A spacecraft of mass m is in a circular orbit of radius 2Rₑ around Earth, whose mass is M and radius is Rₑ. Find the energy required to transfer it to a circular orbit of radius 3Rₑ.
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A spacecraft of mass m is in a circular orbit of radius 2Rₑ around Earth, whose mass is M and radius is Rₑ. Find the energy required to transfer it to a circular orbit of radius 3Rₑ.

G1 Physics · Accepted Answer

Circular-orbit energy is E = -GMm/(2r). Thus E₁ = -GMm/(4Rₑ) and E₂ = -GMm/(6Rₑ). Rₑquired energy = E₂-E₁ = GMm/(12Rₑ). Correct answer: D.