Calculating Angle & Speed to Reach Planet's Moon from Station Orbit

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SUMMARY

The discussion focuses on calculating the angle $\theta$ and additional speed required for a space station in orbit around a planet to reach its moon. Key concepts include tangential velocity, conservation of energy, and the effects of an impulse on orbital mechanics. The participants emphasize that a single impulse will transition the station from a circular to an elliptical orbit, and the initial angular separation between the station and the moon is crucial for determining the necessary parameters. The conversation highlights the complexity of orbital dynamics and the need for precise calculations to achieve the desired trajectory.

PREREQUISITES
  • Understanding of orbital mechanics and Kepler's laws
  • Familiarity with tangential velocity and its role in orbits
  • Knowledge of conservation of energy principles in physics
  • Basic mathematics for calculating angles and velocities
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  • Study the principles of orbital transfers, specifically Hohmann transfers
  • Learn about calculating tangential velocity for circular orbits
  • Research the effects of impulse on orbital paths and energy conservation
  • Explore the mathematical modeling of elliptical orbits and their parameters
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Aerospace engineers, astrophysicists, students studying orbital mechanics, and anyone involved in mission planning for space travel.

dirb
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Homework Statement
Find angle and velocity
Relevant Equations
Unsure
A station is orbiting a planet at a distance R1, a moon is orbiting the planet at distance R2 with the period T. The planet itself has a radius rp and a mass mp. We know that when an object adds its velocity at a point in the orbit, the height of the opposite orbit will increase. Determine the angle $\theta$ and additional speed so that the station reaches the moon of the planet.

I was thinking that it has something to do with tangential velocity, and conservation of energy but I don't know how to write the maths? Which concepts should I use in this problem? thanks!
 
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dirb said:
Homework Statement:: Find angle and velocity
Relevant Equations:: Unsure

We know that when an object adds its velocity at a point in the orbit, the height of the opposite orbit will increase.
Unsure what is meant by "when an object adds its velocity". Do you mean "when an impulse is given to an object in orbit so as to increase its speed"?
And what is the "opposite orbit"? Is this a translation?

As to reaching the moon, a one time impulse to an object in a circular orbit will produce an elliptical one. And even if we got the station into the same circular orbit as the moon, it would necessarily be at the same period as the moon, so still might never reach it. I don't see how the question can be answered without knowing the initial angular separation of the bodies.

Edit: assuming the two given radii are different, the periods are different. Maybe we are to assume the impulse is given at the ideal point (the one requiring the least impulse) in their relative motions.
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

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