108
4 Structure and Mechanism Technology of Lunar Lander
Table 4.1 (continued)
Requirements
Definition
Instructions
Required information
Position
stability
Maintaining the
specified position or
pointing accuracy in a
certain part or direction
of the structure shall
include errors caused by
temperature
deformation, material
yield, mechanical
connection offset, etc.
Primary structure should
maintain the relative
position accuracy
between sensors,
antenna, engine,
payload, and etc.
1) Assigned accuracy
index to primary
structure
2) Temperature range
Structure mass Total mass of the
structural sub-system
and primary
components were less
than the specified value
The mass was usually
assigned to the structural
sub-system, so it was
often the goal of
preliminary design, not
as a fixed requirement
Assigned mass
Operability
All parts should be easy
to install, remove,
adjust, transport, store
and ground test, and
adapt to assembly
operation of the probe
The construction and
installation design of the
components should be
taken into account that
all ground operations
could be performed
Operation requirements
Material
processability
The materials and
manufacturing
processes used for the
components could be
realized
The materials used could
be purchased or
produced, and the
manufacturing processes
used are mature
There were two issues that should be paid special attention in configuration of
lunar lander structure:
(1) Configuration of soft-landing mechanisms. It would directly determine the
force transfer path of the landing impact load, and thus affect the primary
structure configuration. Usually transfer paths of the landing impact and the
launch load were different.
(2) Configuration of large fuel tanks and orbit maneuver engines. The inertial load
of fuel tanks with propellant was the maximum load of the structure during
launch; on the other hand, the room for large fuel tanks and orbit maneuver
engines was big. For lunar lander with large device, the location and room for
installation were also the focus.
The general feature of lunar lander configuration was that the fuel tanks were arranged
in parallel (usually 4 or more), and the lower part of fuel tanks was directly mounted
on the interface ring or short beam, in order to shorten the force transfer path and
lower the center of gravity.
4 Structure and Mechanism Technology of Lunar Lander
Table 4.1 (continued)
Requirements
Definition
Instructions
Required information
Position
stability
Maintaining the
specified position or
pointing accuracy in a
certain part or direction
of the structure shall
include errors caused by
temperature
deformation, material
yield, mechanical
connection offset, etc.
Primary structure should
maintain the relative
position accuracy
between sensors,
antenna, engine,
payload, and etc.
1) Assigned accuracy
index to primary
structure
2) Temperature range
Structure mass Total mass of the
structural sub-system
and primary
components were less
than the specified value
The mass was usually
assigned to the structural
sub-system, so it was
often the goal of
preliminary design, not
as a fixed requirement
Assigned mass
Operability
All parts should be easy
to install, remove,
adjust, transport, store
and ground test, and
adapt to assembly
operation of the probe
The construction and
installation design of the
components should be
taken into account that
all ground operations
could be performed
Operation requirements
Material
processability
The materials and
manufacturing
processes used for the
components could be
realized
The materials used could
be purchased or
produced, and the
manufacturing processes
used are mature
There were two issues that should be paid special attention in configuration of
lunar lander structure:
(1) Configuration of soft-landing mechanisms. It would directly determine the
force transfer path of the landing impact load, and thus affect the primary
structure configuration. Usually transfer paths of the landing impact and the
launch load were different.
(2) Configuration of large fuel tanks and orbit maneuver engines. The inertial load
of fuel tanks with propellant was the maximum load of the structure during
launch; on the other hand, the room for large fuel tanks and orbit maneuver
engines was big. For lunar lander with large device, the location and room for
installation were also the focus.
The general feature of lunar lander configuration was that the fuel tanks were arranged
in parallel (usually 4 or more), and the lower part of fuel tanks was directly mounted
on the interface ring or short beam, in order to shorten the force transfer path and
lower the center of gravity.