C O RP O RATIO N

FINAL REPORT

THE DESIGN, FABRICATION AND DELIVERY

OF A MANIPULATOR FOOT RESTRAINT MOCKUP

FOR SPACE TELESCOPE DEVELOPMENT TESTING

(NASA-CR-178837) THE DESIGN, FABRICATION N86-25121

AND DELIVERY OF 1 HANLPULATOB FOOT BESISAIHT

MOCK OP FOB SPACE TELESCOPE DEVELOPMENT

TESTING Final Bepprt (Essex Corp.) . 12 p Onclas

HC A02/MF A01 CSCL 05fl G3/54 43474

CONTRACT NAS8-36366

APRIL 1 1, 1986

ESSEX REPORT NO. H-86-05

SPACE SYSTEMS GROUP • 690 Discovery Drive, Huntsville, Alabama 35806 • (205) 837-2046
FINAL REPORT

THE DESIGN, FABRICATION AND DELIVERY OF A MANIPULATOR FOOT RESTRAINT

MOCKUP FOR SPACE TELESCOPE DEVELOPMENT TESTING

NAS8-36366

Prepared For:

NATIONAL AERONAUTICS AND SPACE ADMINISTRATION

George C. Marshall Space Flight Center

Marshall Space Flight Center, Alabama 35812

Prepared By:

Michael A. Hollingsworth

ESSEX CORPORATION

690 Discovery Drive

Huntsville, Alabama 35806

April 11, 1986

H-86-05
FOREWORD

This Final Report describes work performed under contract

NAS8-36366 which involved design, fabrication and delivery of a

Manipulator Foot Restraint (MFR) for the Marshall Space Flight Center

(MSFC) Neutral Buoyancy Simulator (NBS).

Essex Corporation appreciates the opportunity to have developed the

MFR under this competitively acquired contract and looks forward to

serving NASA on future contracts.
TABLE OF CONTENTS

Page

FOREWORD i

ACRONYMS AND ABBREVIATIONS ill

1.0 INTRODUCTION 1

1.1 Background 1

2.0 TECHNICAL APPROACH 2

2.1 Review of Manipulator Foot Restraint Concept 2

Drawings

2.2 Preparation of Mockup Drawings 2

2.3 Fabrication and Assembly of Mockup 2

3.0 END ITEM DESCRIPTION 4

3.1 Grapple Fitting 4

3.2 Horizontal Stanchion 4

3.3 Rotatable Foot Restraint Platform 4

3.4 Rotatable/Tiltable Stanchion 4

3.5 Rotatable Tool Carrier and Tool Boards 5

3.6 Payload Interface Mechanism (PIM) 5

4.0 CONCLUSIONS AND RECOMMENDATIONS 7

4.1 Conclusions 7

4.2 Recommendations 7

LIST OF FIGURES

Figure 1: MFR Major Subsystems

ii
ACRONYMS AND ABBREVIATIONS

A7LB - Apollo Extravehicular Activity Pressure Suit

COR - Contracting Officer's Representative

EMU - Extravehicular Mobility Unit (Space Shuttle Pressure

Suit)

EVA - Extravehicular Activity

GFE - Government Furnished Equipment

HST - Hubble Space Telescope

MFR - Manipulator Foot Restraint

MSFC - Marshall Space Flight Center

NASA - National Aeronautics and Space Administration

NBS - Neutral Buoyancy Simulator

ORU - Orbital Replacement Unit

PIM - Payload Interface Mechanism

PVC - Polyvinyl Chloride

RMS - Remote Manipulator System

iii
1.0 INTRODUCTION

1.1. Background

The Manipulator Foot Restraint (MFR) is a subsystem of the Remote

Manipulator System (RMS). This system will play a major role in

servicing the Hubble Space Telescope (HST) on orbit. Mounted on the

RMS, the MFR is the primary workstation for extravehicular activity

(EVA) tasks. The MFR is used for transportation of all orbital

replacement units (ORUs) from the ORU spares carrier to the HST aft

shroud and equipment sections. The MFR is also the primary crew

restraint/translation fixture for all HST maintenance and repair tasks.

In fulfilling the hardware development and crew training objectives

of the MFR neutral buoyancy mockup, the following components listed

below were provided:

1) MFR neutral buoyancy mockup that is totally functional with

flight-type crew interfaces;

2) RMS interface (grapple fixture) that is compatible with the

Marshall Space Flight Center (MSFC) RMS Neutral Buoyancy

Simulator (NBS);

3) Foot restraint plates compatible with both the "EMU" and "A7LB"

pressure suits;

4) Movable stanchion with both tool carrier interfaces;

5) Payload interface mechanism; and

6) Total neutralization capability for the MFR using accepted

methods.

The following sections describe the end items listed above in more

detail, with recommendations for future use of the trainer.
2.0 TECHNICAL APPROACH

In fulfilling contract responsibilities, Essex performed the three

tasks described below.

