تلخیص
In general estimated constant drag coefficient is
used for the dynamic modeling of satellites in an orbit. This
causes uncertainties in the prediction of satellite orbital
perturbations. In the past few decades, seldom requirement
is being observed in the precise determination of the drag
coefficient of spacecraft. It was justified because of lack in
the experimental validation of the theory. However, with the
advancement on new atmospheric models of enhanced
accuracy have abled a better classification of the drag force.
The standard fluid dynamics computational techniques
based on Navier-Stokes equations and empirical codes for
aerodynamic computations are valid only in the continuum
region. For altitudes more than ~ 120 km, the atmosphere is
rarefied and the transport terms in the Navier-Stokes
equations of continuum gas dynamics fail due to insufficient
collision between the molecules. This happens when
gradients of the macroscopic variables become so steep that
their scale length is of the same order as the average
distance travelled by the molecules between collisions, or
mean free path. To accurately predict the aerodynamic
characteristic of satellites flying at such higher altitudes, the
available numerical techniques are discussed and presented
in detail. The results computed based on these models are
compared with the DS2V code by GA Bird. In order to see
the effect of drag coefficient with different velocities and
altitudes, simulations have also been done for a satellite in
low earth orbit initially at 300 km altitude.
Abdul Majid, Muhammad Naeem Owais, Muhammad Nauman Qureshi. (2018) Aerodynamic Drag Computation of Lower Earth Orbit (LEO) Satellites, Journal of Space Technology , Volume 8, Issue 1.
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