\

/ o'j

TWR-17592 VOL. VII

SHUW_

Space Shuttle Production Verification Motor I (PV-I)

Field Joint Protection System

Final Report

Volume VII

I0 December 1990

Prepared for:

NATIONAL AERONAUTICS AND SPACE ADMINISTRATION

GEORGE C. MARSHALL SPACE FLIGHT CENTER

MARSHALL SPACE FLIGHT CENTER, ALABAMA 35812

NAS8-30490

Contract No.

3-5 DR. No.

4B601-03-08

WBS.No.

ECS SS-I005

1",#_._'_---__ CORPORATION

SPACE OPERATIONS

RO Box 707, Brigham City, UT 84302-0707 f80l) 863-3511

(NASA-OR-184105) SPACE SHUTTLE PROOUCTION

VERIFICATION MOTOR i (PV-1) FIELD JOINT

PROTECTION SYSTEM, VOLUME 7 Finn| Report

(fhioko] Corp.) Ii p CSCL 21H

FORM TC 4677 (REV 1-SB)

G3/zo

N91-18Z08

Unclas

0332824
" DOC NO.

TITLE

TVR-17592 VOL. Vll

L624-FY91-M029

VOL REV

Space Shuttle Production Verification Hotor 1 (PV-I)

• Field Joint Protection System "

Final Report

Volume VII

10 December 1990

Prepared by:

S_ge Hardware Design Engineer

Approved by :

Stage Hardware Design

System IntegFi_bn Engineer

SR&QA

7)

/Data Hanagement -

ECS SS-1005

_ CORPORAT/ON

SPACE OPERATIONS

PO BOx 707. Brigham C,ty,UT 84302-0707 (801) 863-351 !

FORM TC NO 1810
__ CORPORATION

SPACE OPERATIONS

Abstract

This report documents the performance of the field Joint protection

system (FJPS) of the Space Shuttle Production Verification Motor I

(PV-I), as evaluated by postfire hardware inspection. Compliance with

specification CPWI-3600 is shown for the FJPS assembly and components.

The simplified FJPS and field Joint heaters performed nominally,

maintaining all joint seal temperatures within the required range. One

anomaly was noted on the Igniter-to-case joint heater during postfire

inspection. The heater buckled off the surface in two areas, resulting

in two hot spots on the heater and darkened heater insulation. The

condition did not affect heater performance during ignition countdown and

all igniter seals were maintained within required temperature limits.

REVISION

FORM TC 7994-310 (REV 2-88)

DocNO TWR-17592

SEC

l vo'VII

I PAGE

i
_'__ CORPORATION

SPACE OPERATIONS

Section

1.0

2.0

3.0

4.0

5.0

CONTENTS

INTRODUCTION 1

OBJECTIVE 1

SUMMARY 3

CONCLUSIONS/RECOMMENDATIONS 3

DISCUSSION 4

5.1 PREFIRE HEATER CONTROL SYSTEM 4

AND PERFORMANCE

5.2 POSTFIRE INSPECTION OF FJPS AND 4

IGNITER HEATER INSTALLATION

5.2.1 Field Joint Protection System 4

5.2.2 Igniter Heater and Forward Dome Power 4

Cable Installation

REFERENCES 6

DISTRIBUTION 7

FIGURES

Figure Page

1 Simplified Field Joint Protection System 2

REVISION

FORM TC 7994-310 (REV 2-88|

DOCNO. TWR-17592 I vo,Vll

SEC

PAGE

ti
7"_ CORPORATION

SPACE OPERATIONS

ACRONYHS

D_rV

FJPS

in

PEEP

PV-1

RSRM

SRB

RTD

TPS

W

oF

dielectric withstanding voltage

field joint protection system

inch

Postflre Engineering Evaluation Plan

production verification motor I

Redesigned Solid Rocket Motor

Solid Rocket Booster

resistive temperature device

thermal protection system

watt

degrees Fahrenheit

REVISION

FORM TC 7994-310 {REV 2-88)

oocso. TNR-17592 T I v°LvII

SEC [ PAGE

iti
"_"_ CORPORATION

SPACE OPERATIONS

1.0 INTRODUCTION

The Space Shuttle Production Verification Motor (PV-1) test was a

full-scale Redesigned Solid Rocket Motor (RSRM) static firing. PV-I was

successfully fired on 18 August 1988 at the Thiokol, Utah-based

operations, test bay T-24. Postfire inspections of PV-1 were performed

per Postflre Engineering Evaluation Plan (PEEP) TNR-16473 (reference 2).

Field joint seal temperatures were maintained using a simplified

field joint protection system (FJPS), shown in figure 1, consisting of

heaters and sensors only. The heaters consisted of primary and redundant

chemlcally etched foll circuits which were superimposed upon one another

and laminated in Kapton and fluoroethylene polymer Teflon. Adjacent to

the heaters were two temperature sensor assemblies, each containing two

resistive temperature devices (RTD). These were covered by a 0.25-in

thick strip of cork held in place by a single Kevlar strap.

The Igniter-to-case joint was fitted with an igniter heater to keep

the igniter seals within the required temperature limits. The heater

consisted of a flexible strip heating element secured around the igniter

adapter flange with adhesive backed tape. Thick cork (0.25-in) was

wrapped around the heater, and the heater and cork were secured in place

with a steel T-bolt latch band clamp.

2.0 OBJECTIVE

The objective of this report is to document any heater anomalies

prior to motor ignition and any anomalies to the FJPS during test firing.

This report will also show PV-1 static test compliance with specification

CPW1-3600, Addendum D, dated 3 August 1987.

