Volume I, Section 11
11 HARDWARE AND EQUIPMENT
{A} For a description of the notations, see Acceleration
Regimes.
This section contains the following topics:
11.1 Introduction
11.2 Tools
11.3 Drawers and Racks
11.4 Closures and Covers
11.5 Mounting Hardware
11.6 Handles and Grasp
Areas
11.7 Restraints
11.8 Mobility Aids
11.9 Fasteners
11.10 Connectors
11.11 Windows
11.12 Packaging
11.13 Crew Personal Equipment
11.14 Cable Management
See the video clips
associated with this section.
{A}
This section provides the design considerations, requirements, and
examples for the following hardware and equipment: Tools, Drawers and
Racks, Closures and Covers, Mounting Hardware, Handles and Grasp Areas,
Restraints, Mobility Aids, Fasteners, Connectors, Windows, Packaging,
Crew Personal Equipment, and Cable Management.
11.2 TOOLS
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11.2.1 Introduction
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This section includes the criteria for manual and power tools. It provides
tool design requirements for normal operations and for planned and unplanned/contingency
maintenance activities. Launch, entry, and temporary tool stowage requirements
are also included along with examples of tool design solutions
(Refer to Paragraph 14.6.2, EVA
Tools, for EVA-unique tool considerations and requirements.)
(Refer to Paragraph 12.3.2, Testability
Design Requirements for information relevant to electronic and analytical
test tools.)
11.2.2 Tool Design Considerations
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Development of in-flight maintainable spacecraft systems must include
consideration of tool selection, transport, stowage, ease of use, and
criticality.
A satisfactory tool complement for future missions should include consideration
of the following factors:
a. Tool Kit Contents - A tool kit should contain all the tools normally
found in a tool collection for comprehensive usage as well as special
tools required for special aerospace hardware. A standard tool kit should
be developed that is based on known system requirements as well as past
experience. This tool kit should include multi-purpose/multi-size tools.
Despite the urge to reduce tool kit weight by not including sockets,
wrenches, etc., that have no identified requirements, crewmembers have
requested that all sizes be included as there are always unexpected
needs that arise for the tool that was left behind.
b. Tool Transfer/Retention Device - A tool caddy should be provided
to carry/translate tools from place to place and should be easily secured
at the workstation. Transparent materials would be desirable so that
the tools can be seen inside the caddy. Internal retention provisions
are necessary to allow the crewmember to temporarily stow and retrieve
small parts and equipment while the work is being done since containing
and locating this equipment is a problem in microgravity.
c. Tool Commonality/Cost-effectiveness - A survey of previous tool
development activities should be conducted prior to initiating costly
tool development for suitable tools that are already in the inventory.
d. Tool Stowage Location - The stowage location of tool kits should
be optimized for accessibility to workstations and maintenance workbenches.
e. Tool Unit Standards - Both English and metric standards must be
accommodated in the tool kits. Some coding system on the tool should
be used to readily distinguish English from metric.
f. Tool Inventory Control - Tools should be identifiable by the automated
inventory control system.
(Refer to Paragraph
13.3, Inventory Control for specific inventory control design considerations
and requirements.)
11.2.2.1 Power Tools
Design Considerations
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Power tools must meet the same design requirements as manual hand-tools
regarding operability. Power tools should be used to accomplish repetitive
manual tasks, such as disengaging captive fasteners or operating mechanical
drive systems. Use of power tools offers enormous returns in reduced
crewmember time and effort and ease of operation.
(See Paragraph 14.6.2, EVA Tools,
for design considerations pertaining to power tools used in an EVA environment.)
Power tools subject the crewmember to specific hazards and stresses
that should be considered. Specific considerations include rotating
components, electrical shock, heat generation, flying particles or sparks,
inadvertent power activation, and hazards to the nonoperating hand.
Power tool design should avoid the use of brush type motors since they
may create hazardous EMI (electromagnetic interference) and provide
an ignition source.
(Refer to Paragraph
6.4, Electrical Hazards, for electrical safety design considerations
and requirements.)
Some types of tools create unique problems. Typical of these are soldering
tools, which can cause burns if the operator touches a tip that is still
hot or lays the tool on flammable materials.
It should be noted that the standard practice has been to accept many
of the above hazards as part of the job and to place the burden of protection
on users, i.e., to recommend wearing eye protectors, using special electrical
grounding devices, wearing gloves, etc. In many cases these are the
only methods available to reduce the hazard potential. However, the
designer should, in each new tool design, review such hazards and attempt
to remove them whenever possible in the design. When this cannot be
accomplished, the designer should assume the responsibility for providing
appropriate warning labels on the tool and/or include properly worded
warning instructional materials with the tool. The designer should know
better than anyone else what hazards a new tool presents.
(Refer to Paragraph 6.2,
General Safety, for more detailed safety design considerations.)
For rechargeable battery-powered tools, the inventory of spare power
packs and the location of recharge stations are important design considerations.
11.2.2.2 Body Stabilization
When Using Tool Design Consideration
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Previous orbital missions have indicated that, when properly restrained,
the crewmembers can perform most manipulative operations on orbit using
standard tools as effectively as these operations can be performed in
an Earth environment. In many in-space maintenance operations, this
adequate restraint was not anticipated in the design of the equipment.
This led to a lot of wasted time and crew frustration. Therefore, it
is very important that adequate interface designs (i.e., designing the
payload for EVA and IVA servicing), adequate body restraints, and a
moderate complement of hand tools be provided so space system servicing
requirements can be met.
(Refer to Section 12.0, Design for Maintainability,
for general and specific requirements for designing payloads for servicing.)
(Refer to Paragraph 9.2.4.2.3,
Workstation Restraints and Mobility Aids, and to
Paragraph 14.4.3, EVA Workstations and Restraints, for specific
requirements related to integrating restraints and workstations.)
11.2.3 Tool Design Requirements
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The tool design requirements in the following subsections apply to
tools that are intended to be used to activate, operate, maintain, and
deactivate manned and unmanned equipment in both EVA and IVA environments.
(Where there are EVA-unique tool design requirements, they are so noted
with reference to Section 14.0.)
11.2.3.1 Hand and
Tool Integration Design Requirements
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11.2.3.1.1 Tool
Handgrip Size and Shape Design Requirements
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Power and manual hand tools shall comply with the following handgrip
size and shape requirements:
(Refer to Paragraph 6.5.3, Touch
Temperature Design Requirements for specific touch temperature criteria.)
a. Gripping Surface - Hand gripping surfaces that minimize abrasion
to the EVA glove material shall be provided on handles of tools.
b. Sleeve Type Adapters - If sleeve-type handle cover adaptors are
used, they shall be adequately secured so they will not slip, rotate,
or come off.
c. Orientation - Tool handles shall be oriented to allow the operator's
wrist to remain in the most natural position while force or guidance
inputs are applies.
d. Auxiliary Controls - If an auxiliary control on the tool must be
manipulated while the operator is holding the tool, the control shall
be located where:
1. The thumb or finger of the holding hand can manipulate the control
without disturbing the tool/fastener holding position.
2. Unintentional or inadvertent control operation is impossible.
11.2.3.1.2 Tool
Handedness Design Requirements
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The following requirements apply to handheld manual tools and handheld
power tools:
a. Tool Operation - All general purpose hand tools shall be one-handed
operable insofar as practical.
b. Tool Installation/Alignment - One hand only shall be required for
tool installation and alignment.
c. Tool Handle Design - Tool handles shall be designed to allow the
operator to use either the left or right hand.
11.2.3.1.3
Tool Actuation Forces and Direction of Action Design Requirements
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All hand tools shall comply with the following:
a. Actuation Force - Hand tools shall require an actuation force of
less than 89N (20 lbs.) or a torque of less than 15 Nm (11 ft-lbs).
b. Throw Angles - Ratcheting tools shall be capable of providing torque
with a minimum throw angle of 45 degrees.
c. Plier-Type Tools - Plier-type tools shall be spring-actuated in
the open direction to permit one-handed operation.
d. Driver-Type Tools - Driver-type hand tools shall not require a push
force to maintain tool engagement while providing torque.
