88
3 System Design of Lunar Lander
3.7 Planning of TT&C Link
The TT&C of lunar lander with ground station should be implemented during flight.
The data downlink and receiving from the lunar rover should be implemented during
lunar surface operation [9].
The TT&C link of Chang’E-3 lunar lander with ground station and the lunar rover
is shown in Fig. 3.28.
The major frequency was X-band for TT&C and data downloading of Chang’E-3
lunar lander. There were two phases for TT&C from separation with launch vehicle
to approaching perilune. When the distance to Earth was within 2×10
4 km, the Sband TT&C link was setup. When Chang’E-3 lunar lander could be accessed by
deep space ground station during LTO, the deep space ground station could support
X-band TT&C and the X-band TT&C link is setup.
When Chang’E-3 lunar lander approached perilune, the X-band TT&C was
maintained. During LOI and circumlunar orbit, the X-band TT&C was used while
Chang’E-3 lunar lander could be accessed by deep space ground station during LOI.
During powered descent, the TT&C link between Chang’E-3 lunar lander with deep
space ground station was setup and data was downloaded by mid-gain antenna.
After soft landing, the X-band data downlink was setup when the directional
antenna was operated normally. The downlink was switched to directional link. When
Chang’E-3 lunar lander was hibernated in lunar night or awakened in lunar daytime,
the downlink was switched to omnidirectional link.
Fig. 3.28 TT&C link of Chang’E-3 lunar lander with ground station and the lunar rover
3 System Design of Lunar Lander
3.7 Planning of TT&C Link
The TT&C of lunar lander with ground station should be implemented during flight.
The data downlink and receiving from the lunar rover should be implemented during
lunar surface operation [9].
The TT&C link of Chang’E-3 lunar lander with ground station and the lunar rover
is shown in Fig. 3.28.
The major frequency was X-band for TT&C and data downloading of Chang’E-3
lunar lander. There were two phases for TT&C from separation with launch vehicle
to approaching perilune. When the distance to Earth was within 2×10
4 km, the Sband TT&C link was setup. When Chang’E-3 lunar lander could be accessed by
deep space ground station during LTO, the deep space ground station could support
X-band TT&C and the X-band TT&C link is setup.
When Chang’E-3 lunar lander approached perilune, the X-band TT&C was
maintained. During LOI and circumlunar orbit, the X-band TT&C was used while
Chang’E-3 lunar lander could be accessed by deep space ground station during LOI.
During powered descent, the TT&C link between Chang’E-3 lunar lander with deep
space ground station was setup and data was downloaded by mid-gain antenna.
After soft landing, the X-band data downlink was setup when the directional
antenna was operated normally. The downlink was switched to directional link. When
Chang’E-3 lunar lander was hibernated in lunar night or awakened in lunar daytime,
the downlink was switched to omnidirectional link.
Fig. 3.28 TT&C link of Chang’E-3 lunar lander with ground station and the lunar rover