Okay, 10,000 grams = density*4/3*pi*r^3. Density uranium is about 19 grams per cubic centimeter. I get radius is about 5 cm and diameter is about 10 cm, At 20 kilometers at 10 cm diameter ball subtends 2*arcsin(5 cm/2000000cm). I get .5 arcseconds. To shrink it down to .1 arcseconds, the 10 cm diameter ball needs to be 100 kilometers away. At 20 kps it would take our uranium ball 5 seconds to travel 100 kilometers. But 5 seconds isn't adequate time to dodge the bullet. Although your arithmetic is hurried and sloppy, your point stands.

A black slug would glow in infra red. There's also radar.

Do you even know which resources they hope to mine first? Have you done any research? Or is your assertion just a frenzied flapping of the lips?

NASA and the air force were one of the first major buyers of integrated circuits. The funded R&D to make electronics more compact and less massive. They kickstarted the miniaturization of electronics. Since then, American firms have been a leader in this trend with huge economic benefits.

I agree with your first sentence, sending prospecting rovers is a good idea. Actually propellent is an acceptable word. Your silly attempt at a gotcha typo flame just blew up in your face. There's plenty we could do with the lunar volatiles. Our ability to do work in remote places is increasing. ROVs, drones, telerobots are growing less expensive and more able. See Who needs humans?.

The Permanently Shadowed Regions (PSRs) of the the moon's polar craters are colder than Pluto. We have some of the strangest real estate in the solar system right in our own back yard. The PSRs might contain massive volatile deposits. If so they could be a source of propellent, radiation shielding as well as life support consumables. There are those who confidently assert we know everything there is to known about the moon. They demonstrate their ignorance.