Extraordinary 20 years on the International Space Station

On October 31, 2000, the Soyuz-U rocket carried the “Soyuz TM-31” manned spacecraft from the Baikonur launch site in Kazakhstan, and on November 2nd with the International Space Station (ISS) Docking, this is the first flight of a long-term expedition team on the International Space Station. At that time, the International Space Station had three large compartments: the Russian “Star” service module, the US “Unity” node module and the “Dawn” functional cargo bay (this was the first component of the International Space Station). Since then, the International Space Station has been in orbit for another 20 years.

The United States first proposed the ISS plan
On November 20, 1998, the “Dawn” functional cargo compartment was carried into space with the “Proton K” rocket, which opened the prelude to the construction of the International Space Station. The International Space Station is jointly developed by 16 countries including the United States, Russia, Canada, Japan, 11 European countries and Brazil. According to the plan, the completed International Space Station will weigh 472 tons, with an average height of 352 kilometers in orbit, and an unfolded area of ​​about 10,800 square meters, equivalent to the size of two football fields. The interior has 1,300 cubic meters, which is equivalent to two. The volume of a Boeing 747 aircraft. The construction of the International Space Station is of great significance. Humans can not only continuously accumulate experience through this, but also lay the foundation for future expeditions to Mars and beyond.

As a multifunctional space research complex, the International Space Station is the world’s largest space program. However, the plan was not a pure space research project at first, but a competition between the two superpowers to defend their dignity. After the end of World War II, the United States and the Soviet Union launched a fierce competition for the program of sending humans into space, which also led to the rapid advancement of human space development. In the 1950s, the American space pioneer Feng? Brown proposed the idea of ​​a large orbital space station. He envisioned a wheel-shaped facility that would slowly rotate to provide artificial gravity for thousands of occupants. However, in the foreseeable future, the concept of such an orbital outpost goes beyond existing technology. On July 29, 1958, the National Aeronautics and Space Administration (NASA) was established and began to consider building a smaller space station.

In 1961, the then-U.S. President John F. Kennedy declared the moon landing as a national goal. Until NASA achieved this goal, the space station program had been of secondary importance. In 1969, US President Richard Nixon commissioned the Space Mission Group (STG) to evaluate the space goals after the Apollo Project. The group proposed to build a space station orbiting the earth in the mid-1970s, and then proposed a more advanced space station. Large-scale space base project. However, this ambitious plan was rejected due to the sluggish economic situation in the United States. In 1972, President Nixon approved the space shuttle project. From 1973 to 1974, the experimental space station SkyLab used the remaining Apollo hardware for experimental flights.

After the 1980s, the idea of ​​developing a “permanent manned space station” was again proposed and gradually developed into the “Freedom” space station program, which is the predecessor of the International Space Station. In 1984, in his State of the Union address, the then President of the United States, Reagan, proposed a plan to build a space base for human life through international cooperation. This was also the first plan in the world to build a prototype of the International Space Station by the United States. However, the political intention of the plan is very obvious, in order to demonstrate the cohesion of Western countries and to compete with the Soviet Union. The plan stipulates that the number of astronauts entering space each year will be allocated in proportion to their contributions. In 1985, 11 European countries joined; subsequently, Canada, Japan and Brazil also joined, preparing to jointly develop this ambitious plan with NASA.

However, the progress of the plan is not smooth. The reason is that NASA’s estimate of the space station is too optimistic, and the huge cost of the “Freedom” space station has overwhelmed the United States. When Reagan approved the space station plan, the construction budget was 8 billion U.S. dollars, and the double keel space station program in the next year has expanded to 16 billion U.S. dollars. In 1987, NASA’s plan to reduce it to a single keel space station was approved, but by 1990 the space station’s budget had soared to 37 billion U.S. dollars. In 1991, the United States General Audit Office issued a report that the total cost of the development and 30-year operation of the “Freedom” space station may reach 118 billion U.S. dollars. However, due to the financial crisis in Europe at that time, the explosion of the “Challenger” space shuttle in 1986, and the gradual disappearance of the political significance of the space station, the “Freedom” space station had to be scaled down again, so plans to build an international space station It was also temporarily shelved. Not only the United States, but European, Canadian, and Japanese astronauts will stay in space for an unpredictable time. On the other hand, despite the fact that the Soviet Union successfully launched a manned mission on the Mir space station, the disintegration of the Soviet Union at the end of 1991 caused domestic turmoil and financial difficulties, making the Mir space station ineffective and aging.

