Space station - tension of the structure

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SUMMARY

The discussion focuses on calculating the tension experienced by a space station of length L and mass M in low Earth orbit, where one side constantly faces the Sun. The participant derived the tension formula as f = M R / 2 g L, where R is the orbit radius and g is the acceleration due to gravity. The analysis also considers the distribution of mass, concluding that the bottom half of the station contributes to the tension calculation. Additionally, the participant raises a valid concern regarding the impact of differential thermal expansion on structural integrity.

PREREQUISITES
  • Understanding of basic physics principles, specifically gravitational forces.
  • Familiarity with orbital mechanics and the concept of low Earth orbit.
  • Knowledge of tension and weight distribution in structural engineering.
  • Basic calculus for solving equations related to mass and force.
NEXT STEPS
  • Research "Orbital Mechanics and Gravitational Forces" to deepen understanding of forces in space.
  • Study "Thermal Expansion Effects in Space Structures" to explore material behavior under temperature variations.
  • Learn about "Structural Analysis of Spacecraft" to understand tension and stress in engineering designs.
  • Investigate "Finite Element Analysis (FEA) for Space Structures" to apply computational methods in tension calculations.
USEFUL FOR

This discussion is beneficial for aerospace engineers, physicists, and structural engineers involved in the design and analysis of space stations and other spacecraft structures.

Privalov
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There is a space station of the length L and uniformly distributed mass M on the low Earth orbit. One side of it always faces the Sun. Which tension will the structure experience?

long_space_station.png


My attempt of the solution: bottom of the station is L/2 meters below the stable orbit at that velocity. Therefore, the mass of the bottom of the station has some weight. In fact, any small mass m at the bottom of the station will weight:

(L/2) / R = m / fg

where:
L - length of space station
m - test mass
R - orbit radius
f - tension or weight
g – acceleration of free fall at the height of the orbit

m is one quarter of total space station weight. Proof: the bottom half of the station has mass M/2. The weight of an object at the height of L/4 will be half of those at the bottom of the station. Therefore, weight M/2, uniformly distributed over bottom half of the station, is equivalent to M/4 at the bottom of the station (in regards to tension).

After solving the equation, I have got:

(L/2) / R = M / 4fg
L / 2R = M / 4fg
L / R = M / 2fg
f = M R / 2 g L


Right or wrong?
 
Last edited:
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In reality I would have thought the differential thermal expansion between the hot and cold side would be more than the gravitational field difference.
 

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