Sci-Fi author's predictions getting close

[a425couple]

The development that Sci-Fi authors like Heinlein, Arthur Clarke,
and many others have predicted is getting closer.

"The Next Great Gold Rush Won't Be Taking Place on Earth
By Ellie Kaufman April 21, 2015
This branded content story is part of a collaboration with United Launch
Alliance on the future of space exploration.---
There's a new gold rush heating up, but the hunt isn't for oil, gas or
tech stocks - it's for asteroids.
There are more than 10,000 near-Earth asteroids shooting by at any given
moment, and many of them contain valuable resources like water, platinum and
iron.
---- Already, private companies are betting big on the potential of
asteroid mining and working hard to get there first. Japan launched
its own asteroid mining operation last year. Serial entrepreneur and
X Prize founder Peter Diamandis believes the first trillionaire will be
made in space. That's right: trillionaire.
"The development, exploration and settlement of space is going to happen
a lot faster than I think people think it will naturally," Lewicki said.
"This isn't
50 years away, it's 10 or 20 years away."

http://mic.com/articles/115786/the-next-great-gold-rush-won-t-be-taking-place-on-earth

A chart purports to show that one medium sized asteroid has
platinim worth more that the UK GDP.
Uhhh - perhaps if it all was sold at the value of the 1st ounce sold!

[steve robinson]

The problem is if the astoriods are that rich in platnuim it will
actually bring the value down

[pete...@gmail.com]

I suspect we'd find more uses for it if we could bring the price down
enough. There was a time when aluminum was considered a precious metal.

Pt is even denser than depleted uranium, so would find uses where dense
weights are needed. It is a noble metal, like gold, and could find a place as
an anti-corrosion coataing. It is quite ductile, and might make excellent bullets. Of course, its use as a chemical catalyst is already well known.

pt

[a425couple]

"steve robinson" <st...@colevalleyinteriors.co.uk> wrote in message ...

> a425couple wrote:
>> The development that Sci-Fi authors like Heinlein, Arthur Clarke,

>> and many others have predicted is getting closer.-----

> http://mic.com/articles/115786/the-next-great-gold-rush-won-t-be-taking-place-on-earth
>>
>> A chart purports to show that one medium sized asteroid has
>> platinim worth more that the UK GDP.

-

>> Uhhh - perhaps if it all was sold at the value of the 1st ounce sold!
>

> The problem is if the astoriods are that rich in platnuim it will
> actually bring the value down

Exactly! That was the point of my last line.
Diminishing value in money per oz. as supply increases.
However, it's uses in production and manufacturing
can really spur huge advances.

[a425couple]

<pete...@gmail.com> wrote in message...

-Of course, its use as a chemical catalyst is already well known.

In Clarke's 2061: "Odyssey three" he 'insinuated' that a huge
number of cheap diamonds would be a key to space elevators.
Does that make some sense?
What other things seem possible?

[Kevrob]

If platinum were cheap enough, it would significantly cut the price of catalytic
converters for pollution control on internal combustion engine cars. How many
beaters around the world have a failed or failing CC?

> In Clarke's 2061: "Odyssey three" he 'insinuated' that a huge
> number of cheap diamonds would be a key to space elevators.
> Does that make some sense?
> What other things seem possible?

An asteroid full of precious metals still might not affect prices much
if transporting the mined materials to planetside manufacturing facilities
is still expensive. What would make the most sense? Building a heat shield
around a shaped chunk and deorbiting the payload for a soft landing somewhere?
Doing as much processing as possible in space in order to have a smaller,
lighter payload?

Kevin R

[David Johnston]

On 4/28/2015 12:57 PM, a425couple wrote:
> The development that Sci-Fi authors like Heinlein, Arthur Clarke,
> and many others have predicted is getting closer.

No. It isn't.

[JRStern]

On Tue, 28 Apr 2015 17:40:00 -0600, David Johnston <Da...@block.net>
wrote:

That's my take too.

Unless there's a huge breakthrough in propulsion technologies it
won't, either. If a million tons in minted gold and platinum coins
was already in orbit around the Earth, I'm not sure it would pay to
land them.

Real-life physics is a bitch.

Well let's see, current prices are OTOO $10,000 per pound *to* orbit.
Not sure what the price is *from* orbit, I'm sure somewhat less but
maybe not that much less. But a pound of gold is currently about
$17,000 so maybe it would pay, somewhat.

Elon Musk says he'll bring the price *to* orbit down under
$1,000/pound, but let's see him do it first.

I think most semi-realistic scifi locates major populations in space
or weaker gravity wells, the moon, asteroids, comets, cannister
cities, before it all comes together. We haven't made a serious start
on that yet.

J.

[Robert Bannister]

On 29/04/2015 6:28 am, Kevrob wrote:

> An asteroid full of precious metals still might not affect prices much
> if transporting the mined materials to planetside manufacturing facilities
> is still expensive. What would make the most sense? Building a heat shield
> around a shaped chunk and deorbiting the payload for a soft landing somewhere?
> Doing as much processing as possible in space in order to have a smaller,
> lighter payload?

So now I've got to insure my house against falling lumps of platinum?
--
Robert Bannister - 1940-71 SE England
1972-now W Australia

[David DeLaney]

On 2015-04-28, pete...@gmail.com <pete...@gmail.com> wrote:
> I suspect we'd find more uses for it if we could bring the price down
> enough. There was a time when aluminum was considered a precious metal.

Yep. This is why, for example, the tip of the Washington Monument was made
out of it.

> Pt is even denser than depleted uranium, so would find uses where dense
> weights are needed. It is a noble metal, like gold, and could find a place as
> an anti-corrosion coataing. It is quite ductile, and might make excellent
> bullets. Of course, its use as a chemical catalyst is already well known.

And of course it's the only metal known that can make a _useful_ female
android, unlike tin.

Dave
--
\/David DeLaney posting thru EarthLink - "It's not the pot that grows the flower
It's not the clock that slows the hour The definition's plain for anyone to see
Love is all it takes to make a family" - R&P. VISUALIZE HAPPYNET VRbeable<BLINK>
http://gatekeeper.vic.com/~dbd/ -net.legends/Magic / I WUV you in all CAPS! --K.

[William Vetter]

a425couple wrote on 04/28/2015 :
> The development that Sci-Fi authors like Heinlein, Arthur Clarke,
> and many others have predicted is getting closer.
>
> "The Next Great Gold Rush Won't Be Taking Place on Earth
> By Ellie Kaufman April 21, 2015
> This branded content story is part of a collaboration with United Launch
> Alliance on the future of space exploration.---
> There's a new gold rush heating up, but the hunt isn't for oil, gas or
> tech stocks - it's for asteroids.
> There are more than 10,000 near-Earth asteroids shooting by at any given
> moment, and many of them contain valuable resources like water, platinum and
> iron.
> ---- Already, private companies are betting big on the potential of
> asteroid mining and working hard to get there first. Japan launched
> its own asteroid mining operation last year. Serial entrepreneur and
> X Prize founder Peter Diamandis believes the first trillionaire will be
> made in space. That's right: trillionaire.
> "The development, exploration and settlement of space is going to happen
> a lot faster than I think people think it will naturally," Lewicki said.
> "This isn't
> 50 years away, it's 10 or 20 years away."
>
> http://mic.com/articles/115786/the-next-great-gold-rush-won-t-be-taking-place-on-earth
>

I had always been under the impression that rare metals were
concentrated in deposits by active geologic processes. Why should Pt
nuggets lie up there waiting for us in the asteroids? Are their
nuggets of precious metals in iron/nickel meteorites?

[Mike Dworetsky]

JRStern wrote:
> On Tue, 28 Apr 2015 17:40:00 -0600, David Johnston <Da...@block.net>
> wrote:
>
>> On 4/28/2015 12:57 PM, a425couple wrote:
>>> The development that Sci-Fi authors like Heinlein, Arthur Clarke,
>>> and many others have predicted is getting closer.
>>
>> No. It isn't.
>
> That's my take too.
>
> Unless there's a huge breakthrough in propulsion technologies it
> won't, either. If a million tons in minted gold and platinum coins
> was already in orbit around the Earth, I'm not sure it would pay to
> land them.
>
> Real-life physics is a bitch.
>
> Well let's see, current prices are OTOO $10,000 per pound *to* orbit.
> Not sure what the price is *from* orbit, I'm sure somewhat less but
> maybe not that much less. But a pound of gold is currently about
> $17,000 so maybe it would pay, somewhat.

If you mean low or "medium" Earth orbit, it doesn't cost much to bring
material down to Earth, just the fuel to permit the return vehicle to use
the atmosphere for braking. There is the cost of launching the empty
retrieval vehicle, of course.

>
> Elon Musk says he'll bring the price *to* orbit down under
> $1,000/pound, but let's see him do it first.
>
> I think most semi-realistic scifi locates major populations in space
> or weaker gravity wells, the moon, asteroids, comets, cannister
> cities, before it all comes together. We haven't made a serious start
> on that yet.
>
> J.

--
Mike Dworetsky

(Remove pants sp*mbl*ck to reply)

[Mike Dworetsky]

Not so much nuggets, but a much higher concentration than on Earth. And not
just in iron-nickel objects, but stony meteoroids and carbonaceous
chondrites also. Other elements also--iridium for example, the marker of
the KT boundary impact.

[William Vetter]

If there is maybe 20X abundance of precious metals, and it exists as a
pretty much a uniform trace in these bodies, what industrial process is
going to separate them economically?

[Anthony Nance]

Or if the supplier(s) controlled how much was available.
- Tony

[Bill Gill]

Of course they do. Just ask Kimball Kinnison when he was posing as
an asteroid miner.

