PERTURBASI ORBITAL PADA SATELIT LAPAN A2 DAN LAPAN A3 AKIBAT VARIASI KERAPATAN ATMOSFER SAAT TERJADI BADAI GEOMAGNET KELAS KUAT

• Main Author: Iftirul Mahlidah, Faiq
• Format: Final Project
• Language: Indonesia
• Subjects: Astronomi
• Online Access: https://digilib.itb.ac.id/gdl/view/47762
• Institution: Institut Teknologi Bandung

Determination of orbit and propagation for satellites operating in low Earth orbit (LEO) need to consider the effects of atmospheric drag, which depend on solar activity expressed in index F10.7 and geomagnetic activity expressed in index Dst. Atmospheric density data used the atmospheric model MSIS-E-90. The analysis of the orbit disturbance on the LAPAN A2 and LAPAN A3 satellites due to variations in atmospheric density when strong class geomagnetic storms occur, precisely on September 7, 2017 and August 26, 2018, was carried out by the author in this final project. From the results of data processing it is known that a decrease in the value of the F10.7 index causes the value of the atmospheric density to go down. As with the Dst index which tends to fall causing an increase in the value of atmospheric density. When a storm occurs, the LAPAN A2 and LAPAN A3 satellites experience a change in the orbit element. However, LAPAN A3 satellites which have polar orbits are more sensitive to storm impacts so that satellites experience an increase in orbital anomalies. The LAPAN A3 satellite with its polar orbit also experiences a decrease in value of semi major axis faster than the LAPAN A2 satellite which has an equatorial orbit. For eccentricity changes, both satellites have nearly circular orbits so the eccentricity values of the two satellites do not change much. In addition, satellites with lower altitudes will have higher ballistic coefficient values, causing satellites to experience altitude decay faster, in accordance with atmospheric density which increases as altitude decreases causing the value of drag acceleration to increase.