my country’s largest flexible solar wing debuts on the space stationFly into the homes of ordinary people
Caption:Two pairs of large flexible solar cell wingsIt is an uncompromising “source of energy” for my country’s space station Source/Xinhua News Agency
If you have an astronomical telescope at this moment, please point its lens at the Chinese space station in space, and you will see two large and two small orange light and shadows, becoming a beautiful landscape in space. These four orange lights are the two pairs of large flexible solar cell wings in the Tianhe core module and Wentian experimental module of the space station. The level and functional performance indicators are also among the best, and it is an uncompromising “energy source” for my country’s space station.
Big size, light weight, high energy
This large-scale flexible solar wing is not the first appearance of this type of product in my country. The Tianhe core module of the space station successfully launched on April 29, 2021 has applied my country’s first large-scale flexible solar cell wing, with an unfolded area of 67 square meters, equivalent to a The size of a standard singles badminton court. After more than a year, this area has been refreshed by his brother Wentian’s experimental cabin. It is equipped with 2 “wings” with a single-wing expansion area of more than 134 square meters, and the power is as high as 18 kilowatts. It is a veritable plus version, with 4 Such solar cell wings can provide 80% of the energy of the three-cabin combination of “Tianhe + Wentian + Mengtian” after the space station is completed.
Although the plus version of the solar wing is a big man, the designers of the Eighth Academy strictly controlled its weight. The solar wing substrate on which the solar cells are pasted is made of ultra-thin and lightweight composite materials, and the thickness of the adhesive layer used to protect the space environment is applied. Strict control is also carried out. Compared with the traditional rigid and semi-rigid solar wings, the thickness of the flexible wings is only 18 cm when fully folded, which is equivalent to the length of a mobile phone and only 1/8 of the rigid solar wings. Only by strictly “slim down”, it can fly into space on the Long March 5B together with the experimental module.
Lose weight, lose volume, but not lose function and energy. After the Wentian experimental module is in orbit, various scientific instruments such as astronomy, geography, biology, and medicine will work one after another. At the same time, the daily life of the astronauts is also inseparable from energy. In summary, the three astronauts work and live in one day. The power consumption of the solar cell is expected to be about 320 degrees. The traditional rigid and semi-rigid solar cell wings cannot meet this demand due to the limitations of volume, weight, power and other factors, while the flexible wings are small in size, large in deployment area, and high in power-to-weight ratio. , 18 kilowatts of electricity can fully guarantee the daily life of astronauts in the space station while satisfying the normal operation of all equipment in the cabin.
80-minute three-dimensional seven-step unfolding: the debut of secondary unfolding technology
For the aircraft, the successful entry of the carrier rocket into the predetermined orbit is only “a hundred miles and a half ninety”, and the successful in-orbit deployment of the solar wing is an important symbol of the successful launch of the mission.
The solar wing of the Wentian experimental cabin will adopt a three-dimensional seven-step movement and unfold in two stages. The whole process will last for 80 minutes, which can be said to affect the designer’s heart every minute. Why did the world pioneer the key technology of “secondary deployment”? Mainly to ensure the absolute safety of the key action of rendezvous and docking. During the rendezvous and docking process, two dozens of ton spacecraft move at a speed of about 7.9km/s. It is necessary to precisely control their position, speed and attitude to ensure reliable docking. If there is a slight deviation, the spacecraft will collide . If the solar cell wings are fully unfolded, the experimental cabin is like holding a huge sail in each hand. A slight shaking will seriously reduce the control accuracy of the experimental cabin’s speed, relative position and flight attitude, and the control difficulty will increase exponentially.
The design team of the Eighth Institute has broken through the key technology of “secondary deployment”. In the independent flight stage after the launch of the experimental cabin, the flexible solar cell wing first deploys a part of the panels to meet the energy demand of the experimental cabin, which can reduce the difficulty of flight control and make the rendezvous and docking stable. Again. After the docking is completed, the full deployment is completed again to establish a complete energy system.
In the three-dimensional seven-step movement, five movements are implemented in the “first deployment”, which lasts about 30 minutes. Figuratively speaking, the solar cell wing performs a standard set of “broadcast gymnastics” movements in space: first, the pyrotechnic “warm-up exercise” is detonated to release the fixation of the solar wing; The bulkhead stands up; then, the locking mechanism “chest expansion motion” is deployed to expand the two solar cell arrays to both sides; the restraint release mechanism “swivel motion” releases the restraint of the storage box; finally, the “stretching motion” of the extension mechanism is well-organized. Push open 20 battery boards in sequence.
After the rendezvous and docking is completed, the “second deployment” process begins, which lasted 50 minutes. The restraint release mechanism appeared again, and the unique secondary unlocking device of the solar wing of the experimental cabin released the restraint for the remaining 64 panels, showing the world The original flexible wing secondary deployment technology. The extension mechanism is still as stable as a mountain, and it stretches longer and longer like a golden hoop, until the 100-square-meter big man is fully unfolded.
During the entire unfolding process, several stretching mechanisms are pushed out in turn, driving the solar wings to unfold outwards, like an accordion being slowly opened, playing its wonderful movement in the universe. In order to achieve safe, reliable and one-time successful deployment, the flexible wing development team of the Eighth Institute has undergone many program demonstrations and conducted a large number of high and low temperature and load deflection tests on the ground, thus ensuring that the stretching mechanism also has repeatable deployment in space. At the same time, the high rigidity and high strength of the extension mechanism can fully support the flexible wing to maintain a stable attitude and fly freely during the flight.
“Silk fan” rotates with two degrees of freedom in space
Compared with the flexible wing of the core cabin, the flexible wing of the Wentian experimental cabin has another difficulty, that is, it needs to achieve dual-degree-of-freedom orientation to the sun in the axial and radial directions. According to the “T-shaped” configuration of my country’s space station, the core module is in the T-shaped “vertical” position, and the Wentian experimental module and the subsequent Mengtian experimental module together form the T-shaped “horizontal”. After the successful launch of the Wentian experimental module, it will first meet and dock with the core module in the “vertical” direction to form an “I-shaped” combination. At this time, the sun and the combination are in the same orientation, and the solar cell wings only need to be in the axial direction for a few days. Rotate at an angle to ensure that the sunlight hits the solar cells perpendicularly. Follow-up, according to the mission process, the Wentian experimental module will rotate to the side of the core module to form an “L-shaped” configuration. As the assembly runs in a circular orbit, the position of the experimental module relative to the sun has been changing, and this change occurs. In order to eliminate the deviation of the solar azimuth and receive the maximum range of solar incidence, the solar wing needs to rotate a dozen times in the radial direction every day, which is really a great test for the large and thin solar cell wings.
The two solar cell wings have a total area of more than 268 square meters and a thickness of only 0.7 mm. Controlling such a large solar cell wing is like dancing two huge fans in space. This fan is made of silk that is as soft as water. Said, any bells and whistles can make it sway. In addition to the control of the configured drive device, the tensioning mechanism on the solar wing is also indispensable.
It looks like a simple wire rope on the outside, but it is actually a set of constant force spring rope system. Through its continuous expansion and contraction, it can ensure sufficient stiffness and attitude control of the solar wing in the complex environment of space. In order to ensure the “safety” of the solar wing during its in-orbit service, the team has completed 400,000 thermal vacuum fatigue life tests and 1 million normal temperature and pressure life tests on the ground after years of research, which fully verified the high reliability and long life of the product.
Xinmin Evening News reporter Ye Wei correspondent Cheng Lei Hu Fangfang
