…without significantly damaging the Moon or the Earth’s orbits, rotation, tidal effects, etc?
And presupposing that I use a reactionless drive to cleave off the desired section of Moon and propel it into solar orbit.
And I’m defining “safely” as any state between “the average person on Earth would hardly notice the difference” and “astronomers wouldn’t be able to notice a difference.” Anything that burns the skies or boils the seas is right out.
So…are we talking a mass the size of “a large hill” or more like “most of New England” that I’ll get to work with?
I am not an astronomer, but my impression is that if you add significantly to he Moon’s mass, it will crash into the Earth and if you subtract from it, it will drift out into space, so cleave away as much as you like.
If I have that backwards, I awkwardly apologize in advance.
Provided that you don’t change the resulting velocity of the system, neither of these statements are true. A significantly more massive moon will increase tidal forces, and ultimately you’ll see a slight change in the Earth’s orbital characteristics due to a shift in the barycenter of the Earth-Moon system, but as long as momentum is conserved, there won’t be any dramatic changes.
I was once talking to a science-fiction/space artist, who complained that the few pounds of rocks the Apollo program brought back to earth had “unbalanced the solar system.” (Yeah? What about the few tons of the Apollo landers that we brought from the Earth to the Moon?)
It was very soon obvious that the poor bastard didn’t know beans about orbital physics.
Given that modern orbital tracing has to take into account mountains (and other mass concentrations) on earth, I’d say that the addition or subtraction of a “mountain’s worth” of mass to or from the Moon would be measurable – it would observably change the Moon’s orbital elements. But, as noted above, that can mean a difference of inches.