11.2.3.2 Tool Commonalty
Design Requirements
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To ensure that the tool complement is kept at a minimum, the following
requirements shall apply:
a. Tool Quantity - The number of different types of tools shall be
minimized.
b. Standard Attaching Hardware and Fasteners - Size and type of attaching
hardware and fastener head configurations shall be standardized throughout
the vehicles to limit the number and kind of tools required to perform
maintenance tasks.
(Refer to Paragraph 11.9, Fastener
Design Requirements, for specific fastener-to-tool interface requirements.)
c. Special Tools - The number of different and special tools required
for maintenance shall be minimized.
d. For every
type and size of fastener used onboard, a corresponding tool(s) shall
be available for removal/replacement.
(Refer to Paragraph 11.9.3.1, Fastener Design
Requirements for specific considerations and requirements).
11.2.3.3 Tool Tethering/Retention
Design Requirements
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The following tool tethering and tool retention requirements shall
be apply:
a. Tool Restraints - A means shall be provided on all tools for restraining
the tool during use.
b. Tool Transporter Devices - Tool carriers shall be provided to transport
tools and to retain these tools during the maintenance activity.
c. Retention of Small Parts - Tool carriers/transfer devices shall
provide a means of retaining small parts and attaching hardware. Items
retainable in this manner shall be visible for retrieval.
d. Tool Restraint During Translation - Tools shall be restrained in
the tool carrier/transfer device with sufficient force to prohibit detachment
during translation.
e. Tool Carrier Attachment - Tool carriers and tool retention devices
shall have provisions to attach the device to the crewmember or to adjacent
structure or equipment.
(See Paragraph 11.7.3.3, Equipment Restraint
Design Requirements, for other applicable restraint requirements.)
f. Inadvertent Tool Disassembly - A means shall be provided to prevent
inadvertent tool disassembly while installing, using, removing, or transporting
the tool.
11.2.3.4 Tool Stowage
Design Requirements
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Tool stowage must allow for ease of retrieval, retention, identification,
and replacement. To accomplish this, the following requirements shall
apply:
a. General - A systematic approach shall be used in stowing tools and
maintenance aids throughout the space module.
b. Stowage Provisions - Provisions for launch, entry, and temporary
in-flight stowage shall be provided.
c. Stowage Location:
1. Specialized tools shall be stowed in areas which correspond to their
functional applications.
2. All general-purpose tools shall be grouped in one specific area.
d. Tool Stowage List - A tool summary or listing of the entire tool
inventory, including stowage locations, shall be available onboard the
space module.
e. Tool Arrangement in Stowage Container - A systematic approach shall
be used in the arrangement of tools in the tool kit.
f. Temporary Stowage at Work Area - A systematic approach and a methodical
layout of tools at the work area shall be required.
(Refer to Paragraph 10.12.3, Stowage
Design Requirements, for other specific stowage requirements.)
11.2.3.5 Tool Labeling
and Identification Design Requirements
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Tool and tool stowage labeling and identification requirements shall
comply with the following:
(Refer to Paragraph 9.5.3, Labeling
and Coding Design Requirements for detailed labeling and coding requirements.)
a. Selection of Names for General Tools - Tool names shall be identical
to those names called out on the tool/ tool label and, in all cases,
will be the most common definitive name recognizable by the crewmembers.
b. Selection of Names for Specialized Tools - Specialized tool nomenclature
shall describe the specific task it is intended to accomplish and shall
not be identified with the equipment it is servicing.
c. Identification of Specialized Tools - When special tools are absolutely
necessary, they shall be coded and/or marked to indicate intended use.
d. Tool Labels - Prominent labels shall be provided adjacent to each
tool in the stowage container/kit if the tool is not readily recognizable.
e. Tool Metric/English Identification - All tools shall be labeled
or coded to indicate whether the tool is sized in metric or English
units.
f. Tool Inventory Control Labeling - Tools shall be tracked by an automated
inventory control identification system.
(Refer to Paragraph 13.3.3, Inventory
Control Design Requirements, for specific requirements.)
g. EVA Tool Compatibility - IVA tools that are EVA compatible shall
be so identified.
11.2.3.6 Tool Access
Design Requirements
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The following tool access volume and operational constraints requirements
are applicable to both IVA and EVA hardware design (refer to
Figure 11.2.3.6-1 for IVA requirements and
Paragraph 14.6.2.3 for EVA requirements):
Notes:
Minimum tool head clearance must be adequate for insertion, actuation,
and removal of drive end of tool. Minimum 0.76 cm (0.3 in) tool
head engagement height. Tool handle offset minimum 7.6 cm (3 in),
maximum 35.5 cm (14 in). Minimum 7.6 cm (3 in) tool handle clearance
(measured from end of handle to nearest obstruction). Minimum
of 180 degrees clearance for lever type tools. Minimum of 360
degrees clearance for driver type tool.
See Figure 14.6.2.3-1
for EVA requirements. |
Reference: 320; NASA-STD-3000
12b
a. Tool Head Clearance - Where only tool access is required, clearance
shall be provided around the fastener or drive stud for insertion, actuation,
and removal of the drive end of the tool.
b. Tool Handle Clearance - A minimum of 7.6 cm (3 in.) shall be provided
for clearance between a tool handle engaged on a fastener or drive stud
and the nearest piece of hardware. The tool handle should be able to
maintain this clearance through a full 180 deg. swept envelope.
c. Tool Head-to-Fastener Engagement Height - The tool socket/fastener
head engagement height shall be sufficient to lower the bearing loads
on the fasteners and tool below the failure limits of the materials.
d. Tool Handle Offset - The maximum tool offset between the tool handle
and the tool head shall be 35.5 cm (14 in.).
e. Access for Tools - Minimum tool access clearance for hand tool actuation
is given in Figure 11.2.3.6-2.
Figure
11.2.3.6-2 Minimal Clearance for Tool-Operated Fasteners
| Opening dimensions |
Task |
.gif) |
A 117 mm (4.6 in)
B 107 mm (4.2 in) |
Using common screw-driver with freedom to turn hand through 180° |
.gif) |
A 133 mm (5.2 in)
B 115 mm (4.5 in) |
Using pliers and similar tools |
.gif) |
A 117 mm (6.1 in)
B 107 mm (5.3 in) |
Using T-handle wrench with freedom to turn wrench through 180°
|
.gif) |
A 203 mm (8.0 in)
B 135 mm (5.3 in) |
Using open-end wrench with freedom to turn wrench through 62°
|
.gif) |
A 122 mm (4.8 in)
B 155 mm (6.1 in) |
Using Allen-type wrench with freedom to turn wrench through 62°
|
| Notes:
1. Refer to Figure
12.3.1.2-1 for other hand and arm access hold dimensions.
2. Refer to Figure 11.2.3.6-1. |
Reference: 1, p. 4.4-7;
NASA-STD-3000 27
11.2.3.7 Special Tool Features Design Requirements
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Compliance with the following special features shall be required when
designing or providing tools for IVA servicing and maintenance tasks:
a. Non-sparking Tools - Non-sparking materials shall be required for
general purpose tools.
b. Nonconductive Tools :
Refer to Paragraph 6.5.2, Touch
Temperature Design Requirements, when tools are to be used in extremely
hot or cold temperature areas.)
(Refer to Paragraph 6.4.3, Electrical
Hazards Design Requirements, for requirements for insulation protection
against electrical hazards.)
c. Finish - Tools shall be capable of being refinished in flight in
order to remove burrs.
(Refer to Paragraph 6.3.3, Mechanical
Hazards Design Requirements, for burrs, corners, edges, and protrusion
design requirements.)
d. Battery Pack :
1. Power tools shall be designed so the battery packs can be replaced
at the worksite.
