Le 19/02/2015 03:53, Mike Horvath a écrit :
> I'm building a bubble around my spaceship to protect from "drag" at
> interstellar velocities. This site says that for subsonic craft a
> parabola is a better shape for the nose. However, an ogive is better at
> supersonic speeds.
> 
> http://www.aerospaceweb.org/question/aerodynamics/q0151.shtml
> 
> Which applies in outer space? Or, should I not use either and use a
> teardrop shape instead?

Imho, the shape is proportionally relevant to the pressure and its
differential (between front and rear). if the spaceship never has to
experience an atmosphere, the shape is irrelevant, only the
cross-section might give a resistance to the solar-wind: it can be a
brick or a sphere, the difference would be in the generated torque, and
hopefully the engine(s) have far enough power to make that influence
negligible.

The density of hydrogen atom in outer space is variable, but the
pressure is in the nano-pascal ( 10^-9 ) range, and we live in
kilohecto-pascal ( 10^5 ), so the influence of the drag is to be
corrected by at least something like a 10^-14 factor.

The far more concerning problem is the difference of temperature between
sunlighted and non-sunlighted surfaces. Ask a comet about it.

Post a reply to this message