Immigrant curtain

The mouse enters the book: Speak like a book.

Tooth extraction: I don't know how to commit suicide.

Dragon king jumps into the sea: Go back to his hometown.

Ponytail rope rubbing: it's not easy to use without sharing.

Monkey looking in the mirror: a monkey's face.

The dog lifts the curtain: all by one mouth.

Oil the horn: it's sharp and slippery.

Rabbit tail: it won't grow.

Snakes eat Monopterus albus: comparison length

Sheep sleeping tiger: unreliable

Eggs hit rocks: If you bite off more than you can chew, you will suffer.

Onion pig nose: pretending to be an elephant

Lesson 7, Little Knowledge

1. Interesting life in space

Astronauts live in an intelligent sealed cabin in space, which can automatically adjust the temperature, humidity, air pressure and air composition, make the air flow continuously, and reprocess waste gas and wastewater.

Take the sealed cabin of Mir space station as an example. The sealed cabin has complete facilities, abundant food, sufficient drinking water and domestic water, and can meet the daily needs of eating, drinking, pulling and sleeping. The cabin is also equipped with entertainment and sports facilities. There is also a small soilless culture place in the cabin, where flowers and vegetables can be planted, which can not only supplement the supply of fresh vegetables, adjust the life of astronauts, but also beautify the environment and purify the air. The bulkhead is decorated with ceiling and floor, so that astronauts will feel that there are up and down, left and right, front and back, just like on the ground. The bulkhead is also decorated with lively street photos and landscape paintings with a wide field of vision, which makes the astronauts seem to live in their hometown.

In addition, through radio and television communication equipment, astronauts can watch TV on the ground, talk to the ground center and their families, meet and even get together. The living environment designed by the designers of spacecraft for astronauts is really the "Peach Blossom Garden" of space.

Although living facilities are complete and superior, living in space is different from living on earth. Astronauts face many practical difficulties if they want to successfully complete tasks such as walking, sleeping, eating and swimming. These are common things on the ground, but they become wonderful and difficult in space.

space walk

Without gravity, astronauts are like fish floating in water in space. With a little support, he can swim around. Instead of going forward, he will roll up, roll forward, roll back and turn a bunch of pounds. If you want to move forward, you must have support points and external forces. It is effortless to move heavy objects in space. Chinese-American astronaut Wang Ganjun once hooked a 400-kilogram instrument with one foot and turned it freely. There are various ways for people to walk in space, such as walking on the floor, ceiling and bulkhead. A special space shoe, whose sole can be connected to the triangular space on the floor, can fix the human body when walking. However, most astronauts like flying and walking, which is both safe and chic.

Anxious sleep

For various reasons, astronauts generally can't sleep well in space.

The first is that the biological clock is disturbed. On the earth, people usually "work at sunrise and rest at sunset" for 24 hours a day, but in space, it takes about 90 minutes to go around the earth, and only 90 minutes a day and night. Astronauts still maintain the law of life on earth, that is, they still arrange their work and rest in a 24-hour cycle. In order not to let the rapid alternation of day and night affect the sleep of astronauts, they wear eye masks when sleeping, or use the intensity of lights to simulate the day and night changes on the ground.

Secondly, noise generated by instruments and equipment and noise generated by static electricity. To this end, astronauts must wear soundproof caps when sleeping, and radio contact with astronauts on the ground has also been stopped. At the same time, taking turns to work can ensure the sleep of every astronaut.

The third is that the astronaut's environment is weightless. Astronauts sleep like their heads and trunks are separated. Floating sleep often scares them, because their bodies are empty and unsupported, just like falling into an abyss. A Soviet astronaut once put his arm out of his sleeping bag while sleeping, and when he woke up, he found two hands floating towards him, which startled him.

Astronauts in space can sleep anywhere: floating in the air, leaning against the bulkhead, tied to the bed or sleeping. But when the speed of the spacecraft changes or vibrates, it is easy to have an accident when sleeping in the air. The best way is to fix the sleeping bag on the bed or bulkhead. The astronaut got into the sleeping bag, zipped up and tied his waist. The European Space Agency has designed a new type of sleeping bag, which is double inflatable. After inflation, the sleeping bag is tightened, which puts some pressure on the astronauts. In this way, it not only improves the blood circulation in the chest, but also eliminates the feeling of falling, so that astronauts have the feeling of sleeping on the ground.

Space shower

For astronauts, bathing in space is the most troublesome thing. They can't take a bath every day like at home, usually every other week. Because water is precious in the space station, bathing is expensive.

Astronauts need a lot of time to take a bath in space, and it takes several hours to prepare. When taking a bath, first step into a ring with a diameter of about 1 m, then pull up the ring, and the folded cloth tube connected with the ring is extended like the bellows of the accordion, and the ring is fixed on the ceiling, so that people can completely cover it inside. Before turning on the faucet, astronauts must fix their feet, otherwise the floating body will roll when washed by water, and wear a respirator and an eye mask, because in weightlessness, water will choke or even drown people.

