1.1 Purpose: This specification defines requirements for
fiber optic cable for use in space flight applications. The cable types described here are intended for
point-to-point applications which use connectors on each end of the cable, where exposure
to mechanical stress will be moderate. These cables are limited to types using a 100/140 m
size core/cladding with graded refractive index profile.
| Element | Material | Dimensional Requirement |
| Primary Jacket | FEP Teflon? | Outer diameter 0.098" +0.002"/-0.005" (2.489 mm +0.051/- 0.127 mm) |
| Strength Members | spiral (helical) or laterally wound Kevlar® | |
| Spacer | Expanded PTFE Gore Tex® | Wall thickness: 0.015" (0.381 mm) |
| Outer Buffer Layer | Fluoropolymer | Wall thickness 0.003" nominal (0.076 mm) Outer diameter 0.063" 0.002" (1.600 0.051 mm) |
| Inner Buffer Layer | GORE-TEX® Expanded PTFE | Helically wound tape, Nominal wall thickness: 0.004" (0.1016 mm) |
| Coating | two layer acrylate (chemically strippable with MEK and Methylene chloride) | Outer diameter: 0.500 25 mm Non-circularity: 10% |
| Hermetic coating | amorphous carbon | 400 angstroms thickness maximum |
| Fiber Cladding | radiation hardened silica | 140 micron +/- 2 micron |
| Fiber Core | radiation hardened silica | 100 micron +/- 3 micron |
| Core/Cladding Offset | 3 microns (test method?) | |
| Core Non-circularity | 5% (test method?) |
1.2 General Specification Unless otherwise specified
in this detail specification, all cable provisions of GSFC specification S-311-339 apply.
1.3 Materials and Dimensions: Specifications for materials
and dimensions which define this cable are shown in Table 1.
1.4 Part Number: The part number for this cable construction
shall be XXXXX-5. The final digit in the part number is intended to differentiate between similar
cables as additional designs emerge, which are appropriate for listing as part of this slash
sheet.
1.5 Absolute Maximum Ratings: The absolute maximum ratings
are as shown below and in Table 1 above.
Attenuation (over operating temperature range):
2.1 Documents: The following documents, of the issue in
effect on the date of invitation for bid or request for proposal, form a part of this specification to
the extent specified herein. A later revision of a specification may be used, as long as, the later
revision does not degrade the specification requirements. STANDARDS
Industry
3.1 Design, Construction and Physical Dimensions: All
cable dimensions, tolerances and limits defined in 1.3 above shall apply.
3.1.2 Coating Geometry: Coating outer diameter and non-circularity
shall be measured in accordance with paragraph 4.5 below and shall meet the limits
shown in Table 1 above. The coating offset measurement shall be made in accordance with
the referenced procedure however the limit shall be that the offset does not cause the
coating wall to be thinner than 0.155 mm. The measurements shall consider the double layer coating
as one layer. The amorphous carbon layer shall be visibly present but is not required
to be measured. Coating geometry measurements shall be performed
as part of Group A testing on every lot.
3.2 Weight: The maximum weight by length shall be 4 g/m.
3.3 Attenuation: The attenuation shall not exceed the
maximum rating stated in 1.5 above. The measurement shall be made using EIA/TIA-526-14 (OFSTP-14) Method B. The delta limit during and following qualification testing shall be 1 dB per 100 meters.
3.4 Bandwidth: The bandwidth shall not be less that that
described in 1.5 above when tested in accordance with the general specification. Bandwidth
shall be included in Group A testing following Attenuation.
3.5 Pull-Proof Connector Compatibility: The cable design
and construction shall allow at least 1mm of free lateral movement of the coated fiber within
a loose buffer or a tight buffered fiber within strength members or a primary jacket
to allow use of this cable with a pull-proof connector.
3.6 Jacket and Buffer Shrinkage: Following preconditioning
for 10 hours at 85°C, the cable jacket and buffer shall not shrink greater than 0.4% by
length.