Bill

[pete...@gmail.com]

On Wednesday, April 29, 2015 at 3:31:24 AM UTC-4, Mike Dworetsky wrote:
> JRStern wrote:
> > On Tue, 28 Apr 2015 17:40:00 -0600, David Johnston <Da...@block.net>
> > wrote:
> >
> >> On 4/28/2015 12:57 PM, a425couple wrote:
> >>> The development that Sci-Fi authors like Heinlein, Arthur Clarke,
> >>> and many others have predicted is getting closer.
> >>
> >> No. It isn't.
> >
> > That's my take too.
> >
> > Unless there's a huge breakthrough in propulsion technologies it
> > won't, either. If a million tons in minted gold and platinum coins
> > was already in orbit around the Earth, I'm not sure it would pay to
> > land them.
> >
> > Real-life physics is a bitch.
> >
> > Well let's see, current prices are OTOO $10,000 per pound *to* orbit.
> > Not sure what the price is *from* orbit, I'm sure somewhat less but
> > maybe not that much less. But a pound of gold is currently about
> > $17,000 so maybe it would pay, somewhat.
>
> If you mean low or "medium" Earth orbit, it doesn't cost much to bring
> material down to Earth, just the fuel to permit the return vehicle to use
> the atmosphere for braking. There is the cost of launching the empty
> retrieval vehicle, of course.

If you have enough empty real estate, you can employ lithobraking, then
use conventional mining methods on the new ore body. You can even top
up the supply when needed.

pt

[Quadibloc]

On Tuesday, April 28, 2015 at 6:22:11 PM UTC-6, JRStern wrote:

> Unless there's a huge breakthrough in propulsion technologies it
> won't, either. If a million tons in minted gold and platinum coins
> was already in orbit around the Earth, I'm not sure it would pay to
> land them.

What costs billions of dollars is launching something *into space*.

Landing on Mars is tricky, because it has too much atmosphere for rocket
engines to work well enough for a landing under rocket power, like on the Moon
- but too little atmosphere to cut down the velocity of a craft we want to land
reliably if that craft is large in size.

Earth, on the other hand, has enough atmosphere to make splashdown from orbit
relatively easy.

So the challenges would be - launching enough rocket power up, from Earth, to
an asteroid, and then changing the asteroid's velocity so as to capture it into
Earth orbit.

Landing good-sized chunks of the asteroid to an ocean splashdown, like a
Mercury capsule, without hitting a city by accident instead, is the easy part.

Of course, unlike a Mercury capsule, an asteroid chunk will require a lot of
floatation to keep it from sinking to the bottom of the sea, not just a little. But even that is one of the lesser challenges.

John Savard

[Quadibloc]

On Tuesday, April 28, 2015 at 6:22:11 PM UTC-6, JRStern wrote:

> Unless there's a huge breakthrough in propulsion technologies it
> won't, either. If a million tons in minted gold and platinum coins
> was already in orbit around the Earth, I'm not sure it would pay to
> land them.

What costs billions of dollars is launching something *into space*.

Landing on Mars is tricky, because it has too much atmosphere for rocket
engines to work well enough for a landing under rocket power, like on the Moon
- but too little atmosphere to cut down the velocity of a craft we want to land
reliably if that craft is large in size.

Earth, on the other hand, has enough atmosphere to make splashdown from orbit
relatively easy.

So the challenges would be - launching enough rocket power up, from Earth, to
an asteroid, and then changing the asteroid's velocity so as to capture it into
Earth orbit.

Landing good-sized chunks of the asteroid to an ocean splashdown, like a
Mercury capsule, without hitting a city by accident instead, is the easy part.

Of course, unlike a Mercury capsule, an asteroid chunk will require a lot of
floatation to keep it from sinking to the bottom of the sea, not just a little. But even that is one of the less

John Savard

[pete...@gmail.com]

Much simpler and safer to lithobrake your ore body on land - no tsunami
risk, and land based mining is a well established industry.

pt

[a425couple]

"Bill Gill" <bill...@cox.net> wrote in message
news:mhqll0$8o1$1...@dont-email.me...

> On 4/29/2015 12:10 AM, William Vetter wrote:
>> a425couple wrote on 04/28/2015 :
>>> The development that Sci-Fi authors like Heinlein, Arthur Clarke,
>>> and many others have predicted is getting closer.
>>>
>>> "The Next Great Gold Rush Won't Be Taking Place on Earth
>>> By Ellie Kaufman April 21, 2015

>>> "The development, exploration and settlement of space is going to happen
>>> a lot faster than I think people think it will naturally," Lewicki
>>> said. "This isn't
>>> 50 years away, it's 10 or 20 years away."
>>> http://mic.com/articles/115786/the-next-great-gold-rush-won-t-be-taking-place-on-earth
>>>
>> I had always been under the impression that rare metals were
>> concentrated in deposits by active geologic processes. Why should Pt
>> nuggets lie up there waiting for us in the asteroids? Are their nuggets
>> of precious metals in iron/nickel meteorites?

> Of course they do. Just ask Kimball Kinnison when he was posing as
> an asteroid miner. Bill

?
en.wikipedia.org/wiki/Lensman_series
Kimball Kinnison meets and marries the product of the complementary human
breeding program, Clarissa MacDougall. She is a beautiful, curvaceous, ...

Ohh, ok.

[a425couple]

"Quadibloc" <jsa...@ecn.ab.ca> wrote in message...

> JRStern wrote:
>> Unless there's a huge breakthrough in propulsion technologies it
>> won't, either. If a million tons in minted gold and platinum coins
>> was already in orbit around the Earth, I'm not sure it would pay to
>> land them.
>
> What costs billions of dollars is launching something *into space*.
>
> Landing on Mars is tricky, because it has too much atmosphere for rocket
> engines to work well enough for a landing under rocket power, like on the
> Moon
> - but too little atmosphere to cut down the velocity of a craft we want to
> land
> reliably if that craft is large in size.
>
> Earth, on the other hand, has enough atmosphere to make

- splashdown from orbit relatively easy.

>
> So the challenges would be - launching enough rocket power up, from Earth,
> to
> an asteroid, and then changing the asteroid's velocity so as to capture it
> into
> Earth orbit.

Yes.

> Landing good-sized chunks of the asteroid to an ocean splashdown, like a
> Mercury capsule, without hitting a city by accident instead, is the easy
> part.

It seems to me, all you need is a fairly small drogue parachute
to reduce speed to less then burn up, and less then deep burial
in Australian desert. Why take risks with ocean?

http://en.wikipedia.org/wiki/Drogue_parachute
A drogue parachute is a parachute designed to be deployed from a rapidly
moving object in order to slow the object, to provide control and stability,

[lal_truckee]

On 4/29/15 8:19 AM, Quadibloc wrote:
> too much atmosphere for rocket
> engines to work well enough for a landing under rocket power

What did you intend to say with that statement? I can't parse any sense
from it.

It recalls the New York Times editorial Jan 13, 1920 claimed rockets
can't work in space since there's no air to push against.

[pete...@gmail.com]

Quaddie's exactly right. It would actually be easier to land on Mars if it
had no atmosphere. TL,DNR: Mars' atmosphere is thick enough to create problems,
but too thin to help.

Partly, its the cube/square law. With current technology, we can't EDL anything
over about a ton. If its bigger, a conventional heatshield doesn't slow you
down enough to use a parachute, and starting a retrorocket facing into a
mach 6 headwind is challenging, even at Martian pressures.

http://www.airspacemag.com/space/mars-dilemma-180952797/

and
http://www.nss.org/settlement/mars/AccessToMars.pdf

From the latter:

We Cannot Land People on Mars Right Now !

This is called the Mars EDL Problem (Entry, Descent and Landing).

* No combination of available parachutes, re-
entry shields and terminal descent rockets
can land a 10 ton payload on Mars right now

* Minimal Crew Lander (expendable lander only)
size is 20 tons, Cargo Landers and Re-usable
Ferries probably weigh 60-200 tons.

* Cargo Ferry should deliver 20+ tons to surface.

pt

[Kevrob]

On Wednesday, April 29, 2015 at 5:50:05 PM UTC-4, lal_truckee wrote:

> On 4/29/15 8:19 AM, Quadibloc wrote:
> > too much atmosphere for rocket
> > engines to work well enough for a landing under rocket power
>
> What did you intend to say with that statement? I can't parse any sense
> from it.

I _think_ he is positing a landing on Mars akin to what the LEM did on the
moon: just use the rocket to slow ascent and touchdown. The shuttle
landed without rockets because it was a lifting body, and was piloted in
as the world's heaviest glider. The LEM and landers like it

In a thin Martian atmosphere, I don't know if an aerodynamic vehicle
would make sense, maybe with rocket assistance. Landers like Viking used
a powered descent and chutes. Pathfinder and the rovers Opportunity and Spirit
also used airbags to cushion descent. Viking had its "aeroshell,"
designed to burn off on descent.

> It recalls the New York Times editorial Jan 13, 1920 claimed rockets
> can't work in space since there's no air to push against.

An air-breathing jet might be useless on Mars, otherwise I don't get the
objection. Reaction doesn't depend on atmosphere outside the ship.

Kevin R

[Kevrob]

On Wednesday, April 29, 2015 at 6:17:02 PM UTC-4, Kevrob wrote:
> On Wednesday, April 29, 2015 at 5:50:05 PM UTC-4, lal_truckee wrote:
> > On 4/29/15 8:19 AM, Quadibloc wrote:
> > > too much atmosphere for rocket
> > > engines to work well enough for a landing under rocket power
> >
> > What did you intend to say with that statement? I can't parse any sense
> > from it.
>
> I _think_ he is positing a landing on Mars akin to what the LEM did on the
> moon: just use the rocket to slow ascent and touchdown. The shuttle
> landed without rockets because it was a lifting body, and was piloted in
> as the world's heaviest glider. The LEM and landers like it

OOPS! Missing text!

