Maker Pro
Maker Pro

Bravo to the SpaceShipOne team!

R

Rolavine

Jan 1, 1970
0
From: Dirk Bruere at Neopax
The US govt does not want cheap civilian space travel.
They foresee Bin Laden up there tossing down rocks.

Are you kidding, not only can they can come in from Mexico for $50 they can
also start working at a taco bell the same day!
 
R

Rich Grise

Jan 1, 1970
0
A ticket on a Zeppelin (trans-Atlantic) was $461 one-way in 1928.
That's about $5K in 2004 dollars. The Zeppelin was a lot more
comfortable and luxurious than a business class seat, of course.

The main difference is that there are valid business and personal
reasons for large numbers of people to cross the oceans. Popping up
100 clicks and down again for a joy ride lacks that aspect. But at a
mere $100-300K per joyride, I'm sure there could easily be thousands
of takers, barring serious safety incidents. Even then, there's a
$60,000 cost, a good chance of dying, and only a 17% chance of success
climbing Everest and that doesn't stop people from trying- and that
takes a lot of training etc. to even think of attempting. The next
closest competitor would probably be to fly in a MIG-25 to
75,000-80,000 feet, where the sky turns indigo, which is much cheaper.
A full orbital flight would be the clincher for Branson & Co., I
think.
I've been musing about space stations and such, and would think that
there'd have to be regular supply rockets for oxygen and probably
argon or SF6 - you wouldn't want nitrogen, mainly because of the
bends if there's a blowout, but was wondering, what happens to the
air that leaks out of a space station? Wouldn't it pretty much tend
to stay pretty much in the same orbit, modified by its initial
velocity, of course? After the Clarke orbit gets loaded up with
motels and crap, will Earth have a ring at some future time?

Cheers!
Rich
 
R

Rich Grise

Jan 1, 1970
0
I read in sci.electronics.design that Dirk Bruere at Neopax


You may be right that the US govt. does, but it's fantasy. Consider how
to get the stuff up there in the first place, and then the accuracy of
nay such bombardment. You'd be lucky to hit the right hemisphere.
--

There have been SF stories about weapons like that - there are
basically big bundles of rebar in orbit, and they can drop them
one at a time, or maybe en masse, and precision guide them to
crack the lids of missile silos. ;-)

On Babylon 5, the Centauris bombarded Narn with huge rocks shot from
mass drivers. =:-O

Cheers!
Rich
 
R

Rich Grise

Jan 1, 1970
0
Some rusty nails in a retrograde orbit would deny the use of space to
everyone for quite some time.
Well, maybe "all" of the rusty nails. ;-)


Cheers!
Rich
 
J

John Woodgate

Jan 1, 1970
0
I read in sci.electronics.design that [email protected] wrote (in
I would LOVE to see what kind of defense is in place to protect a
satellite that high up, from a 'rock' fired by a 'gun' I suppose they
have star trek shields? Those things didn't even help the Enterprise
half the time.....

The missiles aren't 'rocks', they are more like sugar cubes. Multiple
hits hurt more.

Whether there are any counter-measures in place or not, I doubt that
anyone is going to tell us. But not defending against a known threat
doesn't gel well with those of you who think the US 'defends' itself
against imaginary threats.
 
J

John Woodgate

Jan 1, 1970
0
I read in sci.electronics.design that Rich Grise <[email protected]>
After
the Clarke orbit gets loaded up with motels and crap, will Earth have a
ring at some future time?

Yes, probably. Once the three Clarke Space Elevators are in position, it
won't be difficult to build cantilevers out from them to join up,
eventually, into a complete ring.

This is where we switch from Clarke to Niven. Such a ring has been shown
to be unstable, so it will require a stabilising mechanism. However, I
very much doubt that a ring a million miles wide will be constructed.
 
J

John Woodgate

Jan 1, 1970
0
I read in sci.electronics.design that Rich Grise <[email protected]>
wrote (in said:
It'd be really interesting to see his waiting list. :)
I'll have to stop making these multilingual gags here. Look up
'galactos' in your Greek dictionary.
 
C

Charles Edmondson

Jan 1, 1970
0
Rich said:
Rich said:
[...] The feat was accomplished with a total investment of little more
than $20 million ? a far cry from the billions spent by NASA to develop
space vehicles.

Tut tut. There's quite a difference in making a 60 mile hop
and getting into orbit. If they can stay up there for a few
days, then we're talking!

True, but there is some serious money getting involved, like
the guy that owns Virgin Atlantic has started Virgin Galactic.

Way cool name. They're still suborbital, but the rest is
basically engineering.

Cheers!
Rich
Also, what happens when he puts in a second spaceport up in the
highlands, and has the plane go up in one spot, and come down in another...

