8.5 Testing and Verification of Propulsion Subsystem
301
The propellant filling for the Chang’E-3 lunar lander in launch site showed that:
The filling design was suitable and correct; The filling ground equipment worked
reliably; The control of filling parameters satisfied design requirements.
8.6 Summary
The propulsion subsystem of the lunar lander had complicated operation modes
and shall pass complex flight environment, which made it difficult to be developed.
The propulsion subsystem should be designed on the basis of similar technology
according to mission characteristics and requirements, current status and etc. Its
function, performance and robustness should be fully validated through a great many
ground test.
Special attention should be paid in design of propulsion subsystem.
(1) The subsystem and component should be designed to eliminate negative effect
of different uncertain factors in flight, such as reliable expulsion under propellant sloshing and lateral overload, cooling and performance degradation in
low thrust mode of orbit control engine with large throttling ratio, impact of
propellant to sealing rings in case of dynamic sealing between moving parts
and etc.
(2) The design parameters of propulsion subsystem should be optimized to improve
subsystem performance. For example, propellant option should be optimized
for boundary cooling flux, characteristic length of combustion chamber, nozzle
expansion ratio. The lightweight and high performance composite materials
could be applied to effectively reduce mass of propellant and gas tank.
(3) Under resource constraints, system redundancy, fault reconfiguration and
management should be reasonably designed to increase system reliability. For
example, there should be redundancy for attitude control engine branch, independent liquid pipeline management of orbit/attitude control engine, tank overload safety management, redundancy design for winding of stepping motor,
propulsion control unit and etc.
(4) Test solution should be properly formulated to improve measurement precision of subsystem performance. For example, there should be flow resistance
consistency test of tank and pipeline to increase expulsion precision for parallel
tanks, calibration hot firing test for orbit control engine, multi-flux regulation
for regulator and etc.
(5) Ground tests should be conducted fully and adequately. For example, there
should be orbit control engine robustness test, tank vibration, expulsion and
pressure-bearing test, tank vibration test with pressurized gas, long term
pressure-bearing storage test, subsystem hot firing, propellant filling test and
etc.
As more and more countries concern deep space exploration and implement deep
space exploration missions, future large-scale space exploration activities like lunar
301
The propellant filling for the Chang’E-3 lunar lander in launch site showed that:
The filling design was suitable and correct; The filling ground equipment worked
reliably; The control of filling parameters satisfied design requirements.
8.6 Summary
The propulsion subsystem of the lunar lander had complicated operation modes
and shall pass complex flight environment, which made it difficult to be developed.
The propulsion subsystem should be designed on the basis of similar technology
according to mission characteristics and requirements, current status and etc. Its
function, performance and robustness should be fully validated through a great many
ground test.
Special attention should be paid in design of propulsion subsystem.
(1) The subsystem and component should be designed to eliminate negative effect
of different uncertain factors in flight, such as reliable expulsion under propellant sloshing and lateral overload, cooling and performance degradation in
low thrust mode of orbit control engine with large throttling ratio, impact of
propellant to sealing rings in case of dynamic sealing between moving parts
and etc.
(2) The design parameters of propulsion subsystem should be optimized to improve
subsystem performance. For example, propellant option should be optimized
for boundary cooling flux, characteristic length of combustion chamber, nozzle
expansion ratio. The lightweight and high performance composite materials
could be applied to effectively reduce mass of propellant and gas tank.
(3) Under resource constraints, system redundancy, fault reconfiguration and
management should be reasonably designed to increase system reliability. For
example, there should be redundancy for attitude control engine branch, independent liquid pipeline management of orbit/attitude control engine, tank overload safety management, redundancy design for winding of stepping motor,
propulsion control unit and etc.
(4) Test solution should be properly formulated to improve measurement precision of subsystem performance. For example, there should be flow resistance
consistency test of tank and pipeline to increase expulsion precision for parallel
tanks, calibration hot firing test for orbit control engine, multi-flux regulation
for regulator and etc.
(5) Ground tests should be conducted fully and adequately. For example, there
should be orbit control engine robustness test, tank vibration, expulsion and
pressure-bearing test, tank vibration test with pressurized gas, long term
pressure-bearing storage test, subsystem hot firing, propellant filling test and
etc.
As more and more countries concern deep space exploration and implement deep
space exploration missions, future large-scale space exploration activities like lunar