The LEM and landers like it work best in a near vacuum.

[Brian M. Scott]

On Wed, 29 Apr 2015 15:23:10 -0700 (PDT), Kevrob
<kev...@my-deja.com> wrote
in<news:f28d60a4-b07a-4d69...@googlegroups.com>
in rec.arts.sf.written:

> On Wednesday, April 29, 2015 at 6:17:02 PM UTC-4, Kevrob
> wrote:

[...]

>> I _think_ he is positing a landing on Mars akin to what
>> the LEM did on the moon: just use the rocket to slow
>> ascent and touchdown. The shuttle landed without
>> rockets because it was a lifting body, and was piloted
>> in as the world's heaviest glider. The LEM and landers
>> like it

> OOPS! Missing text!

> The LEM and landers like it work best in a near vacuum.

You were just being helpful and trying to create a near
vacuum!

[...]

Brian
--
It was the neap tide, when the baga venture out of their
holes to root for sandtatties. The waves whispered
rhythmically over the packed sand: haggisss, haggisss,
haggisss.

[Robert Bannister]

On 29/04/2015 11:19 pm, Quadibloc wrote:

> Landing on Mars is tricky, because it has too much atmosphere for rocket
> engines to work well enough for a landing under rocket power, like on the Moon

I'd never thought about that before. Now another cherished image from
space opera bites the dust - all those spacecraft landing at spaceports
on worlds with earth-like or thicker atmospheres with nothing more than
a "Hit the retros, Scotty".

[JRStern]

Even with lithobraking I'd like to see some real numbers on what it
takes to slow say a ton mass in LEO to hit a five-mile circle.

With ocean landing in a shallow bay ...

Or a 10g landing in the sand ...

You still have to get a *booster* up there, with enough fuel, and
anything south of lithobraking you need shields and chutes or wings or
something.

I guess if you have time, you can put a tiny 1kg ion engine on it and
wait a few months, but the precision on that would be as minimal as
the power involved.

J.


>
>pt

[Cryptoengineer]

Robert Bannister <rob...@clubtelco.com> wrote in
news:cqd81h...@mid.individual.net:

> On 29/04/2015 11:19 pm, Quadibloc wrote:
>
>> Landing on Mars is tricky, because it has too much atmosphere for
>> rocket engines to work well enough for a landing under rocket power,
>> like on the Moon
>
> I'd never thought about that before. Now another cherished image from
> space opera bites the dust - all those spacecraft landing at
> spaceports on worlds with earth-like or thicker atmospheres with
> nothing more than a "Hit the retros, Scotty".

I have to say I'm find this a little confusing. We have actual
rocket scientists telling us can't land on Mars on retros, yet
Elon Musk's Falcon boosters are getting close to sucessful
landings, purely on retros. No parachutes involved. Perhaps
they are moving at a lower velocity, though Musk is also
talking about recovering the second stages, which do reach
orbital velocity.

Part of the Mars problem is that ships have been going into
EDL as soon as they arrive, with the full velocity of their
interplanetary trip. One of the mitigations the engineers
are proposing involves a preliminary aerobrake pass through
the upper atmosphere and settling into low Mars orbit
before final EDL.

[Greg Goss]

Quadibloc <jsa...@ecn.ab.ca> wrote:

>Landing good-sized chunks of the asteroid to an ocean splashdown, like a
>Mercury capsule, without hitting a city by accident instead, is the easy part.
>
>Of course, unlike a Mercury capsule, an asteroid chunk will require a lot of
>floatation to keep it from sinking to the bottom of the sea, not just a little. But even that is one of the lesser challenges.

UNLIKE a Mercury? Didn't they lose one of the Mercuries when it sank
after the pilot got out?

The book version of this seems to use solar mirrors to melt big
portions of a metallic (civilian term - I cannot comprehend the
astronomer's term) rock. You then blow a bunch of bubbles into it.
Enough bubbles and ...
http://static.trunity.net/files/122101_122200/122124/250px-Pumice_Floating.jpg
--
We are geeks. Resistance is voltage over current.

[Greg Goss]

Greg Goss <go...@gossg.org> wrote:

>Quadibloc <jsa...@ecn.ab.ca> wrote:
>
>>Landing good-sized chunks of the asteroid to an ocean splashdown, like a
>>Mercury capsule, without hitting a city by accident instead, is the easy part.
>>
>>Of course, unlike a Mercury capsule, an asteroid chunk will require a lot of
>>floatation to keep it from sinking to the bottom of the sea, not just a little. But even that is one of the lesser challenges.
>
>UNLIKE a Mercury? Didn't they lose one of the Mercuries when it sank
>after the pilot got out?

http://en.wikipedia.org/wiki/Mercury-Redstone_4#Failed_spacecraft_recovery

[Mike Dworetsky]

Quadibloc wrote:
> On Tuesday, April 28, 2015 at 6:22:11 PM UTC-6, JRStern wrote:
>
>> Unless there's a huge breakthrough in propulsion technologies it
>> won't, either. If a million tons in minted gold and platinum coins
>> was already in orbit around the Earth, I'm not sure it would pay to
>> land them.
>
> What costs billions of dollars is launching something *into space*.
>
> Landing on Mars is tricky, because it has too much atmosphere for
> rocket
> engines to work well enough for a landing under rocket power, like on
> the Moon - but too little atmosphere to cut down the velocity of a
> craft we want to land
> reliably if that craft is large in size.
>
> Earth, on the other hand, has enough atmosphere to make splashdown
> from orbit
> relatively easy.
>
> So the challenges would be - launching enough rocket power up, from
> Earth, to
> an asteroid, and then changing the asteroid's velocity so as to
> capture it into
> Earth orbit.

It takes a huge amount of power (propulsion) to bring an asteroid into Earth
orbit. Even a small asteroid has a alrge mass. If all you want are the
valuable rare minerals, it ought to be far cheaper to mine and extract them
first, then send the finished product back to Earth.

>
> Landing good-sized chunks of the asteroid to an ocean splashdown,
> like a
> Mercury capsule, without hitting a city by accident instead, is the
> easy part.
>
> Of course, unlike a Mercury capsule, an asteroid chunk will require a
> lot of
> floatation to keep it from sinking to the bottom of the sea, not just
> a little. But even that is one of the lesser challenges.
>
> John Savard

[Scott Lurndal]

a parachute requires air. You need to slow down -before-
getting to an altitude where air pressure is sufficient
to cause frictional heating.

[JRStern]

On Wed, 29 Apr 2015 19:47:29 -0500, Cryptoengineer
<treif...@gmail.com> wrote:

>Robert Bannister <rob...@clubtelco.com> wrote in
>news:cqd81h...@mid.individual.net:
>
>> On 29/04/2015 11:19 pm, Quadibloc wrote:
>>
>>> Landing on Mars is tricky, because it has too much atmosphere for
>>> rocket engines to work well enough for a landing under rocket power,
>>> like on the Moon
>>
>> I'd never thought about that before. Now another cherished image from
>> space opera bites the dust - all those spacecraft landing at
>> spaceports on worlds with earth-like or thicker atmospheres with
>> nothing more than a "Hit the retros, Scotty".
>
>I have to say I'm find this a little confusing. We have actual
>rocket scientists telling us can't land on Mars on retros, yet
>Elon Musk's Falcon boosters are getting close to sucessful
>landings, purely on retros.

"We will be landing in ten minutes, or getting close."

J.

[pete...@gmail.com]

You'd have to talk to the locals about that - when the Japanese
landed the Hayabusa probe's sample return capsule in the Woomera
Test Range, they had to get clearance from local Aboriginal elders
before they were allowed to collect it, who checked whether or not
it had landed in a sacred site.

> >http://en.wikipedia.org/wiki/Drogue_parachute
> >A drogue parachute is a parachute designed to be deployed from a rapidly
> >moving object in order to slow the object, to provide control and stability,

> a parachute requires air. You need to slow down -before-
> getting to an altitude where air pressure is sufficient
> to cause frictional heating.

Yes. I'll point out that both Stardust and Hayabusa entered at > 12 km/s, but
with heatshields to slow them to subsonic speeds. Stardust hit 34g when it
was still 55 km up.

If asteroids were solid chunks of nickle-iron, we wouldn't worry too much about
ablation in big ones. But if they're fragile (and we now know that most are),
breakup in the upper atmosphere is a real problem.

You *could* refine the metals in space to make a breakup resistant solid metal
core, and lithobrake that.

If you do, I hope your guidance systems are good, and your liability
insurance is paid up.

pt

[Gutless Umbrella Carrying Sissy]

Cryptoengineer <treif...@gmail.com> wrote in
news:XnsA48BD39536...@216.166.97.131:

> I have to say I'm find this a little confusing. We have actual
> rocket scientists telling us can't land on Mars on retros, yet
> Elon Musk's Falcon boosters are getting close to sucessful
> landings, purely on retros. No parachutes involved.

And showing that it is a very difficult task, even when the flight
time is minutes, at earth normal temperatures, without having to
deal with the effects of months in a vacuum. Impossible, so far, in
fact.

> Perhaps
> they are moving at a lower velocity, though Musk is also
> talking about recovering the second stages, which do reach
> orbital velocity.

I'm not sure what the final speed is on the first stage, but yeah,
it's a *lot* slower than orbital. And remember, the reasons for the
failures so far are, for the most part, expendable supplies.
Specifically, fuel and hydraulic fluid. Add enough of both to land
properly from orbital speeds, and you likely won't be able to
launch at all due to the weight.

And this is all with the action happening close enough for
realistic real time control, rather than a half hour delay.

