Gamma radiation heats gas
The radiation heats the rest of the hydrogen gas, which then expands strongly, and atoms shoot out the nozzle.
Antimatter is the ultimate rocket fuel, because it does not weigh much and therefore does not cost much energy to transport. A few grams is enough to go back and forth to Proxima b.
When antimatter and matter come into contact with each other, they are destroyed and converted into very energy-rich gamma rays. It can heat a propellant, such as hydrogen, which then shoots out a nozzle and pushes the rocket hard.
But first the researchers have to produce antimatter and store it completely isolated in a magnetic vacuum, so that it only comes into contact with normal matter when fired into the engine.
In 2100: Radiation threatens the pioneers
When the four pioneers finally arrive on Proxima b after a successful landing, they are excited. The seven years of weightlessness have left deep marks, despite good training methods to combat physical weakness.
Without their tools, astronauts on Earth would not be able to take a step, let alone Proxima b, where gravity is at least 30 times as powerful. But they still jump around, because their spacesuits are equipped with exoskeletons that support their movements.
The red dwarf Proxima Centauri lets the rock planet Proxima b bathe in a reddish glow. The double star Alfa Centauri A and B is visible in the distance. The radiation is intense.© ESO / M. Kornmesser
However, the joy about the successful landing is only short-lived. The dwarf star constantly emits large doses of carcinogenic x-rays, and the star bursts from time to time.
The x-rays become more intense, after which it rains charged particles on the planet. The astronauts cannot be outside for long periods, so they quickly go to the base, which hopefully has built itself up in the intervening months.
If not, they will face a certain death.
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Present: Lead packs weigh as much as 50 kilos
A space suit that is suitable for Proxima b does not yet exist, but the researchers should be able to develop one in the coming decades.
The best protection against radiation is a heavy element such as lead. But if the space suits are to be given a lead lining over the entire body, like the lead aprons in the hospital's X-ray department, then they weigh around 50 kilos.
The researchers therefore hope that future nanotechnology can be used to make a light material that blocks radiation.
If that fails, then the astronauts with all that lead and the enormous gravity have to rely on special exoskeletons, which provide extra power.
That technology is already there. For example, researchers in South Korea developed exoskeletons that support the employees of a shipyard so that they can lift 100 kilos.
Exoskeletons strengthen the body, allowing astronauts to walk around on planets with extreme gravity, such as Proxima b.© Hyundai
Fortunately, the radiation on Proxima b is not insurmountable for people. If the planet has a thick atmosphere. has, it will inhibit harmful radiation, while a powerful magnetic field can deflect the dwarf star's electrically charged protons and electrons, just as the Earth's magnetic field drives the solar wind largely around the planet.
The thickness of the atmosphere and the force of the magnetic field will be investigated with telescopes in the coming years and are therefore already known when a manned mission departs.
Space telescope examines Proxima b1 / 3
NASA's new James Webb telescope will investigate which substances contain the atmosphere of Proxima b. Based on this, it can be determined whether the planet is viable.© NASA
In 2100: The base is ready
In the harsh landscape, the base appears to be a huge sand castle. In the months prior to the arrival of the astronauts, an unmanned rocket dropped off robbers and housing modules.
The robbers first dug the hole for the foundation. The round modules were then rolled to the hole by pumping air in and out of a number of outside airbags. Then the entire base was automatically inflated and the robots covered it with a thick layer of soil, which should protect the pioneers against the deadly radiation of the dwarf star.
On Proxima b there is 400 times as much X-rays as on Earth.
Full of excitement, the astronauts walk through the plastic door. The hour of truth has arrived. They immediately check the living space, garden, workshop and the lab. Everything works!
Relieved, they prepare a well-deserved feast of freeze-dried food from the supply that was also sold in advance. Finally, they drink something they haven't had for seven years: a cup of instant coffee.
Present: We try to produce food in space
Before we start a base on Proxima b, we must be able to routinely build and manage bases on Mars.
The space organizations NASA and ESA plus universities and companies are currently working on the technology needed to produce water, food and energy on the red planet.
At ESA, scientists are working on a system in which plants and bacteria provide the astronauts with oxygen, food and electricity. The system is built around a greenhouse in which plants and bacteria convert carbon dioxide into carbon, which is used for oxygen and foodstuffs. Oxygen is breathable and forms a connection to water.
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When the colonists have eaten and drunk, bacteria convert their urine and faeces into fatty acids, minerals and ammonium and then into CO2 and manure, which goes back into the greenhouse.
The rest of the waste goes to a power station where microbial fuel cells generate electricity. Nothing is lost that way.
Long before the first manned mission, there are probably small chip satellites circling around Proxima b, which can photograph and monitor the unmanned landings, or build the base.
The researchers want to send micro or chip satellites to Proxima b in 2030, the size of a mobile phone and equipped with a solar sail of a few square meters. Although the satellites leave our solar system at 60,000 km / h, it takes 20 years to reach the planet.© Claus Lunau
In 2100: First trip to the coast
It is morning in twilight country. The star seems huge when it rises above the horizon and the rocks turn into pale red and orange hues. It is a dry, windless day, although it is a bit cloudy.
Two astronauts step into the robber while the other remain at the base, where they keep constant radio contact with their colleagues.
Direct contact with the earth is impossible, because it takes more than four years to send messages home at the speed of light and more than eight years before there is an answer.
The first trip goes to the coast, less than half a kilometer away. Although the caterpillar vehicle can handle the bumpy terrain well, the journey takes hours.
In 2024, the researchers will be able to see the contours of the oceans and shores of Proxima b with the E-ELT telescope in Chile - as at least there is water.© ESO
But once they are there, the two stare breathlessly at the endless sea as the waves break on the rocky coast. Then they bring their bottles to the water to take samples.
When the tired astronauts are home again, it is pitch dark. Only the stars give light.
In the lab they examine the water samples and the analyzes provide a definitive answer to the big question: yes, the water contains life! And not only bacteria, but also plankton and animals. The astronauts are fascinated by the microscope.
In 2107: Astronauts return home sick
Two months after the four astronauts first entered a strange solar system, they left the base again and took a final look at the sky.
The two neighboring stars Alpha Centauri A and B look like two dishes that shine more strongly than all the other stars in the immeasurable space.
The stars are of the same type as the sun and can contain planets in the habitable zone. The living conditions there would then resemble those of the earth more than those of Proxima b.
Proxima Centauri (red circle) is a small red dwarf that gives little light and that revolves around the two larger stars Alfa Centauri A (left) and Alfa Centauri B (right).© Wikimedia Commons / Guy Vandergrift
While the astronauts look at the sky again, they hope that their base will be a stepping stone for more human-friendly planets in the Centaurist system.
The retreat takes another seven years, and at the landing the astronauts are so weakened by the many years of weightlessness that they will never be able to walk without an exoskeleton. The risk of cancer due to radiation during their stay in the capsule and on Proxima b is high.
But the pioneers go down in history as the greatest explorers ever: the first to be on a planet outside the solar system and have paved the way for the colonization of space.