After the above preparations are completed, you can turn on the nozzle, and the water drops will flow to the cloth pipe and the body, and then fly around. Because water is rationed, astronauts must turn off the nozzle when wiping their bodies, and then rinse with the remaining water. Bath sewage will not automatically flow downwards, so it is necessary to start the water pump to pump away the water and air together, and also use a vacuum cleaner to suck away the water droplets attached to the cloth pipe bit by bit. It only takes 15 minutes to take a bath, but it takes about 1 hour to clean up the sewage.

I like to see colorful space and the earth best.

There is no barrier of the atmosphere to block people's eyes and the lens of space telescope. When you look at the stars in space, they are all bright and clear, and there will be no stars flashing. When watching the sunrise, you can't see the moment when the sun jumps out. When watching the sunset, you can see the white light from the sun and see its exact position. Watching the moon is more interesting: during the day, the moon is light blue and very beautiful; At night, the moon looks much brighter than on the earth, as if it were its own light.

However, astronauts prefer to see the earth, the hometown of mankind. All astronauts say that the earth is beautiful from space. During the day, most of the earth is light blue, while the Qinghai-Tibet Plateau in China is green, the Arabian desert is brown, and the Sahara desert is another kind of brown.

Looking at the roof of the world from space, we can clearly see the Himalayas, and even distinguish between forests and lakes and plains and streams. Astronauts on the American Apollo spacecraft flew to the moon, and also saw the Great Wall in Wan Li, China, the speeding trains on Indian soil and the ships in the Myanmar River. Looking at the earth on a sunny day, the peaks of the Himalayas are covered with snow. The Kavil salt desert in Iran is the most fascinating, with brown and white eddies around the red disk. The Bahamas sparkles like jade.

The earth described by astronauts is really beautiful, because they are far away from the home of the earth and overlook their hometown, which contains beautiful humanistic feelings, not to mention the beauty of nature is so breathtaking and amazing!

2. Optimal orbits of nearby stars

Planets, asteroids, comets and satellites in the solar system are all neighbors of the earth. Because these neighbors and the earth are constantly moving, the road from the earth to the neighbors is not as simple and intuitive as the road between cities on the earth, so we need to establish the concept of spatial movement.

Let's look at the moon first. Because the moon orbits the earth, spacecraft can reach the moon along semi-elliptical orbit, elliptical orbit, parabolic orbit and hyperbolic orbit. Among them, the semi-elliptical orbit, that is, the elliptical orbit with the vertex tangent to the lunar orbit, needs the least speed and saves the least energy, which is the best orbit. Spacecraft can be launched from the earth to the moon every day, as long as the appropriate time is chosen.

The orbit to the planet is more complicated. Because the distance between the earth and other planets is different from their cycles around the sun, it takes a certain time to be on the same side of the sun as the earth, that is, the rendezvous period. Only before and after this can spacecraft be launched at them. ?

Conjunctive periodic table

When the spacecraft reaches the second cosmic speed 1 1.2 km/s, it will get rid of the gravity of the earth and orbit around the sun, which is a parabola relative to the earth. Relative to the sun, it is a circular orbit. Similarly, relative to the sun, when the speed is greater than 1 1.2 km/s, it orbits the sun in an elliptical orbit; When it reaches third cosmic velocity 16.7 km/s, it flies away from the sun in a parabolic orbit; When it is greater than 16.7 km/s, it flies away from the sun in a hyperbolic orbit.

Spacecraft can't reach other planets at the speed of 1 1.2 km/s, that is, it runs in a circular orbit relative to the sun. Therefore, the speed of spacecraft flying to other planets must be greater than 1 1.2km/s, that is, it flies in a semi-elliptical, elliptical, parabolic or hyperbolic orbit relative to the sun, so that the orbit is tangent or intersecting with the target planet. Among them, the semi-elliptical orbit needs the least speed and energy, which is called the optimal orbit or the minimum energy route. Because it was put forward by Austrian scientist Horman in 1925, it is also called Horman orbit. There are different minimum speeds and sailing times to reach different planets. At present, spacecraft are generally allowed to enter the transition orbit around the earth and then fly to the detection target. ?

Minimum speed and sailing time of flying to the planet along the optimal orbit.

If the speed of the spacecraft is increased, that is, more powerful rockets are used to make the spacecraft fly along parabolic or hyperbolic orbits, the sailing time can be shortened. If you fly in a parabolic orbit, the time to reach Mars, Neptune and Pluto will only take 70 days, 12 356 days and 19 122 days respectively. ?

