It is important to note that acceleration is a vector quantity, and the direction of the acceleration has a large impact on the overall efficiency. For instance, gravity drag would reduce a 2.6 G thrust directed upward to an acceleration of 1.6 G, for an efficiency of less than 62%. However, the same 2.6 G thrust could be directed at such an angle that it had a 1 G upward component, completely cancelled by gravity drag, and a horizontal component of 2.4 G, unaffected by gravity drag. Achieving 2.4 G accelerat ...
Atmospheric drag is a form of drag, which is the force that opposes an object moving through a liquid or gas.
In astrodynamics depending on the situation atmospheric drag can be regarded as inefficiency requiring expense of additional energy during launch of the space object or as a bonus simplifying return from orbit.
Atmospheric drag - Calculation.
Atmospheric drag can be calculated as follows:
where: cdIncluding:
For a solid object moving through a fluid or gas, drag is the sum of all the aerodynamic or hydrodynamic forces in the direction of the external fluid flow. It therefore acts to oppose the motion of the object, and in a powered vehicle it is overcome by thrust.
Types of drag are generally divided into three categories: parasitic drag, lift-induced drag and wave drag. Parasitic drag includes form drag, skin friction and interference drag. Lift-induced drag is only relevant when wings or a lifting body are present, and is therefo ...
In astrodynamics delta-v is a scalar measure for the amount of "effort" needed to carry out an orbital maneuver, i.e., to change from one orbit to another. A delta-v is typically provided by the thrust of a rocket engine. The time-rate of delta-v is the magnitude of the acceleration, i.e., the thrust per kilogram total current mass, produced by the engines. The actual acceleration vector is found by adding the gravity vector to the vec ...
Atmospheric drag can be calculated as follows:
where: cd is the body's coefficient of drag (that has to be determined experimentally), A is the body's cross-sectional area, ρ is the air density, and v is the body's velocity.
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