3.7 Ionizing Radiation: Performance stability in an ionizing
radiation environment shall be established by test or by analysis to be XXX dB loss
per xxxx meter sample. Cable shall be able to withstand greater than 100K Rad Si total dose and still meet the performance specification for the optical fiber.
3.8 Material Outgassing: The outgassing requirements of
the general specification shall apply to all the materials of the cable with the exception
of the coatings. The overall cable as a whole configuration must meet outgassing requirements.
3.9 Numerical Aperture: The numerical aperture shall be
0.29 0.015 when measured in accordance with the general specification.
3.10 Strippability: The coating shall be strippable by
chemical means. After chemical immersion for not more than 2 minutes in methylene chloride and
wiped with a kim-wipe exposing the hermetic coating.
3.11 Tensile Load (Proof Test): The proof test shall be
performed as part of Group A screening, on every sample lot. For qualification, this test
shall be performed as part of Group I and removed from Group IV.
3.12 Tensile Strength and Elongation: The percent elongation
shall be xxxxx and the tensile strength shall be xxxx when tested in accordance with
paragraph 4.9 below. Tensile strength and elongation shall be testing as part of qualification
in Group IB.
( would like to specify this number for user's benefit and
to establish minimum performance for cables supplied to this spec. Establish these
numbers based on qual testing).
3.13 Flammability: When tested in accordance with paragraph
4.10 herein, the flame shall self-extinguish in less than or equal to 10 seconds and
shall not travel more than 1 cm.
3.14 Impact Testing shall be in accordance with the base
specification and paragraph herein. The change in attenuation shall be less than 0.4 dB
and there shall be no damage to the jacket, following the test.
3.15 Crush (Compressive Strength): Compressive strength shall be verified as specified in paragraph herein. The change in attenuation shall be less than 0.4 dB and there shall be no physical damage to the jacket, following the test.
3.16 Certificate of Conformance: A certificate of conformance
in accordance with the GSFC -S-311-339 paragraph 4.7 shall be provided with each lot
of fiber optic cables delivered to this specification.
3.17 Verification and Review: GSFC retains the option
to review the manufacturer's facility and applicable required documentation. Offshore documentation
shall be made available onshore at the option of the reviewer. Pre-ship
inspection is the option of GSFC and requires one week advance notice from the vendor
for scheduling.
3.18 Qualification: Parts furnished to this specification
shall be product which has been granted qualification approval by NASA/GSFC. Qualification approval
shall be based on the following:
3.18.2 Part Qualification: The cable shall be product
which has passed the qualification inspection requirements of this specification. This requirement
may be satisfied by passing the qualification inspection (see 4.2).
3.18.3 Qualification by Similarity: Qualification may
be granted by GSFC based on existing qualification test data for product of similar design,
manufactured by similar processes and controls. If qualification is to be based
on generic qualification test data or on other conditions, the vendor shall
supply the appropriate supporting documentation. GSFC will have the final
decision on which parts will require qualification testing and which may be
qualified by other means.
3.19 Quality assurance provisions: Quality assurance requirements
shall be as specified in GSFC S-311-339 and Section 4 herein. The product assurance
program shall be subject to review and approval by GSFC.
3.20 Packaging: Packaging shall be in accordance with
GSFC S-311-339 and Section 5 herein. Preparation for delivery shall meet specified requirements
for identification, certification, and data package requirements.
3.21 Data requirements: The deliverable data package is
described in section 6.3 herein.
4.1 Conditions for optical measurements: Light launch
conditions shall be in accordance with the referenced test method. Cladding mode
stripping is not required..
4.2 Qualification maintenance: At the discretion of GSFC
but not less than every other year, the manufacturer will be requested to furnish a summary
of qualification test results for product not older than six months, for retention of
qualification status.
4.3 Serialization: Applicable.
4.4 Core/Cladding offset: The core/cladding offset shall
be measured in accordance with EIA/TIA-455-??? at a minimum of xx places along the sample
and shall meet the limit defined in Table 1 above.
