Calculating Elliptical Orbit Points & Flight Path Angle

In summary, to determine the location of the point(s) on an elliptical orbit where the speed is equal to the circular orbital speed, you can use the equation for velocity in elliptical orbit and equate it with the velocity in circular orbit. This will help you find the values for the semi-major axis. The flight path angle can be calculated using the equation given. At periapsis, the angle is 0 and at apoapsis, the angle is pi. So, the solution is $\gamma = 0,\pi$. However, this method may need further confirmation from someone with more knowledge on the topic.
  • #1
Dustinsfl
2,281
5
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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  • #2
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.
 
  • #3
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?
 
  • #4
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. :)
 
  • #5


To calculate the location of the point(s) on an elliptical orbit where the speed is equal to the circular orbital speed, you can use the vis-viva equation:

v = √(GM(2/r - 1/a))

where v is the speed, G is the gravitational constant, M is the mass of the central body, r is the distance from the central body to the orbiting object, and a is the semi-major axis of the elliptical orbit.

To determine the flight path angle at this location, you can use the following equation:

tan(γ) = (e sin(θ)) / (1 + e cos(θ))

where γ is the flight path angle, e is the eccentricity of the orbit, and θ is the true anomaly (the angle between the periapsis and the current position of the orbiting object).

It is important to note that these equations assume a two-body system and do not take into account any external forces or perturbations. For more accurate calculations, additional equations and factors may need to be considered.
 

FAQ: Calculating Elliptical Orbit Points & Flight Path Angle

What is an elliptical orbit?

An elliptical orbit is a type of orbit in which an object, such as a satellite or planet, follows an elliptical path around another object, typically a larger body such as a planet or star. This type of orbit is characterized by having a slightly flattened shape, with the object moving faster when it is closer to the larger body and slower when it is farther away.

How do you calculate the points of an elliptical orbit?

To calculate the points of an elliptical orbit, you will need to know the semi-major axis (a), semi-minor axis (b), and eccentricity (e) of the orbit. These values can be plugged into the equation for an ellipse: x = a*cos(t), y = b*sin(t), where t represents the angle of the orbit. By plugging in different values for t, you can calculate the x and y coordinates of points along the orbit.

What is the focus of an elliptical orbit?

The focus of an elliptical orbit is one of the two points within the orbit where the larger body is located. The other focus is an empty point opposite of the larger body. These two points are the closest and farthest points from the object in orbit, and the sum of their distances from any point on the orbit will always be equal.

What is flight path angle in an elliptical orbit?

The flight path angle, also known as the flight path angle, is the angle between the direction of the object's velocity and the tangent of the orbit at a specific point. It is a measure of the inclination of the object's path relative to the surface of the larger body. In an elliptical orbit, the flight path angle will change as the object moves along its orbit.

How does the eccentricity of an elliptical orbit affect the flight path angle?

The eccentricity of an elliptical orbit affects the flight path angle by determining the shape of the orbit. If the eccentricity is close to 0, the orbit will be nearly circular and the flight path angle will remain relatively constant. However, if the eccentricity is high, the orbit will be more elongated and the flight path angle will vary significantly as the object moves closer to and farther away from the larger body.

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