ENDEAVOUR - and the spaced-out NASA efforts

[fbenario]

What authority do we have that 'cold welding' actually describes a real phenomenon of vacuums? Any experiments in chemistry or physics?

[hollycrap]

What authority do we have that 'cold welding' actually describes a real phenomenon of vacuums? Any experiments in chemistry or physics?

Yes they are aware of it that's why they have to fake all missions including the unmanned ones, they have not found a solution yet -- nor will they ever

http://esmat.esa.int/Publications/Publi ... TM-279.pdf => © 2009 European Space Agency
http://trs-new.jpl.nasa.gov/dspace/bits ... 4-0141.pdf

[disinpho]

What authority do we have that 'cold welding' actually describes a real phenomenon of vacuums? Any experiments in chemistry or physics?

from wikedpedia (http://en.wikipedia.org/wiki/Cold_welding#In_space):

Mechanical problems in early satellites were sometimes attributed to cold welding. However, in 2006, Henry Spencer stated that the phenomenon of spontaneous cold welding in outer space is "basically a myth", pointing out that "there are no documented cases of it actually occurring in orbit, except in experiments deliberately designed to provoke it (with susceptible materials, great care to avoid contamination, and deliberate mechanical removal of oxide layers, etc.)."[3]
Three years following this 2006 post the European Space Agency published a peer reviewed paper detailing why cold welding is a significant issue that spacecraft designers need to carefully consider. The conclusions of this appropriately titled study can be found on page 25 of "Assessment of Cold Welding between Separable Contact Surfaces due to Impact and Fretting under Vacuum". The paper also cites a documented example from 1991 with the Galileo spacecraft high-gain antenna (see page 2; the technical source document from NASA regarding the Galileo spacecraft is also provided in a link here). [4] [5]
One source of difficulty is that cold welding does not exclude relative motion between the surfaces that are to be joined. This allows the broadly defined notions of galling, fretting, sticking, stiction and adhesion to overlap in some instances. For example, it is possible for a joint to be the result of both cold (or "vacuum") welding and galling (and/or fretting and/or impact). Galling and cold welding, therefore, are not mutually exclusive.

To me, the above paragraph actually introduces a whole lot of other potential problems with moving metal parts in space, and a lot of new technical terms such as galling, fretting, sticking, stiction and adhesion.

The ESA's report can be found at http://esmat.esa.int/Publications/Published_papers/STM-279.pdf. The first paragraph reads:

Abstract
A common failure mode seen during the testing and operation of spacecraft is termed ‘cold welding’. European laboratories refer to this as ‘adhesion’, ‘sticking’ or ‘stiction’. This publication is intended to provide the space community with the most recent understanding of the phenomenon of ‘cold welding’ in relation to spacecraft mechanisms with separable contact surfaces. It presents some basic theory and describes a test method and the required equipment. Cold welding between two contacting surfaces can occur under conditions of impact or fretting. These surfaces may be bare metals, or inorganically or organically coated metals and their alloys. (...)

on page 2, they elaborate:

1.3 Background to the cold welding effect
Surfaces that are exposed to atmospheric conditions are generally covered by physically or chemically absorbed layers. Even in the absence of absorbed water, grease or other macroscopic contaminants, there remain surface layers, such as oxide and nitride layers, which are formed under terrestrial conditions on pure metal surfaces, and can be regarded as natural protection layers against cold welding.
Under vacuum or in a space environment, once these layers are removed by wear, they are not rebuilt and the exposed clean metal surfaces show a higher propensity to cold welding. So, their adhesive and tribological behaviours under vacuum or in a space environment differ significantly from those under terrestrial conditions, and the utility of data collected under the latter conditions is rather restricted. (...)

It sounds to me like any complex mechanical thing would have to be made entirely out of plastic to remain functional in a vacuum, if that is even possible. They say that the moon in the shade is around -110 Celsius or 163.15 Kelvin, and they say this is because there is no air (gas) to retain heat from the sun. This means logically this is the case on the shadow-side of any spacecraft operating in its vicinity as well.

