Could Moon Miners Use Railguns to Launch Ore into Space?

[Elderberry]

By Leonard David, Space.com's Space Insider Columnist | April 12, 2017

 The United States Navy fired a projectile at Mach 6 during a recent test with an electromagnetic railgun, suggesting that early ideas about using such tech to launch payloads from the lunar surface might not be so sci-fi after all.

Mach 6 (six times the speed of sound) is 4,567 mph (7,350 km/h). The escape velocity at the moon is just a shade faster than that — 5,300 mph (8,530 km/h).

The Office of Naval Research work on the EM Railgun launcher is being pursued as a long-range weapon that fires projectiles using electricity instead of chemical propellants. [The Most Dangerous Space Weapons Ever]

 Magnetic fields created by high electrical currents accelerate a sliding metal conductor, or armature, between two rails to launch projectiles.

In 1974, Princeton professor and space visionary Gerard O’Neill first proposed using an electromagnetic railgun to lob payloads from the moon.

"Mass drivers" based on a coilgun design could be adapted to accelerate a nonmagnetic object, O'Neill suggested. One application he proposed for mass drivers: tossing baseball-size chunks of ore mined from the surface of the moon into space, where they could be used as raw material for building space colonies and solar power satellites.

O'Neill worked at the Massachusetts Institute of Technology with Henry H. Kolm and a group of student volunteers to construct a mass driver prototype. Backed by grants from the Space Studies Institute, later prototypes improved on the concept, showing that a mass driver only 520 feet (160 meters) long could launch material off the surface of the moon.

An official at the Office of Naval Research, contacted by Inside Outer Space, said this of O'Neill's seminal work on mass drivers: "Very interesting proposal to use electromagnetic launchers for space vehicles. Considering the fact that the railgun is working with a small hypervelocity projectile, and requires significant power and thermal management, I suspect working out the details for movement of larger space vehicles/payloads is a long way off.

More: http://www.space.com/36442-could-moon-miners-use-railguns-to-launch-ore-into-space.html

[Cripplecreek]

Indeed.

Mass drivers can also be used to move asteroids around as well.

[Suppressed]

"Ore" generally requires processing.  The energy requirements are vast. One baseball at a time?

Maybe someday, but not anytime soon. Someone needs to think about this a bit more.

[Cripplecreek]

"Ore" generally requires processing.  The energy requirements are vast. One baseball at a time?

Maybe someday, but not anytime soon. Someone needs to think about this a bit more.

Also depends on what type of ore you're talking about mining on the moon. Its not particularly Iron rich on the surface. Titanium oxide is pretty common on the moon.

Personally I think the asteroids are where you'll find the purest heavy metals in raw form.

[Ghost Bear]

...

In 1974, Princeton professor and space visionary Gerard O’Neill first proposed using an electromagnetic railgun to lob payloads from the moon.

...

Gerard O'Neill may have been the first to propose some things, but the idea of using EM mass drivers to lob payloads from the moon wasn't one of them...

[geronl]

Also depends on what type of ore you're talking about mining on the moon. Its not particularly Iron rich on the surface. Titanium oxide is pretty common on the moon.

Personally I think the asteroids are where you'll find the purest heavy metals in raw form.

I agree. I also dislike the idea of all those missed ore chunks slowly becoming a ring around the moon or Earth and a hazard to space navigation.

[Suppressed]

Gerard O'Neill may have been the first to propose some things, but the idea of using EM mass drivers to lob payloads from the moon wasn't one of them...

Yup.

[Cripplecreek]

I agree. I also dislike the idea of all those missed ore chunks slowly becoming a ring around the moon or Earth and a hazard to space navigation.

The moon is a better place for a space elevator than earth.

[thackney]

After launched at  5,300 mph, how does it stop to be gathered?

[Cripplecreek]

After launched at  5,300 mph, how does it stop to be gathered?

I'm guessing it would be a launch calculated to fall into orbit for collection.

Frankly it just doesn't sound like a great way of going about it. Refining the metal on the surface first would make more sense but I still think a space elevator would be the way to go.

[InHeavenThereIsNoBeer]

I agree. I also dislike the idea of all those missed ore chunks slowly becoming a ring around the moon or Earth and a hazard to space navigation.

My orbital mechanics is almost non-existent, but is it possible to miss and have the object fall into Earth orbit if you only accelerate the object enough to escape the moon's gravity and then let earth's take over?  Seems to me you're either going to miss the earth completely, hit your target, or miss your target with the payload hitting the earth SOMEWHERE (or it breaks up in the atmosphere).

[geronl]

My orbital mechanics is almost non-existent, but is it possible to miss and have the object fall into Earth orbit if you only accelerate the object enough to escape the moon's gravity and then let earth's take over?  Seems to me you're either going to miss the earth completely, hit your target, or miss your target with the payload hitting the earth SOMEWHERE (or it breaks up in the atmosphere).

Might be a good way to launch space pods with the refined ore inside though, carrying enough fuel to control their trajectories.

[InHeavenThereIsNoBeer]

My orbital mechanics is almost non-existent, but is it possible to miss and have the object fall into Earth orbit if you only accelerate the object enough to escape the moon's gravity and then let earth's take over?  Seems to me you're either going to miss the earth completely, hit your target, or miss your target with the payload hitting the earth SOMEWHERE (or it breaks up in the atmosphere).

Of course, the target is not Earth, which I'd know if I read the headline.

[Gefn]

In 1974, Princeton professor and space visionary Gerard O’Neill first proposed using an electromagnetic railgun to lob payloads from the moon.

Yay Princeton!

So why am I picturing Bender on the moon with the Crushinatator?

[Doug Loss]

Might be a good way to launch space pods with the refined ore inside though, carrying enough fuel to control their trajectories.

As I recall, the design had metallic (magnetic) buckets that contained slugs of whatever material was to be launched; the buckets were decelerated at the end of the launcher and the slugs then left the buckets on their trajectory.  The buckets traveled back to the start and were refilled for relaunch.

[geronl]

As I recall, the design had metallic (magnetic) buckets that contained slugs of whatever material was to be launched; the buckets were decelerated at the end of the launcher and the slugs then left the buckets on their trajectory.  The buckets traveled back to the start and were refilled for relaunch.

sounds like a weapon, lol

[Ghost Bear]

sounds like a weapon, lol

Yup, that's how the Loonies used it (in The Moon is a Harsh Mistress).

[kevindavis007]

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