(or, just outside of Philadelphia...)
 
R

Rich Grise

Jan 1, 1970
0
I read in sci.electronics.design that Rich Grise <[email protected]>

I'll have to stop making these multilingual gags here. Look up
'galactos' in your Greek dictionary.
--

Ah, got it. It's not the multilinguality that was the impediment - it's
that for us Americans, money is simply the first thing that comes to mind
in any situation. ;-)

Cheers!
Rich
 
R

Rich Grise

Jan 1, 1970
0
Rich said:
Rich Grise wrote:

[...] The feat was accomplished with a total investment of little more
than $20 million ? a far cry from the billions spent by NASA to
develop space vehicles.
----------------

Now, what was somebody saying about government funding?


Tut tut. There's quite a difference in making a 60 mile hop
and getting into orbit. If they can stay up there for a few
days, then we're talking!

True, but there is some serious money getting involved, like
the guy that owns Virgin Atlantic has started Virgin Galactic.

Way cool name. They're still suborbital, but the rest is
basically engineering.

Cheers!
Rich
Also, what happens when he puts in a second spaceport up in the
highlands, and has the plane go up in one spot, and come down in
another...

(or, just outside of Philadelphia...)
--
Well, I guess people were paying quite exorbitant prices for a cramped,
uncomfortable, supersonic transatlantic flight until the nuts banned
sonic booms.

But hey, $190,000 for a supply mission to a space station? The freakin'
_governments_ will line up for a ride that cheap!

Cheers!
Rich
 
R

Rich Grise

Jan 1, 1970
0
I read in sci.electronics.design that Rich Grise <[email protected]>


Yes, probably. Once the three Clarke Space Elevators are in position, it
won't be difficult to build cantilevers out from them to join up,
eventually, into a complete ring.

This is where we switch from Clarke to Niven. Such a ring has been shown
to be unstable, so it will require a stabilising mechanism. However, I
very much doubt that a ring a million miles wide will be constructed.
--
Well, wait a minute. The three stations are in stable orbits, while they're
not connected to each other, right? So, if you put little pieces of
construction materiel in orbits that are all interspersed, so you've
got all these little, individual, free-falling objects in the same
orbit, playing follow-the-leader, so to speak, what is it that makes
it unstable if they all decide to hold hands?

Thanks,
Rich
 
J

John Woodgate

Jan 1, 1970
0
I read in sci.electronics.design that Rich Grise <[email protected]>
Well, wait a minute. The three stations are in stable orbits, while
they're not connected to each other, right? So, if you put little pieces
of construction materiel in orbits that are all interspersed, so you've
got all these little, individual, free-falling objects in the same
orbit, playing follow-the-leader, so to speak, what is it that makes it
unstable if they all decide to hold hands?

I agree it looks counter-intuitive. There is a brief mention of the
matter in the introduction to 'The Ringworld Engineers', and more in the
introduction to the excerpt from 'Ringworld' in 'N-Space'. Sometime
before 1970, Ctein and Dan Alderson spent a LONG time calculating the
nature of the instability.

I think you can get an idea of the problem by considering what happens
if Jupiter's gravity, for example, tries to pull a section of the ring
into a higher orbit. Conservation of angular momentum makes that bit
slow down, so the adjacent part that is antispinward tends to overtake,
creating an inflection in the ring if it will flex sufficiently, or
break it if it won't. The effect of the inflection is cumulative,
resulting in growing 'ripples' running round the ring.
 
R

Rich Grise

Jan 1, 1970
0
I read in sci.electronics.design that Rich Grise <[email protected]>


I agree it looks counter-intuitive. There is a brief mention of the
matter in the introduction to 'The Ringworld Engineers', and more in the
introduction to the excerpt from 'Ringworld' in 'N-Space'. Sometime
before 1970, Ctein and Dan Alderson spent a LONG time calculating the
nature of the instability.

I think you can get an idea of the problem by considering what happens
if Jupiter's gravity, for example, tries to pull a section of the ring
into a higher orbit. Conservation of angular momentum makes that bit
slow down, so the adjacent part that is antispinward tends to overtake,
creating an inflection in the ring if it will flex sufficiently, or
break it if it won't. The effect of the inflection is cumulative,
resulting in growing 'ripples' running round the ring.
--

So, if it were theoretically infinitely rigid, it wouldn't break up,
or if it was composed of individually-orbiting modules with flexible
ductwork between them, it could be stable?

I know that something like a dish of water on a turntable is almost
impossible to get centered properly, but that has aggregate effects,
and so a different model, I'd think.