In the absence of sufficient financial resources to sustain the expensive aerospace industry, the United States began to win over Russia. At that time, the United States hoped to integrate the International Space Station program with the Russian “Peace 2” space station, and Russia also hoped to use the support of the United States to complete the launch of the new “Dawn” space station. In 1993, Russia decided to join the cooperation plan proposed by the United States. At the end of that year, the US space shuttle successfully docked with the Russian Mir space station, and the two countries began to cooperate closely. On January 29, 1998, representatives from 16 partner countries including the United States, Russia, European countries, Japan, Canada, and Brazil held a meeting and signed the latest agreement on space station cooperation, which marked the official start of the construction of the International Space Station. However, because Russia has a very strong voice in the International Space Station program, apart from American astronauts, long-term missions are mainly carried out by Russian astronauts.

In November 1998, the first component of the International Space Station, the “Dawn” functional cargo compartment, was launched from the Baikonur space base in Kazakhstan on a proton rocket. After 9 minutes and 48 seconds of flight, “Dawn” No.” cargo hold enters the scheduled orbit. After 14 minutes and 11 seconds, the solar panels at the left and right ends of the cargo hold opened normally and started to work. The cargo tank of “Dawn” is 13 meters long and 3 to 4 meters in diameter, and weighs about 20 tons. It serves as a material storage warehouse. Its external fuel tank can be used to decommission the International Space Station. In addition, the cargo tank also has The function of controlling the orbital height and attitude of the International Space Station. In the initial stage of the construction of the International Space Station, it also provides electricity and fuel for the modules that will enter space later, and plays an important role in maintaining communication with the ground.

On December 4, 1998, the “Unity” node module was launched with the US “Endeavour” space shuttle; on the 6th, the “Unity” docked with the “Dawn”. The “Unity” node module is the second component of the International Space Station. It consists of a cylindrical shell and 6 universal docking devices that can be easily connected to other cabins. It has 6 hatches and is hosted by Boeing Marshall Space. The factory in the flight center was made by NASA and cost about 300 million U.S. dollars.

On July 26, 2000, the “Star” service module was connected to the rear end of the “Dawn” functional cargo bay, becoming the third component of the International Space Station. In late July, the computer on the “Dawn” passed the instructions of the International Space Station to the computer on the “Star”. On September 11, the two astronauts on the space shuttle carrying out the STS-106 mission—Chinese-American astronaut Lu Jie and Russian cosmonaut Yuri Malenchenko, after 6 hours and 14 minutes of extravehicular operations, connected 9 Root the cable between “Star” and “Dawn”. The next day, the astronauts of STS-106 floated into the “Star” cabin for the first time.

The “Star” service module is equipped with early living areas as well as life support systems, communication systems, electronic energy distribution devices, data processing systems, flight control systems and propulsion systems; the two main engines on the cabin can be used to enhance the orbit of the space station height.

On November 2, 2000, the Russian “Soyuz TM-31” manned spacecraft successfully docked with the International Space Station, and three astronauts began to perform a space stranding mission. Since the astronauts of various countries began to perform long-term missions in the last year of the 20th century, the International Space Station has gone through a long and arduous process for 20 years, but it has maintained normal operations.

Preparations for the construction of the International Space Station
The overhead crane accurately and elegantly moved the 10-ton module to the predetermined position, and then the staff began to move, climbed up the structure, and bolted each structure with manual or electric tools…This kind of scene is almost anywhere It can be seen at the construction site. However, the construction of the International Space Station is 250 miles (approximately 400 kilometers) above the earth—a space without air. There, astronauts have to work in the harsh environment of alternating freezing and scorching temperatures every hour-the purpose is to build the “skyscraper” of the International Space Station.