4.5 Coating Geometry. Coating geometry shall meet the
requirements of paragraph above when measured in accordance with EIA/TIA-455-55 (FOTP-55),
Method A. Two samples shall be measured; one from each end of
the cable lot.
4.6 Attenuation: Attenuation shall be measured in accordance
with EIA/TIA-526-14 (OFSTP-14) Method B.
4.7 Temperature Cycling: Temperature cycling shall be
performed in accordance with EIA/TIA-455-3 (FOTP-3) over the rated temperature range. The
rate of temperature change shall be in accordance with FOTP-3. Attenuation measurements shall be
made during and after the cycling and visual examination performed after the test.
4.8 Tensile Load (Proof Test): The tensile load performance
shall be measured in accordance with EIA/TIA-455-31 (FOTP-31). In-line testing is
a suitable substitute for specimen based testing.
4.9 Tensile Strength and Elongation: Tensile strength
and elongation shall be performed in accordance with EIA/TIA-455-89 (FOTP-89) and shall
meet the requirements of 3.12.
4.10 Flammability: A 24 inch sample shall be tested in
accordance with MIL-STD-2223, Method 1006.
4.11 Impact: Impact testing shall be performed in accordance
with the base specification with the exception that the number of cycles shall be 10.
4.12 Crush (Compressive Strength): The cable shall meet
the requirements of the base specification and paragraph 3.15 herein when testing in accordance
with DOD-STD-1678, Method 2040, Procedure II. Optical measurements
shall be performed in accordance with the methods described in the base
specification and in paragraph 3.3 above. The tensile load shall be 90 kg (200
lb) and shall be applied for 1 minute.
5.1 Packaging requirements: The requirements for packaging
shall be in accordance with GSFC-S-311-339.
6.1 Ordering data Procurement documents shall specify
the following:
6.2 Qualification provisions. With respect to products
requiring qualification, awards will be made only for products which have been tested and approved
by GSFC before the time for opening of bids. The attention of the suppliers
is called to this requirement: manufacturers should arrange to have qualification
tests made on products which they propose to offer to GSFC to become eligible
for awards of contracts or orders for products covered by this specification.
The manufacturer shall bear the cost of qualification inspection to this specification.
Information pertaining to qualification of product may be obtained from the activity whose
address is listed in 6.4.
6.3 Deliverable data package: The deliverable data package
for each lot of each lot of each cable type shall include the following:
Bandwidth: 100 MHz/km
Numerical Aperture: 0.29 0.015
Operating Temperature Range: -55°C to +85°C
Storage Temperature Range: -55°C to +85°C
Short Term Temperature Exposure: -55C to +140 for 1 hr
Bend Radius: 50 mm
Military
2.2 Order of Precedence: In the event of a conflict between
the text of this specification and the references cited herein, the text of this specification shall
take precedence. However, nothing in this document supersedes applicable laws and regulations unless
a specific exemption has been granted.
3.1.1 Core/Cladding Offset: Core/Cladding offset
shall be measured in accordance with paragraph 4.4 below as part of Group A testing on every lot.
The offset shall meet the limit described in Table 1 above.
3.18.1 Design and Source Approval: Prior to qualification,
the manufacturer's facility shall be subjected to a survey, at the option of GSFC. The history
and detailed engineering of the specific (part) design will be reviewed, as
will the documented manufacturing and quality control procedures. Only
those sources approved in the design and source phase shall be eligible for
qualification or award of contract under this specification. Source approval and
design approval are not substitutes for part qualification or an equivalent thereof.
6.2.1 NOTICE: When GSFC drawings, specifications, or
other data are sent for any purpose other than connection with a definitely related GSFC procurement
operation, the United States Government thereby incurs no responsibility
nor any obligation whatsoever. The fact that GSFC may have formulated,
furnished or in any way supplied said drawings, specifications, or other
data, is not to be regarded by implication or otherwise as in any manner licensing
the holder or any persons or corporations, or conveying any rights or permission
to manufacture, use, or sell any patented invention that may in any
way be related thereto.
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