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Towards routine, reusable space launch.



 
 
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  #51  
Old June 14th 18, 11:26 PM posted to sci.space.policy,sci.astro,rec.arts.sf.science
Mike Van Pelt
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Posts: 6
Default Towards routine, reusable space launch.

In article ,
Sjouke Burry wrote:
There was a design for interstellar traffic, using a big protection plate
behind the spacepod, using a spring loaded tube to connect them,and
provide a bit of distance between ship and plate.
Explode nuclear bombs behind that shield.
Current technology could implement it, but it would be kind of expensive.


And that's just for the paper to print out the
environmental impact statement!
--
Mike Van Pelt | "I don't advise it unless you're nuts."
mvp at calweb.com | -- Ray Wilkinson, after riding out Hurricane
KE6BVH | Ike on Surfside Beach in Galveston
  #52  
Old June 15th 18, 12:46 AM posted to sci.space.policy,sci.physics,sci.astro,rec.arts.sf.science
Alain Fournier[_3_]
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Posts: 548
Default Towards routine, reusable space launch.

On Jun/14/2018 at 12:53 AM, Fred J. McCall wrote :
Alain Fournier wrote on Wed, 13 Jun 2018
19:39:10 -0400:

On Jun/13/2018 at 5:35 PM, Fred J. McCall wrote :
Doc O'Leary wrote on Wed, 13 Jun
2018 12:57:19 -0000 (UTC):

For your reference, records indicate that
Jeff Findley wrote:

In article , droleary@
2017usenet1.subsume.com says...

For your reference, records indicate that
Jeff Findley wrote:

Sure, sure, Star Trek style transporters with infinite range. I'll get
right on that.

No, you won?t. But you apparently *will* use it as a straw man to avoid
actually addressing the likelihood that new technologies developed in
the future will change the economies of space launches. Hell, that?s
essentially what SpaceX is demonstrating today.

Bull****. SpaceX is not demonstrating any new technologies. They've
combined existing technologies in novel ways to solve the problems
involved in building Merlin engines and Falcon launch vehicles. There
is zero new tech in them. If you believe differently, name a new
technology they're using in their engines, launch vehicles, Dragon, and
etc.

Sigh Of *course* there’s no “new technology” in *anything* that’s
in the world today. Your engineering mindset has you in a motivated
reasoning spiral. The fact remains that, over the course of time,
new technologies have been developed that have made their way into
space programs. SpaceX is taking advantage of some of those
technologies today. It is a safe bet that such innovations will occur
in the future, and somebody will take advantage of them.


And it's an even safer bet that none of those 'new technologies' are
going to replace "throwing stuff aft to move forward". A space
elevator on Earth requires not 'new technology', but 'new physics'.


It would be possible to build a space elevator using materials available
today without any major new technology. But that wouldn't be economical.
Not even remotely close to being economical. New materials would be
needed to build a sane space elevator, but new physics isn't needed.

See for instance
http://space.nss.org/media/2000-Spac...A-CP210429.pdf


I recall reading at least some analyses that said that the tensile
strength required exceeded atomic forces (in other words, an
impossibly strong material).


Without having checked, I would guess that that applies for a non
tapered cable. But if you taper the cable, it is physically possible to
build a cable using several existing materials.


Alain Fournier
  #53  
Old June 15th 18, 12:52 PM posted to sci.astro,sci.physics,sci.space.policy
Jeff Findley[_6_]
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Posts: 2,307
Default Towards routine, reusable space launch.

In article ,
says...

On 2018-06-14 05:22, Jeff Findley wrote:

Innovation in terms of engineering, but not new technology.


OK, I understand your argument.

But just because carbon fibre has existed for some time does not
automatically "void" the "new technology" when it is used in new
applications such as cryo tanks or aircraft fuselage.


Carbon/fibreglass were originally just "fabric" that was cut to right
shape, layed up and resin applied to it and let it cure.


