On the lasting importance of the SpaceX accomplishment.

On Jul 14, 5:52*am, Thomas Womack
wrote:
In article ,
Fred J. McCall wrote:

I'm sorry, but that displays a degree of insanity that I just find
impossible to believe. *Suppose it comes down on Paris or London. *How
many people does it kill, what does it destroy, and what does all that
cost once all the liability suits are settled. *You're talking almost
a million tons of stuff coming in at reentry velocities.

If the Space Station weighed a million tons then we've already won.

It weighs four hundred tons; a rock that size comes in at
interplanetary velocity most years, mostly burns up, and is noticed
only in internal publications of ballistic-missile defence
organisations. *There's an atmosphere in the way; almost everything
burns up almost entirely, and the rest hits no harder than a component
falling off a plane at takeoff.

ISS would have been cheaper as a US-only effort. *Almost every major
program costs more if you involve other governments.

It would have been very much cheaper, yes, because it wouldn't have
happened; it escaped cancellation as being a reasonably impressive way
of keeping Russian rocket scientists from departing en-masse.

Tom

the re entry speed of a asteroid is normally very fast and most of it
burns up

the re entry speed of ISS modules will be far slower, and structural
parts stronger than a asteroid

as such a out of control ISS is a much larger hazard than a asteroid,
espically since the ISS ground track is over the most populated part
of our world

On 14/07/2012 14:52, Thomas Womack wrote:
In ,
Fred J. wrote:
I'm sorry, but that displays a degree of insanity that I just find
impossible to believe. Suppose it comes down on Paris or London. How
many people does it kill, what does it destroy, and what does all that
cost once all the liability suits are settled. You're talking almost
a million tons of stuff coming in at reentry velocities.

If the Space Station weighed a million tons then we've already won.

It weighs four hundred tons; a rock that size comes in at
interplanetary velocity most years, mostly burns up, and is noticed
only in internal publications of ballistic-missile defence
organisations. There's an atmosphere in the way; almost everything
burns up almost entirely, and the rest hits no harder than a component
falling off a plane at takeoff.

ISS would have been cheaper as a US-only effort. Almost every major
program costs more if you involve other governments.

It would have been very much cheaper, yes, because it wouldn't have
happened; it escaped cancellation as being a reasonably impressive way
of keeping Russian rocket scientists from departing en-masse.

Tom



Re-entry is an interesting subject alright - comparing a nearly
circular orbit re-entry like the ISS or other (man made) satellites
with a much more direct straight-into the atmosphere entry like
Shoemaker-Levy. Velocities and angles and rates of burning up - makes
my head spin with all the possibilities.


--
T

On Fri, 13 Jul 2012 20:55:55 -0700 (PDT), bob haller
wrote:

lets not forget that the stations modules have a finite lifetime. you
can replace all sorts of parts on a old car but that doesnt make it
new, and breakdowns on old vehicles are to be expected.

So do B-52s, KC-135s, T-38s and P-3s, all of which are still in active
military service over 50 years after they were delivered.

so unless all parties involved are prepared to begin replacing entire
modules one day something critical will beak down with possibly
disasterous results.

Ah, Bob. This wouldn't be sci.space without one of your "THEY'RE ALL
GONNA DIE!" fear-mongering at least once a week.

the station is now past its design life.......

Nope. 2015. 15 years guaranteed on-orbit life, which is more of less
through 2015. But most of the hardware is directly descended from
Freedom designs, which were specced for 30 years. On the Russian side,
there's not much difference between the ISS modules and Mir modules,
and Mir went a decade past its design life, only really be hampered by
careless fires set off inside and by the Russians ramming it with a
Progress freighter in a very-poorly conceived budget-saving demo.

et it age gracefully and not run it till it kills.

Of course, it can and almost certainly will be periodically inspected
by astronauts and cosmonauts to make sure nothing is about to "kill",
and if a show-stopper appears, then it can be deorbited. But if it is
earning its keep, there's no reason to deorbit it prematurely.

incidently a out of control station will tumble shedding modules as it
tumbles, spreading them over its entire ground track . many parts will
survive re entry, the ground track is mostly over populated areas...

