The scientists from the Harbin University of Technology and Taiyuan University of Technology in China have developed a new design for large-scale space solar panels based on an inflatable space truss, which after its deployment in orbit, forms a rigid frame and significantly raises the solar panels’ resistance to bending and vibration. The inflatable elements allow the scientists to compactly place the structure inside a launch vehicle and then deploy it to the dimensions of hundreds of meters after orbit insertion.
As space technology advances, the size of solar panels is constantly increasing. It is especially important for the projects of orbital solar power plants, which could one day start collecting solar energy in space and transmit it to Earth. However, as solar panels increase in size, they become increasingly flexible. Even a slight rotation of a satellite can cause strong vibrations in the structure, which can persist for a long time.
To address this challenge, the scientists considered two options for strengthening the solar panels. The first involved installation of several long inflatable beams behind the panels. The second involved creating a complete space truss, reminiscent of the bridge frame or a building structure.
First, the researchers manufactured and tested a 4-meter-long prototype. It was found out that the inflatable beams indeed increased the structural rigidity: the fundamental natural frequency increased by approximately 21%. However, calculations showed that this effect was insufficient for truly large systems.
Therefore, the scientists simulated operation of a solar array over 150 meters long. It turned out that installation of inflatable beams made virtually no difference: the fundamental oscillation frequencies increased by less than 2%, which had virtually no impact on the structural stability.
A spatial inflatable truss showed significantly better results. Without diagonal braces, it increased the fundamental oscillation frequency by approximately 13 times compared to a conventional solar array. Adding of diagonal braces further increased the structural rigidity: the first six natural frequencies increased more than 2.6 times compared to a truss without braces.
The scientists also tested behavior of the system during the satellite maneuvers. In the model, the apparatus rotated 10° after which the solar array began to oscillate. Calculations showed that a spatial truss not only reduces the vibration amplitude but also allows the structure to return to a stable state more quickly. The additional use of damping materials accelerates attenuation of vibrations even further.
According to the researchers, the proposed technology might be used in construction of future orbital solar power plants, large communication antennas, and other ultra-large space structures.
