Celestial Mechanics Flashcards Preview

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Flashcards in Celestial Mechanics Deck (9)
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1
Q

Newton’s law of gravity

given in exam

A

Gm1m2
F = ———- . ( r_ / r )
r^2

where r is magnitude of vector r_

2
Q

Kepler’s first law

A

Planets move in elliptical orbits with the sun at one focus of the ellipse

3
Q

Kepler’s second law

A

The line joining the sun to a planet sweeps out equal area in equal times
(gets faster closer to the focus(sun))

4
Q

Kepler’s third law

A

The square of the orbit period t, is proportional to the third power of the semi-major axis of the orbit

t^2 ∝ a^3

5
Q

General equation for a ellipse

A

P
r = ——————–
1 + eCosθ

e = 0 is a circle
0

6
Q

Equation for Kepler’s third law

given in exam

A

4π^2
t^2 = ———— . a^3
Gm1

7
Q

What is the Hohmann transfer

A

when a spacecraft transfers between and LEO to a GEO

8
Q

What happens during the Hohmann transfer

A

Two impulse velocities are used. First to take spacecraft out of circular orbit r1, and second to put it into circular orbit r2

9
Q

What is the equation to find the semi-major axis in a Hohmann transfer

A

a = (r1 + r2) / 2