The required velocity to transfer the payload into a Lunar Transfer Orbit was calculated using a low energy Hohmann transfer. The orbits involved in the payload transfer from the eMMET to the lMMET and then from the lMMET to the eMMET are as follows:
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eMMET’s CoM orbit about the Earth
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eMMET to lMMET transfer orbit
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Moon’s orbit about the Earth
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lMMET’s CoM orbit about the Moon
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Circular Lunar orbit at radius
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lMMET to eMMET transfer orbit
Orbital Paths involved in payload transfer.
At the apogee of orbit 2, the velocity of the payload, arriving at the lMMET, must have zero velocity relative to the lMMET’s upper tip. The payload at this point is assumed to be under the influence of the Moon’s gravity and its velocity relative to the Moon is taken to be the orbital velocity at its radius from the Moon’s centre, plus the velocity of the Earth relative to the Moon (equal to the velocity of the Moon about the Earth).​
The velocity of the payload at the tip of each tether is given below, the subscript 1 represents the tip furthest from its orbiting body. (Note the velocities given are relative to the celestial body it orbits)
