Calculating Elliptical Orbit Points & Flight Path Angle

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Discussion Overview

The discussion revolves around determining the points on an elliptical orbit where the speed matches the local circular orbital speed and calculating the corresponding flight path angle at these points. The scope includes theoretical and mathematical reasoning related to orbital mechanics.

Discussion Character

  • Technical explanation
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant asks for guidance on the equations needed to find the points on an elliptical orbit where the speed equals the local circular orbital speed.
  • Another participant provides equations for the velocities of elliptical and circular orbits and suggests equating them to find values for \(r\).
  • A participant states that the velocities are the same at the periapsis and apoapsis, and presents the equation for the flight path angle.
  • It is noted that at periapsis, the flight path angle is 0, and at apoapsis, it is \(\pi\), raising a question about whether these are the complete solutions.
  • A later reply confirms the previous assertion about the angles but expresses uncertainty regarding the method used, indicating a desire for further insights from other members.

Areas of Agreement / Disagreement

Participants generally agree on the points where the speeds are equal (periapsis and apoapsis) and the corresponding flight path angles. However, there is uncertainty about the method and completeness of the solution, indicating that the discussion remains unresolved.

Contextual Notes

There is a lack of clarity regarding the algebraic steps taken to arrive at the conclusions about the flight path angles, and the discussion does not fully resolve the implications of these findings.

Dustinsfl
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Determine the location of the point(s) on an elliptical orbit at which the speed is equal to the (local) circular orbital speed. Determine the flight path angle at this location.

What equation(s) should I be using or thinking about for this?
 
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dwsmith said:
Determine the location of the point(s) on an elliptical orbit at which the speed is equal to the (local) circular orbital speed. Determine the flight path angle at this location.

What equation(s) should I be using or thinking about for this?

Hi dwsmith, :)

The velocity of an object in elliptical orbit is given >>here<< and that of a circular orbit is given >>here<<. So by equating two speeds you will be able to find values for \(r\). The equation for the flight path angle is given >>here<<.

Kind Regards,
Sudharaka.
 
Sudharaka said:
Hi dwsmith, :)

The velocity of an object in elliptical orbit is given >>here<< and that of a circular orbit is given >>here<<. So by equating two speeds you will be able to find values for \(r\). The equation for the flight path angle is given >>here<<.

Kind Regards,
Sudharaka.

So the velocities are the same on the semi-major axis. That is, on the periapsis and apoapsis.
The flight path angle is giving by
$$
\tan\gamma = \frac{e\sin\theta}{1 + e\cos\theta}
$$
At periapsis, the angle is 0, and at apoapsis, the angle is pi.
So $\gamma = 0,\pi$? Is this really the solution?
 
dwsmith said:
So the velocities are the same on the semi-major axis. That is, on the periapsis and apoapsis.
The flight path angle is giving by
$$
\tan\gamma = \frac{e\sin\theta}{1 + e\cos\theta}
$$
At periapsis, the angle is 0, and at apoapsis, the angle is pi.
So $\gamma = 0,\pi$? Is this really the solution?

Assuming you have done the algebra correctly, the answer is yes. I am not too confident about the method used since my knowledge about these kind of problems related to physics is quite limited. Hope some other member will be able to provide more insight on this problem. :)
 

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