The mission to Proxima b

Oceans, lakes, and rivers could exist on Proxima b. Not only might the rocky planet resemble Earth with water and bearable temperatures, it is also so close to us that the first astronauts could visit it in 2100.

Brave new world. In 2100, an awesome scenario appears in front of four dazed astronauts, as they step out onto the stony ground in the dusk. In the distance, they can make out a landscape of twisted rocks, the rhythmical sound of waves rolling ashore breaks the silence, and above them, there is a huge, red, glowing sphere. After travelling for seven years, the first astronauts have reached the Proxima b planet.

In 2016, when a team of astronomers discovered the planet via the La Silla Observatory in Chile, astronomers throughout the world cheered, as Proxima b is some-thing as rare as a rocky planet orbiting its star in the habitable zone, in which water and life could exist. In addition, the planet was orbiting the Sun’s closest neighbour – the Proxima Centauri dwarf star – which is located only 4.25 light years from Earth. Although that is the equivalent of 271,000 times the distance between Earth and the Sun, it is so close that a mission to the planet is not a completely insane idea, but could be realized before today’s infants become very old people.

2093 ASTRONAUTS TRAVEL FOR SEVEN YEARS

The joy of expectation is extreme, as the four astronauts enter the crammed space capsule. The two women and two men are the first ever to be heading for another solar system.

The flight out of Earth’s gravitational field goes according to plan. Now, the four astronauts are to mount the large, inflatable modules including gym, green-house, and living quarters. Although the space capsule is full of freeze-dried food and water, huge amounts of both are required to keep four people alive for seven years. So, the space pioneers are to produce both en route. In the greenhouse, they will grow plants in shelf systems, using artificial light and faeces as fertilizer. All urine is cleansed and reused as drinking water.

Many hours of the day are spent on intense physical exercise and the growing of the vital crops. But the mission to Proxima b is long, and although the new antimatter rocket travels through the Solar System at a dizzying speed of 180,000 km/s, the days become ever longer, and the company still more nerve-racking. When the four astronauts finally approach their destination, the level of boredom is almost impossible to bear in spite of daily routines and a wellstocked electronic library including books, films, and games.

2017 NASA WORKING ON ANTIMATTER ROCKET

Whether the astronauts will ever reach Proxima b is highly dependent on whether scientists are able to design an antimatter rocket. If so, a craft could reach the foreign planet in only seven years.

Antimatter rockets are still pure science fiction, but the concept is so realistic that engineers from the NASA Institute for Advanced Concepts have begun to design a spacecraft powered by antimatter. The latter is the ultimate rocket fuel, as it does not weigh very much and so does not require any energy to carry it. A few grammes would be sufficient to go to Proxima b and back again. When antimatter encounters matter, both are destroyed and converted into extremely high-energy gamma radiation, that could heat a propellant such as hydrogen, which escapes through a nozzle, providing the rocket with immense momentum.

Right now, scientists are struggling to produce antimatter and store it completely isolated in an air-void magnetic trap, so it will only get in contact with ordi-nary matter in the engine.

2100 RADIATION THREATENS PIONEERS

Everybody is extremely happy, when the four pioneers are finally standing on the surface of Proxima b following a successful landing. In spite of improved exercise methods to counteract physical weakening, the seven years in a state of weightlessness are evident. Without help, the astronauts would not even be able to take one step on Earth, and the gravity on Proxima b is at least 30 % more powerful. Nevertheless, they are jumping about like happy kids. Their sophisticated spacesuits include exoskeletons, which strengthen their motions and allow them super powers.

However, the celebration of the successful landing is a brief one. The dwarf star is constantly emitting large quantities of cancer-causing X-radiation, and at brief

intervals, the star erupts, intensifying the X-radiation and subjecting the planet to intense showers of charged particles. The astronauts cannot be outside for very long, so they quickly head for the base, which has hopefully built itself in previous months. If not, the astronauts will die.

2017 SUITS WEIGH UP TO 50 KG

A spacesuit for use on Proxima b does not yet exist, but scientists should be able to develop a suitable suit over the next decades.

