66
3 System Design of Lunar Lander
For example, there was a 7500 N throttlable engine for orbit control of the CE-3
lunar lander. The distribution of density, static pressure, dynamic pressure, stagnation pressure, static temperature, dynamic temperature, stagnation temperature, axial
velocity, radial velocity and stream line of the flow field inside and outside the nozzle
was analyzed for 7500 N engine plume. The plume angle was set 45° for the 7500 N
engine. The relative position of the plume angle to all navigation sensors is shown
in Figs. 3.8, 3.9, and 3.10. The effects of plume field should be considered when the
navigation sensors are designed.
During powered descent, the throttlable engine was ignited continuously. The
engine plume interacts with lunar surface directly. The thermal status of lunar lander
was influenced by reflux of engine plume on lunar surface. On the other hand, lunar
dust activated by engine plume may affect on function of lunar lander. The flow
field of throttlable engine plume at 1500 N was analyzed by axial symmetric Direct
Simulation Monte Carlo (DSMC) method. The distribution of stream line is shown
in Figs. 3.11 and 3.12 when the distance of the bottom of engine nozzle to lunar
surface was 3 m and 5 m.
It is shown in the analysis results that the remote field of engine plume spread
freely. It is also shown that along with gas free spread, the density, pressure and
temperature decreased while the Mach number increased. Where the distance to
engine nozzle was 25 m, the density was about 2 × 10
−7 kg/m
3 , the pressure was
Fig. 3.8 Relative position of 7500 N engine plume angle to laser ranging sensor
Fig. 3.9 Relative position of 7500 N engine plume angle to microwave ranging sensors and
speedometers
3 System Design of Lunar Lander
For example, there was a 7500 N throttlable engine for orbit control of the CE-3
lunar lander. The distribution of density, static pressure, dynamic pressure, stagnation pressure, static temperature, dynamic temperature, stagnation temperature, axial
velocity, radial velocity and stream line of the flow field inside and outside the nozzle
was analyzed for 7500 N engine plume. The plume angle was set 45° for the 7500 N
engine. The relative position of the plume angle to all navigation sensors is shown
in Figs. 3.8, 3.9, and 3.10. The effects of plume field should be considered when the
navigation sensors are designed.
During powered descent, the throttlable engine was ignited continuously. The
engine plume interacts with lunar surface directly. The thermal status of lunar lander
was influenced by reflux of engine plume on lunar surface. On the other hand, lunar
dust activated by engine plume may affect on function of lunar lander. The flow
field of throttlable engine plume at 1500 N was analyzed by axial symmetric Direct
Simulation Monte Carlo (DSMC) method. The distribution of stream line is shown
in Figs. 3.11 and 3.12 when the distance of the bottom of engine nozzle to lunar
surface was 3 m and 5 m.
It is shown in the analysis results that the remote field of engine plume spread
freely. It is also shown that along with gas free spread, the density, pressure and
temperature decreased while the Mach number increased. Where the distance to
engine nozzle was 25 m, the density was about 2 × 10
−7 kg/m
3 , the pressure was
Fig. 3.8 Relative position of 7500 N engine plume angle to laser ranging sensor
Fig. 3.9 Relative position of 7500 N engine plume angle to microwave ranging sensors and
speedometers