This brings me to another mindbender, if the craft is made of aluminium the parts would expand and contract with about 0.5% when subjected to temperatures from 130C in sunlight to -110 C in shade, meaning a 1m sheet of aluminium would expand and contract with about 5.5mm, meaning the tolerance between each part would be 11mm, how in the world would they keep such a craft airtight?
I found the numbers at http://www.madsci.org/posts/archives/1997-03/849679535.As.r.html and used google and a calculator at http://www.calctool.org/CALC/eng/default/cte (I'm no expert)

Keeping a plane together when subjected to subsonic flight (and the temperature-fluctuations that go with) is hard enough, something that supposedly caused many problems for the engineers of the SR-71, a black project originating in the 60's. None of the novel solutions applied to the SR-71 to counter thermal expansion where used on Apollo 11 to my knowledge.

[hollycrap]

Besides in the conclusions of the essay by ESA "Assessment of Cold Welding between Separable Contact
Surfaces due to Impact and Fretting under Vacuum", published November 2009, their recommendations show they still don't know what kind of materials would be able to withstand cold welding and fretting, nor understand what exactly causes the phenomenon That means no successful spacecraft has ever traveled more than a few dozen miles into space or the problem would have been solved more that half a century ago, what with all reported missions to outer space

5 Conclusions

1. Test equipment (Annex A) and a test method (Annex B ) have been
developed to study the cold welding of material interfaces that make
contact under impact and fretting conditions. The method and the results
represent a step forward in studies of cold welding effects from ‘common
experience’ to measurable data that will be useful for designers of
spacecraft applications.

2. In order to provide engineers with the experimental data, AIT has set up
an online database that aims to bring together all the data generated from
all studies performed for ESA and industry. The database can be accessed
free of charge after registration: http://service.arcs.ac.at/coldwelddata.

3. It has been shown that the theoretical predictions are by no means
comparable with experimental data. The main reason is that the
adhesion force is driven by the ‘real contact area’, which can not be
predicted. Hertzian theory would predict a ‘nominal contact area’,
neglecting surface roughness and surface contamination. The latter in
particular is the main contributor and remains unpredictable.

4. A wide range of material combinations, including metal–metal (SS17-
7PH in contact with itself and Al alloy AA 7075 in contact with itself),
metal–polymer (SS17-7PH versus Vespel SP3), as well as several
coatings on steel, aluminum and titanium have been investigated under
impact and fretting conditions. The data can be found in Annex C. These
results and those of future work are now searchable online.

5. Tests have revealed that the range of adhesion forces in uncoated metal–
metal contacts with typical engineering surfaces and without coatings
depend on the type of contact:

– in static contact, adhesion forces were below 0.5 N,
– under impact, adhesion forces were up to 2 N, and
– under fretting, adhesion forces in excess of 18 N were found.

Basic material physics (type of atomic bonds) indicate that no technically
measurable adhesion between metals and polymers and ceramics can
be expected. A few tests on steel or aluminum and polyimide have not
contradicted this premise.

6. In order to avoid cold welding, polymers or ceramics can be selected, but
these materials may not be suitable for space hardware and mechanisms.
Hence, metal–metal contacts often cannot be avoided. In that case, in
order to reduce the risk of cold welding, the first strategy would be to use
dissimilar alloy pairs, e.g. stainless steel versus hard steel (low adhesion
is likely). The second strategy would be to apply coatings, although here
the type of contact and the substrate material need to be well known.

7. Under impact, hard coatings on stainless steel (TiC, for instance) may
break, so that although the risk of adhesion is lower, it is still present.
Soft coatings made of solid lubricants (e.g. MoS2) can repair themselves
during impact, so they are more effective in preventing adhesion than hard
coatings. Stainless steels are generally too soft to support hard coatings
under impact conditions. Hard anodised aluminum can withstand
impact. Titanium alloys must be coated with hard coatings to resist cold
welding if only impact is expected.

8. Under fretting conditions, none of the investigated coatings on stainless
steel (SS17-7PH) is able to prevent cold welding. Also MoS2 is not
effective under fretting, and the lubrication is quickly lost. Hence, the
best strategy must be to use different steels (maximum one of which
should be austenitic). Hard coatings should not be used on hard steels.
In contrast with steel, hard anodising of aluminium prevents adhesion
under fretting conditions, but much loose debris is formed. A thick
‘Keronite’ coating (20 µm), which is based on a plasma-electrolytic
oxidation (PEO) process, is not only resistant to fretting but also avoids
debris formation. A test using an uncoated titanium pin against coated
titanium discs did not provide a ‘general solution’. All thin coatings – solid
lubricants and hard coatings – were destroyed in the fretting contact. The
best combinations still showed medium adhesion after breakage of the
coating. The combination titanium and low-adhesion steel also did not
provide a solution. Further research will target thick coatings produced
by PEO (Keronite).