2. Power tools using battery packs shall have a level-of-charge indicator
or an indication as to when a battery pack is required to be replaced
or recharged.
3. Hazards associated with charging and stowage of rechargeable batteries
(such as toxic or flammable offgassing, leakage of corrosive electrolytes
or high temperatures) shall be addressed and controlled.
11.2.4 Example Tool Design Solutions
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Examples of previously used IVA tools are included in this section
to illustrate how tools are constructed, stored, identified, transferred,
tethered, or restrained at work locations. These proven examples should
be considered when developing new tools and maintenance aids for future
missions.
(Refer to Paragraph 14.6.2.4,
Example EVA Tools Design Solutions, for description of EVA tools.)
11.2.4.1 Example Manual Tools
{A}
The following IVA tools have flown successfully on STS missions:
(Refer to Reference 150 for complete details on STS tools.)
a. Off-the-Shelf STS IVA Tools - Examples of off-the- shelf IVA tools,
stowage, and identification methods are shown in
Figure 11.2.4.1-1, Figure 11.2.4.1-2
and Figure 11.2.4.1-3.
b. Stowage Provisions - Stowage provisions are shown in
Figure 11.2.4.1-1, Figure 11.2.4.1-2
and Figure 11.2.4.1-3. Tool trays
include provisions for individual hand tools in the trays by providing
cushions fabricated from white foam with a fine cell structure. Very
accurate cuts were required to provide adequate retention for launch,
in-flight, and enter environments. Tools were individually identified
at each location. The foam is coated with a fire-retardant seal material.
c. Tool Kits and Tool Pouches - Tool kits and tool pouches (Figure
11.2.4.1-3) were used to retain small tool packages to worksites.
These kits or pouches had provisions (snaps, straps, Velcro, etc.) for
attaching the units to the worksite structure.
Figure
11.2.4.1-1 Examples of IVA Hand Tools, Stowage, and Identification
Reference: 150, p. 3.23-10;
NASA-STD-3000 13
Figure
11.2.4.1-2 Miscellaneous IVA Tool Stowage Examples
Reference: 150, p. 3.23-14;
NASA-STD-3000 14
Figure
11.2.4.1-3 Tool Translation and Retention Pouch Examples
Reference: 150, p. 3.23-16
and -18; NASA-STD-3000 15
11.2.4.2 Example Power Tools
{A}
The vacuum cleaner is an example of an IVA power tool used on Skylab,
Shuttle and Spacelab missions. The vacuum cleaner is a tool which is
presently used for cleaning intake screens to black box cooling fans,
orbiter air filters, and Spacelab Environmental Control System (ECS)
filters. The unit is also used for general housekeeping chores.
(Refer to Paragraph 13.2
Housekeeping, for housekeeping design considerations and requirements.)
Another example of IVA power tools is the EVA Power Tool utilized to
remove panel fasteners in an IVA mode.
(Refer to Paragraph 14.6.2.4.2,
Example EVA Power Tool Design Solutions, for a description of this STS
EVA power tool.)
11.3
DRAWERS AND RACKS
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11.3.1 Introduction
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This section provides the design considerations and requirements for
drawers and racks. This includes the definition of size, interfaces,
operating mechanisms, location relative to workstations and traffic
patterns, ease of use, restraints, and utility connections.
Stowage drawers are a specific type of stowage compartment.
(Refer to Paragraph
10.12, Stowage Facility for general and specific stowage design
considerations and requirements that are also applicable to drawers.)
Equipment drawers are a specific type of equipment mounting hardware
that are designed to facilitate equipment replacement and maintenance.
(Refer to Section 12.0, Design for Maintainability,
for general and specific maintainability design considerations and requirements
that are also applicable to equipment drawers.)
11.3.2 Drawer and Rack Design Considerations
{A}
There are two types of drawers that are used in space modules: storage
drawers and equipment drawers. Stowage drawers and equipment drawers
are similar in that both are mounted in racks, cabinets, or housings;
they are designed to slide out to provide the user with access to their
contents; they stay in the open position until pushed back into the
stowed position; and they can be removed from the housing/cabinet by
some secondary unlatching operation. They are distinguished from each
other by the fact that stowage drawers are used to stow normally removable
contents, whereas equipment drawers are used to mount subsystem components.
The contents of a stowage drawer can be removed or replaced easily as
the contents are restrained by soft restraints (e.g., foam cutouts,
elastic bungee cords, etc.) which can be easily manipulated by hand
without using any tools. The contents of an equipment drawer, on the
other hand, usually need to be removed or replaced using a hand tool.
Equipment drawers always have utility connections(such as power and
thermal control), whereas stowage drawers generally have none.
Because of their similarities, stowage and equipment drawers need to
be designed with many of the same design considerations and requirements.
The drawer becomes a workstation when the crewmember has a need to
access its contents. This requires adequate crewmember restraint while
using it, handles and latches that are designed for one-handed operation,
ease of access to the contents, restraint of the drawer/rack in the
opened position, Commonalty with other drawers/racks, etc.
Racks are structural housings into which equipment drawers and other
types of equipment mounting hardware are installed. The racks are either
single-wide units (i.e., they are designed to mount a single stack of
equipment drawers) or they are double-wide units (i.e., they are designed
to mount a side-by-side stack of equipment drawers so they can house
a double-wide equipment drawer). The racks generally have built-in utility
(e.g., thermal, power, data) distribution systems which are designed
to provide interfaces with each of the installed equipment drawers.
The rack's utility system interfaces with the space module's utilities
distribution system at standardized locations.
In the closed position, drawers should be designed to contain particulates,
liquids, or gaseous matter. Drawer opening and closing mechanisms should
incorporate some form of motion damping to prevent disturbance of the
micro-g environment and to hold the drawer at intermediate positions
for zero-g operations. The use of magnetic latches on drawers and doors
should be avoided if at all possible
11.3.3 Drawer and Rack
Design Requirements
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11.3.3.1 Drawer
and Rack Interfacing Requirements
{A}
Stowage drawers, equipment drawers and racks shall be designed to provide
the following interfacing features:
a. Size :
1. Unless prohibited by functional needs, all racks shall be designed
to house single-wide drawers (and other types of equipment mounting
hardware) that shall be 48.26 cm (19.00 in) wide or double-wide drawers
that shall be 96.52 cm (38.00 in) wide.
(Refer to Paragraph 2.3.2, Standardization
Design Requirements, for the general standardization requirements.)
2. If equipment is intended to be launched and returned in the Shuttle
stowage lockers, it shall be sized per
Figure 11.3.3.1-1.
b. Location Related to Traffic Patterns - Racks that require frequent
drawer deployment shall be located in areas that do not have high traffic.
(Refer to Paragraph 8.7.3, Traffic
Flow Design Requirements, for general and specific requirements related
to blocking traffic patterns.)
Note: Tolerances: 0.0002 cm (0.0001 in) Small tray; 0.0005 cm
(0.0002 in) Large tray |
Reference: 350, Figure
4 and 5; NASA-STD-3000 229
c. Unobstructed Volume for Use - Provide adequate clearance such that
the drawers can be opened, removed, and replaced without obstructions
from adjacent hardware.
d. Easily Removable - Rack and drawer interfaces shall be designed
such that the drawers can be removed from their rack or cabinet along
a continuous straight or slightly curved path without using tools.
e. Limit Stops:
1. Provide limit stops that will prevent the drawer from being unintentionally
pulled out of the rack.
2. The limit stops shall be designed to hold the drawer in the full
open position.
3. The limit stops shall be capable of being disengaged without using
a tool to enable drawer removal.
f. Drawer Movement Forces - Drawer opening/closing or removal/installation
shall not require a force greater than 156 N (35 lbs).
(Refer to Paragraph 4.9.3, Strength
- Design Requirements, for crewmember strength requirements.)
g. Alignment Guides - Provide guide pins or equivalent to aid in alignment
when replacing a drawer into its rack or cabinet.
