XPost: alt.astronomy, sci.military.naval, alt.fan.heinlein

from
https://www.space.com/electromagnetic-launch-moon-mass-drive

Could we launch resources from the moon with electromagnetic railguns?
News
By Leonard David published yesterday
What does a nuclear aircraft carrier have to do with the moon?

Comments (10)
a cylindrical object is launched from the surface of the moon by a long
metal rail
A cylindrical 220 pound (100 kilogram) launch package is shown after
emerging from the end of a lunar electromagnetic launcher. (Image
credit: General Atomics Electromagnetic Systems)

In 1974, the late Princeton University professor and space visionary
Gerard O'Neill proposed using electromagnetic rail guns to lob payloads
from the moon.

O'Neill suggested using "mass drivers" based on a coil gun design to
accelerate a non-magnetic object. One application for mass drivers was launching moon-derived materials into lunar orbit for in-space
manufacturing. O'Neill also worked at MIT on mass drivers, along with
colleague Henry H. Kolm, and a group of farsighted student volunteers,
to fabricate their first mass driver prototype. Backed by grants from
the Space Studies Institute, later prototypes improved on the mass
driver concept.

That was five decades ago. Catapult yourself to today and ask this
question: What's the U.S. Navy's Gerald R. Ford nuclear aircraft carrier
got to do with the moon?

Future lunar economy
Late last year, General Atomics Electromagnetic Systems filed a final
report to the Air Force Office of Scientific Research's (AFOSR). That
report was titled "Lunar Electromagnetic Launch for Resource
Exploitation to Enhance National Security and Economic Growth."

The author of that appraisal is Robert Peterkin, director of operations
for the organization's Albuquerque, New Mexico office.

Underscored in the 30-page document is that the moon is rich in useful resources, including silicon, titanium, aluminum and iron. The prospect
of tapping into lunar water also looms large.

"A not-too-distant future lunar economy will make use of these lunar
resources to resupply, repair, and refuel spacecraft in lunar orbit at
lower cost than delivering terrestrial resources from Earth's deep gravitational well," explains the report.

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an illustration of a long metal rail buried into the surface of the moon

A lunar launcher as viewed by space artist Pat Rawlings, published by
the Lunar & Planetary Institute in 1985. (Image credit: LPI)
Machinery, structures, systems
Electromagnetic launches of material from the lunar surface, the report continues, can be significantly more efficient than conventional rocket launches that rely on chemical fuels that are imported from the Earth to
the moon.

Outlined in the assessment are recommendations on how to mature the
technology necessary to launch extracted and processed lunar material
into cislunar space to sustain a set of emerging space missions.

A particularly important aspect of developing a lunar economy, the
report advises, is moving mass off the surface of the moon reliably, affordably, and safely. "Undoubtedly, the first spiral of a development
cycle for a lunar ecosystem will rely of supply of machinery,
structures, and supporting systems from the Earth."

a long metal rail above a series of rectangular magnets inside a hangar

A U.S. Office of Naval Research Electromagnetic Railgun Laboratory
launcher located at the Naval Surface Warfare Center. (Image credit:
U.S. Navy)
Superior choice
Using lunar resources to repair and resupply cis-lunar spacecraft
requires advances in several technologies including a reliable way to
move material off the lunar surface, Peterkin told Space.com.

For that task, a modern electromagnetic launcher is a superior choice,
Peterkin said, because it can use abundant solar energy as a prime
energy source instead of importing chemical rocket fuel from Earth.

"The U.S. government should fund an evolution of the existing
electromagnetic aircraft launch system, now operating reliably on the
U.S. Navy's Gerald R. Ford nuclear aircraft carrier," Peterkin points out.

Manufactured by General Atomics, that carrier-based hardware is called
the Electromagnetic Aircraft Launch System (EMALS).

a fighter jet lifts off from the surface of an aircraft carrier at sea

An F/A-18F Super Hornet flies over the USS Gerald R. Ford. (Image
credit: US Navy/Erik Hildebrandt)
Path to get there
RELATED STORIES:
 —  Could US Navy's Railgun Help Tap Moon's Resources?

 — NASA moon orbiter spots Chinese lander on lunar far side (photo)

— Astronomers call for radio silence on the far side of the moon

Peterkin said that moving this Earth-based technology down the road
involves achieving higher speed, at lower mass — showcasing work that accelerates into fast forward mode a lunar launch capacity.

The lickety-split speed required to hurl pound-class payloads from lunar terrain into a low circular orbit around the moon is 3,758 miles per
hour (1.68 kilometers per second).

"To prove viability, we need to demonstrate that this approach can
achieve a lunar orbit speed," said Peterkin, "for at least 100 launches
without needing to replace launcher components."

As the report to the Air Force Office of Scientific Research contends,
"while it is important to envision a mature state in which a
self-sustaining lunar ecosystem extracts, processes, and launches
material into lunar space to construct, supply, and sustain cislunar
spacecraft and space settlements, it is equally important to establish a
path to get there."