In order not to increase the demand for rocket power, we can also use small thrusters such as electric rockets on the spacecraft to accelerate the spacecraft after it enters orbit and shorten the sailing time. For example, it only takes about 3 years to reach Pluto. The route at this time is a spiral line under the action of the sun's gravity and thrust. ?

After the spacecraft is in orbit, it can also increase its speed with the help of planetary gravity during the voyage and fly to the target planet. You can also use planetary gravity to change the flight direction and detect multiple planets. The flight path at this time is a complex curve.

3. Build the moon into a human settlement.

Develop the moon

In order to develop the moon and transform it into a human habitat, whether people can adapt to the weight of the moon can be verified through practice. Just like building a space city, the key to solving basic problems such as air, water, food and a radiation-proof shelter is still water. ?

Scientists have long predicted that there may be frozen water at the poles of the moon. 1994 65438+ 10, an icy lake was discovered at the south pole of the moon by the Clementine lunar probe launched by the United States. 1998 65438+ 10, another probe launched by the United States, Lunar Explorer, confirmed the existence of Antarctic glacial lakes on the moon, with an area of 5,000-20,000 square kilometers, and a larger glacial lake with an area of10,000-50,000 square kilometers was found in the Arctic. It is believed that scientists have chosen an address for the lunar base, which is on the edge of a crater near the Antarctic ice lake, where it is a permanent day and can make full use of solar energy. ?

Lunar base

Scientists have put forward many plans to build human bases on the moon.

One plan of American scientists is to send a folding living room on the moon to the moon first, and then send the first people to the same place on the moon by spaceship. They turned the spaceship into a temporary dormitory. Then several groups of construction workers will be sent to carry out the construction with the temporary dormitory as the work shed. First, expand the folded moon living room, which is a big room with five floors. Then connect to the temporary dormitory and install an exit. Finally, the living room is covered with 3 meters thick moon sand to form a semi-underground structure, which can not only prevent radiation damage, but also avoid the influence of huge temperature difference on the moon surface.

One plan that Japanese scientists imagine is to send robots to the moon first to level a field, and then send them to civil engineering vehicles, cylindrical electric heaters, solar cells and communication equipment.

Lunar observatory

The robot will install power supply and communication equipment, and then start construction work. First, dig a trench with a depth of 5m and a width of 10m with a civil work truck, put a cylindrical electric heater with a diameter of 3m in the center of the trench, then cover it with thick sand, and then heat it with electricity to melt the sand around the cylinder. After cooling off the power, it condenses into a glassy hole wall, and the electric heater is drawn out, which is a hole with one end closed. Install doors and windows at one end of the opening, and then install power supply, communication, safety regulation, water storage and water supply equipment in it, fill air and store water and food, so that people can live. Several such rooms make up an outpost. ?

After the establishment of the lunar outpost, ore conveyors, raw material processing plants and manufacturing workshops were shipped from the earth. They form a self-replicating factory, which can replicate some ore conveyors, a material processing factory and a manufacturing workshop. If we keep doubling, we can build a primary permanent base in a few years. Then a large number of people will be stationed to develop industrial, agricultural, scientific experiments and scientific exploration activities, make rocket fuels such as liquid hydrogen and liquid oxygen, build space bases flying into deep space, and make the primary lunar manned base develop into a permanent manned base. After the scale continues to expand, the moon can be built into a human settlement.

4. Make Mars another home for mankind.

Space Port —— A Bridge between the Earth and Mars

In addition to building a space city and developing the moon, another close destination for immigrants to space is Mars. From the introduction of the environmental characteristics of Mars, we can know that emigrating to Mars still needs to solve basic problems such as air, water, food, gravity adaptation and radiation protection. Water is the key.

Mars landers and Martian rocks covering semi-underground houses can shield radiation. Whether people can adapt to the gravity on Mars can be verified by experiments. Air, water and food, gravity adaptation and radiation protection. Water is the key. Mars landers and Martian rocks covering semi-underground houses can shield radiation. Whether people can adapt to the gravity on Mars can be verified by experiments. Air, water and food can all be solved by constructing a closed ecological circulation system.

Develop Mars

Scientists have put forward various ideas to transform the entire Martian environment. For example, a large reflector is arranged in the orbit around Mars to reflect sunlight to Mars, thus increasing the temperature of the atmosphere and surface of Mars. At the same time, build a gas production plant on Mars to produce ozone and other gases that can produce greenhouse effect, form a thick atmosphere, resist ultraviolet rays, and further increase the temperature of the atmosphere and surface of Mars. After the temperature rises, the frozen water at the poles and under the surface of Mars gradually melts. In this way, there will be water on Mars. If there is not enough water on Mars, it can be extracted from its two satellites. In the process of transforming the atmosphere and raising the temperature, simple life such as yeast and bacteria can survive and multiply first. Finally, people can live as comfortably as on earth.

Mars base

Developing Mars is the same as developing the moon. First, an outpost will be established on Mars, then it will be developed into a primary base and a permanent base, and finally the entire Martian environment can be transformed.