(Refer to Paragraph 11.5.3.2, Alignment Devices
Design Requirements, for detailed requirements.)
h. Shuttle Compatibility - If equipment is intended to be launched/returned
within the Shuttle, it shall be designed for compatibility with the
Shuttle stowage system.
i. Stowage Trays
1. Provide limit stops that will prevent the tray form being unintentionally
pulled out of the drawer.
2. The limit stops shall be designed to hold the tray in the 3/4 open
position.
3. The limit stops shall be capable of being disengaged without using
a tool.
11.3.3.2 Design
Requirements Common to Both Stowage and Equipment Drawers
{A}
In addition to the requirements given in Paragraph
11.3.3.1, all stowage and equipment drawers shall be designed to
provide the following features:
a. Latches/Handles/Operating Mechanisms - All latches, handles, and
operating mechanisms shall be designed to be easily latched/unlatched
and opened/closed with one hand by the entire crewmember population
without having to use any operating instructions.
(Refer to Paragraph
3.3, Anthropometrics and Biomechanics-Related Design Data, for crewmember
population anthropometrics.)
(Refer to Paragraph 4.9.3, Strength
Design Requirements, for crewmember strength capabilities.)
(Refer to Paragraph 11.6.3, Handle and Grasp
Area Design Requirements, for handle and grasp area configuration requirements.)
b. Latch/Unlatch Status - The design shall be such that it is obvious
when the drawer is not fastened/locked when in the closed position.
11.3.3.3 Stowage Drawer Design
{A}
In addition to the requirements given in Paragraphs
11.3.3.1 and 11.3.3.2, stowage drawers shall
be designed to meet the following requirements:
a. Restraint of Contents:
1. Drawer contents shall be restrained in such a way that the items
shall not float free when the drawer is opened, or jam the drawer so
it cannot be opened or closed.
2. Drawer contents shall be restrained in such a way that the contents
can be removed/replaced without using a tool.
(Refer to Paragraph 11.7.3, Equipment Restraints,
for specific restraint requirements.)
b. Arrangement in Housing/Cabinet - Drawers shall be arranged within
their housing/cabinet such that the most frequently accessed drawers
are in the most accessible locations.
c. Access to Contents - The contents of drawers shall be arranged such
that the contents are visible and accessible when the drawer is in the
open position.
d. Identification of Contents - In the stowed position, the contents
of drawers shall be identified by labeling.
(Refer to Paragraph 9.5.3, Labeling
and Coding Design Requirements, for specific requirements.
11.3.3.4 Equipment Drawer Design Requirements
{A}
In addition to the requirements given in Paragraphs
11.3.3.1 and 11.3.3.2, equipment drawers
shall be designed to meet the following requirements:
a. Utility Connections:
1. The utility connections shall be designed to be easily disconnected/connected
when the drawer is in the fully opened position.
(Refer to Paragraph 11.10.3, Connector Design
Requirements, for general and specific connector design requirements.)
2. If the utility connection is via a flexible umbilical, sufficient
cable length shall be provided such that the drawer can be fully opened
without disconnecting the cables.
(Refer to Paragraph 11.14.3, Cable Management
Design Requirements, for general and specific design requirements.)
b. Equipment Layout on Rack:
1. Components shall be mounted in an orderly array on a two-dimensional
surface, rather than stacked one on another (i.e., a lower layer shall
not support an upper layer).
2. Items of the same or similar form, but having different functional
properties, shall be mounted with a standard orientation throughout
the unit, but shall be readily identifiable and distinguishable, and
shall not be physically interchangeable.
3. Delicate items shall be located or guarded so that they will not
be susceptible to damage while the unit is being handled or maintained.
11.4
CLOSURES AND COVERS
{A}
11.4.1 Introduction
{A}
Closures and covers design considerations, requirements, and example
design solutions are provided in this section.
(Closures should not be confused with the subject of hatches and doors
which are covered in Paragraph
8.10)
11.4.2 Closures and Covers Design Considerations
{A}
Closures and covers are necessary to prevent loose items, such as small
tools, fasteners, and refuse from drifting into undesirable areas because
1) some small items/components cannot be easily retrieved for use if
they migrate into inaccessible locations, 2) the items/components may
drift into areas where they could cause damage to mechanical or electrical
components with which they might come in contact, and 3) these floating
items may become lost inside an equipment housing.
Some equipment closures and covers require ventilation holes. These
ventilation holes should be small enough that crewmembers cannot inadvertently
insert an object which might touch high voltage or moving parts. Ventilation
holes, grids, screens, or mesh are susceptible to becoming collection
surfaces for the accumulation of particulate and fibrous debris (e.g.,
dead skin flakes, fabric lint, packaging scraps, etc.).
(Refer to Paragraph 13.2.3 Housekeeping
Design Requirements, for particulate matter control requirements.)
11.4.3 Closures and
Covers Design Requirements
{A}
Equipment housings (e.g., electrical bays, cabinets, lockers, and consoles)
shall be designed to provide closures and covers for inaccessible areas.
The following requirements shall apply:
a. Sealing - The inaccessible areas shall be sealed to prevent small
items from drifting into them.
b. Removal - Closures shall be quickly and easily removed to allow
maintenance of equipment.
c. Securing - It shall be obvious when a closure is not secured, even
though it may be in place.
d. Loads - Nonstructural closures should be capable of maintaining
closure and of sustaining a crew-imposed minimum design load of 556
N (125 lbf) and a minimum ultimate load of 778 N (175 lbf).
e. Instructions - If the method of opening a cover is not obvious from
the construction of the cover itself, instructions (including applicable
tool instructions) shall be permanently displayed on the outside of
the cover.
f. Clearance - Bulkheads, brackets, and other units shall not interfere
with removal or opening of covers.
g. Application - An access cover shall be provided whenever frequent
maintenance operations would otherwise require removing the entire case
or cover, or dismantling an item of equipment.
h. Self-Supporting Covers - All access covers that are not completely
removable shall be self-supporting in the open position.
(Refer to Section 12, Design for Maintainability,
for other maintainability design considerations and requirements.)
i. Ventilation Screen Access - Where ventilation screens, holes, or
grids are used, the ventilation surface shall be accessible for vacuuming
in its installed position.
(Refer to Paragraph 13.2.3.3
Vacuum Cleaning Design Requirements, for more detailed requirements.)
11.4.4 Example Closures and Covers Design Solutions
{A}
Special hardware items, such as metal or rubber trim strips, moldings,
fairings, or cover plates, can be used to seal off the inaccessible
areas and meet the closure requirements. An example is shown in
Figure 11.4.4-1.
Reference: 1, Figure B-23,
p. B-13; NASA-STD-3000 99
11.5
MOUNTING HARDWARE
{A}
11.5.1 Introduction
{A}
This section includes design considerations and requirements for installation
and mounting of hardware and equipment. This section covers items such
as access, visibility, spacing between components, alignment aids, shims,
and washers.
11.5.2 Mounting Hardware Design Considerations
{A}
For manned space modules that will require in-flight checkout, maintenance,
and replacement of hardware, it is very important that the hardware
components be mounted in such a way that the crew can perform these
operations with minimal inconvenience. This requires attention to hardware
design details such as accessibility, clearance between components,
forces to disengage the items, alignment, and shimming.
11.5.3 Mounting Hardware
Design Requirements
{A}
11.5.3.1 General
Mounting Design Requirements
{A}
The following general requirements apply to mounting hardware:
a. Equipment Mounting - Equipment items shall be designed so that they
cannot be mounted improperly.
b. Drawers and Hinged Panels - Subsystem components which are frequently
pulled out of their installed position for checkout shall be mounted
on equipment drawers or on hinged panels.
(Refer to Paragraph 11.3.3, Drawer and Rack
Design Requirements, for specific requirements.)
c. Layout - Components shall be mounted so that a minimum amount of
place-to-place hand movements will be required during operations.
d. Covers or Panels - Removal of any replaceable item shall require
opening or removing a minimum number of covers or panels.
