uggs bestellen Momentum wheel unloading on orbit t

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Momentum wheel unloading on orbit to keep improving things in the GEO satellite applications

vo · m ~ · tanc ~ (21) from (21), we can see the work of unloading thruster, affecting the satellite in orbit, the tangential speed. As thruster installation on the angle of the fixed stars, uninstall control and unloaded weight of a direction west of the thrust has a strict linear relationship, it can be unloaded, the change in momentum wheel speed calculation of GEO satellite orbit to improve things the amount of Aa, can also be used formula (10), calculation of solar radiation pressure to solve the semi-major axis to improve the amount of unloading △ n, but the latter is more complex to do is derived. By (13) and (21) get the momentum wheel speed change and Aa relationship: △ Ⅱ = a [(2a (2 / r a 1 / a )·)/( m · · · z · tanot)] · △ (22) when the earth orbit is nearly circular orbit approximately when, ro, momentum wheel speed changes at this time relationship with the Aa simplified to: / Xa = a 2 [(,[link widoczny dla zalogowanych]。)·· △ vM · cotc ~] / m · Vo-. (23) This is the momentum wheel unloading by changes in the momentum wheel speed calculation of satellite semi-major axis change on a mathematical model. 3 Simulation results of fixed longitude 80.0. Example of a GEO satellite on the type (23) simulation,[link widoczny dla zalogowanych], the satellite is about the daily drift acceleration 0.00036 (.) / D,[link widoczny dla zalogowanych], in orbit to maintain accuracy ± 0.06. When things can get satellite orbit theory to maintain a period of 51 days. Ho = 50N · m · s, Vo = 27600 (.) / S, the momentum wheel speed simulation used the measured data, shown in Figure 6, thrusters 54 single branch work, uninstall 4 times, 4 times the change in momentum wheel speed △ Total 3190r/rain. Figure 62 006 stars in an over in June to August when the saturation drive wheels under the unloading speed of change by (23) semi-major axis can be obtained to improve the amount of unloading, according to the daily drift acceleration 0.00036 (.) / D, will theory of semi-major axis range to keep things and practical things were kept semi-major axis variation, uninstall the change in coupling to fit the semi-major axis, and then to keep things semi-major axis of the range is normalized, the simulation results shown in Figure 9 below. Figure 7 things to keep the actual characteristics of semi-major axis variation of startling violence unloaded coupled Figure 8,[link widoczny dla zalogowanych], the change in characteristics of semi-major axis can be seen from Figure 9, if not the thing to keep the track curve is linear, constant slope east from the satellite orbit drift to the western boundary of the border; if the things to keep, track changes in slope close to zero, and fully intends to drift westward, to ensure that fixed longitude; if only by the (continued on page 82) 11110OOO = unitary} Gu violence. 82. Space control in 2008 (Continued from page 73) to help unload the westward momentum wheel coupling, orbital curve tracks interventions than do the small slope of the curve, and the satellite can not be fully intends to drift westward, but the satellite orbit has improved things volume. To keeping the momentum wheel unloading and semi-major axis of the orbit shown in Table 1. Figure 9 Normalized simulated and compared in Table 1 after the orbital semi-major axis orbit coupling compared momentum wheel unloading nearly 1 / 4 track westward drift, indicating that the momentum wheel unloading slow down the satellite orbit semi-major axis speed of westward drift , extended the things to keep cycle. 4 Conclusion The theory of the momentum wheel speed analysis, a change in use of semi-major axis momentum wheel unloading a new mathematical model based on the actual measurement data, the model simulation have proved that the use momentum wheel unloading improving GEO orbit cycle something to keep the feasibility of three-axis can be generally applied to GEO satellites. Because solar radiation pressure constant cyclical characteristics, momentum wheel unloading must be regularly carried out, so the method for the effective conservation of satellite fuel,[link widoczny dla zalogowanych], extend the service life of satellites and space management of spacecraft in orbit has a very important significance.
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