The best radiation protection is offered by heavy elements such as lead, but if the spacesuits are to include lead protection of the entire body – just like the lead gowns used in hospital X-ray departments – they will weigh about 50 kg. So, scientists hope that future nanotechnology will produce a light material that halts radiation. If not, the astronauts must wear quite heavy spacesuits, and that can only be done, if a spacesuit’s integrated exoskeleton can contribute extra power. The technology is already in the pipeline, as in South Korea, scientists are developing exoskeletons that are to enable shipyard workers to easily lift loads of 100 kg.

Fortunately, the radiation on Proxima b is not necessarily inhuman. If the planet has a dense atmosphere, it would reduce the unhealthy radiation, whereas a strong magnetic

field could divert the charged protons and electrons around the dwarf star in the same way as Earth’s magnetic shield diverts most solar wind. Both atmosphere and magnetic field will be studied by telescopes before the first manned mission.

2100 THE BASE IS READY

In the deserted landscape, the base looks like a huge sandcastle. In the months prior to the arrival of the four astronauts, an unmanned rocket has landed both rovers and living quarter modules. First, the rovers dig a hole for the foundations, and subsequently, the spherical modules set in motion by alternatively pumping air in and out of a series of external airbags, rolling themselves into the hole. Once there, the entire base is automatically inflated, before the rovers cover it in a thick layer of soil, which will protect the four pioneers against the fatal radiation from the dwarf star.

The exited astronauts enter the plastic door. This is the moment of truth. They immediately check every-thing in living quarters, greenhouse, workshop, and lab. It works! Happy and relieved, they make themselves a well-deserved festive meal of freeze-dried food brought from Earth before they arrived. The astronauts end their meal with something that they have not enjoyed for seven years: a cup of instant coffee.

2017 FOOD WILL BE MADE ON SITE

A base on Proxima b requires that we are able to build and operate bases on Mars. NASA, ESA, universities, and private companies are developing the technology for producing water and food and generating energy on the Red Planet as we speak.

ESA scientists are working on a system, by which plants and bacteria provide astronauts with oxygen, food, and electricity. The system is based on a green-house, in which plants and bacteria convert carbon dioxide into carbon, which is used for oxygen and food. The oxygen is turned into air for the astronauts to breathe and into water. When the colonists have finished eating and drinking, bacteria convert both urine and faeces into fatty acids, minerals, and ammonia – and later into carbon dioxide and nitrate fertilizer, which goes back into the greenhouse. The rest of the waste is placed in the power plant, where microbial fuel cells finally generate power. Nothing is wasted.

Long before the first manned mission, tiny chip satellites will probably be orbiting Proxima b to record unmanned landings and follow up on base construction.

2100 FIRST EXCURSION TO THE COAST

One morning in the land of dusk, the star seems huge, as it rises above the horizon, colouring the rocks in pale red and orange hues. It is a calm, dry day, although there are a few clouds in the sky. Two astronauts enter the rover, while the others remain at the base, where they are in constant radio contact with their colleagues. Direct contact with Earth is impossible, as it takes more than four years to send messages back at the speed of light, and more than eight years to get a reply.

The coast, which is the destination of the first expedition, is less than 500 m away. Although the rover is a tracked vehicle, which can handle the impassable terrain, the drive takes several hours. Finally, the astronauts arrive. Speechless, they stare across the endless sea, as waves roll onto the rocky coast. They collect water samples and head back to the base.

As the exhausted astronauts finally reach the base, it is totally dark, the only light coming from stars in the sky. The water samples are studied in the base lab, and the analyses answer one major question: yes, the water includes life! And not only bacteria, but plankton and small creatures. Fascinated, the astronauts stare at the tiny animals in the microscope.

2107 ASTRONAUTS ARE WEAK UPON RETURN

Two months after the four astronauts stepped onto a planet in a different solar system, the team left the base, taking one last look at the sky.

The two close stars of Alpha Centauri A and B stood out – large as teacups and shining more brightly than any other star. The stars are the same type as the Sun and could have planets in the habitable zone. If so, the living conditions there will be more like the conditions on Earth than on Proxima b.

As the astronauts stared into space one last time, they wondered whether their base may one day become a stepping stone for going to other, more Earth-like planets in the Centauri system.

The flight back to Earth took another seven years, and subsequently, the astronauts are so weak following many years in a state of weightlessness that they will never walk again without exoskeletons.

The risk of cancer caused by radiation is substantial, but the pioneers know that they will be remembered as great explorers, perhaps even the greatest: the first people on a planet outside our Solar System.