(Refer to Paragraph 11.4.3, Closures and Covers
Design Requirements, for specific requirements.)
e. Installation/Removal Force - Hardware mounted into a capture-type
receptacle that requires a push-pull action shall require a force less
than 156N (35 lbf) to install or remove.
(Refer to Paragraph 4.9.3, Strength
Design Requirements.)
f. Rear Access - Equipment to which rear access is required shall be
free to open or rotate to their full distance travel and remain in the
open position without being supported by hand.
g. Tools - Whenever possible, items shall be replaceable with a common
hand tool.
(Refer to Paragraph 11.2.3, Tool Design Requirements,
for specific tool requirements.)
h. Direction of Removal - Replaceable items shall be removable along
a straight or slightly curved line, rather than through an angle.
i. Visibility - Visual access for alignment and attachment of equipment
shall be provided.
(Refer to Paragraph 11.5.3.2, Alignment Devices
Design Requirements, for specific alignment requirements.)
j. Spacing - Mounting bolts and fasteners shall be spaced far enough
from other surfaces to allow personnel to manipulate them.
(Refer to Paragraph 11.2.3.6, Tool Access
Design Requirements, and Paragraph 11.9.3, Fastener
Design Requirements, for specific requirements.)
k. Number of Mounting Bolts - Use the minimum number of fasteners,
consistent with stress and vibration requirements, so that the crewmember's
workload is minimized.
(Refer to Paragraph 11.9.3.1, General Fastener
Design Requirements, for other fastener requirements.)
l. Shims, Washers - Where shims or washers are permitted in an IVA
application, the following rules shall be followed:
1. Shims shall be bound together in a shim assembly.
2. Shim assemblies shall be tethered or restrained at the location
or point of use and identified as to location or point of use.
3. A similar requirement shall be observed for washers and other loose
items which are auxiliary connector/fastener devices.
11.5.3.2 Alignment
Devices Design Requirements
{A}
The following alignment methods for replaceable hardware shall be used:
a. Alignment Marks - If proper interface orientation is not obvious
by virtue of external geometry or if adequate visibility cannot be provided
for hardware that will be mounted on-orbit, the hardware design shall
incorporate alignment marks and/or orientation arrows.
1. Alignment marks shall be applied to both mating parts and the marks
shall align when the parts are in the operational position.
2. An alignment mark shall consist of a straight line of a width and
length appropriate to the size of the item.
Alignment marks shall be clearly visible to a crewmember performing
hardware removal/replacement.
(Also see Paragraph 9.5.3.1.5,
Alignment Marks/ Interface Identification Design Requirements.)
b. Alignment Devices - Guide pins or their equivalent shall be provided
to assist in alignment of hardware during mounting, particularly on
modules that have integrated connectors.
(Refer to Paragraphs 11.10.3.3, Structural
Connectors Design Requirements, and 11.10.3.4,
Optical Connectors Design Requirements, for connector alignment requirements.)
c. Keying - All replaceable hardware shall be designed so that it will
be physically impossible to install it in the wrong orientation or location.
d. Replaceable Hardware Identification - Replaceable hardware shall
be identified with nomenclature that aids the crewmember in identifying
the hardware name, alignment of the hardware, and the correct use of
attaching parts.
(Refer to Paragraph 9.5.3, Labeling
and Coding Design Requirements, for specific requirements.)
11.5.4 Example Mounting Hardware Design Solutions
{A}
Examples of successful mounting hardware designs from previous space
missions are included in this section.
a. Alignment Marks - Figure 11.5.4-1
shows an example of how to use alignment marks. The alignment mark size
on the equipment and the mating structure shall align when the parts
are in the operational position.
b. Identification of Movable Equipment - Moving equipment from the
launch location to the orbital or planetary operational location will
require providing information to the crewmember which shows the correct
use of the attaching parts. Figure 11.5.4-2
shows an example of attachment interface markings on movable equipment.
11.6
HANDLES AND GRASP AREAS (FOR PORtable ITEMS)
{A}
11.6.1 Introduction
{A}
This section includes design criteria for handles and grasp areas.
The requirements for these items are similar in that they both pertain
to use with removable or portable units. However, these requirements
should not be confused with handholds and handrails.
(Most of the design criteria for handholds and handrails is provided
in Paragraph 11.8, Mobility Aids.
Paragraph 11.8 also contains criteria
on equipment mobility aids other than handles and grasp areas.)
Figure
11.5.4-1 Example of Mounting Hardware Alignment Marks
Reference: 1, para 4.8.4.1,
p. 4.8-6; NASA-STD-3000 17
Figure
11.5.4-2 Example of Attachment Interface Markings on Movable Equipment
Reference: 1, Figure B-28,
p. B-15; NASA-STD-3000 16
(Refer to Paragraph 11.3.3, Drawer and Rack
Design Requirements, for requirements pertaining to handles and mechanisms
for drawers and racks.)
11.6.2 Handle and Grasp Area Design Considerations
{A}
Handle or grasp area designs should consider the following factors:
a. The mass properties of the item to be moved.
b. The operational location of the item relative to other items.
c. The manner in which the item is to be handled.
d. The distance the item needs to be moved.
e. The frequency with which the item may need to be handled.
f. The additional uses which the handle may serve, such as the anchor
for a tether or as a handhold.
g. Handles should be located on either side of the center of mass.
h. The number and location of handles shall be determined by the mass,
size, and shape of the object. (Refer to
Paragraph 8.8.2).
i. Handles should be recessed or fold flush with surfaces to minimize
potential for snagging clothing, equipment, or restraints.
11.6.3 Handle and Grasp
Area Design Requirements
{A}
11.6.3.1 General
Handle and Grasp Area Design Requirements
{A}
The following general requirements shall be observed:
a. Provide Handles - All removable or portable units shall be provided
with handles or other suitable means for grasping, tethering, handling,
and carrying.
b. Exempt Items - Items less than 0.03 m3 (1 ft3)
whose form factor (shape) permits them to be handled easily shall be
exempt from the above requirement.
c. Labeling of Nonhandling Areas - Built-in features that appear to
be suitable for grasping/tethering/ restraining and are not suitable
must be labeled to indicate that these features are not suitable for
these purposes.
(Refer to Paragraph 9.5.3, Labeling
and Coding Design Requirements, for specific requirements.)
11.6.3.2 Handle
and Grasp Area Location Design Requirements
{A}
The following general location requirements of handles or grasp areas
shall apply:
a. Interference - Handles and grasp areas shall be located so that
they do not interfere with equipment location or maintenance.
b. Clearance - Clearances shall be provided between handles and obstructions
consistent with anthropometric requirements.
c. Tether Attachments - Handles and grasp areas shall be suitable as
tether or bracket attachment positions.
d. Location - The location of handles or grasp areas shall be such
that they do not constitute passageway hindrances or safety hazards.
If they must be located in passageways they shall be recessed and designed
to minimize chance of crewmember injury or inadvertent contact.
e. Location/Front Access - Handles and grasp areas shall be placed
on the accessible surface of an item consistent with the removal direction.
11.6.3.3 Nonfixed Handles Design Requirements
{A}
Hinged, foldout, or attachable (i.e., nonfixed) handles shall comply
with the following:
a. Locked or Use Position - Nonfixed handles shall have a stop position
for holding the handle perpendicular to the surface on which it is mounted.
b. One-Handed Operation - Nonfixed handles shall be capable of being
placed in the use position by one hand and shall be capable of being
removed or stowed with one hand.
c. Tactile or Visual Indicators - Attachable/removable handles shall
incorporate tactile and/or visual indication of locked/unlocked status.
11.6.3.4 Handle Dimensions Design Requirements
{A}
IVA handles for movable or portable units shall be designed in accordance
with the minimum applicable dimensions in
Figure 11.6.3.4-1.
