Recently, Zhou Jianping, chief engineer of manned space engineering, responded to questions about the difficulty of astronauts leaving the capsule on the Tiangong space station. He said that further outgoing activities will become more and more complex, when we build the space station will put away the core module solar sail board (for ease of writing, hereinafter collectively referred to as "solar wing"), through the coordination of astronauts and robotic arms, it will be installed in another position in the experimental module, such an operation task is much more complicated than the current installation of equipment, the completion of this thing should be a landmark.
Extravehicular spacesuit cameras capture the sky and core module
So, why shift the core capsule solar wing?
First look at the dynamics of Shenzhou XIII, in the astronauts smoothly entered the Flight Control screen of the Tianzhou III cargo spacecraft, you can see that the Tiangong assembly has carried out a rolling posture adjustment, and the radial interface that was originally facing the earth side has turned to the zenith direction, and three days after this event, aerospace photography enthusiasts have also photographed the Tiangong combination of this posture.
The running posture of the Tiangong assembly after rolling and adjusting the posture
A combination of celestial palaces photographed by Spanish space enthusiasts
The rolling posture adjustment is because the solar wing with a large core cabin area will form an occlusion to the solar wing of the Shenzhou 13 spacecraft, thus affecting the power generation capacity of the latter.
The solar wing of the core cabin in the rolling posture adjustment is obviously occluded to the solar wing of Shenzhou 13
Of course, the core reason for the shift of the core capsule solar wing is not only because of the obstruction of the Radial Interface of the Shenzhou spacecraft, but also the problem of the larger experimental cabin solar wing occluding the core cabin solar wing.
The solar wings of the two experimental modules are even larger
Experimental module solar wing ground test
Obtaining electrical energy through the solar wing is an important energy acquisition route for various types of human spacecraft at present, and manned spacecraft are no exception.
Solar wing occlusion has always been a problem that must be faced by the construction of large manned space stations, such as the various modules of the Mir space station are not in the same plane, and the problem of solar wings occlusing each other is very prominent, and therefore 40% of the power generation capacity is lost.
Mir space station
In order to solve this problem, the International Space Station has specially designed a truss with a length of 109 meters, each sealed module is mainly attached to the center of the truss in the form of axial docking, and the 8 solar wings are symmetrically arranged at both ends of the truss, because the spacing is large enough, so the problem of shielding the truss solar wings between each other has been alleviated.
International Space Station
However, the problem of the truss solar wing occlusion of the solar wing of the Zvezda service module was not cured, and the heat sink of the thermal control system interfered with the module of the Aurora, while the truss solar wing and the solar wing of the Zvezda service module and the heatsink formed a shield on the solar wing of the docked spacecraft, and the problem of power generation capacity loss was further aggravated.
The problem of solar wing occlusion on the International Space Station remains prominent
On the other hand, the Tiangong space station has locked in the root of the problem of mutual obstruction of the solar wings from the beginning of the design, which has to start from the design concept.
As the name suggests, the Tianhe core module is the hub of the Tiangong space station, but we did not take the old road of Mir or the International Space Station, but designed a "core assembly" based on the concept of integration, and the three modules (Tianhe cabin, Q sky module, dream module) can be regarded as a more complete "core module".
Three-cabin core assembly ground validation module
This also indicates that the Tiangong space station will not stop at the currently disclosed "three-cabin configuration", and subsequent expansion modules will be expanded on this basis.
The Tiangong space station will continue to grow
The core assembly refers to the Tianhe core cabin + Wentian experimental module + Mengtian experimental module to form a more efficient and unified three cabins of the whole station, specifically in the structure and motion control, information system, energy system, thermal control fluid circuit, manned environment, propulsion system for organic integration.
For example, the energy system, from the perspective of the composition configuration, we have abandoned the old way that the various modules of the Mir space station are not in the same plane, but have innovated the T-shaped configuration in the same plane, and the two large experimental modules are symmetrically arranged in the two or four quadrants of the node module, thus forming a structure with a span of about 40 meters, and the larger experimental module solar wings are at both ends of this structure, thus achieving the truss effect of the International Space Station.
The two experimental chambers will act as trusses
Tiangong space station also innovated the engineering application of two-way power supply technology, first of all, the power supply of the three cabins of the core assembly can be interconnected, the visiting spacecraft can also obtain power energy from the core assembly, and if the core assembly has a power supply gap, the visiting spacecraft can also reverse the power supply core assembly, which is not possible in the past Mir space station or the current international space station.
Both the Tianzhou and Shenzhou spacecraft can reverse power the space station
The solar wing shift of the Celestial and Core Modules is also a concrete practice of the organic integration of the energy systems of the core assemblage, and this pair of solar wings will be transferred to the tail ends of the two experimental module trusses.
The transfer of the solar wing in orbit requires the intervention of astronauts out of the cabin, as Zhou Jianping said, this operation is much more difficult than the task of installing equipment outside the cabin. Throughout the history of human manned spaceflight, similar extravehicular operations have never been done before, which can be said to be a world-class problem.
Day and core cabin solar wing
The core capsule solar wing is based on flexible materials, the texture is gentle, and the length is also very large, the length of the single wing reaches 12.6 meters, the width is about 5.3 meters, and the area is 67 square meters, if you want to directly transfer such a large-size component, even if the robotic arm and astronauts cooperate, it is difficult to do foolproof, so the solar wing must have the function of converging in orbit.
This picture shows the size of the core cabin's solar wing
If you want to close the core cabin solar wing, you need to first look at its "way to come", the core cabin into orbit after the solar wing using the "three-dimensional five-step unfolding scheme", equipped with 6 active mechanisms: first, 15 fireworks detonation, lift the solar wing and the small column segment bulkhead fixation, followed by the lifting mechanism to lift the solar wing from the bulkhead, and then unfold the locking mechanism to expand the two solar cell arrays to the sides, the constraint release mechanism to lift the collection box constraint, and finally the extension mechanism to drive the solar cell wing to fully unfold. The whole process lasts about 40 minutes.
Renderings of the solar wing unfolding process of the day and core cabin in orbit
The core capsule solar wing unfolds in orbit to shoot
As you can imagine, unfolding is already so complicated that it is bound to be even more complicated to close. When the solar wing is shifted to position, the power supply channel needs to be reorganized.
The flexible solar wing development team of the 805 Institute of the Eighth Academy of Aerospace Science and Technology Group refers to this series of operations as "energy expansion functions in orbit", which require close cooperation between extravehicular astronauts, robotic arms, space stations and other parties to achieve.
Renderings of the robotic arm assisting the astronaut to transfer the solar wing of the core capsule
There are many benefits of core cabin solar wing transfer, first of all, it solves the problem of the experimental cabin solar wing occluding the core cabin solar wing, and also solves the problem that the sun wing of the radial port Shenzhou spacecraft is obscured by the core cabin solar wing, and the sun wing exposure rate of each cabin ship of the Tiangong Space Station will be fully optimized.
Core capsule solar wing transfer mounting target position
Under the premise that the sun rate is guaranteed, the power supply capacity of the three-knot flexible gallium arsenide battery with the international leading level of the solar wing configuration will also be guaranteed, and it is precisely because of this that the proportion of scientific research equipment of the Tiangong space station can surpass the international space station, so that the benefits of scientific research output can be maximized.