>
> Part of the Mars problem is that ships have been going into
> EDL as soon as they arrive, with the full velocity of their
> interplanetary trip. One of the mitigations the engineers
> are proposing involves a preliminary aerobrake pass through
> the upper atmosphere and settling into low Mars orbit
> before final EDL.
>

Interesting thought, if the numbers work out. But don't lower
orbits require _higher_ velocities? So reentry from the lower orbit
would actually exaggerate the problem of slowing down, because the
initial speed would be higher.

--
Terry Austin

"Terry Austin: like the polio vaccine, only with more asshole."
-- David Bilek

Jesus forgives sinners, not criminals.

[pete...@gmail.com]

On Thursday, April 30, 2015 at 1:39:05 PM UTC-4, Gutless Umbrella Carrying Sissy wrote:
> Cryptoengineer <treif...@gmail.com> wrote in
> news:XnsA48BD39536...@216.166.97.131:
>
> > I have to say I'm find this a little confusing. We have actual
> > rocket scientists telling us can't land on Mars on retros, yet
> > Elon Musk's Falcon boosters are getting close to sucessful
> > landings, purely on retros. No parachutes involved.
>
> And showing that it is a very difficult task, even when the flight
> time is minutes, at earth normal temperatures, without having to
> deal with the effects of months in a vacuum. Impossible, so far, in
> fact.

It looks like an iterative debugging process, and I don't think there's
much doubt they'll figure it out. The next test is in June.

> > Perhaps
> > they are moving at a lower velocity, though Musk is also
> > talking about recovering the second stages, which do reach
> > orbital velocity.
>
> I'm not sure what the final speed is on the first stage, but yeah,
> it's a *lot* slower than orbital. And remember, the reasons for the
> failures so far are, for the most part, expendable supplies.
> Specifically, fuel and hydraulic fluid. Add enough of both to land
> properly from orbital speeds, and you likely won't be able to
> launch at all due to the weight.

SpaceX also plans to retrieve the second stage, which does reach orbit.
They haven't started on that one yet.

> And this is all with the action happening close enough for
> realistic real time control, rather than a half hour delay.
> >
> > Part of the Mars problem is that ships have been going into
> > EDL as soon as they arrive, with the full velocity of their
> > interplanetary trip. One of the mitigations the engineers
> > are proposing involves a preliminary aerobrake pass through
> > the upper atmosphere and settling into low Mars orbit
> > before final EDL.
> >
> Interesting thought, if the numbers work out. But don't lower
> orbits require _higher_ velocities? So reentry from the lower orbit
> would actually exaggerate the problem of slowing down, because the
> initial speed would be higher.

The real rocket scientists seem to think this is the right way to
do it. If you start in high orbit, you've farther to fall to get
to the atmosphere, and I suspect the speed gained in that fall is
the same or higher as the speed of the lower orbit - after all, you've
more potential energy to get rid of.

Deorbiting starts with a retro rocket burn to kill your orbital velocity.

pt

[Gutless Umbrella Carrying Sissy]

pete...@gmail.com wrote in
news:81cbce99-8afc-40da...@googlegroups.com:

> On Thursday, April 30, 2015 at 1:39:05 PM UTC-4, Gutless
> Umbrella Carrying Sissy wrote:
>> Cryptoengineer <treif...@gmail.com> wrote in
>> news:XnsA48BD39536...@216.166.97.131:
>>
>> > I have to say I'm find this a little confusing. We have
>> > actual rocket scientists telling us can't land on Mars on
>> > retros, yet Elon Musk's Falcon boosters are getting close to
>> > sucessful landings, purely on retros. No parachutes involved.
>>
>> And showing that it is a very difficult task, even when the
>> flight time is minutes, at earth normal temperatures, without
>> having to deal with the effects of months in a vacuum.
>> Impossible, so far, in fact.
>
> It looks like an iterative debugging process, and I don't think
> there's much doubt they'll figure it out. The next test is in
> June.

I agree. But it shows that doing the same thing at a range of 35
million miles (or more) is *hard*.

>
>> > Perhaps
>> > they are moving at a lower velocity, though Musk is also
>> > talking about recovering the second stages, which do reach
>> > orbital velocity.
>>
>> I'm not sure what the final speed is on the first stage, but
>> yeah, it's a *lot* slower than orbital. And remember, the
>> reasons for the failures so far are, for the most part,
>> expendable supplies. Specifically, fuel and hydraulic fluid.
>> Add enough of both to land properly from orbital speeds, and
>> you likely won't be able to launch at all due to the weight.
>
> SpaceX also plans to retrieve the second stage, which does reach
> orbit. They haven't started on that one yet.

And there are a number of "companies" that plan to mine the moon
for, I'm not sure what, or mine asteroids for platinum, or
whatever. Planning to do so and doing so are not necessarily even
remotely connected.

(That said, if anybody can pull it off, it's SpaceX, but you're
talking a job that's a *lot* more challenging - the first stage
isn't making any kind of reentry.)

>
>> And this is all with the action happening close enough for
>> realistic real time control, rather than a half hour delay.
>> >
>> > Part of the Mars problem is that ships have been going into
>> > EDL as soon as they arrive, with the full velocity of their
>> > interplanetary trip. One of the mitigations the engineers
>> > are proposing involves a preliminary aerobrake pass through
>> > the upper atmosphere and settling into low Mars orbit
>> > before final EDL.
>> >
>> Interesting thought, if the numbers work out. But don't lower
>> orbits require _higher_ velocities? So reentry from the lower
>> orbit would actually exaggerate the problem of slowing down,
>> because the initial speed would be higher.
>
> The real rocket scientists seem to think this is the right way
> to do it. If you start in high orbit, you've farther to fall to
> get to the atmosphere, and I suspect the speed gained in that
> fall is the same or higher as the speed of the lower orbit -
> after all, you've more potential energy to get rid of.

I think the main advantage is that you don't have to take the mass
of what you're slowing down against (air) with you. That's a big
advantage. But if it were obviously the best course, they'd have
been doing it all along.

>
> Deorbiting starts with a retro rocket burn to kill your orbital
> velocity.

No. Deorbiting starts with a retro rocket burn to slow your orbital
velocity to below orbital velocity. On the moon, yeah, you need to
kill it completely. On Mars, even with its thin atmosphere, not so
much.

Which is to say, it's complicated and difficult, under the best of
conditions, which is why we have a 50% failure rate on Mars
landers.

[David DeLaney]

On 2015-04-29, Quadibloc <jsa...@ecn.ab.ca> wrote:
> Landing on Mars is tricky, because it has too much atmosphere for rocket
> engines to work well enough for a landing under rocket power, like on the Moon
> - but too little atmosphere to cut down the velocity of a craft we want to
> land reliably if that craft is large in size.

And of course American ingenuity, based on the sacred teachings of one R.
Goldberg, found a way around this using an erector set, inflatable mattresses,
a deck of cards, a lampshade, and a very nervous mouse...

Dave
--
\/David DeLaney posting thru EarthLink - "It's not the pot that grows the flower
It's not the clock that slows the hour The definition's plain for anyone to see
Love is all it takes to make a family" - R&P. VISUALIZE HAPPYNET VRbeable<BLINK>
http://gatekeeper.vic.com/~dbd/ -net.legends/Magic / I WUV you in all CAPS! --K.

[David DeLaney]

On 2015-04-30, Gutless Umbrella Carrying Sissy <taus...@gmail.com> wrote:
> Interesting thought, if the numbers work out. But don't lower
> orbits require _higher_ velocities?

Yes. This is why close-orbit of Earth goes around the world in 80 minutes,
while geosync satellites further out take a day and the Moon needs nearly a
month...

Dave, listening carefully for *r**l36's footsteps

[pete...@gmail.com]

On Friday, May 1, 2015 at 12:53:25 AM UTC-4, David DeLaney wrote:
> On 2015-04-30, Gutless Umbrella Carrying Sissy <taus...@gmail.com> wrote:
> > Interesting thought, if the numbers work out. But don't lower
> > orbits require _higher_ velocities?
>
> Yes. This is why close-orbit of Earth goes around the world in 80 minutes,
> while geosync satellites further out take a day and the Moon needs nearly a
> month...

You're missing part of the picture. We're talking about how much energy (fuel)
you have to expend or dispose of to get to the orbit, or back down to Earth.

It's true that a satellite in low earth orbit is moving around the planet
almost 3x as fast as one in GEO (not 18x - GEO is much bigger than LEO).

However, putting a satellite in GEO involves lifting it 37,000 extra
km. That's a *lot* of potential energy, all of which becomes kinetic when
it comes out of orbit, and has to be disposed of for landing to occur.

It takes about 3.29*10^7 joules/kg to get to LEO, and 5.78*10^7 for GEO. That's
extra energy you're going to have to get rid of getting out of the higher
orbit.

Its a lot easier, and require less energy to reach lower orbits than
higher ones.

pt

[Dimensional Traveler]

On 4/30/2015 9:50 PM, David DeLaney wrote:
> On 2015-04-29, Quadibloc <jsa...@ecn.ab.ca> wrote:
>> Landing on Mars is tricky, because it has too much atmosphere for rocket
>> engines to work well enough for a landing under rocket power, like on the Moon
>> - but too little atmosphere to cut down the velocity of a craft we want to
>> land reliably if that craft is large in size.
>
> And of course American ingenuity, based on the sacred teachings of one R.
> Goldberg, found a way around this using an erector set, inflatable mattresses,
> a deck of cards, a lampshade, and a very nervous mouse...
>

LOL.

Of course, that was only possible because we hadn't been polluted by
that silly rational metric system. :D


--
Veni, vidi, snarki.

[Brian M. Scott]

On Fri, 01 May 2015 20:49:27 -0700, Dimensional Traveler
<dtr...@sonic.net> wrote
in<news:55444948$0$36567$742e...@news.sonic.net> in
rec.arts.sf.written:

Mouseonal units were so much cuter!