True, but that's essentially still the state of the art today.
Composite layup machines have been around for decades. A guy I used to
work with wrote the layup software for the Cincinnati Milacron machines
back in the 1980s. What they sell today evolved from those machines:

https://metal-cutting-
composites.fivesgroup.com/products/composites/fiber-placement-
systems/cincinnati-viper-fps.html

Wouldn't you agree that it is new technology to take the raw strands in
a large spool, and lay individual strands in a computer optimized
position/direction just after the strand has been impregentated with resin?


Nope, as I said, been done at least since the 1980s in an automated
fashion. Sure the tech keeps getting better allowing for bigger
structures, but it's an evolution of tech that's decades old.

This new tech allows totally new applications that were not possible
before with that same material.

Airbus for instance developped new tech to combine 2 existing materials:
glass fibre and aluminium (Glare which has layers of aluminium, layes of
glass fibtre composited together). You can view this as either a new
material, or just "engineering" of 2 existing materials.


Materials tech is always evolving. This is a tad different than carbon
fiber layup, so I'd count that as new, whenever it was first done. I'm
not a materials engineer, so I don't know when that would be for glass
fiber and aluminum.

Coming back to SpaceX, I am not sure if their building an all composite
cryo tank for BFR represents new tech or not. If they are using the same
techniques/equipment as Boeing uses for the 787 for instance, it woudn't
be "new technology". But it is also possible that they develop new way
to lay the fibre to make the tank. There is also the issue of the resin
and how it is cured which could potentially represent new tech
(especially if they do away with an autoclave or curing oven).


X-33 attempted to do just that. It failed due to the complex geometry.
BFR/BFS is sticking with traditional cylindrical tanks, which is a
proven geometry for carbon fiber composites. They're being pretty
conservative as far as their use of carbon fiber goes, IMHO.

From what I've read, they'll be sticking with traditional techniques to
minimize development risks. I fully expect them to cure it in an
autoclave.

Orbital ATK, or whatever it's called now, is doing much the same with
their OmegA SRB segments. Again, this is a proven technology used by
Orbital ATK for many programs. NASA had a composite wound SRB program
many decades ago. It was canceled due to cost overruns, but that
technology is in use today and proposed for SRB upgrades for SLS, but
that wouldn't fly for maybe 10+ years given the pace of SLS Block 1
development.

http://www.spaceflightinsider.com/or...e-on-one-with-
atks-charlie-precourt-about-composite-materials-and-nasas-space-launch-
system/

Jeff
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These posts do not reflect the opinions of my family, friends,
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  #54  
Old June 15th 18, 12:56 PM posted to sci.space.policy,sci.physics,sci.astro,rec.arts.sf.science
Jeff Findley[_6_]
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Posts: 2,307
Default Towards routine, reusable space launch.

In article , says...
It would be possible to build a space elevator using materials available
today without any major new technology. But that wouldn't be economical.
Not even remotely close to being economical. New materials would be
needed to build a sane space elevator, but new physics isn't needed.

See for instance
http://space.nss.org/media/2000-Spac...A-CP210429.pdf


I recall reading at least some analyses that said that the tensile
strength required exceeded atomic forces (in other words, an
impossibly strong material).


Without having checked, I would guess that that applies for a non
tapered cable. But if you taper the cable, it is physically possible to
build a cable using several existing materials.


That's my understanding as well. Better materials would make a tapered
cable practical. Today's materials result in a very huge tapered cable
necessitating a huge counterweight making the whole thing impractical.

So, we're arguing about impossible versus impractical here. Either way,
it's not going to be built with today's materials.

Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.
  #55  
Old June 15th 18, 07:59 PM posted to rec.arts.sf.science,sci.astro,sci.physics,sci.space.policy
Steve Willner
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Posts: 1,172
Default Towards routine, reusable space launch.

The [JWST] telescope is folded, not only the solar arrays.

In particular the 6.5-m primary mirror is folded as well as many
other pieces. It's frightening to watch the deployment videos.

In article ,
Fred J. McCall writes:
And THAT is because you cannot make a single mirror that large to
adequate precision,


At least three observatories with seven telescopes in active use will
be surprised to learn that. Not to mention additional ones planned.

