The effects of greenhouse gases on thermospheric density contribute to an increase in orbital lifetimes. The effects are most pronounced for altitudes higher than 600 kilometers; in many cases, the simulations show that orbital lifetimes could double within the next 20 years even without the greenhouse effects. This is due to near the peak of the 11-year solar cycle. Note that ballistic coefficients 175 and 520 cm2/kg have been omitted for brevity, but follow the same trend. Click on image to enlarge. More »