# Presentation: 238696

## Section 15

_***Section 15***_
***Mechanical***

*** ******. . . Pete Alea***
*EO-1 Mechanical Lead, Swales Aerospace, Inc.*

## Contents

***Contents***

***Mechanical Activities Since Last Red Team Review***
***Scheduled Mechanical Operations - Pre-Ship***
***Special Topics***

## “As Run” Final System Level S/C Verification (as conducted)

## Projected Power On Time

## Mechanical Activities

***Mechanical Activities***

***Setup for  Second Thermal Vacuum Test***
***Designed, fabricated and proof tested new test fixture to replace payload cart for Chamber 225***
***Performed fitcheck of fixture in chamber prior to installation of satellite***

## Thermal Vacuum Configuration

**Satellite Installed on Fixture**

**Satellite In Chamber 225**

## Pre-Ship Mechanical Ops

***Pre-Ship Mechanical Ops***

## Issues

***Issues***

***None ! Currently there are no open mechanical problem reports !***
***No residual risk items remain for the satellite mechanical system***
***We are ready to ship !***

## Special Topic:

***Interpoint Converter Lid Stiffener***

*** ******. . . Pete Alea***
*EO-1 Mechanical Lead, Swales Aerospace, Inc.*

## Response To Interpoint Converter Failures

***Response To Interpoint Converter Failures***

***Following Red Team Review Status on 3/28/00 it was determined by GSFC Code 300 that best approach was to reduce vacuum induced deflections on all existing MTR28XXD devices. ***
***Process developments initiated jointly by GSFC, Swales and Litton to address issue. The intent was to develop a Center wide solution across all programs with EO-1 being the first implementation. Also close participation by MAP, TIMED, and SIRTF programs which included LMCO and INTERPOINT involvement.***

## Response To Interpoint Converter Failures

***Response To Interpoint Converter Failures***

***A number of different designs assessed and tested by GSFC, Swales and Litton.  Primary focus was on bonding kovar doubler to outer surface of MTR28XXD cover. General Criteria was as follows:***
***Performed in-situ on board so that part removal was not required.***
***Test verifiable after bonding.***
***General approach that could be applied to different configurations (bonded versus mechanical). ***
***For bonding contamination was of primary concern.**** *

## Qualification Process

***Three parallel path approach to create an analytical model that predicts the observed cover deflection & evaluate various design solutions, qualify the manufacturing process, and test verify the final flight article.***

## Converter Rework Flow 

***The rework flow for the EO-1 AST DC Converters is shown below***
***This flow is typical of all EO-1 DC-DC Converter reworked, except for the AST specific chassis machining.***

## AST Converter Rework Flow

***AST Converter Rework Flow***

**Initial PWB Configuration**

**Setup in Vacuum Chamber**
**After Converter Bonding**

**Final Converter/Doubler Configuration**

**Initial 1773 Chassis**

**Final Chassis Configuration**
**After Machining**

## Summary of all Converters Reworked

***Summary of all Converters Reworked***

***EO-1***
***ACDS, 2 Converters***
***GPS PCU, 1 Converter***
***AST PS, 2 Converters***
***MAP***
***AST 1 & 2 PS, 3 Converters***
***TIMED***
***AST 1 & 2 PS, 4 Converters***
***TIDI, 1 Converter***
***SIRTF***
***AST 1 & 2 PS, 4 Converters***

***ICM***
***Housekeeping CCA, 4 Converters***
***Power Supply CCA, 12 Converters***
***Individual Spare Converters, 15***

**Total Converters Reworked = 48**

## Special Topic:

***Workmanship Vibration Option***

*** ******. . . Pete Alea***
*EO-1 Mechanical Lead, Swales Aerospace, Inc.*

## Vibration Test Assessment

***Vibration Test Assessment***

***Assess the need for additional testing of the EO-1 Satellite since the protoflight level test performed in August 1999.***
***One Swales internal review held along with two reviews to Code 540, Mechanical Systems Branch, Panel***

## Satellite Team Position

***Satellite Team Position***

***The recommendation from the satellite team to Swales & Code 540 panels was that ***_***no***_*** further vibration testing is required for the following reasons:***
***There were no mechanical issues resulted from the system level vibro-acoustic test in August of 1999***
***Procedures and personal used to perform all rework on the satellite is comparable or identical to those used before the system environmental tests.***
***Technical and Quality oversight has remained at the highest level during the entire rework period. Open problem records, prior to the second thermal/vacuum test, were minimal.***
***No satellite primary structure was changed or removed during the rework process, except equipment panels. Panels were removed only to de-integrate the necessary electrical sub-systems and maintained in a controlled area.***

## Satellite Team Position (continued)

***Satellite Team Position ****(continued)*

***All equipment panels are mounted to the spacecraft by way of close tolerance holes with shank fasteners. Locking inserts are used and prevailing torque is verified prior to panel installation. Uralane thread staking is utilized when running torque falls below the minimum torque requirements of MIL-N-25027.***
***In our opinion, the high frequency vibration induced by an acoustic test will not mechanically work the electrical harness sufficiently to reduce the risk of discovering a poorly mated connection. The team believes this risk to be extremely low due to the three tier approach used during the mating and torque of electrical connections.***
*Electrical Tech mates connectors, hand tightens screws, and completes entry into mate/demate logbooks.*
*Mechanical Tech torques and stakes screws*
*QAE verifies all operations*

## Response levels from a flight level acoustic test are expected to be very low and comparable to the shipping environment.

***Response levels from a flight level acoustic test are expected to be very low and comparable to the shipping environment.***

***Satellite Team Position ****(continued)*

## Satellite Team Recommendation

***Satellite Team Recommendation***

_***No***_*** further vibro-acoustic testing of the EO-1 Satellite is required.***
***Satellite electrical functional testing to be preformed prior to and after shipping should be sufficient to uncover any loose connections.***

## Mechanical Systems BranchRecommendation

**Stephen J. Brodeur/540/Associate Chief, Mechanical Systems Center**
** ****7/12/2000**

***Mechanical Systems Branch******Recommendation***

***The MSB unanimously concurs with the position of the  EO-1 Project and Swales’ EO-1 personnel that no further vibration testing, either sine or acoustic, of the spacecraft is necessary.***
***In summary, the MSB feels that the probability of anomalies caused by rework of subsystems, new hardware added to the spacecraft, or assembly/disassembly is low.   The probability of detection of such anomalies in a sine test is low but the risk of the test is moderate.  The probability of detection of such anomalies in a very low risk acoustic test is virtually nonexistent.  On balance, then, the MSB feels that the benefits of further testing are not worth the risks.***