Join our Space Forums to keep talking space on the latest missions,
night sky and more! And if you have a news tip, correction or comment,
let us know at: community@space.com.

Leonard David
Leonard David
Space Insider Columnist
Leonard David is an award-winning space journalist who has been
reporting on space activities for more than 50 years. Currently writing
as Space.com's Space Insider Columnist among his other projects, Leonard
has authored numerous books on space exploration, Mars missions and
more, with his latest being "Moon Rush: The New Space Race" published in
2019 by National Geographic. He also wrote "Mars: Our Future on the Red
Planet" released in 2016 by National Geographic. Leonard has served as
a correspondent for SpaceNews, Scientific American and Aerospace America
for the AIAA. He has received many awards, including the first Ordway
Award for Sustained Excellence in Spaceflight History in 2015 at the AAS Wernher von Braun Memorial Symposium. You can find out Leonard's latest
project at his website and on Twitter.

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SEE ALL COMMENTS (10)
10 COMMENTS
COMMENT FROM THE FORUMS
Rocky
1. Giving your someone Byzantine registration system I see why there are
very few comments.
2. Crediting Gerard O'Neill with this is a little silly since everyone
knows the idea had been around for years (see Robert heinlein's moon is
a harsh Mistress)
3. A much simpler system is available. I don't remember who it was that
did the math on this but it turns out a 50 horse electric motor and a 1
km Kevlar tether can sling a good size load (I don't remember how large)
into space from the Moon with a whole lot less power and infrastructure.
REPLY
Unclear Engineer
I am having a hard time envisioning the lunar orbit aspects of this
proposal. Whatever speed the railgun can impart to a projectile, the
orbit of that projectile around the Moon will be elliptical, not
circular, and will intersect the lunar surface - i.e., crash back onto
the surface unless there is some sort of rocket motor on the projectile
that will fire at the highest point of the thrown path to raise the
lowest parts of the orbit to make it roughly circular. So, a rail gun
would really only be a "first stage" to any launch vehicle intended to
get lunar material into lunar orbit.

I suppose that it is theoretically possible to throw a motorless
projectile directly into the path of a satellite that is already in
orbit around the Moon, and have that satellite "catch" the projectile.
But, in reality, that is a substantial crash between the faster moving satellite and the slower moving rail gun projectile (at the point of
coincident orbits). And then the orbiting satellite would need to use a
rocket motor (and fuel) to reestablish its orbital speed, because
picking up the slower mass would necessarily decrease the satellite's
speed and cause it to go into an eliptical orbit that would have its low
point closer to the lunar surface (if not under it).
REPLY
bigpaise
This story reminds me of a novel by James P. Hogan, "The Two Faces of Tomorrow". It involves a mix of the rail gun / lunar mining system and
AI. The whole plot would make an interesting movie, a thought which I've
always had but it would still be relevant for today's world.
REPLY
Gill Wright
Rocky said:
1. Giving your someone Byzantine registration system I see why there are
very few comments.
2. Crediting Gerard O'Neill with this is a little silly since everyone
knows the idea had been around for years (see Robert heinlein's moon is
a harsh Mistress)
3. A much simpler system is available. I don't remember who it was that
did the math on this but it turns out a 50 horse electric motor and a 1
km Kevlar tether can sling a good size load (I don't remember how large)
into space from the Moon with a whole lot less power and infrastructure.
Given what Heinlein wrote in 1965 "The Moon is a Harsh Mistress" the articulation of lunar mass launch was well crafted nearly 60 years ago,
as Rocky so aptly pointed out. The book is a very interesting read of
how the Loonies were living in 2074 to 2076. The technologies Heinlein
project are very reachable with what we now know. I do not think we will
go down the 'penal colony' pathway he envisioned, and wrapped a story
around. I think humanity will be a bit smarter than the social
constructs of the early 1960's, as we begin to develop the ARTEMIS infrastructure in the 21st century.

The technologies of Lunar mass launch are well under development. All
you need to do is look at the following 3 technologies currently in
terrestrial enterprises:

1. HYPERLOOP: a means of maglev transport in a 'vacuum tube' here on Earth
2. The Boring Company: a means to cost effectively drill horizontal
tunnels on Earth, or Lunar regolith.
3. SpaceX Starship: a means to eventually transport mass, like a
horizontal boring machine to the lunar surface.

With a Boring machine on the Lunar surface, likely the South Pole, the
regolith can be extracted for mineral and water content to process into materials for lunar construction. Plus sub-surface tubes, and eventually
larger caverns will provide necessary radiation protection for sustained
human presence in the Lunar habitation structures. It will take time to
further develop these into a viable lunar infrastructure, but the
technologies are well understood.

Given that Elon Muck and Jeff Bezos both read Robert Heinlein and
O'Neil, in their formative years, it seems to me that they are
developing the industrial means to implement such a Lunar infrastructure
in the coming decade, or so.

Time will tell..🖖👨‍🚀



Frankly, I think the space industry has a sound handle far beyond the application of a Naval catapult.
REPLY

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