The Manipulator Foot Restraint (MFR) is a subsystem of the Remote Manipulator System (RMS) which plays a major role in servicing the Hubble Space Telescope (HST) in orbit. Flight drawings were used to construct the MFR to guarantee that the mockup components were functionally equivalent to the flight MFR. Material surface finishes and tolerances that were compatible to the Neutral Buoyance Simulator (NBS) environment were used. Recommendation for improvements are discussed

Hollingsworth, M. A.

English

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C O R P O R A T I O 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 H A N L P U L A T O B 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
https://ntrs.nasa.gov/search.jsp?R=19860015650 2020-03-20T15:30:07+00:00Z
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 low-
fidelity 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.


The design, fabrication and delivery of a manipulator foot restraint mockup for space telescope development testing

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