The changes — dP/dt of nodal periods P of four satellites are made the objects of investigations during a common period of 15 months, the satellites being Explorer I, Vanguard I, Sputnik III and Explorer IV. In the first place an elimination of the gradual increase of — dP/dt towards the end of the lifetime of a satellite is attempted by converting — dP/dt into another and more constant quantity y (y equal to — dP/dt times a P-dependant quantity). After that, various factors affecting y—and indirectly affecting — dP/dt—are considered, the factors being a latitude effect, a day-night effect, a southern hemisphere effect, a charged particle effect and finally a cosmic dust effect. This last-mentioned effect, which may be different from a pure meteoric effect, is presumed to be of rather longperiodic and irregular character; however, it must affect various satellite orbits almost contemporarily and in analogous ways. Some evidence of this effect is brought forward, and possible connections with zodiacal light, climate and other phenomena are discussed.


Geomagnetic Activity Satellite Orbit Semimajor Axis Central Meridian Common Period 
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Copyright information

© Springer-Verlag Wien 1961

Authors and Affiliations

  • Asger Lundbak
    • 1
  1. 1.Danish Meteorological InstituteCopenhagenDenmark

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