Our space station construction work is steadily advancing, in the construction phase, we will use six launch missions to complete the construction of the space station in orbit, including the tianzhou iv cargo spacecraft, shenzhou xiv manned spacecraft mission has been implemented, both spacecraft have been docked with the core module of tianhe. According to the plan, ask the sky experimental module will be launched this month, the dream sky experimental module will also be launched in october this year, in the two experimental module arrived in the sky and the core module for rendezvous and docking later, we will also choose the opportunity to launch the sky boat no. 5 cargo spacecraft, shenzhou 15 manned spacecraft, when the shenzhou 14 spacecraft will be with the shenzhou 15 manned spacecraft to achieve the first in-orbit rotation.

From the current situation, our country's space industry, especially the progress of manned spacecraft is very big, in the previous several manned spacecraft mission, the single flight time is actually not very long, but after the launch of the core module of tianhe, shenzhou manned spacecraft in orbit flight time has been breaking records, shenzhou 12 manned spacecraft flight time reached 3 months, while shenzhou 13 shenzhou xiii and the ongoing shenzhou xiv manned spacecraft mission time is 6 months, 6 months in orbit will be our space station construction, operation phase of a regular mission length, that is, the next launch of shenzhou xv or xvi, xvii spacecraft in orbit time will be half a year.

The reason why the orbit time was not long before and now the flight time is getting longer is actually quite simple. One of the reasons is that in some previous manned missions, are only launched a manned spacecraft, the spacecraft can carry food, water, oxygen and other supplies are very limited, plus the spacecraft is very small, the astronauts in the small spacecraft life, work is not very comfortable, so can not fly for a long time. With the emergence of the space station, the astronauts have more space, and we can transport food, water and other supplies to the space station through the cargo spacecraft for resupply, so that the time in orbit can be longer.

In fact, the longer the time in orbit, we need to solve not only the inorganic resupply problems of food, water, oxygen, propellant, etc., but also the various problems faced by astronauts flying in orbit for a long time. One of the most common problems we talk about is that astronauts are in a weightless environment in space for a long time, their bodies will change, and they may even have some problems that we do not have in regular people. For example, on the ground we will be subject to gravity, our body fluids will flow naturally to the limbs, but in the weightless environment of space body fluids will not be able to flow naturally to the whole body, especially the lower limbs, this time the astronaut's head body fluids will be more. This is also the reason we see astronauts in the space station "Fat", the real situation is not the astronauts fat, but a large number of body fluids gathered in the head caused.

6 months of space flight, a lot of bone loss

If it is only a short flight, say about 1 month of flight, then the main problem faced by the astronaut is still the distribution of body fluids, but as the flight time gets longer, the astronaut will slowly develop muscle atrophy, bone loss and other problems, and may even have problems with the immune system, endocrine system, etc. If the problem is only the redistribution of body fluids, this is also very good solution. Because when the astronauts return to earth after the mission, they will re-adapt to the gravity environment on the ground, body fluids will also adapt and adjust according to the gravity environment on the ground, and will soon return to normal.

Scientists' studies have shown that the bone loss that occurs during prolonged space flight has 2 consequences, one of which is osteoporosis, and the other is a greater likelihood of kidney stones. After the problem of bone loss, the recovery process is long and slow, and it is difficult to return to normal levels.

In a new study published in the journal scientific reports, researchers found more details about the massive bone loss that astronauts experience after a six-month flight in space. If spaceflight lasts for six months or even longer, astronauts may experience permanent bone loss equivalent to decades of aging. Because of the long, slow recovery process from bone loss, scientists also found that these astronauts could only recover half of their bone mass even 1 year after returning to earth.

In this study, researchers compared the bones of 17 astronauts, all of whom had been stationed on the international space station for 4-7 months, with an average age of 47, in order to accurately test the bone loss that occurred in these astronauts and how well they recovered. The researchers scanned the wrists, ankles and lower legs of these astronauts before they left for the iss, and again when they returned to earth. The results found that their bone loss was alarming, with eight of the astronauts continuing to experience increased bone loss after returning to earth. Bone loss is a problem that has a greater impact on astronauts, which may cause their bones to break or fracture more easily.

Humans can not walk the earth?

In near-earth orbit flight are facing such problems, if we humans in the future to achieve manned landing on mars or even immigration to mars, we may face even more problems. Because in going to mars or other planets, the flight time is longer, after all, a single trip to mars may take two or three years, this flight time is now the vast majority of astronauts cumulative flight time of three or four times. In addition, when flying to mars and other planets, the spacecraft will be in a more complex cosmic environment. Therefore, it is very important to find ways to reduce the astronauts in space bone loss and other problems, if these problems can not be solved, then we humans want to mass migration to mars may face all kinds of difficulties.