At 11:06 on February 27, the Long March 8 Yao-2 carrier rocket ignited and took off from China's Wenchang Cosmodrome, successfully launching 22 satellites, refreshing the mainland's "one arrow and multiple stars" launch record!
So, is it not that the more satellites launched, the more they can prove that space technology is great? Let's listen to the answer of Qian Hang, a rocket designer of the first academy of China Aerospace Science and Technology Corporation!
The technical requirements for launching multiple satellites at a time are indeed very high, and only China, Russia, the United States, India, Japan, and the European Space Agency in the world have mastered this capability. But in fact, the number of satellites is not the key, the launch technology is more important.
01 What is "one arrow and many stars"?
The earliest "one arrow and many stars" launch on the mainland dates back to September 20, 1981. On the same day, the Storm-1 carrier rocket successfully launched three scientific experiment satellites, Shijian-2 A and Shijian-2 B. Since then, the mainland has become the fourth country in the world to master the "one arrow, many stars" technology.
The "one arrow, many satellites" technology is a launch technology that uses a carrier rocket to simultaneously or successively send several satellites into the earth's orbit. This superior launch method can make full use of the carrying capacity of the launch vehicle and reduce the cost of satellite launch.
The "one arrow, many stars" technology is divided into two categories
■ Launch all payloads to the same track;
■ Launch different satellites into their respective orbits.
The requirements for launch vehicles are different for these two types of launches. The first type of launch mission is that after the last substation of the launch vehicle is shut down, it is only necessary to release the load carried in turn. Among them, the main issue to consider is to avoid collisions after the release of each load. This problem is actually not difficult to solve, as long as there is a slight difference in speed when releasing satellites, or a slightly different release time, each satellite will generally drift farther and farther, because the relative speed at the time of release is not large, even if the collision will not produce a large amount of debris.
For the way to launch multiple satellites into different orbits, it requires the launch vehicle to have the ability to change orbits after entering the initial orbit, which is not something that conventional launch vehicles can do.
One arrow and many stars
The mainland has done many times in practice
On June 25, 2016, the Long March 7 rocket successfully flew for the first time. This launch, the Expedition No. 1 A upper class also successfully achieved its first flight. After separating from the Long March 7 rocket, the expedition 1 A upper stage "ferryed" a total of 5 kinds of 6 different needs of the payload to different orbits, and carried out the on-orbit demonstration and verification of new technologies such as the new generation of spacecraft shrinkage return module, multi-satellite orbit deployment, on-orbit refueling, and cubestar.
The Long March 7 rocket flew for the first time
02 The main load must be well taken care of
In general, launch vehicles have a main payload for each launch mission. The main payload can be one satellite or multiple satellites, but generally not too many. Each launch mission of the launch vehicle is basically carried out around the main payload, that is, the target orbit, launch window, etc. are basically determined according to the requirements of the main payload. The load can only be determined to carry it if it can work on such an orbit.
The requirements of the main payload for launch are generally more complex than those carried on board. Before launch, the main payload is generally required to perform a lot of tests on the launch tower, and the wired or wireless test channel is generally guaranteed from the launch tower to the control center.
In addition, in many cases, the fairing of the launch vehicle is required to have a transmission window made of non-metallic materials, so that the measurement and control signal of the main load can be reliably exchanged with the ground station before and during launch of the launch vehicle.
Long March 11 rocket star arrow docking
Before the launch of the launch vehicle, the researchers have to carry out a lot of static and dynamic analysis to ensure that the load can withstand the harsh mechanical conditions during the launch of the launch vehicle, and if necessary, the joint vibration test of the star and arrow will be carried out to ensure that there is no problem.
For the load, it will not be "taken care of" so thoughtfully. In many cases, there is no signal interface between the payload and the launch vehicle, but when the load is released, the satellite is told through a device such as a stroke switch that it has entered orbit and can start work.
The general launch mission will be the first to release the main load, before that, the launch vehicle in the acceleration process, if the load on the load falls off or resonates with the rocket launch, it will also affect the safety of the main load, so the requirements for the load is also to not affect the safety of the main mission as a premise.
03 Carrying tasks will become the norm
With the rapid development of electronic components and satellite payload technology, the functions of satellites are becoming more and more powerful. Micro-nano satellites weighing only a few kilograms to tens of kilograms, or even smaller leather satellites, can accomplish many tasks that only large satellites used to be able to complete.
In this type of satellite, a considerable part of it is made of cheap commercial devices, and its launch cost is relatively expensive. Therefore, such satellites are also more inclined to use the on-board mode to launch into orbit. In general, they are not very "picky" about the type of track, and the requirements for the accuracy of the orbit are not high. After the launch vehicle has completed the release of the main payload, the use of the remaining carrying capacity to carry as many micro-nano satellites into orbit has become a common phenomenon in recent years.
Among these moons, Cube Star became a very important and popular standard star. They follow standard dimensional specifications and mechanical and electrical interfaces. At present, the universal CubeStar release device can achieve no adverse effects and interference on the main load.
Source: China Aerospace Science and Technology Group's official WeChat public account
Text/Yang Yuguang, Li Shujiao, Fu Yifei
Editor/Yang Sishuang
Audit/Yang Jie
Executive Producer/Xu Chunmei