Every JWST presentation I've seen that mentioned the subject said
that using a deployable (folding) mirror is because the Ariane 5
shroud is too small to fit a 6.5-m mirror. I wouldn't be surprised
if there are "black" programs with the same difficulty.

That said, this particular use case doesn't necessarily justify a
rockoon approach, which will be difficult at best for large boosters.

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  #56  
Old June 15th 18, 08:13 PM posted to rec.arts.sf.science,sci.astro,sci.physics,sci.space.policy
Fred J. McCall[_3_]
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Posts: 10,018
Default Towards routine, reusable space launch.

(Steve Willner) wrote on Fri, 15 Jun 2018
18:59:07 -0000 (UTC):

The [JWST] telescope is folded, not only the solar arrays.


In particular the 6.5-m primary mirror is folded as well as many
other pieces. It's frightening to watch the deployment videos.

In article ,
Fred J. McCall writes:
And THAT is because you cannot make a single mirror that large to
adequate precision,


At least three observatories with seven telescopes in active use will
be surprised to learn that. Not to mention additional ones planned.


You can do things with earthbound scopes that you cannot do with
something you're going to shoot into space.


Every JWST presentation I've seen that mentioned the subject said
that using a deployable (folding) mirror is because the Ariane 5
shroud is too small to fit a 6.5-m mirror. I wouldn't be surprised
if there are "black" programs with the same difficulty.


Nope. They use a mirror roughly the size of Hubble's. Remember,
they're looking at something relatively close as such things go.


That said, this particular use case doesn't necessarily justify a
rockoon approach, which will be difficult at best for large boosters.


Yes. The point is that a balloon does NOT replace a 'first stage'.


--
"The reasonable man adapts himself to the world; the unreasonable
man persists in trying to adapt the world to himself. Therefore,
all progress depends on the unreasonable man."
--George Bernard Shaw
  #57  
Old June 16th 18, 12:21 AM posted to sci.space.policy,sci.physics,sci.astro,rec.arts.sf.science
Alain Fournier[_3_]
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Posts: 548
Default Towards routine, reusable space launch.

On Jun/15/2018 at 7:56 AM, Jeff Findley wrote :
In article , says...
It would be possible to build a space elevator using materials available
today without any major new technology. But that wouldn't be economical.
Not even remotely close to being economical. New materials would be
needed to build a sane space elevator, but new physics isn't needed.

See for instance
http://space.nss.org/media/2000-Spac...A-CP210429.pdf


I recall reading at least some analyses that said that the tensile
strength required exceeded atomic forces (in other words, an
impossibly strong material).


Without having checked, I would guess that that applies for a non
tapered cable. But if you taper the cable, it is physically possible to
build a cable using several existing materials.


That's my understanding as well. Better materials would make a tapered
cable practical. Today's materials result in a very huge tapered cable
necessitating a huge counterweight making the whole thing impractical.

So, we're arguing about impossible versus impractical here. Either way,
it's not going to be built with today's materials.


Yes. But I think I am a little less optimistic than you about it
becoming practical in the future. If we have fantastic materials in the
future, maybe an elevator will become more practical, but SpaceX is
likely to figure how to build fantastic rockets if you give them
fantastic materials. So if you can build an elevator that would seem
practical today, that elevator might compete with a rocket that can be
reused 1000 times between inspections AND have high orbital mass fraction.

It is possible that we find a way to build a practical cable but not
find any major improvement to rocket technology. But I wouldn't count
too much on that.

Of course maybe I just read too much into your sentence "Better
materials would make a tapered cable practical."


Alain Fournier
  #58  
Old June 16th 18, 01:18 AM posted to sci.space.policy,sci.physics,rec.arts.sf.science
Sergio
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Posts: 37
Default Towards routine, reusable space launch.

On 6/15/2018 6:21 PM, Alain Fournier wrote:
On Jun/15/2018 at 7:56 AM, Jeff Findley wrote :
In article , says...
It would be possible to build a space elevator using materials
available
today without any major new technology. But that wouldn't be
economical.
Not even remotely close to being economical. New materials would be
needed to build a sane space elevator, but new physics isn't needed.