Brian
--
Using her breasts as a shelf was the most practical thing
Helene had done all day. -- Meljean Brook, _The Kraken
King_

[David DeLaney]

On 2015-05-02, Brian M. Scott <b.s...@csuohio.edu> wrote:
> Dimensional Traveler <dtr...@sonic.net> wrote

>> On 4/30/2015 9:50 PM, David DeLaney wrote:
>>> On 2015-04-29, Quadibloc <jsa...@ecn.ab.ca> wrote:
>
>>>> Landing on Mars is tricky, because it has too much
>>>> atmosphere for rocket engines to work well enough for
>>>> a landing under rocket power, like on the Moon - but
>>>> too little atmosphere to cut down the velocity of a
>>>> craft we want to land reliably if that craft is large in size.
>
>>> And of course American ingenuity, based on the sacred
>>> teachings of one R. Goldberg, found a way around this
>>> using an erector set, inflatable mattresses, a deck of
>>> cards, a lampshade, and a very nervous mouse...
>
>> LOL.
>
>> Of course, that was only possible because we hadn't been
>> polluted by that silly rational metric system. :D
>
> Mouseonal units were so much cuter!

But - that left us vulnerable to Grand Fenwick!!

Dave, and subject to occasional princess epidemics

[Gene Wirchenko]

On Wed, 29 Apr 2015 12:31:38 +0000 (UTC), na...@math.ohio-state.edu
(Anthony Nance) wrote:

>Kevrob <kev...@my-deja.com> wrote:

[snip]

>> An asteroid full of precious metals still might not affect prices much
>> if transporting the mined materials to planetside manufacturing facilities
>> is still expensive.
>
>Or if the supplier(s) controlled how much was available.

Stretching a supply? Easy with such a ductile metal.

Sincerely,

Gene Wirchenko

[Quadibloc]

On Wednesday, April 29, 2015 at 3:50:05 PM UTC-6, lal_truckee wrote:
> On 4/29/15 8:19 AM, Quadibloc wrote:
> > too much atmosphere for rocket
> > engines to work well enough for a landing under rocket power

> What did you intend to say with that statement? I can't parse any sense
> from it.

Oh, I was referring to a real phenomenon. All that wind hitting the Mars
spacecraft as it is trying to slow down means that the gases in the combustion
chamber of its rocket engines are pushed in... and so it doesn't work properly,
as it would work if it weren't bothered on a place like the Moon.

A spaceship doing re-entry, after all, is moving *really fast*. Even in Mars'
thin atmosphere, if you're doing something well over 10,000 MPH, it's starting
to get as bad as having hurricane-force winds blowing up into your rocket
engines on Earth.

John Savard

[Quadibloc]

On Wednesday, April 29, 2015 at 4:10:42 PM UTC-6, pete...@gmail.com wrote:

> * Minimal Crew Lander (expendable lander only)
> size is 20 tons, Cargo Landers and Re-usable
> Ferries probably weigh 60-200 tons.

Of course, this discloses the *solution* to the problem.

The only limiting factor in how small a spaceship, whether used to lift
astronauts from the Earth to a transport ship in orbit, or to put astronauts on
Mars, can be... is the fact that you can't cut an astronaut into pieces and
then reassemble him later, and expect him to be alive and mobile afterwards.

Hence, it really *ought* to be able to make a space pod that could land one
astronaut on Mars from Mars orbit that weighs no more than *one* ton, which is
small enough that we *could* land it.

And I see that one ton really was how much a Mercury capsule weighed. Of
course, they really had to work to make it that light - for example, they made
its outer shell out of *beryllium*.

John Savard

[treif...@gmail.com]

John - the *experts* - actual rocket scientists - are saying that the minimal
crew lander is 20 tons. While we don't know how many people that carries, I
suggest that your argument that we should be able to do it with one ton
craft is based on - well - not thinking things through.

Mercury capsules didn't have to supply life support after landing. Also, they
could use parachutes and heat shields for the entirety of their deceleration.
Neither of these apply to a Mars lander. Curiosity hit over 12G on the way in,
which is pretty rough.

Yes, you might be able to get a person alive on the surface with current
technologies, but keeping them alive is a different problem.

(and no, we can't make sure they land within easy walking distance of
pre-dropped supplies - the technology just isn't that precise.)

pt

[Anonymous Remailer (austria)]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA512

When I read about "the potential of asteroid mining" I don't think
about profits, or making minerals less expensive. I think about
Bhopal, Chernobyl, Three Mile Island, Malaysia Airlines Flight 370,
the Costa Concordia, Andreas Lubitz, ISIS/ISIL + hacking, Fukushina
#1 and too many coal mine disasters to list.

Murphy is already in space.

Not hard to find a city destroying sized asteroid that could be
shoved to land on a city.

Be nice if a lot of thought were given to the real problems with
bringing asteroid close to the Earth before anyone started getting
all giddy about spending their millions from such an enterprise.


Adamastor Glace Mortimer

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[Quadibloc]

On Saturday, May 2, 2015 at 7:38:31 PM UTC-6, treif...@gmail.com wrote:

> (and no, we can't make sure they land within easy walking distance of
> pre-dropped supplies - the technology just isn't that precise.)

Oh yes we can, and without having to land them at a precise location either.

Just drop *lots* of supplies over a large area, so that the astronaut will be
certain to be within easy walking distance of *some* of them.

At the moment, the new information about the severity of the radiation issue is something for which I can't see a simple fix without depending on new technology. On my web site, at

http://www.quadibloc.com/science/spaint.htm

I have a difficult fix for the cosmic ray issue in space, but while it's reasonable for space habitats, I think it's more than people would be willing to pay for in the case of a manned space mission.

John Savard

[Gutless Umbrella Carrying Sissy]

treif...@gmail.com wrote in
news:0bb03379-47bd-496f...@googlegroups.com:

> Mercury capsules didn't have to supply life support after
> landing. Also, they could use parachutes and heat shields for
> the entirety of their deceleration. Neither of these apply to a
> Mars lander. Curiosity hit over 12G on the way in, which is
> pretty rough.
>

Mercury capsules were called capsules because they didn't have any
maneuvering capabilities to speak of (the Gemini was the first
spacecraft with a command module). It certainly didn't have anything
like the ability to land in as thin an atmosphere as Mars.

[Gutless Umbrella Carrying Sissy]

Quadibloc <jsa...@ecn.ab.ca> wrote in
news:cb175497-1929-4ec3...@googlegroups.com:

> On Saturday, May 2, 2015 at 7:38:31 PM UTC-6, treif...@gmail.com
> wrote:
>
>> (and no, we can't make sure they land within easy walking
>> distance of pre-dropped supplies - the technology just isn't
>> that precise.)
>
> Oh yes we can, and without having to land them at a precise
> location either.
>
> Just drop *lots* of supplies over a large area, so that the
> astronaut will be certain to be within easy walking distance of
> *some* of them.
>

Now you're increase the cost by at least one order of magnitude.
Perhaps two. Nice going, there, Tex.

[a425couple]

"Anonymous Remailer (austria)" <mixm...@remailer.privacy.at> wrote in...

> When I read about "the potential of asteroid mining" I don't think
> about profits, or making minerals less expensive. I think about
> Bhopal, Chernobyl, Three Mile Island, Malaysia Airlines Flight 370,
> the Costa Concordia, Andreas Lubitz, ISIS/ISIL + hacking, Fukushina
> #1 and too many coal mine disasters to list.
>
> Murphy is already in space.
>
> Not hard to find a city destroying sized asteroid that could be
> shoved to land on a city.

Some evidence would seem to indicate, that Austrian
"Anonymous Remailer" can type on a computer, and
connect with the internet, but yet is fearful of any
'new' advances.

Hmmm, suppose he also wants to go back to where one
farmer and one draft animal were needed to make
one furrow?
http://en.wikipedia.org/wiki/Mechanised_agriculture
http://en.wikipedia.org/wiki/Productivity_improving_technologies_%28historical%29
http://en.wikipedia.org/wiki/Luddite

[Kevrob]

It's also not like those in the group are ignorant of the idea of
using sheer mass as a weapon from space. That's at least as old
as Heinlein's MOON IS A HARSH MISTRESS.

Kevin R

[J. Clarke]

In article <2d048e90-ee13-4f95...@googlegroups.com>,
kev...@my-deja.com says...

Actually goes back to Doc Smith, where ultimately entire planets were
used for such purposes. I recall one place that they wanted to kill
really dead got sandwiched between two of htem with opposing intrinsics.

[William December Starr]

In article <xn0jlbll...@reader80.eternal-september.org>,
"steve robinson" <st...@colevalleyinteriors.co.uk> said:

> The problem is if the astoriods are that rich in platnuim
> it will actually bring the value down

"Okay, you've just crashed the Earth's economy. Now what?"

Approximate bit of dialogue from one of the books in Alexis
Gilliland's Rosinante trilogy, probably the third one, THE
PIRATES OF ROSINANTE.

(Note: not space opera, despite the title.)

-- wds

[monte...@gmail.com]

Down from orbit is much easier than up to orbit. Especially as you can use both high specific impulse rocket engines like ion engines for example, and you do not need high thrust to get down.

You just need enough velocity change to cause your orbit to dip into the atmosphere. Friction with air does the rest. That could be as cheap as 100 meters/sec or less.

To get from the earth's surface to orbit takes 8000 meters/sec.

[tian]

On 05/03/2015 02:00 AM, Anonymous Remailer (austria) wrote:
> When I read about "the potential of asteroid mining" I don't think
> about profits, or making minerals less expensive. I think about
> Bhopal, Chernobyl, Three Mile Island, Malaysia Airlines Flight 370,
> the Costa Concordia, Andreas Lubitz, ISIS/ISIL + hacking, Fukushina
> #1 and too many coal mine disasters to list.
>

I think of the enormous amounts of fuel that it takes to get there.
Then I think of the enormous volume of space between there and
another asteroid worth visiting. Seems to me to be a low return project.

