'The higher from the Earth, or gravity, the longer the lifespan,' he explained, adding that having a lower altitude gives Diwata-1 an atmospheric drag
and makes it decay faster.
Ballistic descent uses the atmospheric drag
to slow down the spacecraft - in other words, the atmospheric air resistance pushes up against the falling rocket.
Argonne's research also informs the design and manufacture of exotic composites and ceramics that help hypersonic aircraft withstand the stresses created by atmospheric drag
. It's difficult to predict the behavior of such materials under actual operating conditions.
Tracking the reentry impressed upon scientists the sensitivity of predictions to solar activity, the state of Earth's thermosphere, and atmospheric drag
During the re-entry, atmospheric drag
will rip away solar arrays, antennas and other external components at an altitude of around 100 kilometers (60 miles), according to the Chinese space office.
But space observers are unsure where 8.5-ton spacecraft would land -- it is currently losing altitude at the rate of 6km per week due to atmospheric drag
The governing equation of motion for an uncontrolled space object entering into the atmosphere perturbed by the atmospheric drag
uncertainty but ignoring the lifting force can be described by the following equations with position r and velocity v with their corresponding initial conditions r([t.sub.0]) and v([t.sub.0]) .
The drags sails, each with an area of approximately one square meter, are intended to decrease the ballistic coefficient of the satellite and use atmospheric drag
to accelerate orbital decay.
The atmospheric drag
reduces the orbital energy of the rocket bodies and lowers the orbit until reentry occurs.
The next perturbing force is the atmospheric drag
, a force caused by the friction of the satellite body against the air molecules.
As the vehicle prepares to drop back the Earth, a tube around it should expand like a Hawaiian puffer fish, creating atmospheric drag
to dramatically slow it down from Mach 4, or four times the speed of sound.