Q meaning in Space Science ?

In incompressible fluid dynamics dynamic pressure (indicated with q {\displaystyle q} , or Q, and sometimes called velocity pressure) is the quantity defined by:

where (using SI units):

It can be thought of as the fluid's kinetic energy per unit volume.

For incompressible flow, the dynamic pressure of a fluid is the difference between its total pressure and static pressure. From Bernoulli's law, dynamic pressure is given by

where p 0 {\displaystyle p_{0}} and p s {\displaystyle p_{\text{s}}} are the total and static pressures, respectively.