Why do rockets launch at night?

Question 1: Why does the rocket launch at night have nothing to do with day and night, but with the weather? It may be windy and rainy during the day, but not at night, so it will be launched at night. When the weather is fine and when to launch.

What do you mean it wasn't an exploding rocket that hit the wall? You mean missiles? wipe the sweat away

Question 2: Why do satellites always launch at night? Pay attention to the launch of these spacecraft, we can see that their launch time is late at night at the end of the year and the beginning of the year. In fact, all the satellites launched by China in the past were launched at night, either before midnight or after midnight. Some students may ask: Why do spacecraft and satellites launch at night? Wouldn't it be more convenient to launch satellites during the day?

Facts have proved that choosing the launch time of the spacecraft is very particular. Due to the limitation of the carrying capacity of the launch vehicle, the capacity of the battery it carries is limited. If the satellite reaches an altitude of tens of thousands of kilometers and the sun shines on more than 1 1,000 solar batteries with the largest included angle, the solar batteries can take over the work of the batteries, so that the satellite can obtain inexhaustible energy. However, if the satellite is not launched at the best time at night, the satellite will not be able to receive solar energy at the best angle in the morning and at night, and the satellite will not work normally. On the other hand, this is also to let the optical tracking and measuring equipment on the ground capture the tracking target. There is a simple reason. In the dark night sky, the launch vehicle flying into space with flame is very conspicuous and prominent.

Why do some satellites launch in the first half of the night, while others launch in the second half of the night? This is related to the type of satellite launched, the set orbit and its distance from the earth. China Fengyun-2 meteorological satellite has an orbital altitude of 35,800 kilometers, and its launch time is over 8 pm. Shenzhou spaceship has a higher orbital altitude, and its launch time is set at 65,438+0 am. Because of the high altitude of the satellite, the time to receive the maximum angle of the sun can be advanced, and the function of solar cells will play an early role.

So, why launch a spaceship in the cold winter? This is because China's TT&C network in space will be TT&C managed and recycled after the launch of the spacecraft. This TT&C network consists of several domestic TT&C stations in Chinese mainland, TT&C stations abroad and four ocean-going space survey ships named "Roy" in China. Since there are no monitoring points in the southern hemisphere, this task can only be completed by four ocean-going survey vessels. However, the summer climate conditions in the southern hemisphere are relatively stable, and there are fewer waves in the ocean. In order to facilitate the monitoring and work of ocean-going survey vessels, shenzhou spaceship's launch time is chosen in autumn and winter, which is just the opposite of the southern hemisphere.

The choice of satellite launch time has profound scientific reasons.

Question 3: Why do you choose to launch rockets and space shuttles at night? The "time" here actually refers to the "launch window". The so-called "emission window" is caused by the movement of the earth and other stars themselves. In fact, for the launch vehicle itself, there is no strict launch window limit and it can be launched at any time. However, in the launch test of launch vehicle, it is generally chosen to launch in the evening or before dawn. Because the sun is near the horizon at this time, the sky at the launch site and the rocket flight area is dark, and the rocket will be irradiated by sunlight after it is ignited to a certain height, which makes the arrow body reflecting sunlight form a great contrast with the background sky, so that the optical tracking and measuring instrument on the ground can clearly track and measure the flight trajectory of the rocket, observe the attitude and external image of the rocket in flight, and the tracking and measuring effect is better. But when the launch vehicle is used to launch spacecraft, it can't be too casual. Because each spacecraft undertakes different tasks and the instruments and equipment installed on the spacecraft have different requirements, they put forward various requirements and restrictions on the launch window, and these requirements sometimes contradict each other. Therefore, when choosing the launch time, we must consider various requirements and choose a more suitable launch time after comprehensive balance. The main factors that affect and limit the launch time are: 1. The need for ground observation. Lighting condition requirements for ground targets. Requirements for lighting conditions of solar cell wings on spacecraft. Requirements of spacecraft 5 for attitude measurement equipment. Requirements for lighting and meteorological conditions when spacecraft returns to the ground. In addition, the requirements of satellite orbit accuracy and the relative position of the target celestial body and the earth also require careful selection of the launch window. For example, when launching probes to the moon, planets and other stars, they must be launched when the earth is in a favorable relative position with the target celestial body to be detected. However, when launching a space probe, the launch window width is generally wide, and some can be calculated in days. In a word, the launch window is determined according to the spacecraft's own requirements and various external constraints. Because the relative positions of the sun, the earth and other stars are constantly changing, even if spacecraft of the same type and orbit are launched, their launch windows are not fixed. Knowing this truth, people will not be surprised. Spaceships are launched sometimes in the morning, sometimes at night, sometimes during the day and sometimes at night. Here, it should also be mentioned that if the launch vehicle fails temporarily or misses the launch window due to weather and other reasons, it can only wait for the next launch window. When some spacecraft are launched, there are multiple windows in a day, and some wait only a few days or more before launching. -From the Internet. . .

Question 4: Why do rockets launch at night? Not necessarily, it depends on the window time.