--
Tian
http://tian.greens.org
Latest change: Added pictures from San Jose Bike Party's Bunny Ride.
There's a 5 ACTIONS pin on an Oregon quarter in my home.

[Brian M. Scott]

On Tue, 5 May 2015 22:16:00 -0400, "J. Clarke"
<j.clark...@gmail.com> wrote
in<news:MPG.2fb343696...@news.eternal-september.org>
in rec.arts.sf.written:

> In article <2d048e90-ee13-4f95...@googlegroups.com>,
> kev...@my-deja.com says...

[...]

>> It's also not like those in the group are ignorant of
>> the idea of using sheer mass as a weapon from space.
>> That's at least as old as Heinlein's MOON IS A HARSH
>> MISTRESS.

> Actually goes back to Doc Smith, where ultimately entire
> planets were used for such purposes. I recall one place
> that they wanted to kill really dead got sandwiched
> between two of htem with opposing intrinsics.

The penultimate trick in the Lensman series, though, was
tossing a free planet from Nth space, with ‘a mass of about
eight times ten to the twenty-first power’ metric tons and
an ‘absolutely impossible intrinsic velocity of over
fifteen times that of light’, at a planet -- and another
one into the planet’s sun. (The ultimate trick was all
mental.)

Brian
--
It was the neap tide, when the baga venture out of their
holes to root for sandtatties. The waves whispered
rhythmically over the packed sand: haggisss, haggisss,
haggisss.

[Michael Black]

On Wed, 6 May 2015, tian wrote:

> On 05/03/2015 02:00 AM, Anonymous Remailer (austria) wrote:
>> When I read about "the potential of asteroid mining" I don't think
>> about profits, or making minerals less expensive. I think about
>> Bhopal, Chernobyl, Three Mile Island, Malaysia Airlines Flight 370,
>> the Costa Concordia, Andreas Lubitz, ISIS/ISIL + hacking, Fukushina
>> #1 and too many coal mine disasters to list.
>>
> I think of the enormous amounts of fuel that it takes to get there.
> Then I think of the enormous volume of space between there and
> another asteroid worth visiting. Seems to me to be a low return project.
>

There's likely secondary value in it all.

When space colonies were a big idea from O'Neill, there was a whole
integrated package, mining allowed for the big structures but also allowed
value to be sent to earth.

One of the weird things is that having always had science fiction there
(even when the space program was revving up, there were all those
"artist's renditions" that were only a step away from fiction), what if
none of it is practical? That comes as a real shocker, the expectation
has always been there that space would be the future, and it would be
gained, and not just in a small way.

Michael

[J. Clarke]

In article <micmf...@enews2.newsguy.com>, tnha...@aceweb.com.nospam
says...

>
> On 05/03/2015 02:00 AM, Anonymous Remailer (austria) wrote:
> > When I read about "the potential of asteroid mining" I don't think
> > about profits, or making minerals less expensive. I think about
> > Bhopal, Chernobyl, Three Mile Island, Malaysia Airlines Flight 370,
> > the Costa Concordia, Andreas Lubitz, ISIS/ISIL + hacking, Fukushina
> > #1 and too many coal mine disasters to list.
> >
> I think of the enormous amounts of fuel that it takes to get there.
> Then I think of the enormous volume of space between there and
> another asteroid worth visiting. Seems to me to be a low return project.

The "enormous amounts of fuel" are only needed to get from Earth's
surface into orbit. Once you're in orbit you can use much much more
efficient engines.

[J. Clarke]

In article <alpine.LNX.2.02.1...@darkstar.example.org>,
et...@ncf.ca says...

The trouble is that you have to put hte necessary infrastructure into
place. And as long as we're throwing away multimillion dollar rockets
with ever launch it won't get there.

[William December Starr]

In article <1a09yudm2dyn5$.1q0vxyh6...@40tude.net>,

"Brian M. Scott" <b.s...@csuohio.edu> said:

> The penultimate trick in the Lensman series, though, was
> tossing a free planet from Nth space, with 'a mass of about
> eight times ten to the twenty-first power' metric tons and
> an 'absolutely impossible intrinsic velocity of over
> fifteen times that of light', at a planet -- and another
> one into the planet's sun. (The ultimate trick was all
> mental.)

"Hey, your shoelace is untied"?

-- wds

[a425couple]

"Michael Black" <et...@ncf.ca> wrote in message...

> On Wed, 6 May 2015, tian wrote:
>> On 05/03/2015 02:00 AM, Anonymous Remailer (austria) wrote:
>>> When I read about "the potential of asteroid mining" I don't think

>>> about profits, ---

>>>
>> I think of the enormous amounts of fuel that it takes to get there.
>> Then I think of the enormous volume of space between there and
>> another asteroid worth visiting. Seems to me to be a low return project.
>>
> There's likely secondary value in it all.
> When space colonies were a big idea from O'Neill, there was a whole
> integrated package, mining allowed for the big structures but also allowed
> value to be sent to earth.
> One of the weird things is that having always had science fiction there
> (even when the space program was revving up, there were all those
> "artist's renditions" that were only a step away from fiction),

> what if none of it is practical? That comes as a real shocker, the
> expectation has always been there that space would be the future, and it
> would be gained, and not just in a small way. Michael

Yes.
I have trouble seeing how it will turn out. Over 40 years
since we landed men on the moon.

But, I am reminded of:
"Seward actually began negotiations with the Russians before
receiving authorization from Johnson. --- The agreement was
signed in March 1867 and transferred Alaska to the United
States in return for a payment of $7.2 million ---
The treaty was ratified by the U.S. Senate by a single vote.
Criticism in the press was harsh, portraying the newly acquired
wasteland as "Seward's Folly," "Seward's Icebox" or Johnson's
"polar bear garden." It was not until the 1890s with the discovery
of gold that public attitudes regarding Alaska began to change.
http://www.u-s-history.com/pages/h230.html

[Kay Shapero]

In article <mior0...@news4.newsguy.com>, a425c...@hotmail.com
says...

All too often there's a generation or two between the really big
discoveries and exploitation of same.

--

Kay Shapero
Address munged, try my first name at kayshapero dot net.

[Anonymous Remailer (austria)]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA512

In article <miao1...@news6.newsguy.com>

"a425couple" <a425c...@hotmail.com> wrote:
>
> "Anonymous Remailer (austria)" <mixm...@remailer.privacy.at> wrote in...
> > When I read about "the potential of asteroid mining" I don't think
> > about profits, or making minerals less expensive. I think about
> > Bhopal, Chernobyl, Three Mile Island, Malaysia Airlines Flight 370,
> > the Costa Concordia, Andreas Lubitz, ISIS/ISIL + hacking, Fukushina
> > #1 and too many coal mine disasters to list.
> >
> > Murphy is already in space.
> >
> > Not hard to find a city destroying sized asteroid that could be
> > shoved to land on a city.
>
> Some evidence would seem to indicate, that Austrian
> "Anonymous Remailer" can type on a computer, and
> connect with the internet, but yet is fearful of any

> 'new' advances. ....

- From the evidence above one would be tempted to think that
a425couple can't read other people's names unless their E-mail
address is attached. Or maybe he prefers to be called newsdawg?

As for "fearful of any 'new' advances," I'm just noting that there
is plenty to be concerned about when people make a mad dash for a
quick buck. When the mad dash involved people in the past, and
present, working in mines that were unsafe or in places that were
not a good place to put a mine in the first place the death tolls
were relatively limited. Wildcat miners are as likely to be
successfully self-regulating in space as they have shown themselves
to be on Earth for a very long time.

It's another aspect of the asteroid mining proposition. If you
don't like to consider too many aspects of something, you're free
to keep it as simple as you please.

Adamastor Glace Mortimer

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[Quadibloc]

On Wednesday, May 6, 2015 at 3:41:30 PM UTC-6, Michael Black wrote:

> One of the weird things is that having always had science fiction there
> (even when the space program was revving up, there were all those
> "artist's renditions" that were only a step away from fiction), what if
> none of it is practical? That comes as a real shocker, the expectation
> has always been there that space would be the future, and it would be
> gained, and not just in a small way.

Since men didn't land on Mars in 1985, which was what people were expecting
during the Apollo program, it's not surprising some people wondered if the
Apollo program was a hoax.

But while it wasn't, since private enterprise has yet to put anyone on the Moon
again, clearly going to the Moon isn't "practical". The Moon landing helped
prove to some uncommitted nations that the U.S. was ahead of the Soviet Union -
so it might have saved India from Communism.

Without any similar compelling reason, it's not surprising that funding for
Mars has been more limited. After 9/11, we have an urgent down-to-earth problem
on our plate. Spending money on pure science... happens, but it's less
attractive than things that bring tangible rewards quickly.

There's no point decrying that; one can but hope the economy will pick up so
that such luxuries become more affordable.

And microelectronics has improved. Why, cell phones even have speech
recognition! Maybe we'll have science-fiction robots soon that we can talk to
and tell them to pick things up and move things around.

Of course, a robot smart enough, say, to wash dishes by hand and mow the lawn
would initially be much more expensive than a dishwasher and one of those fancy
tractor lawnmowers. Not to mention a Roomba, which is a little robot in its own
right. And a robot that could cook or wash clothes... that would require
another generation of advances!

John Savard

[Quadibloc]

On Wednesday, May 6, 2015 at 3:41:30 PM UTC-6, Michael Black wrote:

> That comes as a real shocker, the expectation
> has always been there that space would be the future, and it would be
> gained, and not just in a small way.

While the Apollo missions really happened, they were only one step away from
flying cars and jetpacks - which didn't.

