[ExI] Space governance

Adrian Tymes atymes at gmail.com
Sun Sep 27 15:28:30 UTC 2020


On Sun, Sep 27, 2020 at 12:34 AM Ben Zaiboc via extropy-chat <
extropy-chat at lists.extropy.org> wrote:

> On 27/09/2020 06:37, Adrian Tymes wrote:
>
> On Fri, Sep 25, 2020 at 11:38 AM Dave Sill via extropy-chat <
> extropy-chat at lists.extropy.org> wrote:
>
>> On Fri, Sep 25, 2020 at 12:50 PM Adrian Tymes via extropy-chat <
>> extropy-chat at lists.extropy.org> wrote:
>>
>>> If these habitats are, say, cylinders 2 km wide, to allow them to be
>>> spun up to 1 G, that's enough of a technical (and imposed-by-human-biology)
>>> standard that people might not want to mess with it.  2 km wide suggests
>>> maybe 5 km long maximum, for structural stability.
>>>
>>
>> What about rotational stability? Wouldn't want your habitats flipping
>> when they're full of people.
>>
>> https://www.youtube.com/watch?v=1VPfZ_XzisU
>>
>
> Per that video, you weight it so the axis of rotation is not the one
> that's going to cause that sort of flipping.
>
>
> That would mean short, fat cylinders, not long thin ones, no?
>

How short and fat, though?  If 2 km wide by 5 km long is too long and
thin...

2 km diameter is not the minimum for safe 1 G spin gravity (studies suggest
500 m, possibly smaller - see
https://www.artificial-gravity.com/sw/SpinCalc/ if you wish to play with
the numbers).  Wider is certainly possible.  If 2x5 is enough for about
628K people, then 4x4 (so that length does not exceed width) should allow
just over 2M.

The counterpoint, at least in the system I had been thinking of, is that
the first habitat would start off only 100 meters - possibly only 10 meters
- wide, since in its earliest days it would host less than 100 people for a
while (less than 10 to start), and making far more habitat than necessary
would be difficult to justify.  2x0.01 would still be enough for over 1,250
people;  4x0.01 could house over 5,000.  If the eventual "objective" is to
go to 4 km wide, there will be a stronger temptation to start off with just
500 km wide (0.5x0.01 is small enough that we're talking a single apartment
building of about 31K square meters; even if we allocate 90% of the space
to workshops, labs, agriculture, and open space, that's still right sized
for about 100 people) - but once the initial radius is established, it will
be far more difficult to expand the radius (which involves disrupting
existing residential areas) than to simply extend the disc into a cylinder
(which does not disrupt anyone's living situation).  One could perhaps
fully enclose the first cylinder within a wider second cylinder, but that
presents a source of danger so long as the first cylinder spins much faster
than the second within the second; the residents could be transitioned to
the second cylinder once it's ready, and the first despun, but there will
likely be resistance to "abandoning" the "historical" first colony
structure.  There will be even more resistance if the first cylinder is not
within the second, as they will be seen as entirely different habitats.  A
much higher chance of long term success can be had by just starting at the
radius it is desired to end up at.

It's interesting that we hadn't really understood this until relatively
> recently. Makes me wonder what other physics we are still completely in the
> dark about.
>

My hunch is that the nature of dark matter/energy will become clearer once
we have observatories scattered around the solar system (if not before
then), and may well come down to the margin of error from Earth-only
observations including results with strange consequences that will be ruled
out by the greater precision such system-wide observation baselines will
give.

I'm also wondering if a long thin cylinder flipping about a perpendicular
> axis would be the disaster we are assuming (everything inside being thrown
> about). What forces would the people inside actually feel? Is it possible
> they wouldn't even notice unless they were looking out of the window? Maybe
> it would be a cool quirk of orbital habitats, and only be awkward for
> docking and astronomical observations, rather than disastrous.
>

No, it'd be brief but it would be significant turbulence for anyone
inside.  For spin gravity to work properly, the object providing spin
gravity has to spin and experience no other motion.  Any other motion is
felt as other motion.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.extropy.org/pipermail/extropy-chat/attachments/20200927/6b8f20aa/attachment.htm>


More information about the extropy-chat mailing list