From: \"BEVERLY, DAVID W. (JSC-NX)\" \<david.w.beverly1@jsc.nasa.gov\>

To: \"\'Henning Leidecker\'\" \<hleideck@pop500.gsfc.nasa.gov\>,

craig.t.mueller@aero.org, jkolasin@pop700.gsfc.nasa.gov,

melanie.ott@gsfc.nasa.gov, jplante@swales.com,

me@leidecker.gsfc.nasa.gov, ray.prestridge@lmco.com,

Anna@seawire.traveller.com, DChalk@BICCGeneral.com,

DZevotek@BICCGeneral.com, DRothermel@BICCGeneral.com, jli@spectran.com,

dyoung@spectran-specialty.com, mseifert@spectran.com,

Harold.Battaglia@SW.Boeing.com, carmen.c.moore@boeing.com,

BANKSE@pgocm1.ksc.nasa.gov, Daniel.Tambert-1@kmail.ksc.nasa.gov,

John.White3@West.Boeing.com, DAVID.GILL@West.Boeing.com,

\"BUZZARD, FRANK T. (JSC-EA)\" \<frank.t.buzzard1@jsc.nasa.gov\>,

klw@lucent.com, djd@lucent.com, jcanham@mscmail.gsfc.nasa.gov,

Alan.D.English-1@usa.dupont.com

Cc: \"PILOLA, PATRICK S. (PAT) (JSC-OB)\"
\<patrick.s.pilola1@jsc.nasa.gov\>

Subject: RE: SSQ21654 should be redesigned in light of our findings!

Date: Thu, 20 Jan 2000 18:34:56 -0600

X-Mailer: Internet Mail Service (5.5.2448.0)

Henning, I was pleased to hear the general consensus from the group
today

that a \"redesigned\" cable would be in NASA\'s best interest.

My feeling on the 21654 cable, even before we had these problems, was
that

it was a compromise that needed to be fixed, the problem was when and
how.

I see our present predicament as being an ideal time to push for a new

cable. I don\'t think JSC has the expertise to make the \"right\"
decisions

on the best approach for a new cable. I would very much like to see the

working group address some of the design criteria that best fits what
NASA

needs and is closer to a standard product.

But I sure agree with David\'s comment that our problem right now is
getting

the station cable back into production with it\'s problems understood
and

fixed, if at all possible. Once we have a handle on the immediate
problem I

would very much like the group come up with a strawman or basic
\"needs\"

document for a future fiber cable. I do think the process of defining
the

requirements, finding a source and qualifying cable will take at least 6

months and probably closer to a year.

Thanks to you Henning, and to all of you for the time you are giving to
fix

this major Space Station problem.

David Beverly

NX-EEE Parts

\(281\) 483-0250 Mobile:(713) 825-5624

Fax: (281) 244-2318

E-mail: david.w.beverly1@jsc.nasa.gov

\-\-\-\--Original Message\-\-\-\--

From: Henning Leidecker \[mailto:hleideck@pop500.gsfc.nasa.gov\]

Sent: Thursday, January 20, 2000 4:00 PM

To: craig.t.mueller@aero.org; jkolasin@pop700.gsfc.nasa.gov;

melanie.ott@gsfc.nasa.gov; jplante@swales.com;
me@leidecker.gsfc.nasa.gov;

ray.prestridge@lmco.com; BEVERLY, DAVID W. (JSC-NX);

Anna@seawire.traveller.com; DChalk@BICCGeneral.com;

DZevotek@BICCGeneral.com; DRothermel@BICCGeneral.com; jli@spectran.com;

dyoung@spectran-specialty.com; mseifert@spectran.com;

Harold.Battaglia@SW.Boeing.com; carmen.c.moore@boeing.com;

BANKSE@pgocm1.ksc.nasa.gov; Daniel.Tambert-1@kmail.ksc.nasa.gov;

John.White3@West.Boeing.com; DAVID.GILL@West.Boeing.com; BUZZARD, FRANK
T.

(JSC-EA); klw@lucent.com; djd@lucent.com; jcanham@mscmail.gsfc.nasa.gov;

Alan.D.English-1@usa.dupont.com

Subject: SSQ21654 should be redesigned in light of our findings!

Gentles,

I wear several hats, as do we all. For several months, I have been
working

full time on the ISS Fiber Optic Cable Team, whose task is to produce a

reliable risk assessment of the fiber optic cable presently installed in
the

US Lab module. But I am also a NASA employee whose job is fixing
problems

related to mission assurance.

I wrote the following to Dave Beverly, who works for NASA/ISS in support
of

their (Electronics) Parts Control Board. I did not send it to \"team

distribution\" since it is not focused on producing a reliable risk

assessment of US Lab cable. But today\'s telcon makes it clear that
there is

interest in the SSQ fiber spec, so now I am sending it to \"team

distribution\".

I welcome comments and discussion!

Sincerely,

Henning Leidecker

=============================

Dear David Beverly,

I recommend to ISS that ISS redesign SSQ21654, and document it through a

reissue of the specification. The redesign should incorporate additional

quality and reliability requirements such as minimum yield limits for
the

fiber manufacturer.

That is, I think it is a bad idea to re-qualify companies (SpecTran,
BICC)

to ensure they can produce cable to the present version of SSQ21654

(together with its current updates). The present design places a source
of

HF acid next to a glass fiber that can be substantially etched wherever

there is a breach in the carbon coating intended to protect the fiber,
and

we know that carbon coating breaches happen. Not only does this present
a

potentially dangerous situation; experience shows that it has produced

unacceptable cables. I have no confidence that controls can be
implemented

to ensure that future production to the present specification will be
flaw

free to the extent required by ISS over its planed 15 year life. Also,
we

cannot presently non-destructively screen for all the defects we know
will

lead to catastrophic failure.

We know that we have HF acid etch pits in abundance in 1998/1999 vintage

cable (roughly every dozen feet in some cases), and we have one large
etch

pit in the 10,000 feet of 1996 vintage cable that has been tested.
(There is

the possibility that this same 10,000 feet of cable has many small etch
pits

\-\-- we are presently checking for this.) We have never seen any test
data

for 1997 vintage cable, so we do not know the situation for it.

The present design was created by a particular group of individuals on
the

basis of the best knowledge of that time. Today, we know more. In

particular, we have substantial evidence that extruding a FEP buffer in
air

over this carbon-coated fiber creates sufficient HF acid to create etch
pits

where the carbon coating is breached. And there is a possibility that

subsequent events (including mechanical agitation and exposure to space

radiation) will create additional HF acid. We have evidence that ESD
events

can create suitable breaches in the carbon coating, and there may be
other

ways too for breaches to happen, including process-failures at SpecTran.
I

suspect that the group of individuals who designed SSQ21654 would no
longer

endorse the present design for use in high reliability, long life

situations.

The governing document is an ISS specification, and it is ISS\'s

responsibility to update the specification in light of present
knowledge. We

should not wait for Boeing to do this on their own initiative; however,

Boeing has valuable knowledge and should assist in the redesign. I
recommend

that this redesign be made an item of priority, since the lack of
suitable

cable is presently affecting the construction of ISS items.

Sincerely,

Henning Leidecker