Qualification Objectives (CEI Paragraph)

BR. Certify the ability of the field joint assembly

to maintain the temperature of the field

joints. (3.2.1.11.a)

CH. Certify the function of the igniter heater.

(3.2.1.5.3., SCN 42)

REVISION

FORM TC 7994-310 (REV 2-88)

DOC NO.

TWR-17592

]voLVII

I 1
_"__--4_ CORPORATION

SPACE OPERATIONS

N

e_

REVISION OOCNO.TVR-17592 I voL VII

SEC I PAGE 2
__ CORPORA T/ON

SPACE OPERATIONS

3.0 SU_IARY

Postfire inspection results indicate that the simplified FJPS was in

excellent condition with no signs of abnormal heat effects. The field

joint heaters performed nominally during ignition countdown, maintaining

the field joints within the required temperature limits. No anomalies

were observed on the FJPS.

One anomaly was noted on the Igniter-to-case joint heater during

postfire inspection. The heater buckled off the surface in two areas,

resulting in two hot spots on the heater and darkened heater insulation.

A corrective action was initiated to remove the adhesive backed tape from

the heater-to-lgnlter adapter interface. This will eliminate bondline

stresses induced by improper alignment of the heater strip during

installation. The condition did not effect heater performance during

ignition countdown and all igniter seals were maintained within the

required 75 ° to 120°F temperature range.

4.0 CONCLUSIONS/RECOMMENDATIONS

The JPS heaters and ignlter-to-case joint heater performed

adequately and maintained the joint temperatures within the required

range during test fire countdown. Postflight inspection verified that

the FJPS performed as designed. The anomaly reported on the

igniter-to-case joint heater did not effect heater performance during

ignition countdown.

Listed below are the conclusions as they relate to the objectives

and CEI paragraphs.

Qualification Objectives

(CEI paragraph number)

BR. Certify the ability

of the field joint

heater assembly to

maintain the

temperature of the

field joint.

(3.2.1.11.a)

Pass/Fail Criteria

The fle]d joint

temperature must be

maintained between

75 ° and 120°F prior

to motor ignition.

Conclusions

Certified. Minimum

recorded joint heater

sensor temperature was

86°F at T-O, ensuring

acceptable field joint

temperatures.

REVISION

FORM TC 7994-310 IREV 2-88)

OOCNO.TVR-17592 [ voLVll

sEc iPAGE3
"_"_ CORPORATION "

SPACE OPERATIONS

CB. Certify the

function of the

igniter heater.

(3.2.1.5.3, SCN 42)

5.0 DISCUSSION

The 4gnlter henter

must maintain the

igniter seals

between 64 ° and

130°F prior to

motor ignition.

C@rt_fied. The i_niter

heater functioned

adequately throughout

ignition countdown and

maintained all igniter

and safe and arm seal

temperatures within

required limits.

5.1 PREFLIGHT HEATER CONTROL SYSTEM AND PERFORMANCE

The three field joint heaters performed nominally during ignition

countdown, maintaining the temperature at the controlling RTD at or above

IO0"F, with a maximum deviation of -0.1 ° and +0.4°F. The remaining RTD's

showed a minimum joint temperature of 86°F at T-O, ensuring field joint

temperatures within the required 75 ° to 120 ° range.

The Igniter-to-case joint heater performed nominally, maintaining

the igniter joint within the required 64 ° to 130°F range during ignition

countdown. The minimum igniter Joint temperature occurred during

building rollaway when one temperature sensor dropped from 128 ° to 115"F

as a result of convective cooling.

5.2 POSTFLIGHT INSPECTION OF FJPS AND IGNITER HEATER INSTALLATION

5.2.1 Field Joint Protection System

The simplified FJPS was in excellent condition with no signs of

abnormal heat effects on the cork strip or Kevlar band. No anomalies

were observed on the FJPS.

5.2.2 Igniter Heater and Forward Dome Power Cable Installation

One

postflre

adapter

darkened

degradation of insulation

(DNV), or continuity.

anomaly on the igniter-to-case joint heater was noted during

inspection. The heater buckled off the surface of the igniter

in two places, which caused two hot spots on the heater and

heater insulation. Subsequent testing of the heater showed no

resistance, dielectric withstanding voltage

REVISION

FORM TC 7994-310 (REV 2-88)

DOC NO. TVR-17592 ivo_II

SEC I PAGE 4
"_"_ CORPORATION

SPACE OPERATIONS

The condition was caused by stresses induced on the igniter

heater-to-lgniter adapter bondline during heater installation and

operation. During installation adhesive backed tape was applied between

the heater and adapter. Local stress areas were introduced into the

bondline In places where the flexible heater strip was not properly

aligned, yet was held in place by the tape. Normal expansion of the

heater strip during heater operation caused the strips to buckle in these

areas. As a result of thls anomaly a corrective action was initiated to

remove the adhesive backed tape from the heater to adapter interface.

Inspection of the heater power cables revealed no anomalies.

REV, S,ON oocNo. TNR-17592 ] voLVII

SEC j PAGE

FORM TC 7994-310 (REV 2-88) 5
_"_ CORPORATION ....

SPACE OPERATIONS

I__CES

I. TWR-17592, VOL. I, Revision B, 'Space Shuttle Production Verification

Motor 1 (PV-I) Static Fire Final Test Report', D.M. Garecht, August

1989.

2. TI_R-16473, VOL. VII, Revision A, 'Qualification and Production

Verification Motor Postfire Engineering Evaluation Plan (Joint

Protection System Component)', S.W. Olsen, 13 January 1989.

REVISION

FORM TC 7994-310 {REV 2-88}

GOCNO TWR-17592

SEC

I PAGE

6