[lux]

Wouldn't this affect satellites too?

[hollycrap]

Wouldn't this affect satellites too?

You betcha

[lux]

... not to mention space probes, rovers, space stations, moon buggies, space-based weapons & telescopes, etc. etc.

[hollycrap]

... not to mention space probes, rovers, space stations, moon buggies, space-based weapons & telescopes, etc. etc.

And don't forget the Voyager that already surpassed the limits of the solar system and still keep transmitting. The odds of that imaginary junk of crap being pierced by micrometeorites, suffer cold welding, being rendered useless by cosmic rays and solar flares etc etc etc are a 1 followed by a million 0's against one.

There you go. We are living a simulation inside a simulation .. ad infinitum

[lux]

NASA claims Voyager 1 & 2 are still out there, billions of kilometers from Earth, still sending back data as they exit the solar system.

[hollycrap]

Space Exploration is the goose that lays the golden eggs. So how to give up such a profitable farce?

Above we showed that in 2009 more experiments are needed by ESA in order to assess the resistance of keronite to cold welding for space craft.

However I found at least two references where they claim keronite has already been used for years in space gear and craft.

From http://www.keronite.com/page-view.php?p ... -treatment

They state:

The Keronite system owes its origins to the space program and is still in operation on satellites and other spacecraft today, where it enables the extensive use of light alloys, which in turn increases the potential of the payload by reducing the weight of other elements of the craft. Keronite passes even the most rigorous space agency tests in applications where components are, for example, one moment facing the intense heat of the sun and in the next turned to face the extreme cold of deep space. The adhesion properties mean that even in these conditions the treatment does not come off.

The Company is currently working with both NASA and ESA to treat parts on active space programs and on development projects for the surface treatment of new materials.

And in this document I found this hilarious poster



Ref => https://docs.google.com/viewer?a=v&q=ca ... 5r_0VWQ7WQ

However in this site they don't even mention the word "space" in keronite's applications

Applications

Because of the flexibility and multi-functional nature of Keronite ceramic surfaces, the industrial applications are extremely wide ranging: from automotive body and engine parts to consumer products, textile machinery, tooling and moulding applications, and more recently, architectural panels for the external cladding of buildings.

ref => http://www.powdertech.co.uk/keronite.html

Further there's not yet an entry about keronite in the wikipedia. They still have time to make a new one convincing people this alloy was used in the sputnik satellite

[simonshack]

However in this site they don't even mention the word "space" in keronite's applications

Applications

Because of the flexibility and multi-functional nature of Keronite ceramic surfaces, the industrial applications are extremely wide ranging: from automotive body and engine parts to consumer products, textile machinery, tooling and moulding applications, and more recently, architectural panels for the external cladding of buildings.

Most curious indeed...

Conversely, the word "ceramic" is never mentioned in the ESA technical COLD WELDING report (as posted above):

A thick‘Keronite’ coating (20 µm), which is based on a plasma-electrolytic
oxidation (PEO) process, is not only resistant to fretting but also avoids
debris formation. A test using an uncoated titanium pin against coated
titanium discs did not provide a ‘general solution’. All thin coatings – solid
lubricants and hard coatings – were destroyed in the fretting contact. The
best combinations still showed medium adhesion after breakage of the
coating. The combination titanium and low-adhesion steel also did not
provide a solution. Further research will target thick coatings produced
by PEO (Keronite).
http://esmat.esa.int/Publications/Publi ... TM-279.pdf

Whereas Powdertech (the KERONITE experts) make it very clear on their website that :

"The patented Keronite process uses Plasma Electrolytic Oxidation (PEO) to transform the surface of light alloys such as aluminium and magnesium into a dense, hard ceramic with outstanding resistance to corrosion and wear. As a ceramic, the surface has other useful characteristics: it acts as a thermal barrier and an electrical insulator, and yet, unusually for a ceramic, the Keronite layer remains flexible and resistant to cracking or chipping and provides extremely good adhesion for scratch-resistant topcoats.
"
http://www.powdertech.co.uk/keronite.html#

************************
But hey! I think I found an entry for Keronite's space-cousin in Wickedpedia :
http://en.wikipedia.org/wiki/Kryptonite

[hollycrap]

Simon are you suggesting that ...

