Science and technology have reached a state that will allow producing a spacecraft for a mission to the planet Mars and other planets. But there is one big obstacle on the way of manned visiting even the closest planet Mars: human space exploration is impossible, the human body will not survive the flight.
Imagine human space exploration in a flight to Mars: low gravity, ionizing radiation exposure, traveling millions of kilometers for six months.
Without any "countermeasures" to protect muscles, bones, cells, it is impossible.
Effect of weightlessness
One of the biggest problems in preserving the health of astronauts when they travel through the solar system is simply to prevent physiological changes caused by weightlessness. Muscle and bone atrophy is perhaps the most famous change.
Weightlessness also changes the sense of balance, so that, for a while, after astronauts return to 1-g, they feel the world revolves around their heads.
Even subtle changes in the body after the flight can be critical. Here on earth, we don't have any problems probing the position of our limbs: if you decide to raise your hand, you know how necessary it is to move it to take action. But in space, this proprioceptive (sense of position) ability is not similar. Onboard the spacecraft, certain countermeasures are necessary.
Astronauts aboard the International Space Station work about two hours a day, using treadmills, bicycles, and devices specially designed to train the body. Medicines can help with some problems: bisphosphonates, for example, are used on the ground to slow the rate of bone loss in osteoporosis patients. These countermeasures work well enough for short flights. For a long-term space mission, a completely different approach should work better: artificial gravity.
Artificial gravity
In theory, artificial gravity is easy to achieve. Conventional laboratory centrifuges do this. However, spinning an entire spacecraft can be expensive and complex. That's why researchers at research centers have developed small centrifuges.
Ionizing radiation
The next problem for human space exploration is ionizing radiation.
The main content of radiation is to limit the impact that astronauts can have in outer space. In a long-term mission, astronauts will have to be in space for up to several months and, most importantly, the type of radiation in deep space is more dangerous than in low-Earth orbit.
Space emits not only basic elementary particles but also many dangerous ones. A spacecraft must include protection that can absorb cosmic rays.
To completely block radiation, carbon shields of a couple of meters thick are required: impractical, because of weight and volume. Strange as it may seem, 30-35% of the radiation can be blocked by shields only five to seven centimeters thick. Astronauts will still have to cope with 70% of the radiation that will pass through the shields.
Antioxidants and vitamin C can help deal with particle radiation before it can harm the body. Scientists are looking for ways to help the body cope with radiation. One way is to destroy damaged, abnormal cells inside the body. It explores the cell cycle, from cell division to checking your genes and correcting errors in radiation damage. Pharmaceuticals that give cells a better chance of correcting their own problems are considered.
There may be other problems, such as slow healing of wounds and the inoperability of the immune system, for example.
Even if people were able to prevent the damage caused by radiation and weightlessness these days, this would still only be part of the medical problems of astronautics that need to be solved in order to explore Mars and other planets.
In general, flights to other planets require a person with different capabilities.
Human space exploration in the near future will be carried out by launching unmanned aerial vehicles and analyzing the information they transmit.