Research Of Magnetic Technology For The Bias Momentum Satellite With Gravity Gradient Boom In Powered Flight Phase

China's spacecraft-level electronic components for aerospace applications mainly rely on imports。Abroad to break the blockade and embargo of China's technology, equipped with pilot countries to develop small satellites, the reliability of critical components for domestic in-orbit testing and certification. Magnetron conditions and use gravity gradient boom and bias momentum wheel as actuators not only reduces the quality and size of the satellite, but also make the three-axis stabilized attitude control system with high accuracy.This paper, under the conditions of magnetic study the method of how the gravity gradient stretch and bias momentum wheel startup to the nominal speed.Firstly, establish three actuators'mathematical model and described their's working principle.And then study the method of gravity gradient boom's stretching program. Proposed two major research programs under the conditions of magnetic. One is designed fixed speed to stretch gravity gradient boom. To finish the process of the stretch gravity boom at the special stretching speed. And demonstrated the feasibility of the design by simulation . The second is at the condition of magnetic moment and the star's attitude angle and angular velocity to finish the the stretching of gravity gradient boom by logical attitude feedback loop. The speed of the gravity gradient boom is based on attitude angles and attitude angular velocity changes in real-time change. Reasonable designed to stretch boom speed of gravity gradient, Ensure that the process of the stars in the extended posture and stability, and compare the two method of gravity gradient boom's stretching.Next, study the method for the start up the speed of the bias moment wheel, that installed at the pitch-axis. If the wheel is suddenly spun up to its nominal speed, the large momentum produced together with the existing momentum due to the nominal rotational motion will result in a high disturbance and unstable motion. Finish the start up of the bias moment wheel's speed at the condition of the magnetic control. Avoiding the disturbance when the wheel increased its RPM. Based on magnetic moment saturation limit designing the method of momentum wheel spin speed. Finally ,analysis the various operating modes'characters when the stars in orbit attitude control . From the simulation to test and verify the design of is right and can be applied on the attitude control of the stars. A proposed strategy to startup the wheel show that its pitch momentum wheel can startup successfully to its nominal speed from rest. And the gravity-gradient boom can stretch to its length. And the the star can be stabilized finally.