Foreign Object Debris (FOD) Proposal

Karen Iftikhar

Foreign Object Debris (FOD) Proposal

Karen Iftikhar

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NASA TECHNICAL STANDARDS - REVISION

Documents - • AIA/NAS 412 FOREIGN OBJECT DAMAGE/FOREIGN OBJECT DEBRIS

(FOD) PREVENTION• Does not cover FOD as it applies to Space Vehicles and their associated

payloads

• NASA/TM-2004-213118 REDUCED-ORDER MODELING AND WAVELET ANALYSIS OF TURBOFAN ENGINE STRUCTURAL RESPONSE DUE TO FOREIGN OBJECT DAMAGE (FOD) EVENTS

• Describes model of engine turbo fan subjected to FOD

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NASA TECHNICAL HANDBOOKS & SPECIFICATIONS

IN DEVELOPMENT

Background – Why are we concerned?

• In-process contamination can adversely effect critical bonding surfaces, fluid wetted surfaces, cleanliness critical, e.g., thermal control surfaces once hardware is placed in service

• Surface contaminants/particulate or FOD can become airborne during launch/ascent or in zero-G environment resulting in potential for:

• Hardware impact damage from debris displaced during flight• Astronaut safety and health hazards – eye or ear irritants, inhalation or

ingestion concerns • Subsystem problems (electrical and mechanical interfaces, etc.) with

shorting electrical components, binding mechanisms or leaking seals • Lack requirement/data relating ground processing surface cleanliness to on-orbit

airborne levels

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OTHER TECHNICAL STANDARDS IN DEVELOPMENT

• What is Contamination?• Presence of any unwanted matter which could be detrimental to the required operation,

reliability, or performance of a part, component, subsystem or system. (JSC-SN-C-0005D)• What is a Foreign Object Debris (FOD)?

A substance, debris or article alien to or unintended to become part of the final material, product, process, assembly or vehicle that could potentially cause

(1) internal damage through ingestion or incorporation into the product, or

(2) external damage through contact with the product. • Foreign objects or debris can include:

• Clippings, plastic tie wraps, lacing cord, safety or lock wire, metal chips, solder, paint, etc.

• Gum, food, wrappers, jewelry, keys, coins, paper, pens, paper clips, staples, tacks, cloth, tape, shop wipes, Q-tips, etc.

• Processing tools or parts (e.g., extra fasteners, washers)

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NASA TECHNICAL STANDARDS - REVISION

Surface Cleanliness Requirements• External surfaces require Visibly Clean (VC) standard• Internal Surfaces require VC sensitive

Definitions:Visibly Clean (VC) – The absence of all particulate and non-particulate matter visible to the

normal unaided (except corrected vision) eye. (JSC-SN-C-0005D, Table A.1 and A.2)

VC Standard – Viewed from 5-10 feet (~1.5-3 m) with incident light >50-foot candles (See Notes 2, 3 & 5)

VC Sensitive - Viewed from 2-4 feet (~0.6-1.3 m) with incident light >50-foot candles (See Notes 2, 3 & 5)

Notes: (2) Cleaning is required if the surface in question does not meet VC under the specified incident light and observation distance conditions.

(3) Exposed and accessible surfaces only. (5) Areas of expected contamination may be examined at distances closer

than specified for final verification.

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NASA TECHNICAL STANDARDS - REVISION

PLEASE REMEMBER - • The cleanliness of critical GSE and flight hardware has a direct effect on

the safety and performance of the vehicle and personnel• All production personnel working with flight hardware are directly

responsible for achieving and maintaining the required level of cleanliness