[ExI] Need creative help

Mon Jun 8 07:02:18 UTC 2026

I think O'Neill mentioned a 2 for one orbit, half a lunar month. But it
does not make any difference as long as it is in free space.

At one point, I looked into lunar elevators. They work by going through L1
and hanging down into the Earth's gravity. As I recall, if you extended
that part to around 190,000 km you were at the end of a Hohmann transfer
orbit to GEO.

The big problem with any space colony proposal is to find something for the
inhabitants to do. That takes materials. A space elevator off the moon
would give them that.

hBest wishes,

Keith

On Sun, Jun 7, 2026 at 4:24 PM Mark Sonter <
mark.sonter at asteroidenterprises.com> wrote:

> Hi Kieran,
>
>
>
> A 3:1 lunar resonant orbit (ie 9-day period) will have a perigee a couple
> of thousand km above GEO and an apogee a couple of thousand km below EM L1
> altitude, but 180 degrees away (work it out).
>
>
>
> We had a bit of a look at this when I was associated with Deep Space
> Industries, but nothing was ever written up / published.
>
>
>
> Cheers,
>
>
>
> Mark
>
>
>
> --
> Mark J Sonter, mobile 0447 755 598  (delete '0' & replace with '61'
> country code if calling from overseas)
>
>
> Director & Principal Consultant, Radiation Advice & Solutions Pty Ltd, abn
> 31 891 761 435
> Principal, Asteroid Enterprises Pty Ltd, abn 53 008 115 302
> Chairman, Off Earth Resources Pty Ltd, abn 31 664 219 372
>
> Adjunct Assoc Prof, Andy Thomas Centre for Space Resources, Univ of
> Adelaide
>
> 116 Pennine Drive, South Maclean, Queensland 4280, Australia
>
> Please use marksonter at gmail.com for general or radiation related
> communications, and mark.sonter at asteroidenterprises.com for space related
> topics.
>
>
>
>
> “Keep everything as simple as possible, but no simpler” - A. Einstein
>
>
>
> *From:* k.a.carroll via Power Satellite Economics <
> power-satellite-economics at googlegroups.com>
> *Sent:* Thursday, 4 June 2026 8:56 PM
> *To:* Mark Sonter <mark.sonter at asteroidenterprises.com>;
> jerome.glenn at millennium-project.org; 'Paul Werbos' <paul.werbos at gmail.com>;
> 'John Clark' <johnkclark at gmail.com>
> *Cc:* 'Keith Henson' <hkeithhenson at gmail.com>; 'ExI chat list' <
> extropy-chat at lists.extropy.org>; extropolis at googlegroups.com; 'Power
> Satellite Economics' <power-satellite-economics at googlegroups.com>
> *Subject:* RE: Need creative help
>
>
>
> Mark;
>
>
>
> Interesting. I assume that you mean an orbit in a 3:2 orbital resonance
> with the Moon, just as Hilda is in a 3:2 orbital resonance with Jupiter?
>
>
>
> Has anyone published anything on the orbital dynamics of such a
> quasi-Hilda in the Earth-Moon system? If so, I’d be interested to take a
> look.
>
>
>
> - Kieran
>
>
>
> *From:* power-satellite-economics at googlegroups.com <
> power-satellite-economics at googlegroups.com> *On Behalf Of *Mark Sonter
> *Sent:* Wednesday, June 3, 2026 11:15 PM
> *To:* jerome.glenn at millennium-project.org; 'Paul Werbos' <
> paul.werbos at gmail.com>; 'John Clark' <johnkclark at gmail.com>
> *Cc:* 'Keith Henson' <hkeithhenson at gmail.com>; 'ExI chat list' <
> extropy-chat at lists.extropy.org>; extropolis at googlegroups.com; 'Power
> Satellite Economics' <power-satellite-economics at googlegroups.com>
> *Subject:* RE: Need creative help
>
>
>
> What about habitats in an Earth-Moon Hilda orbit?
>
>
>
> ‘The Hilda Habitats’
>
>
>