In the whole process of developing Mars, the traffic between the earth and Mars will gradually get busy. Most of the voyage from Earth to Mars and from Mars to Earth is a space vacuum. It is uneconomical for a spacecraft to take off from the ground and fly directly to Mars through the atmospheric space, and it will consume energy due to acceleration and deceleration. At the same time, many complex requirements and structures of spacecraft flying through the atmosphere are completely unnecessary in the space vacuum environment. Therefore, scientists put forward a mode of transportation by subsection relay.

One idea is to build a spaceport on the gravity balance point (free point) between the earth and the moon in orbit around the earth and Mars. A spacecraft is placed between the orbits of the Earth and Mars, and its orbit is tangent or intersecting with the orbits of the Earth and Mars. People who go to Mars go to the Earth Space Port by spacecraft such as the Space Shuttle, where they transfer to a transshipment ship and fly to the Freedom Point Space Port. After refueling there, fly to the survey ship, rendezvous and dock with it (or dock on the survey ship after rendezvous), fly to Mars together, and after rendezvous with Mars, fly to the space port of Mars by refueling transshipment ship. There, the crew changed to the Mars lander and landed on Mars. The return program is the opposite.

This segmented mode can use the atmosphere of the earth and Mars for braking, and at each space port, the energy of the descending transshipment spacecraft can be transferred to the ascending spacecraft by using the principle of momentum moment transfer to save energy. There can be two crew cabins on the survey spacecraft, which rotate up and down around the survey spacecraft to produce artificial gravity. When going to Mars, it will gradually decrease, so that the crew can comfortably and gradually transition to Mars gravity. When returning, the hovering speed is gradually accelerated, making the gravity gradually transition to the earth's gravity.

5. Five development directions of international manned space flight

Zhang, deputy commander-in-chief of China's manned spaceflight project, believes that at present and in the future, international manned spaceflight will mainly develop in five directions:

The first is the International Space Station. 1998 1 16 countries, mainly the United States, Russia, Japan and European countries, began to build the International Space Station. At present, the work is progressing smoothly and is expected to be completed in 2007. The completed space station weighs 420 tons and has a service life of 10 to 15 years, and can accommodate 6-7 astronauts at most. The research fields of the International Space Station include microgravity processing, life science, space science, earth science, engineering technology experiment and commercial product development.

Second, space-based space flight. The unique nature of geosynchronous orbit determines that satellites in this orbit will provide the most effective application for human services. The way to make full use of orbital position resources is to develop large satellites, but the technical difficulty and cost of ground development are extremely high. The new idea is to develop a large space station into a space base, assemble a large satellite in space, and then send the satellite into geosynchronous orbit by using an orbital maneuvering vehicle. Space base can also be used to maintain and repair satellites to ensure their long-term stable operation.

Third, the moon base. The lunar environment has the characteristics of small gravity, vacuum, sterility, small magnetic field, large temperature difference, long alternation period of day and night, special geological conditions and raw material resources of the earth. The lunar base is expected to become the first activity place established by human beings on an extraterrestrial planet. The activities of human landing on the moon stopped after the Apollo program in the United States, and the voice of returning to the moon in 10 years has become louder and louder. It is predicted that in the next 20 years, mankind will return to the moon, use space and space bases to assemble and maintain the Earth-Moon orbit transport ship, and finally build the moon base.

Fourth, manned landing on Mars. This will be the most remarkable symbol of human exploration spirit in the 2 1 century. Since the 1960s, human beings have started the research on manned Mars flight. Because Mars is far away from the earth, it takes two years and three months to go back and forth to Mars once. During this period, astronauts need hundreds of tons of food, water, air and facilities needed to live and work on Mars. Spacecraft returning from Mars orbit should also be sent to orbit around Mars in advance. Therefore, many technical problems need to be solved. The United States, Russia and other countries have reached an agreement on joint Mars exploration and formulated a manned Mars flight plan, with the goal of achieving manned Mars landing in the next 30 years or so.

Fifth, space tourism. On April 28th, 20001year, Tito, an American aged 6 1 year, flew to the International Space Station on the Russian Federation TM-32 spacecraft, becoming the first space tourist. At present, many enterprises in Russia, the United States, Japan and other countries have put forward various low-cost, reusable suborbital vehicle schemes and stepped up their research and development. In the next 20 years, more people will go into space as tourists, and space tourism will eventually become an industry.

Zhang pointed out that major countries in the world have spared no expense to develop manned space flight in different ways; The depth and breadth of international cooperation in manned space flight are deepening; A large number of space application technologies will be developed to provide a stage for the research of space science such as materials and life. With the development of manned space technology, human's ability to use space resources will be continuously enhanced, and human will realize leap-forward development through the exploration and development of this new field of space.