That is one way to put, succinctly, why we aren't on Mars yet. It's not
technically impossible - but it doesn't pay for itself, and not enough people
see a good reason to pay for it.

John Savard

[Greg Goss]

Quadibloc <jsa...@ecn.ab.ca> wrote:

>Without any similar compelling reason, it's not surprising that funding for
>Mars has been more limited. After 9/11, we have an urgent down-to-earth problem
>on our plate. Spending money on pure science... happens, but it's less
>attractive than things that bring tangible rewards quickly.

I think of the fight with the extremist variants of Islam as "Cold War
Two". So the tactics that worked to defeat the USSR can still be
contemplated.

The demonstration of technical competence may have saved India, but I
think it was the collapse of the consumer marketplace and the need of
a high-tech society for open communications that was the final defeat
of the USSR. With open communications, the residents of the inferior
system could determine that the competing system worked better.

If the existence of wealthy middle and under classes ended Cold War
One, then I think a consumer society can have a similar impact on Cold
War Two. So we contain 'em with small brushfire wars and let 'em know
how we're getting along.

Mohammed Atta and the other 9/11 fanatics were apparently regulars at
US strip clubs. The consumer society does have attractions to the
target audience, though they want the REST of their society to buckle
under to AD 800 lifestyles.

The US wildly over-reacted to 9/11, especially with destabilizing much
of the Arabian peninsula. Since it was an Asian country that refused
to give up the criminal mastermind, knocking over Iraq (thus creating
ISIS) was a stupid idea.

9/11 should not have bankrupted the US, unless the guys in charge of
the US reacted stupidly. So saying that 9/11 "on our plate" prevents
exploration missions is a non sequitur.
--
We are geeks. Resistance is voltage over current.

[Cryptoengineer]

Greg Goss <go...@gossg.org> wrote in
news:cs9lql...@mid.individual.net:

> Quadibloc <jsa...@ecn.ab.ca> wrote:
>
>>Without any similar compelling reason, it's not surprising that
>>funding for Mars has been more limited. After 9/11, we have an urgent
>>down-to-earth problem on our plate. Spending money on pure science...
>>happens, but it's less attractive than things that bring tangible
>>rewards quickly.
>
> I think of the fight with the extremist variants of Islam as "Cold War
> Two". So the tactics that worked to defeat the USSR can still be
> contemplated.
>
> The demonstration of technical competence may have saved India, but I
> think it was the collapse of the consumer marketplace and the need of
> a high-tech society for open communications that was the final defeat
> of the USSR. With open communications, the residents of the inferior
> system could determine that the competing system worked better.
>
> If the existence of wealthy middle and under classes ended Cold War
> One, then I think a consumer society can have a similar impact on Cold
> War Two. So we contain 'em with small brushfire wars and let 'em know
> how we're getting along.
>
> Mohammed Atta and the other 9/11 fanatics were apparently regulars at
> US strip clubs. The consumer society does have attractions to the
> target audience, though they want the REST of their society to buckle
> under to AD 800 lifestyles.

There's an old Analog story (early 70s?) in which humans are fighting
a protracted war against mysterious aliens. The humans inflict huge
casualty numbers on the aliens, but they don't give up, inflicting
huge material losses against the humans.

The upshot of the plot is that both sides think they're winning. The
aliens are a hive mind, and losing individuals doesn't matter, while
the humans have far better material production capabilities than the
aliens.

Each side can't understand why the other isn't suing for peace. The
problem is that they don't understand the other's goals.

Your description of the West vs ISIS reminds me of that. You think
the Arab extremists can be seduced by the fleshpots of the civilized
West.

The problem is that ISIS isn't really about establishing a Caliphate
as a world power; ISIS is about bringing on the Muslim version of
Armageddon - the end of the world. They *want* war. They *want* to
die - I was reading just yesterday about how non-Arab ISIS members
are really pissed at being passed over for suicide bomber missions
in favor of members who are Saudis or have Saudi connections. (this
is turning up on Chechen Muslim social media).

ISIS' actions are consistant with their trying to foment war between
Muslim and Muslim, and Muslims with everyone else. We should not assume
that the methods of the Cold War are going to work as well as they did
on the Soviets.

pt

[J. Clarke]

In article <XnsA4A2C7B2A6...@216.166.97.131>,
treif...@gmail.com says...

So you're saying to just pave the place and let Allah sort 'em out?

[Cryptoengineer]

"J. Clarke" <j.clark...@gmail.com> wrote in

news:MPG.2fc9dd9af...@news.eternal-september.org:

I'd like to think people could do better than that, but history is
against us.

I'd *like* to see Muslims in general declare ISIS apostates.
Unfortunately, some Muslim authorities have already looked into that,
and its a non-starter. ISIS members are very,
very sinful Muslims in the eyes of most, but they don't meet the
requirements for takfir (this could be argued, but so far, that's where
things stand).

ObSF: McDonough's Song, from "As simple as ABC"
one of Kipling's SF works, is quite
relevent. Indulge me for quoting it in full:

Whether the State can loose and bind
In Heaven as well as on Earth:
If it be wiser to kill mankind
Before or after the birth--
These are matters of high concern
Where State-kept schoolmen are;
But Holy State (we have lived to learn)
Endeth in Holy War.

Whether The People be led by The Lord,
Or lured by the loudest throat:
If it be quicker to die by the sword
Or cheaper to die by vote--
These are things we have dealt with once,
(And they will not rise from their grave)
For Holy People, however it runs,
Endeth in wholly Slave.

Whatsoever, for any cause,
Seeketh to take or give
Power above or beyond the Laws,
Suffer it not to live!
Holy State or Holy King--
Or Holy People's Will--
Have no truck with the senseless thing.
Order the guns and kill!
Saying --after--me:--

Once there was The People--Terror gave it birth;
Once there was The People and it made a Hell of Earth
Earth arose and crushed it. Listen, 0 ye slain!
Once there was The People--it shall never be again!

pt

[John F. Eldredge]

On Thu, 30 Apr 2015 23:53:22 -0500, David DeLaney wrote:

> On 2015-04-30, Gutless Umbrella Carrying Sissy <taus...@gmail.com>
> wrote:
>> Interesting thought, if the numbers work out. But don't lower orbits
>> require _higher_ velocities?
>
> Yes. This is why close-orbit of Earth goes around the world in 80
> minutes, while geosync satellites further out take a day and the Moon
> needs nearly a month...
>
> Dave, listening carefully for *r**l36's footsteps

Are you talking about angular velocity, or linear velocity? Increased
linear velocity produces a higher orbit, with lower angular velocity.

[David DeLaney]

On 2015-05-24, John F. Eldredge <jo...@jfeldredge.com> wrote:
> On Thu, 30 Apr 2015 23:53:22 -0500, David DeLaney wrote:
>> On 2015-04-30, Gutless Umbrella Carrying Sissy <taus...@gmail.com>

>>> Interesting thought, if the numbers work out. But don't lower orbits
>>> require _higher_ velocities?
>>
>> Yes. This is why close-orbit of Earth goes around the world in 80
>> minutes, while geosync satellites further out take a day and the Moon
>> needs nearly a month...
>>
>> Dave, listening carefully for *r**l36's footsteps
>
> Are you talking about angular velocity, or linear velocity? Increased
> linear velocity produces a higher orbit, with lower angular velocity.

Linear. Almost nobody talks about angular velocity when looking at actual
orbits, because it means you're looking at the orbit from a place off of it,
and throwing away info on how far something on the orbit is away from you.
(Some consequences of that are what lead to things like 'retrograde motion'
for planetary movements in our skies.)

And increased linear velocity along your orbit means you now have too much
angular _momentum_ (not velocity) to stay in that orbit, and you transition
to an ellipse that touches your old orbit there and goes further out, with
the rest of it slowing down until it reaches _its_ furthest point, where it'll
be moving even SLOWER than the circular orbit it's tangent to there, which
in turn will be slower-moving than your old inner orbit.

Yes, the Moon's got a bigger orbit at 238,000 miles out from Earth than the
geosych satellites do at 23,000 miles out... but it doesn't move _eleven_
times slower around that orbit (238/23), but about _29_ times slower. So no,
it's not "still moving as fast linearly as the lower orbit is" or anything
like that.

Summary: increasing your linear velocity in an orbit puts you in a higher
orbit, with on-average LOWER linear velocity than you had before. Decreasing
your linear velocity, similarly, causes you to fall into a LOWER orbit, which
mostly moves _faster_ than the one you were in, fastest when it's closest to
what you're orbitting.

t^2 ~ d^3, and equal areas swept out in equal times...

Dave
--
\/David DeLaney posting thru EarthLink - "It's not the pot that grows the flower
It's not the clock that slows the hour The definition's plain for anyone to see
Love is all it takes to make a family" - R&P. VISUALIZE HAPPYNET VRbeable<BLINK>
http://gatekeeper.vic.com/~dbd/ -net.legends/Magic / I WUV you in all CAPS! --K.

[Brian M. Scott]

On Sun, 24 May 2015 21:18:04 -0500, David DeLaney
<davidd...@earthlink.net> wrote
in<news:womdnVTPgKrBG__I...@earthlink.com> in
rec.arts.sf.written:

[...]

> Summary: increasing your linear velocity in an orbit puts
> you in a higher orbit, with on-average LOWER linear
> velocity than you had before. Decreasing your linear
> velocity, similarly, causes you to fall into a LOWER
> orbit, which mostly moves _faster_ than the one you were
> in, fastest when it's closest to what you're orbitting.

Or to quote _Shockwave Rider_:

Go faster in order to drop back to a lower orbit?
Doesn’t work. Drop back to a lower orbit; you
go faster!

Or from earlier in the book:

You are in circular orbit around a planet. You are
being overtaken by another object, also in circular
orbit, moving several km./sec. fater. You accelerate
to try and catch up.