From 1998 to 2011, during the more than ten years of assembling the International Space Station weighing 472 tons, Earth’s orbit became a construction site, and human beings began to move away from the Earth on an unprecedented scale. Since the start of manned flights, astronauts have performed extravehicular operations more than twice as many times as before. They use an inchworm-like robotic arm, a robotic arm like human hands, and a robotic eye that can fly freely around the International Space Station to carry out extravehicular assembly activities. Before the completion of the assembly of the International Space Station, 3 rockets were launched 46 times and more than 100 assembled parts were sent into space. These accessories are either fixed by screws or locks, or connected to each other by wires and ducts, making the International Space Station a huge whole.

Assembling the International Space Station is a work of unimaginable complexity and unpredictable developments and changes. In order to meet this challenge, technicians and astronauts have conducted meticulous exercises on assembly procedures through extravehicular activity tests 10 years ago, such as preparing tools and test equipment, and have accumulated rich experience. From 1998 to 2004, in order to carry out the assembly, equipment installation and research of the International Space Station, NASA carried out 37 space shuttle missions. The astronauts carried out a total of 960 hours and more than 1920 people outside the cabin in about 160 days. This is much longer than the extravehicular activity time of Ed White, the first American astronaut to take a spacewalk in 1964. It can be seen that the assembly speed of the International Space Station has been quite fast in the past few years, and the number of compartments including the European Space Agency’s Columbus experimental module and Japan’s “Hope” experimental module has also been increasing.

As part of the preparatory work, since 1991, NASA has carried out more than 12 extravehicular activities during the space shuttle mission, and through the two missions of the Hubble Space Telescope, it has done the indispensable complex work for the construction of the International Space Station. Ready to prepare. Of course, many astronauts who have experience in extravehicular activities have also learned some new knowledge in the process of assembling the International Space Station in orbit around the Earth.

In Sonny Carter near NASA Johnson Space Center in Houston, Texas, there is a neutral buoyancy laboratory built in 1997. The laboratory has a large swimming pool (the pool is 62 meters long, 31 meters wide, 12.34 meters deep, and can hold 6.5 million gallons of water), as well as a full-scale physical model of the International Space Station, payload, and cruise vehicle. A prototype space shuttle payload bay, which was withdrawn after the space shuttle was decommissioned. Astronauts can simulate the extravehicular activity mission to be performed here.

The flight experiment of the extravehicular activity machine of the International Space Station began with the return of the space shuttle to space after the “Challenger” explosion accident. From April 5th to 11th, 1991, NASA implemented the STS-37 space mission. Astronauts Jerry Ross and Jay Abto completed the spacewalk, the main purpose of which is to plan for a large orbital observatory worth up to 500 million. The US dollar’s ​​second Compton gamma-ray observation satellite turned on a malfunctioning antenna to test carts for transporting people and machinery, as well as astronauts in spacesuits weighing about 170 kilograms while performing activities outside the International Space Station. The increased weight was measured, etc.; Rose also strengthened the functions of new tethers, extravehicular activity tools, tripods, jet-type back clips, space suits, and the movement of bulk items during extravehicular activities.

Assemble the International Space Station
In preparation for the official assembly of the International Space Station, NASA announced in August 1996 that two astronauts, Ross and Jim Newman, would be the first crew members to carry out extravehicular activities to perform STS-88 space missions. In June 1997, NASA designated more than 5 astronauts to perform the extravehicular assembly mission of the International Space Station. So far, all the team members for the first 6 extravehicular assembly tasks are in place. Setting the crew list in advance allows the designated astronauts to have sufficient time to conduct specialized training for the complex and critical task of assembling the International Space Station.