2.1 Review of Manipulator Foot Restraint Concept Drawings

At the onset of the contract, Essex received documentation and

drawings of the MFR. This documentation was reviewed to determine

fabrication techniques, processes, and materials to be used, and to

define missing information and discrepancies which may have occurred due

to design changes or other reasons. Drawings and information which had

not yet been received or for which clarification was required were

requested from the Contracting Officer's Representative (COR).

2.2 Preparation of Mockup Drawings

As drawings were received from NASA, Essex designers discussed

possible concepts with the COR. Concept sketches of the MFR were then

prepared and presented to the COR for approval. Approved engineering

drawings and red lined drawings of mockup parts were prepared.

2.3 Fabrication and Assembly of Mockup

The approved engineering drawings of the MFR developed in task 2.2

were submitted to the Essex machine shop. The parts were fabricated

with materials and techniques best suited for simulations in the

underwater environment of the MSFC NBS.

The primary fabrication material for the mockup was 6061-T6

aluminum with 5052-H32 aluminum used where a bent sheet or plate was

needed. All fasteners were either stainless steel rivets or stainless

steel bolts with brass nuts to prevent galling. Bronze was used on

bearing surfaces because of its resistance to corrosion and low

coefficient of friction.
Fabrication techniques reflected fidelity needs of the MFR. For

instance, areas with crew interfaces were machined to accurately

represent the flight hardware. Areas requiring only volumetric

representation of a hardware item were fabricated of aluminum sheet

and/or angle. Corners and edges of all parts were radiused to meet

standards in MSFC-STD-512A.

When the major MFR parts were completed, they were assembled for a

fit check. After verification that all mechanisms functioned properly,

the MFR was disassembled and parts were given surface finish treatment.

Surface finish of the parts included hard anodizing and painting with

white Plasite according to MSFC NBS specifications.

The MFR was then reassembled and the COR approved it for delivery.

Upon delivery to the NBS, the MFR was neutralized using PVC tubes and

foam. With the neutralization complete, all mechanisms and crew

interfaces were tested to verify proper operational characteristics.
3.0 END ITEM DESCRIPTION

The MFR mockup supplied by Essex represents all of the components

of the flight hardware. A detailed description of the hardware is given

below. Refer to Figure 1 for the location of components on the MFR.

3.1 Grapple Fitting

The grapple fitting represents the flight version volumetrically.

The fitting interfaces and is compatible with the RMS at the MSFC NBS.

A grab plate was added to aid in locking the RMS to the grapple fitting.

3.2 Horizontal Stanchion

The horizontal stanchion is a volumetric component. Its structure

is a rigid aluminum angle frame with .090 aluminum skin riveted to it.

It is painted with white Plasite paint to MSFC NBS specifications.

3.3 Rotatable Foot Restraint Platform

The rotatable foot restraint platform is similar in construction to

the flight version. High fidelity is found in the areas of expected

crew interface. Only machined pockets were omitted where crew

interfaces were not affected. The foot restraint plates are compatible

with both the "EMU" and "A7LB" pressure suits.

3.4 Rotatable/Tiltable Stanchion

The rotatable/tiltable stanchion is generally high fidelity.

Movement and operations and volume are representative of the

flight-version MFR. Mockup peculiar construction techniques were used

where necessary to aid in the serviceability of the component.
3.5 Rotatable Tool Carrier and Tool Boards

The tool carrier and tool boards have the same rotation capability

as the flight component. The carrier is high fidelity in all areas of

crew interface. The component has flight movement and forces on all

mechanisms. The shape is volumetrically correct with construction cost

and serviceability considered.

3.6 Payload Interface Mechanism (PIM)

The PIM is flight-like in all areas of crew interface. All

mechanisms are high-fidelity with flight-like operations and forces.

The component is similar in construction to the flight-version PIM with

accurate volumetric representation. The Government Furnished Equipment

(GFE) tether reel was not incorporated into the PIM because it was

unavailable.
ORIGINAL PAGE IS

OF POOR QUALITY

Figure 1: MFR Major Subsystems

6
4.0 CONCLUSIONS AND RECOMMENDATIONS

The following conclusions and recommendations are based on

principles, procedures and methods of application used during this

endeavor.

4.1 Conclusions

Flight drawings were redlined and used to construct the MFR to

guarantee that mockup components were functionally equivalent to the

flight MFR. Material surface finishes and tolerances that are

compatible to the NBS environment were used.

4.2 Recommendations

This high-fidelity MFR must be treated differently than the lowfidelity MFR because of its flight-type mechanisms. If a maintenance

and operations procedure is followed, the down time for repair on the

high-fidelity MFR will be minimized. This procedure is described below.

Lifting the MFR in and out of the NBS requires two men on deck and

two in the water. After a test the MFR should be taken out of water and

placed on its stowage rack. While the MFR is on the stowage rack, it

should be washed thoroughly inside and out with fresh water. All

mechanisms, cables, bolts, and nuts should be visually inspected.

Periodic lubrication of all moving parts is necessary to prevent the

moving parts from locking up.