ARISSat-1 Height Profile

The following graphs show the decrease in average height (km) of ARISSat and the fall rate (km/day) since the launch on 08/03/2011 and until 21/11/2011. The calculations are made by me from the daily Keplerian data. It is clearly visible the irregularity of the fall rate, due to variations in solar flux, which cause variations in the density of the atmosphere and therefore in drag.

The blue graph is the mean height h=(perigee+apogee)/2 calculated from keplerians at intervals of 5 days.

The red graph is the rate of h change from the blue graph for each interval dt of 5days : y=dh/dt and x=date. This is only a simple calculation to just have an idea of how the h decay rate is increasing with time.

73 de Roland PY4ZBZ

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