Atmospheric drag as the cause of the secular decrease in the semimajor axis of Lageos's orbit

摘要: An unmodeled acceleration is causing the semimajor axis of Lageos to decrease at rate about 1.1 mm day−1. Drag from charged particles or neutral helium both most probable cause. The orbital decay conceivably explained by theories particle drag. Unfortunately, these are not yet developed point where a definitive statement as importance drag can be made. Neutral may also cause decay. While abundance required account for secular high, it helps solve "helium problem." hydrogen probably accounts no more than 12 percent observed