Re-Orbiting Asteriods to make a bigger Moon.

[Nomial_Control]

Hey Just wanted to know, that in the near future, as part of NASA's Orion Mission, they will have to redirect an asteroid around a safe orbit around the moon. If that is possible, we could make an entire satellite/moon out of asteroids. Even though it may take a long time, but I mean, hey, its the future!

[Shpaget]

Why?

What's the point?

[Kerbart]

Hey Just wanted to know, that in the near future, as part of NASA's Orion Mission, they will have to redirect an asteroid around a safe orbit around the moon. If that is possible, we could make an entire satellite/moon out of asteroids. Even though it may take a long time, but I mean, hey, its the future!

Well, the moon's mass is about 7.35×10²² kg. The boulder that the Orion mission intends to capture, from what I understand, is around 94 metric tons or 9.4×10⁴ kg. That means you need around 7.8×10¹⁷ boulders to pull this off.

Now, let's go for a mini-moon. 1/10^th of the radius of the moon, and thus 1/1000^th of it's mass (I'm wildly assuming that Moon and Asteroids have the same density).

So we only need 7.8×10¹⁴ boulders to pull this off. Progress!

And now let's say that we launch a mission to capture one every day. Then we'd only need 2.1×10¹² years to do this. Which is about 500× times as long before the Sun renders the Earth uninhabitable.

So, “even though it may take a long time†and it would be incredibly cool, it's not exactly feasible.

(Ignoring all other practical problems)

Edited September 13, 2015 by Kerbart

[Scotius]

It would make sense if we would find an asteroid with some sort of useful materials (a big lump of ice covered in isolating dust and rocks would be perfect). Then we could build a base inside, making use of the materials at the same time. Problem is, a rock containing useful amounts of stuff, by necessity would have to be big and unwieldy.

[kerbiloid]

Total mass of the Solar asteroid belt is 4% of Moon mass.

[stibbons]

I say we start with the asteroid redirect and then proceed straight to the final goal: stealing Phobos.

[clivman]

Total mass of the Solar asteroid belt is 4% of Moon mass.

Ceres is of similar size to the moon. Unless you mean NEO's you might want to check your facts.

[kerbiloid]

Ceres is of similar size to the moon. Unless you mean NEO's you might want to check your facts.

Diameter of Ceres = 950 km, Moon diameter = 3470 km.

I.e. Ceres is 4 times less than Moon.

Also, its mass is about 1.5% of Moon mass (9.4·10²⁰ vs 7.4·10²² kg).

And this is ~30% of total asteroid belt mass.

Ceres, Vesta and Pallas are in total 2.5% of Moon mass and they contain 50% of full asteroid belt mass.

[Brotoro]

Fact-checking is good.

[Slam_Jones]

While that would be cool and prohibitively expensive and everything, do we really need to mess with the tides?

[fredinno]

Just steal Ikiwowa or something, then put it in HEO, and call it "Minmus". Or put it in Lunar Orbit- then it will be a Moon orbiting a Moon, answering your question.

On the other hand,

Yo Dawg, I heard you like moons...

[kerbiloid]

JOr put it in Lunar Orbit- then it will be a Moon orbiting a Moon, answering your question.

Lunar orbits are unstable. Low orbits due to the mascons, high ones - due to the Earth.

So placing a rock as a satellite of the Moon means that you would require a good home insurance.