What has proven to be the best method for measuring the mass of a Galilean satellite of Jupiter?

Question

Quizplus · Accepted Answer

The best method for measuring the mass of a Galilean satellite of Jupiter is to observe the slight changes in the motion of a spacecraft caused by gravitational force, as the spacecraft passed near the satellite. This is known as the gravitational assist technique and has been used successfully in numerous spacecraft missions to measure the masses of Jupiter's moons. Option A is also a valid method, but it is not as accurate as the gravitational assist technique. Option B is not a practical method as it requires a lunar lander vehicle which is not possible on a satellite of Jupiter. Option C is also not a practical method as it requires the presence of neighboring satellites which may not exist or may have unpredictable orbits.

What Has Proven to Be the Best Method for Measuring