See for instance
http://space.nss.org/media/2000-Spac...A-CP210429.pdf


I recall reading at least some analyses that said that the tensile
strength required exceeded atomic forces (in other words, an
impossibly strong material).

Without having checked, I would guess that that applies for a non
tapered cable. But if you taper the cable, it is physically possible to
build a cable using several existing materials.


That's my understanding as well.* Better materials would make a tapered
cable practical.* Today's materials result in a very huge tapered cable
necessitating a huge counterweight making the whole thing impractical.

So, we're arguing about impossible versus impractical here.* Either way,
it's not going to be built with today's materials.


Yes. But I think I am a little less optimistic than you about it
becoming practical in the future. If we have fantastic materials in the
future, maybe an elevator will become more practical, but SpaceX is
likely to figure how to build fantastic rockets if you give them
fantastic materials. So if you can build an elevator that would seem
practical today, that elevator might compete with a rocket that can be
reused 1000 times between inspections AND have high orbital mass fraction.

It is possible that we find a way to build a practical cable but not
find any major improvement to rocket technology. But I wouldn't count
too much on that.

Of course maybe I just read too much into your sentence "Better
materials would make a tapered cable practical."


Alain Fournier


how about a Space Slingshot ?
  #59  
Old June 16th 18, 02:05 AM posted to sci.space.policy,sci.physics,rec.arts.sf.science
Alain Fournier[_3_]
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Posts: 548
Default Towards routine, reusable space launch.

On Jun/15/2018 at 8:18 PM, Sergio wrote :
On 6/15/2018 6:21 PM, Alain Fournier wrote:
On Jun/15/2018 at 7:56 AM, Jeff Findley wrote :
In article , says...
It would be possible to build a space elevator using materials
available
today without any major new technology. But that wouldn't be
economical.
Not even remotely close to being economical. New materials would be
needed to build a sane space elevator, but new physics isn't needed.

See for instance
http://space.nss.org/media/2000-Spac...A-CP210429.pdf


I recall reading at least some analyses that said that the tensile
strength required exceeded atomic forces (in other words, an
impossibly strong material).

Without having checked, I would guess that that applies for a non
tapered cable. But if you taper the cable, it is physically possible to
build a cable using several existing materials.


That's my understanding as well.* Better materials would make a tapered
cable practical.* Today's materials result in a very huge tapered cable
necessitating a huge counterweight making the whole thing impractical.

So, we're arguing about impossible versus impractical here.* Either way,
it's not going to be built with today's materials.


Yes. But I think I am a little less optimistic than you about it
becoming practical in the future. If we have fantastic materials in the
future, maybe an elevator will become more practical, but SpaceX is
likely to figure how to build fantastic rockets if you give them
fantastic materials. So if you can build an elevator that would seem
practical today, that elevator might compete with a rocket that can be
reused 1000 times between inspections AND have high orbital mass fraction.

It is possible that we find a way to build a practical cable but not
find any major improvement to rocket technology. But I wouldn't count
too much on that.

Of course maybe I just read too much into your sentence "Better
materials would make a tapered cable practical."


Alain Fournier


how about a Space Slingshot ?


What do you mean by Space Slingshot?


Alain Fournier
  #60  
Old June 16th 18, 04:34 AM posted to sci.space.policy,sci.physics,sci.astro,rec.arts.sf.science
Fred J. McCall[_3_]
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Posts: 10,018
Default Towards routine, reusable space launch.

JF Mezei wrote on Fri, 15 Jun 2018
22:13:01 -0400:

On 2018-06-15 19:21, Alain Fournier wrote:

Yes. But I think I am a little less optimistic than you about it
becoming practical in the future. If we have fantastic materials in the
future, maybe an elevator will become more practical,


Apart from lifting geostationary satellites to just below orbit and then
let them use their own thrusters to position to their assigned
slot/longitude, what other use would a space elevator have ?


You go above the GEO point on the cable and get flung on
interplanetary trajectories.


--
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territory."
--G. Behn
 




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