Figure
11.6.3.4-1 Minimum IVA Handle Dimensions for IVA Applications
| Illustration |
Type of Handle |
Dimensions in mm (in inches) |
| (Bare Hand) |
| X |
Y |
Z |
.gif) |
Two-finger bar |
32 (1-1/4) |
65 (2-1/2) |
75 (3) |
| One-hand bar |
48 (1-7/8) |
111 (4-3/8) |
75 (3) |
| Two-hand bar |
48 (1-7/8) |
215 (8-1/2) |
75 (3) |
.gif) |
T-bar |
38 (1-1/2) |
100 (4) |
75 (3) |
.gif) |
J-bar |
50 (2) |
100 (4) |
75 (3) |
.gif) |
Two-finger recess |
32 (1-1/4) |
65 (2-1/2) |
75 (3) |
| One-hand recess |
50 (2) |
110 (4-1/4) |
90 (3-1/2) |
.gif) |
Finger-tip recess |
19 (3/4) |
- |
13 (1/2) |
| One-finger recess |
32 (1-1/4) |
- |
50 (2) |
Curvature of handle or edge
(DOES NOT PRECLUDE USE OF OVAL HANDLES) |
Weight of item:
|
Minimum diameter
|
|
Up to 6.8 kg
(up to 15 lbs) |
D = 6 mm (1/4 in) |
Gripping efficiency is best if finger can curl around
handle or edge to any angle of 2/3 π rad (120°) or more
|
6.8 to 9.0 kg
(15 to 20 lbs) |
D = 13 mm (1/2 in) |
9.0 to 18 kg
(20 to 40 lbs) |
D = 19 mm (3/4 in) |
Over 18 kg
(Over 40 lbs) |
D = 25 mm (1 in) |
| T-bar post |
T = 13 mm (1/2 in) |
Reference: 2, Figure 48,
p. 197; NASA-STD-3000 18
11.7
RESTRAINTS
{A}
11.7.1 Introduction
{A}
This section provides the design considerations, requirements, and
example design solutions for personnel and equipment restraints. Portable
and fixed foot restraints, body restraints, and equipment restraint
devices are included.
The related topic of portable and fixed handholds and handrails are
found in Paragraph 11.8, Mobility
Aids. Placement of restraints within the space module is described in
Paragraph 8.9, Mobility
Aids and Restraints Architectural Integration. The integration of restraints
with workstations is addressed in
Paragraph 9.2.4.2.3, Work Station Restraints and Mobility Aid Design
Requirements.
{A}
11.7.2.1 Introduction
{A}
This section provides the personnel restraints design considerations,
requirements, and examples. Foot restraints, body restraints, and sleep
restraints are described.
11.7.2.2 Personnel
Restraints Design Considerations
{A}
Personnel restraints are required at liftoff, during major thrusting
maneuvers, microgravity/partial-gravity operations, and during return-to-earth
operations. This section includes seat belts, shoulder harnesses, fixed
and portable foot restraints, and body restraints. Donning/ doffing,
loads, materials, color, temperature limits, and dimensional requirements
are included for each type of personnel restraint.
(Refer to Paragraph
14.4, EVA Workstations and Restraints, for EVA restraint design
considerations and requirements.)
(Refer to Paragraph 11.8, Mobility
Aids, for the related topic of handholds and handrails.)
(Refer to Paragraph 9.2.4, Human/Workstation
Configuration, for design considerations and requirements related to
integration of restraints and workstations.)
Openings, holes, ductwork, and protrusions in and around equipment
have been used by crewmembers as informal microgravity body restraints.
Equipment designers must take this into account when designing equipment.
These informal restraints are acceptable for short-duration tasks. They
should not be the only method of restraint for long-duration operations
where IVA foot restraints or fixed body restraints should be considered.
Foot restraints (and/or body restraints) may be required for tasks
requiring precision. Unique foot restraint designs should be minimized
and standardized design should be maximized. Any portion of the restraint
worn on the foot shall be as low in mass as possible. In order to aid
foot restraint ingress and egress, handholds that are located between
the waist and shoulder should be available at all workstations. Commonalty
requirements for foot restraint attachment, finish, durability, and
color should be incorporated into the design.
Foot restraints can be built into the equipment or into the crewmember's
shoes.
(Refer to Paragraphs 9.2.4.2.3,
Workstation Restraints and Mobility Aids Design Requirements, and 8.9.3.2,
IVA Restraint Locations Design Requirements, for foot restraint location
requirements.)
11.7.2.3 Personnel
Restraints Design Requirements
{A}
11.7.2.3.1
General Personnel Restraints Design Requirements
{A}
All EVA and IVA personnel restraints (i.e., seat belts, shoulder harnesses,
body restraints, foot restraints, and sleep restraints) shall comply
with the following requirements:
(Refer to Paragraph 14.4.3.4,
EVA Crew Restraint Design Requirements, for EVA-unique requirements.)
a. Comfort - Restraint forces shall be reasonably distributed over
the body to prevent discomfort and shall not require conscious effort
to remain constrained.
b. Allowable Comfort Time - Comfort of the IVA restraint system shall
allow for a four-hour uninterrupted use.
c. Muscular Tension - Restraint design shall minimize or eliminate
muscular tension.
d. Anthropometric Range - All personnel restraints shall accommodate
the specific population of users for whom the system is to be designed.
e. Microgravity Posture - Personnel restraints to be used in microgravity
applications shall be designed for microgravity posture compatibility.
(Refer to Paragraph 3.3.4.3, Neutral
Body Posture Data - Design Requirements, for specific anthropometric
requirements.)
f. Cleaning and Repair - The personnel restraint system shall be capable
of being cleaned and repaired on-orbit.
11.7.2.3.2 Foot
Restraint Design Requirements
{A}
11.7.2.3.2.1 General Foot Restraint Design Requirements
{A}
The following general requirements apply to all fixed and portable
foot restraints:
(Refer to Paragraph 14.4.3.4,
EVA Crew Restraint Design Requirements, for EVA-unique foot restraint
requirements.)
a. Range of Motion - All foot restraints shall maintain foot position
to allow the crewmember a complete range of motion (roll, pitch, and
yaw).
(Refer to Paragraph 3.3.3.2.2,
Body Posture Design Considerations, for further information.)
b. Comfort - Foot restraints shall provide comfortable support.
c. Interchangeability - Attachment interfaces for foot restraints (portable-to-portable
and fixed-to-fixed) shall be interchangeable throughout the space module.
d. Positive Retention - The foot restraint shall be positive and firmly
hold the user in the desired position.
e. Load Reaction - Foot restraints shall provide the capability to
react to loads applied by the crewmember.
f. Abrasion Resistance - Reinforcements shall be provided for any fabric
areas exposed to high abrasion.
g. Ventilation - IVA foot restraints and covers shall allow ventilation
to the feet.
h. Fixed Foot Restraints - The fixed foot restraint shall be capable
of being removed for replacement/repair.
i. Portable Foot Restraints - The portable foot restraint shall be
capable of being installed and removed easily and quickly without tools.
11.7.2.3.2.1 Foot Restraint Donning/Doffing Design Requirements
{A}
Foot restraints shall comply with the following donning and doffing
requirements:
(Refer to Paragraph 14.4.3.4,
EVA Crew Restraint Design Requirements, for EVA-unique foot restraint
donning and doffing requirements.)
a. Donning - Foot restraints shall be attached or donned with minimum
effort.
b. Quick Release - Rapid ingress/egress shall be inherent to all IVA
foot restraints.
c. No-Hand Operation - The use of hands for placing/ removing the foot
shall not be required for foot restraint ingress/egress.
d. Handholds - Handholds or structure between waist and shoulder shall
be available at all foot restraint locations to aid foot restraint ingress
and egress.
(Refer to Paragraph 8.9.3.1, Required
IVA Mobility Aid Integration Design Requirements, for the specific requirements.)
e. Entrapment - All foot restraints shall minimize danger of entrapment.