That's why Station has two independent control methods... The USOS's
side and the Russian side's. That doesn't include Progress or ATV,
which can also do the job. ISS is not SkyLab.

a station breaking up will cause mass panic, espiically if modules and
parts start coming down in populated areas........

90% or so chance it would come down at sea or in unpopulated areas
(deserts), though.

Brian

lets not forget that the stations modules have a finite lifetime. you
can replace all sorts of parts on a old car but that doesnt make it
new, and breakdowns on old vehicles are to be expected.

So do B-52s, KC-135s, T-38s and P-3s, all of which are still in active
military service over 50 years after they were delivered.


Brian

if the modules could be returned to earth and completely refurbished
this is true. in the case of military jets only the airframes havent
been changed. all other parts have perodically upgraded or totally
replaced.....

Thomas Womack wrote:
Fred J. McCall wrote:
I'm sorry, but that displays a degree of insanity that I just find
impossible to believe. Suppose it comes down on Paris or London. How
many people does it kill, what does it destroy, and what does all that
cost once all the liability suits are settled. You're talking almost
a million tons of stuff coming in at reentry velocities.

If the Space Station weighed a million tons then we've already won.

It weighs four hundred tons; a rock that size comes in at
interplanetary velocity most years, mostly burns up, and is noticed
only in internal publications of ballistic-missile defence
organisations. There's an atmosphere in the way; almost everything
burns up almost entirely, and the rest hits no harder than a component
falling off a plane at takeoff.

And your big rocks are pretty solid. I expect that hollow "rocks"
break up a lot earlier in their entry.

--
I used to own a mind like a steel trap.
Perhaps if I'd specified a brass one, it
wouldn't have rusted like this.

On Sat, 14 Jul 2012 09:30:41 -0700 (PDT), bob haller
wrote:



lets not forget that the stations modules have a finite lifetime. you
can replace all sorts of parts on a old car but that doesnt make it
new, and breakdowns on old vehicles are to be expected.

So do B-52s, KC-135s, T-38s and P-3s, all of which are still in active
military service over 50 years after they were delivered.

if the modules could be returned to earth and completely refurbished
this is true.

It is true regardless.

in the case of military jets only the airframes havent
been changed. all other parts have perodically upgraded or totally
replaced.....

The airframes are likewise the only part of ISS modules that can't be
changed. Pretty much everything else can be changed out. It was
designed that way deliberately, Bob.

Brian

......

The airframes are likewise the only part of ISS modules that can't be
changed. Pretty much everything else can be changed out. It was
designed that way deliberately, Bob.

Brian

Dockings of visiting spacecraft, thermal cycles during each orbit of
Earth, reboost maneuvers and crew exercise can affect the space
station's structural health. Without the ability to inspect the shell
of the craft, like airplane engineers would do on Earth, NASA must use
computer models to predict how cracks and deformities propagate in
space.

So theres no way to directly inspect the modules, a not anticipated
issue may appear, similiar to the square window issues in the first
commercial airliner. plus space is a very challenging environment

On Sat, 14 Jul 2012 12:48:44 -0500, Brian Thorn wrote:

On Sat, 14 Jul 2012 09:30:41 -0700 (PDT), bob haller
wrote:



lets not forget that the stations modules have a finite lifetime. you
can replace all sorts of parts on a old car but that doesnt make it
new, and breakdowns on old vehicles are to be expected.

So do B-52s, KC-135s, T-38s and P-3s, all of which are still in active
military service over 50 years after they were delivered.




if the modules could be returned to earth and completely refurbished
this is true.

It is true regardless.

in the case of military jets only the airframes havent been changed. all
other parts have perodically upgraded or totally replaced.....

And once again, Bob, you get it wrong.

All of Above name aircraft have been through a continual process of inspection, IRAN,
overhaul and rebuild for decades. About the only thing still original
on a KC-135R (Especially after Pacer Crag) is the data plate.
B-52s even more so, even though both types have relatively few
hours on them for their ages - all that time spent on alert during
the Cold War.
The T-38s have also been through several complete rebuilds.
The P-3s not so much, but they go through an intense
(almost Space Shuttle) level of mandatory inspection and
special maintenance (Such as fresh-water high pressure washdowns
after each flight - the corrosion from flying over the oceans
for all those years is a tremendous problem.)
It's interesting that you didn't mention other contemporaneous types,
the C-141B (Which got its wings flown off during Desert Shield/Desert
Storm), and the Handley Page Victor (Supporting the Black Buck operations
in the Falklands War did them in)
It's not just the years, it's the mileage.

