The unmanned craft, weighing 1,300 pounds and standing approximately five feet tall, will then begin an about seven-week journey to the moon, from where it will send back images of the rocky surface and conduct experiments on the lunar magnetic field
But early spacecraft found no evidence for a global lunar magnetic field
. Later, samples returned from the Apollo 15 mission showed evidence of an ancient magnetic field roughly one tenth the strength of that at Earth's surface.
After significantly dissipating about 3.5 billion years ago, for reasons not known or understood, we didn't know whether the lunar magnetic field
still lingered for some time.