A positive means of releasing the foot from the restraint shall be provided.
11.7.2.3.2.2 Foot Restraint Loads Design Requirements
{O}
IVA foot restraints must meet the following load requirements:
(Refer to Paragraph 14.4.3.4,
EVA Crew Restraint Design Requirements, for EVA restraint loads.)
a. Tension Loads - Foot restraints shall be designed to withstand a
tension load of 445 N (100 lbf) as a minimum (see
Figure 11.7.2.3.2.3-1.)
Reference: 1, Figure 4.2-3;
NASA-STD-3000 19
b. Torsion Loads - The restraints shall withstand a torsion load of
200 Nm (150 ft-lb) as a minimum with the torsion vector normal to the
floor. (See Figure 11.7.2.3.2.3-1.)
c. Factor of Safety - The yield factor of safety shall be 1.10 and
ultimate factor of safety shall be 2.00.
11.7.2.3.2.3 Foot Restraint Durability and Color Design Requirements
{A}
The durability and color of IVA and EVA foot restraints shall comply
with the following:
a. Durability - Finish shall be durable, smooth, and scratch resistant
to prevent undue wear on footwear.
b. Color - Color for all foot restraints of a given type shall have
a contrast ratio of approximately 10:1 or greater with the background.
11.7.2.3.3 Body Restraint Design Requirements
{A}
11.7.2.3.3.1 Body Restraint Donning/Doffing Design Requirements
{A}
The following crewmember body restraint donning and doffing requirements
shall apply to all tether attachments, seat belts, and shoulder harnesses:
a. Latching Mechanisms - The latching mechanism attachment will require
a positive action by the crewmember to both latch and unlatch the mechanism.
b. One-Handed Operation - The latching mechanism shall have the capability
of being latched and unlatched with one hand.
11.7.2.3.3.2
Body Restraint Loads Design Requirements
{O}
The following load requirements shall apply to seat belts, shoulder
harnesses, and IVA tethers:
(Refer to Paragraph 14.4.3.4,
EVA Crew Restraint Design Requirements, for EVA-unique body restraint
load requirements.)
a. Seat Belts and Shoulder Harnesses - IVA seat belts and shoulder
harnesses installed at stations designated as occupied during launch
and landing shall be designed so the occupant making proper use of the
equipment will not suffer serious injury when the following ultimate
inertia forces acting separately are imposed on the crewmember:
1. Downward (Eyeballs Up): 2.0 -Gz
2. Backward (Eyeballs Out): 9.0 -Gx
3. Sideward : 1.5 ± Gy
4. Upward (Eyeballs Down): 4.5 +Gz , or any lesser force that will
not be exceeded when the landing loads resulting from impact with an
ultimate descent velocity of five ft/sec at design landing weight.
(Refer to Paragraph 5.3.3.1, Linear
Acceleration Design Requirements for acceleration coordinate system
and requirements.)
b. Body Harnesses - Body harnesses shall have lifting attach points
(D-rings) which can be used in lifting or hoisting the crewmember during
egress operations in a 1-g environment. The body harness shall be designed
to support the load of the crewmember while being lifted or hoisted.
The body harness can be designed to be an integral part of the seat
belt and shoulder harness restraint system or be designed as a separate
harness to be worn in addition to the seat belt and shoulder harness
restraint system.
c. Tether Attachments - IVA tether attachments shall be capable of
sustaining a load of 756 N (170 lbs) along the longitudinal axis. They
shall be designed so as to preclude any side loading.
d. Attach Points for Tether Attachment - IVA translation and mobility
handhold tether attachment attach points shall be designed to a minimum
ultimate load of 902 N (250 lbf) in any direction.
11.7.2.3.3.3 Body Restraint Finish and Color Design Requirements
{A}
Markings, labeling, and colors shall be in accordance with
Paragraph 9.5.
11.7.2.3.3.4 Body Restraint Dimensional Design Requirements
{A}
The following dimensional requirements shall apply to all seat belts,
shoulder harnesses, and tethers:
(Refer to Paragraph 14.4.3.4,
EVA Crew Restraint Design Requirements, for EVA-unique restraint dimensional
requirements.)
a. Commonalty - Seat belts, shoulder restraints, waist restraints,
and tether attachments shall be uniform in size, shape, and method of
operation within the limits of task performance and other design tradeoffs.
b. Size - Task requirements for which the attachment is designed shall
dictate the actual size of the hooking and latch mechanism.
11.7.2.3.4 Sleep Restraints Design Requirements
{OP}
Sleep restraint design shall meet the following requirements:
a. Extremity Restraint - Sleep restraints shall include provisions
to prevent leg and arm float and prevent the head from moving during
sleep.
b. Trapped Air - Sleep restraint design shall eliminate excessive or
unevenly distributed trapped air.
c. Individual Sleep Restraints - One sleep restraint shall be provided
for each crewmember.
d. Stowage, Transport, Cleanability - Sleep restraints shall be easily
stowable, transportable, and cleanable on-orbit.
e. Features - A sleep restraint shall incorporate the following features:
1. Adjustable, flexible restraint straps.
2. Arm slits.
3. Adjustable, removable pillows/head- strap.
4. Adjustable thermal protection.
f. Opening/Closing - A sleeping bag opening/closing device that extends
the full length of the bag shall be provided.
g. Torso Restraint - Torso restraining straps shall be provided to
allow the crewmembers to restrain themselves in their choice of sleeping
position.
h. Opening/Closing - The opening/closing device shall be capable of
easy use, including quick opening in case of emergency.
i. Opening/Closing Device Replacement - The opening/ closing device
shall be easily replaceable.
11.7.2.4 Example Personnel Restraint Design Solutions
{O}
The following figures provide examples of personnel restraint design
solutions:
Figure 11.7.2.4-1 shows the sleep
restraint configuration used on the orbiter.
Figure 11.7.2.4-2 shows examples of
foot restraints used in the Skylab.
Figure 11.7.2.4-3 show an example
of a lower leg restraint available on the Skylab.
Figure 11.7.2.4-4 lists the types
of body restraints versus crew tasks that were used on the Skylab.
Reference: 150, p. 3.18-26;
NASA-STD-3000 20
Reference: 155, Page
3-47 - 3-49; NASA-STD-3000 101
Note: Dimensions of lower leg restraint: A (length) = 432 mm
(17.0 in), B (distance from mounting structure) = 127 mm (5.0
in), C (height), 76 mm (3 in). |
Reference: 155, pp. 3-51,
3-53; NASA-STD-3000 102
Figure
11.7.2.4-4 Skylab Crew Tasks Vs. Body Restraints
Skylab Crew Tasks Vs. Body Restraints
| Crew task |
Body restraint mode |
| Hand-hold |
Toe (foot loop) |
Foot (triangular cleat) |
| Meal preparation |
x |
|
x |
| Eating |
x |
|
x |
| Flight data management |
x |
|
x |
| Consoles/vehicle operations |
x |
|
x |
| Body waste collection |
x |
x |
|
| Activation/deactivation |
x |
|
x |
| Experiment operations |
x |
|
x |
| General crew task, maintenance, and housekeeping |
x |
|
x |
| Whole-body cleaning |
x |
x |
|
| Stowage operations |
x |
|
x |
| Equipment transfer |
x |
|
x |
| Personal hygiene |
x |
x |
x |
Reference: 155, Page
3-54; NASA-STD-3000 103
Skylab flight experience demonstrated that foot restraints are adequate
for most tasks. A pelvic restraint, for use with portable foot restraints
at the Apollo Telescope Mount Control Station, was not required. The
adjustable grid restraint provided adequate force cancellation, stability,
and reach capability.
For most simple, short-term tasks a handhold or any graspable structure
provides sufficient restraint.