How does this relate to the ISS? You can't pull a full inspection,
taking apart the structure and performing Non-Destructive Testing
on it. We don't have the knowledge base yet to be able to predict
what the long-term effects of the space environment are going to be.
Any predictions now are guesses, surmise, and prejudice.


The airframes are likewise the only part of ISS modules that can't be
changed. Pretty much everything else can be changed out. It was designed
that way deliberately, Bob.

What everybody seems to miss, or ignore, is that the ISS just being there is a
vital part of long endurance spaceflight. If we can't build structures, power systems,
environmental systems, and all the rest that can't be trusted beyond the next
scheduled resupply flight, than anything like a mission beyond the Moon
is right out. Mir was jack-legged together - the crew spent most of their time
(Especially in the later years) working at not dieing. The Russians, and we,
learned a lot, but not enough. ISS's history shows that we still have a lot to learn.
That's going to be the big takeaway, not the Classic Space Nerd goals of
large semiconductor wafers and Zero-G sex.

--
Pete Stickney
Failure is not an option
It comes bundled with the system

In article ,
says...

Jeff Findley wrote:

In article 42848d20-dd90-48d3-8b3e-
, says...
well since ares orion wouldnt be operational till after 2020, and by
that time whats left of ISS will be in the pacific.....

This is not a given. Mir stayed in orbit long after its design lifetime
was up. The shuttle bringing up spare parts had a lot to do with this.
Given the multitude of resupply ships both flying to ISS and in
development, I don't see spare parts being much of an issue.


Well, yes, it is a given because once we're done with it we will
deorbit it as we are responsible for anything it might hit if we don't
and it does an uncontrolled reentry.

True, once it's deorbited, it's done. I don't discount the possibility
that the Russians may try to extend the program somehow. They've been
toying with the idea of taking "their" ISS modules and using them as an
initial starting point for a "new" station.

Not out of the question, but if NASA's in charge, I'd wager it's far
more likely to contain ISS derived modules. After all, they might get
the Europeans to build the HAB module, which means NASA wouldn't have to
pay for it.


Oh, don't be silly! You think we don't pay for the stuff others do?
That's like saying we don't have to pay because we're going up on
Russian boosters!

The Russians are a huge exception because there is currently no other
way for the US to get crew. In other cases, we tend to barter for
hardware and/or services. Direct cash payments to other countries are
generally frowned upon.

Buying modules from Bigelow means paying for them. That's not
completely out of the question, I think it's unlikely to happen without
Bigelow "proving" their inflatables are safe for human occupancy.

The original idea for the Bigelow inflatable's came from the
government; Lowell Wood at LLNL, to be precise.

True, but others still see inflatables as a new, as yet to be trusted,
technology.

Jeff
--
" Ares 1 is a prime example of the fact that NASA just can't get it
up anymore... and when they can, it doesn't stay up long. "
- tinker

In article ebf1dedd-8d49-425c-a8e7-5436464d4d66
@u20g2000yqk.googlegroups.com, says...


lets not forget that the stations modules have a finite lifetime. you
can replace all sorts of parts on a old car but that doesnt make it
new, and breakdowns on old vehicles are to be expected.

So do B-52s, KC-135s, T-38s and P-3s, all of which are still in active
military service over 50 years after they were delivered.

if the modules could be returned to earth and completely refurbished
this is true. in the case of military jets only the airframes havent
been changed. all other parts have perodically upgraded or totally
replaced.....

No, ISS modules cannot be returned to earth intact. In case you hadn't
noticed, the space shuttles are headed for museums. No other vehicle
which is currently flying or is likely to fly in the next decade can
return such large payloads to earth intact.

Jeff
--
" Ares 1 is a prime example of the fact that NASA just can't get it
up anymore... and when they can, it doesn't stay up long. "
- tinker