Thanks,
Rich
 
J

John Woodgate

Jan 1, 1970
0
I read in sci.electronics.design that Rich Grise <[email protected]>
So, if it were theoretically infinitely rigid, it wouldn't break up,

Presumably, but that's not real.
or
if it was composed of individually-orbiting modules with flexible
ductwork between them, it could be stable?

No; I explained about the growing ripples. However flexible you made it,
it would eventually break. But the structure CAN be made stable.

There is some discussion at:

http://www-2.cs.cmu.edu/afs/cs.cmu.edu/user/mnr/st/std137

and a Google for 'Ringworld +stability' bring up lots of hits.
 
R

Rich Grise

Jan 1, 1970
0
I read in sci.electronics.design that Rich Grise <[email protected]>


Presumably, but that's not real.


No; I explained about the growing ripples. However flexible you made it,
it would eventually break. But the structure CAN be made stable.

There is some discussion at:

http://www-2.cs.cmu.edu/afs/cs.cmu.edu/user/mnr/st/std137

and a Google for 'Ringworld +stability' bring up lots of hits.
--

So, given the current trends of just tossing stuff up there any old time,
and the possibility of leaky spaceships, and certainly rocket exhaust,
would it eventually form a ring a la the other planets that have rings?
Admittedly, you might need to carry more skin patch kit than food,
but what might an "end result" be as sort of a limit if current space
activity should grow to the point of, say, commercial aviation, or
Disneyland? And with ordinary evolutionary technology, of course.

Thanks,
Rich
 
J

John Woodgate

Jan 1, 1970
0
I read in sci.electronics.design that Rich Grise <[email protected]>
So, given the current trends of just tossing stuff up there any old
time, and the possibility of leaky spaceships, and certainly rocket
exhaust, would it eventually form a ring a la the other planets that
have rings? Admittedly, you might need to carry more skin patch kit than
food, but what might an "end result" be as sort of a limit if current
space activity should grow to the point of, say, commercial aviation, or
Disneyland? And with ordinary evolutionary technology, of course.

I'm not quite with you. If you mean what would happen if a constructed
ring broke up, then yes, it would form a relatively stable ring of
fragments. The Cassini-Huygens project is already showing that we don't
know everything about planetary ring dynamics, in spite of it appearing
to be a fairly simple matter of Newtonian mechanics.

Incidentally, there is another form of instability of a solid ring
system. It can oscillate normal to its plane relative to the central
mass. It isn't clear to me whether the oscillation amplitude is always
bounded or can grow until the ring is ejected from the system.
 
R

Rich Grise

Jan 1, 1970
0
I read in sci.electronics.design that Rich Grise <[email protected]>


I'm not quite with you. If you mean what would happen if a constructed
ring broke up, then yes, it would form a relatively stable ring of
fragments.

No. I mean, start from today. There are a bunch of satellites in orbit,
and a bunch of space junk. People keep launching stuff. The "fragments"
are being put up there one at a time, in the form of communication
satellites, international space stations, weapons of mass destruction,
whatever.

Is it inevitable that a point is reached where stuff crashes into each
other? How close could stuff get before the orbits all get unstable?

Maybe what I'm getting at is, how long can we keep launching stuff
before there isn't any room for new stuff without breaking something?
The Cassini-Huygens project is already showing that we don't
know everything about planetary ring dynamics, in spite of it appearing
to be a fairly simple matter of Newtonian mechanics.

Incidentally, there is another form of instability of a solid ring
system. It can oscillate normal to its plane relative to the central
mass. It isn't clear to me whether the oscillation amplitude is always
bounded or can grow until the ring is ejected from the system.

Oh, I learned this at the age of about 10, with the hula-hoop. ;-)

Thanks,
Rich
 
J

John Woodgate

Jan 1, 1970
0
I read in sci.electronics.design that Rich Grise <[email protected]>
Maybe what I'm getting at is, how long can we keep launching stuff
before there isn't any room for new stuff without breaking something?

There is already a significant hazard from old debris. IIRC, the Space
Station was hit a while back by a small particle. But in general, near-
Earth space is BIG; it's preferred orbits that get polluted. I vaguely
recall a prediction that by 2050 a large sum (several billion yuan) will
need to be spent on clean-up.
 
R

Rich Grise

Jan 1, 1970
0
I read in sci.electronics.design that Rich Grise <[email protected]>


There is already a significant hazard from old debris. IIRC, the Space
Station was hit a while back by a small particle. But in general, near-
Earth space is BIG; it's preferred orbits that get polluted. I vaguely
recall a prediction that by 2050 a large sum (several billion yuan) will
need to be spent on clean-up.
--

Does the choice of currency indicate any prejudice on the part of the
predictors as to who is going to be footing this bill?

Thanks,
Rich
 
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