[fbenario]

Is this the same Kelly as our beloved Gabby Giffords Kelly?

NASA Chief Under Fire For Personal Shuttle Use

NASA Administrator Michael Griffin has yet to respond to recent allegations that he used NASA space shuttles on as many as one dozen unauthorized outings to such destinations as New York City, the French Riviera, and his vacation home near Ketchum, ID.

A report issued Monday by NASA's Oversight Commission indicates a cumulative 1.8 million miles unaccounted for on the Atlantic, Discovery, and Endeavor shuttles. In addition, shuttle pilot James Kelly reported numerous occasions on which he found the pilot seat "adjusted for someone else."
...
Trajectory-optimization engineer Russ Holcum said he'd long suspected that Griffin "had an in" with the staff in Engineering and Fabrication. Said Holcum: "I figured he knew someone who cut him an extra set of keys or two."

Holcum added: "More than once, I heard him ask the Mission Control guys if they'd mind 'counting him down' on his way out before a long weekend."

In a press conference held Tuesday, NASA spokesperson Arjun Congrove apologized to taxpayers for the billions of dollars expended on the unauthorized missions.

"The shuttle costs an estimated $2 billion per launch, not counting delays and repairs, and for Mr. Griffin to use it to take his wife on luxury shopping trips to Europe is not appropriate," Congrove said. "We apologize to affected personnel at NASA, and to the good people of New York City whose homes were vaporized by Mr. Griffin's several unauthorized launches near LaGuardia Airport."

Griffin may face penalties ranging from dismissal to having his salary garnished for the next 376 years in order to pay for fuel.

http://www.theonion.com/articles/nasa-c ... -use,1822/

[hollycrap]

Is this the same Kelly as our beloved Gabby Giffords Kelly?

NASA Chief Under Fire For Personal Shuttle Use

NASA Administrator Michael Griffin has yet to respond to recent allegations that he used NASA space shuttles on as many as one dozen unauthorized outings to such destinations as New York City, the French Riviera, and his vacation home near Ketchum, ID.

A report issued Monday by NASA's Oversight Commission indicates a cumulative 1.8 million miles unaccounted for on the Atlantic, Discovery, and Endeavor shuttles. In addition, shuttle pilot James Kelly reported numerous occasions on which he found the pilot seat "adjusted for someone else."
...
Trajectory-optimization engineer Russ Holcum said he'd long suspected that Griffin "had an in" with the staff in Engineering and Fabrication. Said Holcum: "I figured he knew someone who cut him an extra set of keys or two."

Holcum added: "More than once, I heard him ask the Mission Control guys if they'd mind 'counting him down' on his way out before a long weekend."

In a press conference held Tuesday, NASA spokesperson Arjun Congrove apologized to taxpayers for the billions of dollars expended on the unauthorized missions.

"The shuttle costs an estimated $2 billion per launch, not counting delays and repairs, and for Mr. Griffin to use it to take his wife on luxury shopping trips to Europe is not appropriate," Congrove said. "We apologize to affected personnel at NASA, and to the good people of New York City whose homes were vaporized by Mr. Griffin's several unauthorized launches near LaGuardia Airport."

Griffin may face penalties ranging from dismissal to having his salary garnished for the next 376 years in order to pay for fuel.

http://www.theonion.com/articles/nasa-c ... -use,1822/

The onion is a news spoof satirical site. All their news are mock ups. They might have other purposes though as disorienting the public on evident fakery, as the shuttle was.

[reel.deal]

"More than once, I heard him ask the Mission Control guys if they'd mind 'counting him down' on his way out before a long weekend."

"We apologize to affected personnel at NASA, and to the good people of New York City whose homes were vaporized by Mr. Griffin's several unauthorized launches near LaGuardia Airport."

Griffin may face penalties ranging from dismissal to having his salary garnished for the next 376 years in order to pay for fuel.

full link: http://www.youtube.com/watch?v=nWVc_jmuf7w
http://www.youtube.com/watch?v=nWVc_jmuf7w