> Closer than L4 or L5. Resonant with the Moon. Close to GEO at Perigee, and
> to EM L1 altitude at apogee..
>
>
>
> Can be fed by mass launched from Moon, or imported from NEAs.
>
>
>
> Comments?
>
>
>
> Mark
>
>
>
> --
> Mark J Sonter, mobile 0447 755 598  (delete '0' & replace with '61'
> country code if calling from overseas)
>
>
> Director & Principal Consultant, Radiation Advice & Solutions Pty Ltd, abn
> 31 891 761 435
> Principal, Asteroid Enterprises Pty Ltd, abn 53 008 115 302
> Chairman, Off Earth Resources Pty Ltd, abn 31 664 219 372
>
> Adjunct Assoc Prof, Andy Thomas Centre for Space Resources, Univ of
> Adelaide
>
> 116 Pennine Drive, South Maclean, Queensland 4280, Australia
>
> Please use marksonter at gmail.com for general or radiation related
> communications, and mark.sonter at asteroidenterprises.com for space related
> topics.
>
>
>
>
> “Keep everything as simple as possible, but no simpler” - A. Einstein
>
>
>
> *From:* power-satellite-economics at googlegroups.com <
> power-satellite-economics at googlegroups.com> *On Behalf Of *
> jerome.glenn at millennium-project.org
> *Sent:* Wednesday, 3 June 2026 11:16 PM
> *To:* 'Paul Werbos' <paul.werbos at gmail.com>; 'John Clark' <
> johnkclark at gmail.com>
> *Cc:* 'Keith Henson' <hkeithhenson at gmail.com>; 'ExI chat list' <
> extropy-chat at lists.extropy.org>; extropolis at googlegroups.com; 'Power
> Satellite Economics' <power-satellite-economics at googlegroups.com>
> *Subject:* RE: Need creative help
>
>
>
> The reason was the merger with L-5 Society and National Space Institute
> (sometime referred to as No Space Intelligence).
>
>
>
> Jerry
>
>
>
> *From:* power-satellite-economics at googlegroups.com <
> power-satellite-economics at googlegroups.com> *On Behalf Of *Paul Werbos
> *Sent:* Wednesday, June 3, 2026 8:32 AM
> *To:* John Clark <johnkclark at gmail.com>
> *Cc:* Keith Henson <hkeithhenson at gmail.com>; ExI chat list <
> extropy-chat at lists.extropy.org>; extropolis at googlegroups.com; Power
> Satellite Economics <power-satellite-economics at googlegroups.com>
> *Subject:* Re: Need creative help
>
>
>
>
>
>
>
> On Wed, Jun 3, 2026 at 8:20 AM John Clark <johnkclark at gmail.com> wrote:
>
>
>
>
>
> On Tue, Jun 2, 2026 at 10:14 PM Keith Henson <hkeithhenson at gmail.com>
> wrote:
>
>
>
>
>
> *> **L5 Society was the best name I ever came up with*
>
>
>
> *And that was a great name! It's simple and sticks in the mind. Why they
> chose to change it to something generic and completely forgettable I have
> no idea. *
>
>
>
> This is one small example of the many, many things I saw with my own eyes.
>
>
>
> The decision was to merge L5 with Von Braun's National Space Institute, to
> create NSS. I was the L5 rep to these discussions. If Gary Oleson still
> joins these discussions, he may also have relevant memories. The key person
> on the NSI side was Carol Rosin, whom I remember quite well from about four
> connections which immediately come to mind. (JUST now, I searched... she
> still has a big web presence; it says she is 82 years old now. Merger was
> intended to bring greater strength through greater unity, but opening to a
> larger constituency can sometimes dilute focus. O'Neill had a clear vision,
> and it is sad how it is not so visible to the world now as it was then.
>
>
>
>
>
>
>
>
>
>
>
> *John K Clark*
>
>
>
>
>
>
>
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