The launch window refers to the appropriate time range for the launch of the launch vehicle (that is, the time range allowed for the launch of the launch vehicle). The size of this range is also called the width of the emission window. The width of the window is wide or narrow. The width is calculated in hours or even days, and the width is only tens of seconds or even zero. The launch window is determined according to the spacecraft's own requirements and various external constraints. Because the relative positions of the sun, the earth and other stars are constantly changing, even if spacecraft of the same type and orbit are launched, their launch windows are not fixed. Knowing this truth, people will not be surprised. Spaceships are launched sometimes in the morning, sometimes at night, sometimes during the day and sometimes at night.

Question 5: Why do rockets launch at night? Why did you choose to launch a space rocket at night? The main reason is the continuous tracking of rockets. It is easy to observe and track the rocket's tail flame in the dark environment at night, and the temperature at night is lower, and the infrared signal of the rocket is stronger, which is easy to track.

Question 6: Why launch a rocket? It doesn't matter whether shenzhou spaceship is at night or at night. Mainly consider the weather conditions over the launch site to ensure the launch safety of the spacecraft. In addition, military and political influence may also be considered.

Generally speaking, there is no need to consider any solar energy during the launch of spacecraft, which means that synchronous communication satellites in operation only consider their own energy needs. The precision instruments of spacecraft and satellites are encapsulated in the fairing of the rocket and will not be damaged by solar radiation and cosmic radiation. The distance between the orbit and the earth is related to the geographical latitude of the launch site and the fuel used to launch the rocket, but it has nothing to do with the launch time. put on file

Question 7: Why did China's rocket launch the Shenzhou VII manned spacecraft in 10? The main reason is that from a technical point of view, in order to ensure the success of astronauts' extravehicular activities. Zhang Jianqi, deputy commander-in-chief of China's manned spaceflight project and the general command of "Shenzhou VII" mission, pointed out that for the Shenzhou VII astronauts to leave the cabin, it is first assumed that the astronauts will leave the cabin on the sunny side to ensure the safety of the cabin, and at the same time, the downloaded images will be clearer. We also hope that when the astronauts return, it will be as daytime as possible. After a lot of calculations, it will be launched before the end of September, which will ensure that the sunny side will leave the cabin and it will not be too dark when returning. According to the planned window from September 25th to 30th, if the launch time is selected at around 9: 00 p.m. 10, the astronauts can be ensured to disembark on the sunny side and return at around 5: 40 p.m., and it will not be too dark, which can ensure the astronauts to return more safely.

Why do astronauts leave the cabin on the sunny side, that is, on the side of the spacecraft that can receive sunlight? Because few people leave the earth's surface, it is impossible for people to imagine the temperature of space from the temperature of the earth's surface. The height of Shenzhou VII spacewalk is nearly 400 kilometers from the earth's surface. Space is dark, and interstellar space is equivalent to a vacuum, so nothing can reflect sunlight. What is the temperature in space? About 3K, which is nearly 300 degrees below zero, now you know one of the functions of astronauts' thick spacesuits.

When Shenzhou VII is in the dark without sunshine, the temperature will be as low as-150℃, while when shenzhou spaceship flies to the sunny side, the temperature will be as high as 150℃, which is the main reason why astronauts choose to leave the cabin in the sunny side. Why did you choose September 25th? Because the startup window after entering 10, especially after the middle of 10, is very narrow, which is not conducive to startup and recovery. In addition, around the autumnal equinox, the solar activity is more intense, which also has a negative impact on TT&C communication of spacecraft. According to the analysis of meteorological data for many years, the weather in Jiuquan Satellite Launch Center is mainly sunny at the end of September, especially in the evening, which is very suitable for spacecraft launch. What is the "launch window" mentioned here? The launch window refers to the appropriate time range for the launch of a launch vehicle. The size of this range is also called the width of the emission window. The width of the window is wide or narrow, and the width is calculated in hours or even days; The reduction is only a few tens of seconds or even zero. Launching a spacecraft is just like going out, but it is only "going out" under the highest modern technology. As mentioned above, one of the conditions of the "launch window" is to ensure that the astronauts get out of the cabin on the sunny side. In fact, many conditions are also affected by sunlight. For example, the requirements for the lighting conditions of solar cell wings on spacecraft. At present, most spacecraft, such as satellites and manned spacecraft, are powered by solar cells. When the spacecraft enters the orbit, the solar cell needs to be irradiated by sunlight to generate electricity for the spacecraft immediately. There are also requirements for attitude measurement equipment on spacecraft. Attitude measurement devices on spacecraft, such as infrared horizon and sun sensor, need the spacecraft, the earth and the sun to be in a good relative position to measure the flight attitude of the spacecraft, which is also a factor to be considered when selecting the launch window.

Question 8: Why do domestic rockets mostly launch at night, while American space shuttles mostly launch during the day? Not necessarily. Can't you see there is day and night? Because the rocket launch needs to be carried out with the window open, generally considering the orbit of the launched detector or satellite, it needs to fly in the direction of the earth's rotation. (Hope to adopt)

Question 9: Why do most domestic rockets launch at night, while the late-launch rocket selected by the United States for launching the space shuttle can mainly track the rocket in the dark environment at night, and it is easy to observe the trajectory of the rocket tail flame, and the infrared signal of the rocket is stronger at night.

Question 10: Why launch a rocket at night? This has nothing to do with day and night, but it has something to do with the weather. It may be windy and rainy during the day, but not at night, so it will be launched at night. When the weather is fine and when to launch.

What do you mean it wasn't an exploding rocket that hit the wall? You mean missiles? wipe the sweat away