See you later, accelerator.

Brian
--
It was called ‘Birdsong at Eventide’, and it went, ‘Ting
_pling_ ting pling _ting_, ting tong, ting tong, ting
tonggg clonk, bother!’ At least, that is how it went
when Myrtle played it. -- _Larklight_, by Philip Reeve

[Cryptoengineer]

David DeLaney <davidd...@earthlink.net> wrote in

news:womdnVTPgKrBG__I...@earthlink.com:

While the moon takes 29 times as long to orbit the Earth as a
satellite in GEO, is it *not* moving at 1/29th the speed. It's
11 times farther away, so the circumference of its orbit it 11 times
as long. As a result, it's movement through space (relative to a
hypothetical non-rotating Earth) is 11/29 the speed - about 1/3
that of GEO, not 1/29th.

Despite the lower speed, it also takes more energy to get there
(which was the original question) - you have to lift stuff over
200,000 miles further out of Earth's gravity well.

If it was otherwise, it would be easier to send a rocket to
the next star than into LEO.

pt

[J. Clarke]

In article <cse0ne...@mid.individual.net>, jo...@jfeldredge.com
says...

Not quite. Figure the orbital circumference divided by the period and
you will find that more distant objects are moving more slowly in terms
of both linear and angular velocity.

What may be confusing you on this issue is the need to increase speed in
order to gain altitude. That increase doesn't carry to the higher
altitude.

If you want to get a "feel" for this sort of thing instead of just being
finicky numbers to calculate, play with Orbiter
<http://orbit.medphys.ucl.ac.uk/download.html> or Kerbal
<https://kerbalspaceprogram.com/en/>. Orbiter tries for realism and is
free, Kerbal is more fun but isn't free. Both have reasonably accurate
orbital mechanics.

[Quadibloc]

On Friday, May 22, 2015 at 11:40:25 PM UTC-6, J. Clarke wrote:
> In article <XnsA4A2C7B2A6...@216.166.97.131>,
> treif...@gmail.com says...

> > ISIS' actions are consistant with their trying to foment war between
> > Muslim and Muslim, and Muslims with everyone else. We should not assume
> > that the methods of the Cold War are going to work as well as they did
> > on the Soviets.

> So you're saying to just pave the place and let Allah sort 'em out?

I can understand people reacting in this way to my posts.

After all, I do note that given human nature the way it is, that _is_ the fate
that is risked by the Muslim world if terrorism continues... since, in all the
time that has passed since the Roman empire, which dealt with irregular warfare
in just that way, no really effective counterinsurgency strategies have been
found.

This isn't what I advocate, it's what I fear - and use as an argument for
taking more reasonable, but forceful, actions to stop terrorism quickly, to
reduce the risk of this happening.

But I think it should be clear that he is saying that the people *who join
terrorist movements such as ISIS* "want to die", not Muslims in general.

John Savard

[lal_truckee]

On 5/25/15 5:35 AM, Quadibloc wrote:
> On Friday, May 22, 2015 at 11:40:25 PM UTC-6, J. Clarke wrote:
>
>> So you're saying to just pave the place and let Allah sort 'em out?
>
> I can understand people reacting in this way to my posts.
>
> After all, I do note that given human nature the way it is, that _is_ the fate
> that is risked by the Muslim world if terrorism continues... since, in all the
> time that has passed since the Roman empire, which dealt with irregular warfare
> in just that way, no really effective counterinsurgency strategies have been
> found.

Malayan Emergency (1947-1960)
British victory won against an attempted Communist revolution in Malaya.

[Magewolf]

On 5/25/2015 8:15 AM, J. Clarke wrote:

> If you want to get a "feel" for this sort of thing instead of just being
> finicky numbers to calculate, play with Orbiter
> <http://orbit.medphys.ucl.ac.uk/download.html> or Kerbal
> <https://kerbalspaceprogram.com/en/>. Orbiter tries for realism and is
> free, Kerbal is more fun but isn't free. Both have reasonably accurate
> orbital mechanics.
>

Kerbal is the best crash simulator ever made. I had one rocket that
tried to reenact the swamp castle story from Monty Python and the Holy
Grail almost to a T.

[Robert Bannister]

I don't know the answer, but it is clear that almost every action the
West takes whether direct action or propaganda, has an adverse effect on
the Muslim community. The moderate Muslims in our own countries are
participating less and less with authorities because everything we say
and do now seems like lies and anti-Muslim rhetoric. We do need to
engage more with the moderates while there are still some left - sorry,
not "more" but "better".
--
Robert Bannister - 1940-71 SE England
1972-now W Australia

[Kevrob]

The following would be as true of some followers of Christianity as it is
of some Muslims, the type whose politics get them called "Islamists:"

For some of these folks, no comment that can't be interpreted as,
"Yes, your religion is true, all the other ones are wrong, and everyone
should follow the interpretation that [name of nutbar clergyman here]
has been inspired by [insert deity(ies) here] to provide for us" is taken
as an affront.

Mainstream Muslims who apologize for ISIL/Al Qaeda, etc, are like Mainstream
Christians making excuses for a (theoretical, nowadays*) explicitly
Christian state persecuting "heretics" or organizing pogroms. What is
really needed is the equivalent of the Enlightenment in the countries
where this conflict is raging. Good luck waiting for that to happen.
Perhaps Muslims living elsewhere can pull that off, if they don't
get murdered trying.

Kevin R

*We have had inter-religious warfare in the former Yugoslavia, and while
the IRA boyos planting bombs aren't all Catholic (I'd suppose many of
the explicitly marxist ones may be atheists) the fighting in NI has
its religious component. Definitely not "It can't happen here."

[William December Starr]

In article <womdnVTPgKrBG__I...@earthlink.com>,

David DeLaney <davidd...@earthlink.net> said:

> Summary: increasing your linear velocity in an orbit puts you in a
> higher orbit, with on-average LOWER linear velocity than you had
> before. Decreasing your linear velocity, similarly, causes you to
> fall into a LOWER orbit, which mostly moves _faster_ than the one
> you were in, fastest when it's closest to what you're orbitting.

And then zero when you reach it.

-- wds

[William December Starr]

In article <830d8cce-8cbb-4fbe...@googlegroups.com>,

Kevrob <kev...@my-deja.com> said:

> For some of these folks, no comment that can't be interpreted as,
> "Yes, your religion is true, all the other ones are wrong, and
> everyone should follow the interpretation that [name of nutbar
> clergyman here] has been inspired by [insert deity(ies) here] to
> provide for us" is taken as an affront.

I think one of us is wrong as to how many negatives the first line
of that statement should have had.

-- wds

[David DeLaney]

On 2015-05-25, Cryptoengineer <treif...@gmail.com> wrote:
> David DeLaney <davidd...@earthlink.net> wrote in

>> Yes, the Moon's got a bigger orbit at 238,000 miles out from Earth
>> than the geosych satellites do at 23,000 miles out... but it doesn't
>> move _eleven_ times slower around that orbit (238/23), but about _29_
>> times slower. So no, it's not "still moving as fast linearly as the
>> lower orbit is" or anything like that.
>

> While the moon takes 29 times as long to orbit the Earth as a
> satellite in GEO, is it *not* moving at 1/29th the speed. It's
> 11 times farther away, so the circumference of its orbit it 11 times
> as long. As a result, it's movement through space (relative to a
> hypothetical non-rotating Earth) is 11/29 the speed - about 1/3
> that of GEO, not 1/29th.

Read my paragraph again. I said it wasn't moving the SAME linear speed; I
-never- said "it's moving 1/29th the speed". From my paragraph you can easily
see that it's moving about 11/29ths the speed, or 238/(29*23).

[Kevrob]

On Tuesday, May 26, 2015 at 2:39:28 PM UTC-4, William December Starr wrote:
> In article <830d8cce-8cbb-4fbe...@googlegroups.com>,
> Kevrob <kev...@my-deja.com> said:
>
> > For some of these folks,

/n/o/ any

> > comment that can't be interpreted as,
> > "Yes, your religion is true, all the other ones are wrong, and
> > everyone should follow the interpretation that [name of nutbar
> > clergyman here] has been inspired by [insert deity(ies) here] to
> > provide for us" is taken as an affront.
>
> I think one of us is wrong as to how many negatives the first line
> of that statement should have had.

Better?

Kevin R

[10313...@compuserve.com]

On Sunday, May 24, 2015 at 10:34:34 PM UTC-4, Brian M. Scott wrote:
> On Sun, 24 May 2015 21:18:04 -0500, David DeLaney
> <davidd...@earthlink.net> wrote
> in<news:womdnVTPgKrBG__I...@earthlink.com> in
> rec.arts.sf.written:
>
> [...]
>
> > Summary: increasing your linear velocity in an orbit puts
> > you in a higher orbit, with on-average LOWER linear
> > velocity than you had before. Decreasing your linear
> > velocity, similarly, causes you to fall into a LOWER
> > orbit, which mostly moves _faster_ than the one you were
> > in, fastest when it's closest to what you're orbitting.
>
> Or to quote _Shockwave Rider_:
>
> Go faster in order to drop back to a lower orbit?
> Doesn't work. Drop back to a lower orbit; you
> go faster!
>
> Or from earlier in the book:
>
> You are in circular orbit around a planet. You are
> being overtaken by another object, also in circular
> orbit, moving several km./sec. fater. You accelerate
> to try and catch up.
>
> See you later, accelerator.
>
> Brian

"East takes you out, out takes you west, west takes you in, in takes you east; north and south bring you back again." [Larry Niven: The Integral Trees]

"East" is the direction of orbit.

JimboCat
--
"Most books didn't say 'And then they refused to give up, no matter how sensible it would have been, because that would've been too embarrassing'; but a great deal of history made a lot more sense that way." [Harry Potter and the Methods of Rationality]