The initial assembly mission of the International Space Station could only be carried out after docking with the space station with the help of a space shuttle, but afterwards the astronauts borrowed spacesuits through the Russian service module for extravehicular assembly work. In NASA’s 9th Space Shuttle Assembly Mission (STS-104), the Quest Joint Airlock was docked with the International Space Station. The airtight cabin consists of two parts, one is the airtight cabin for assembly work from the International Space Station to the outside of the cabin, and the other is the instrument cabin. The instrument compartment can be used to temporarily spend the night for astronauts who are not out of the cabin, and it is also to allow astronauts who are active outside the cabin to fully release the residual nitrogen in the body after returning to the air-tight cabin to prevent decompression sickness.

In addition to the new equipment, tools and ideas for the construction of the space station, extravehicular activities also require the use of enhanced space suits. The spacesuit for astronauts is technically a spacesuit called “extravehicular mobile device”, which can be used for up to 25 extravehicular activities. Although the size can be adjusted and perfected by skilled experts before and after the flight, when the astronauts of the International Space Station encounter a space suit with an unsuitable size, they cannot adjust it immediately, but have to recycle it to the ground before it is adjusted. Further improvements make the astronauts more comfortable to wear. In addition, during the assembly operations of the International Space Station, astronauts performing extravehicular activities have to withstand colder temperatures than those using space shuttles. Therefore, in order to maintain a proper temperature and take in sunlight at the best angle, astronauts cannot arbitrarily. Change posture.

In order to build and maintain the International Space Station, astronauts who are active outside the cabin must work together with space robots. The robotic arm of the space shuttle and the newly equipped robotic arm of the International Space Station have become cranes that accurately move large modules and components. In addition, it is also a mobile lifting platform to help astronauts easily move from one work location to another. The Canadian-made robotic arm on the space shuttle is equipped with a more powerful space vision system, through which astronauts performing extravehicular activities can have a panoramic view of the International Space Station. In the past space shuttle missions (STS-74, STS-80, STS-85) experiments, astronauts manipulated the robotic arm through the video displayed on the laptop computer and a series of annotations.

The new robotic arm called “Space Station Remote Control System” developed by Canada is about 16.7 meters long. Like an inchworm, it can move flexibly on a truss with a total length of about 107 meters outside the International Space Station, covering almost the entire International Space Station. Canada has also developed a special-purpose robotic arm, composed of two small robotic arms, installed at the forefront of the main robotic arm, allowing more complex maintenance operations. In addition, the International Space Station is also equipped with a free-flying camera-an autonomous extravehicular mobile robot AERCam used to check the external conditions of the International Space Station.

Change in use of the International Space Station
Since its completion in 2011, the International Space Station has been in service for a full 10 years. During this period, the International Space Station has conducted more than 1,760 scientific experiments and researches, covering the fields of biology, earth and universe sciences, education and physics. It has obtained a large amount of precious scientific data and made great contributions to the development of human space. . According to the original plan, the service period of the International Space Station will last until 2016, but all countries participating in the development have agreed to extend its use until 2024, and some countries say it can be extended to 2030. However, American astrophysicist Jonathan McDowell said that because the US and Russian compartments are already very aging, they may fail frequently after 2024 and cannot operate normally, so it is not realistic to postpone to 2030.

Considering that the International Space Station will be fully operational and operating expenses, in recent years, participating countries have increasingly advocated converting it to civilian operations, and further promoting the commercial use of the International Space Station. In June 2019, NASA announced the commercial use policy of opening the International Space Station to private companies, intending to resell the right to use the International Space Station to private companies. At 7:27 pm on November 15, 2020, 55-year-old Japanese astronaut Noguchi Satoshi and NASA astronauts Mike Hopkins, Victor Giver and Shannon Walker took the SpaceX together. The new “Resilience” Dragon spacecraft developed by the company was launched by the Falcon 9 rocket from the 39-A launch pad of the Kennedy Space Center in Florida into the orbit of the International Space Station, and successfully arrived at the International Space Station at 11 noon on the 16th. This marked the beginning of the official operation of the manned spacecraft developed by private enterprises, and it also marked the beginning of the “space travel era” in which anyone can realize their dreams in space.

In the heroic twilight years, the International Space Station is about to come to an end, but the pace of mankind’s exploration of space will never stop!