11.7.3 Equipment Restraints
{A}
Video clips associated with this section are:
{A}
This section provides the design considerations, requirements, and
examples of equipment restraints required to retain tools and equipment
at workstations. These equipment restraints include tethers, tape, bungee
cords, Velcro, and other such devices.
(Refer to Paragraph 11.9, Fasteners,
and Paragraph 11.8.3, Equipment Mobility Aids,
for related equipment restraint design considerations and requirements.)
(Refer to Paragraph 8.9,
Mobility Aids and Restraints Architectural Integration, for equipment
restraint location design considerations and requirements.)
(Also refer to Paragraph 13.4.3.2,
Hardcopy Information Management Design Requirements, for specific requirements
for restraining documents and loose papers.)
11.7.3.2 Equipment
Restraint Design Considerations
{A}
Temporarily restraining equipment in microgravity is very important.
Everything from large equipment modules to small nuts and bolts needs
to be secured at the storage and work sites to keep them from floating
away. A variety of means have been employed in previous space modules
(e.g., gray tape, bungee cords, Velcro, tethers, and bags) with varying
degrees of success.
The restraints need to be standardized, multipurpose, easy to use,
require no tools to operate, and easily stowable.
Adhesive-type restraints (tapes) need to be easy to peel off of the
roll, easy to tear, and should not leave an adhesive residue when removed
from a surface.
11.7.3.3 Equipment
Restraint Design Requirements
{A}
All IVA and EVA equipment restraints shall be designed to the following
requirements:
a. Hand Operated :
1. Equipment restraints shall be designed such that tools are not required
to attach or detach the restraint.
2. Equipment restraints shall be designed such that they can be attached/detached
by either the left or right hand.
b. Blind Operation - The equipment restraints shall be designed such
that they can be attached/detached without having to look at them.
c. Adjustability - Provide the capability to adjust the restraint to
adapt to a wide range of sizes of the items to be restrained and to
provide the user with the capability to restrain the item at a preferred
location relative to the restraint attachment points. This does not
preclude fixed- length tethers used for specific applications.
d. Positive Restraint - The restraint shall secure the item in such
a way that the item will not come loose due to inadvertent touching,
air currents, vehicle dynamic motions, or due to other predictable environmental
conditions.
e. Cause No Damage - The equipment restraint shall be designed such
that it cannot pinch, abrade, or cut the item to be restrained or the
interfacing surfaces and adjacent hardware.
f. No Adhesive Residue - Adhesive equipment restraints shall not leave
an adhesive residue on the item or on the spacecraft surface when the
adhesive restraint is detached.
g. Tethers:
1. Common attachment method - All equipment tethers shall use a common
attachment method.
2. Tether attachment points - All equipment items that require tethering
shall have a standardized tether hook receptacle as an integral part
of the item. This standardized receptacle shall also be provided on
the interfacing surface to which the item is to be secured.
3. Tether lock status indication - The tether hook shall be designed
in such a way that it will be easy to recognize when the hook is locked/unlocked
in both day and night lighting conditions.
h. Loads :
1. Minimum load - The minimum design load shall be based on the expected
crew-imposed and environmental loads to be applied to the item in the
normal operating conditions.
2. Maximum load - The maximum design load shall be based on the resultant
load imposed by a crewmember attempting to dislodge a restrained item
that has become entrapped in adjacent hardware. The stress of this activity
should not exceed the design load of the surface to which the restraint
is attached or the design load of the entrapping hardware (i.e., the
restraint should break before the item, attachment surface, of entrapping
hardware breaks).
(Refer to Paragraph 4.9.3, Strength
Design Requirements, for definition of maximum crew imposed loads.)
i. Color - Equipment restraints shall be of a standardized color to
distinguish them from other types of loose equipment or items that will
be restrained.
(Refer to Paragraph 9.5.3.2, Coding
Design Requirements, for color selection criteria.)
j. Grounding :
(Refer to Paragraph 6.4.3, Electrical
Hazards Design Requirements, for specific requirements.)
k. Commonalty - Provide Commonalty of design for equipment restraints
to the maximum extent possible.
l. Individual Restraints :
1. Individual restraints shall be designed to restrain one hardware
item only.
2. Individual restraints shall be used when the restrained item is
large in size, sensitive, or delicate or when attachments are difficult
or complex in operation
m. Group Restraints :
1. Group restraints shall be used to restrain like-sized items wherever
possible.
2. Group restraints shall provide a system that allows the removal
of one item at a time.
n. Throw-Away Restraints - Any restraint device that is utilized during
vehicle launch, and upon activation or usage removal is discarded, shall
meet the following requirements:
1. Large throw-away restraints shall be designed to be torn apart or
be of soft, crushable materials to accommodate the openings of onboard
trash collection/disposal systems.
2. The throw-away restraints shall be color coded as a throw-away item.
(Refer to Paragraph 9.5.3.2, Coding
Design Requirements, for specific requirements.)
o. Velcro - When Velcro is used as a restraint, the item to be restrained
will be equipped with hook-type Velcro and the restraining surface will
be equipped with pile-type Velcro.
11.7.3.4 Example Equipment Restraint Design Solutions
{O}
Figure 11.7.3.4-1 shows examples of
previously used equipment restraints.
a. Temporary Stowage Bags - These bags provided an acceptable method
of temporary retention of equipment during Skylab missions. These bags
should be designed so that the contents are visible (i.e., use transparent
plastic or netting).
b. Gray Tape - Apollo, Skylab, and shuttle missions have used gray
tape extensively as a temporary restraint for IVA operations. Use in
EVA was not always acceptable because the adhesive capabilities may
have been affected by temperature extremes.
c. Cable Restraint Clips - These were used extensively in Apollo and
Skylab missions.
d. Velcro - Velcro provides an acceptable equipment restraint.
NOTE: The adhesive holding the Velcro pad must be stronger than the
hook/pile retention capability. Adhering qualities of the hook and pile
are quite material dependent. Temperature constraints may prohibit EVA
use.
e. Straps With Snaps and/or Velcro
NOTE: Crewmembers require handholds or foot restraints to mate female
snaps to spacecraft structure studs in microgravity environment. Snaps
are also difficult to align during EVA.
f. Metal and Elastic Bungee Springs with Snaps or Flat Hooks - These
are recommended for IVA use only. These were the most widely accepted
retention devices used on Apollo, Skylab, and shuttle missions.
NOTE: Both the metal springs and the elastic tend to stretch after
extended use and snaps are difficult to attach to structure-mounted
interfacing studs in a microgravity environment.
g. EVA Tethers - Fixed length, adjustable, and retractable tethers
have been used extensively in EVA operations but can also be used for
IVA operations.
h. Rubber Bands - Experience on Skylab missions has shown that rubber
bands proved to be an excellent device to hold flight manuals and checklists
from inadvertently opening in microgravity.
i. Other Devices - There are many other equipment restraint devices
that have been tried. These include pip pins, dogleash clips, pinch
clamps, and snap rings.
(Refer to Reference 155,
Section 3.2.2, for examples of equipment restraints used on the Skylab.)
Reference: 150, p. 3.4-2;
NASA-STD-3000 21
11.8
MOBILITY AIDS
{A}
11.8.1 Introduction
{A}
This section contains design considerations, requirements, and examples
for personnel and equipment mobility aids. Design criteria include dimensions,
coding, texture, design loads, temperature limits, and mounting.
(Also, refer to Paragraph
8.9, Mobility Aids and Restraints Architectural Integration.)
Items such as tethers, hooks, restraints, and temporary stowage devices
which interface with mobility aids are described in
Paragraph 11.7. Handles and grasp areas on the portable equipment
covered are detailed in Paragraph 11.6.
11.8.2 Personnel Mobility
Aids
{A}
11.8.2.1 Handhold
and Handrail Design Considerations
{A}
Handholds and handrails are the hardware interfaces used for crewmember
mobility aids. They are necessary in both IVA and EVA applications for
crewmembers to use as they move from place to place during the performance
of their tasks.
Han
