334
10 TT&C and Telecommunication Technology …
In the typical lunar soft-landing mission, the implementation of
telemetry/telecommand and telecommunication function should overcome technical challenges including remote telecommunication during powered descent
and on lunar surface. To ensure that the lunar lander could be monitored in all
mission phases, the TT&C and Telecommunication subsystem should be capable of
telemetry/telecommand and telecommunication in 4 × 10
5 km. Telecommunication
during powered descent and on lunar surface was peculiar in lunar soft-landing
mission. The process of powered descent was one of the key phases to mission
success. In the process of powered descent, the attitude of the lunar lander varied
in a large range. It was required that the information of operation status of the
lunar lander and the images of descent camera in powered descent process should
be transmitted to ground in real-time. Telecommunication on lunar surface was
different from the telecommunication link among the traditional spacecrafts or
between ground and spacecraft, where the telecommunication link performance was
affected by the lunar surface. Telecommunication on lunar surface was a technology
challenge that has never been faced before the Chang’E-3 mission in China.
There are three parts in his chapter based on telemetry/telecommand and telecommunication instruments onboard the Chang’E-3 lunar lander. The first one is
analysis of the characteristics of telemetry/telecommand and telecommunication
technology for the lunar lander. Then the design and key technology principles
of telemetry/telecommand and telecommunication subsystem are described based
on the analysis. The second one is the latest development of new technologies
in telemetry/telecommand and telecommunications for deep space exploration in
China. The third one is design and verification of the Chang’E-3 lunar lander.
10.2 Development Status
In early space missions, the carriers of tracking, telemetry and telecommand were
independent. From 1950s to mid of 1960s, it was found that more carrier frequencies were easy to interfere with each other and there were difficulties in spacecraft configuration, while the ground facilities were large and complex, difficult to
operate. In the mid of 1960s, the unified carrier telemetry/telecommand system was
come up. Only one uplink carrier and one downlink carrier were required to realize
the telemetry/telecommand of spacecraft [3]. In 1980s, along with application of
spacecraft, different carriers were used in spacecraft telemetry/telecommand and
telecommunication. A unified carrier telemetry/telecommand system was applied in
the telemetry/telecommand. Generally, suppressed carrier modulation was applied
for telecommunication and the baseband signal was directly modulated to the carrier
[1].
Since Luna 1 was launched by the Soviet Union in January 1959, the United States,
Russia, Japan, ESA, China and India had successfully launched lunar probes up to
date. The telemetry/telecommand and telecommunication subsystem used by lunar
10 TT&C and Telecommunication Technology …
In the typical lunar soft-landing mission, the implementation of
telemetry/telecommand and telecommunication function should overcome technical challenges including remote telecommunication during powered descent
and on lunar surface. To ensure that the lunar lander could be monitored in all
mission phases, the TT&C and Telecommunication subsystem should be capable of
telemetry/telecommand and telecommunication in 4 × 10
5 km. Telecommunication
during powered descent and on lunar surface was peculiar in lunar soft-landing
mission. The process of powered descent was one of the key phases to mission
success. In the process of powered descent, the attitude of the lunar lander varied
in a large range. It was required that the information of operation status of the
lunar lander and the images of descent camera in powered descent process should
be transmitted to ground in real-time. Telecommunication on lunar surface was
different from the telecommunication link among the traditional spacecrafts or
between ground and spacecraft, where the telecommunication link performance was
affected by the lunar surface. Telecommunication on lunar surface was a technology
challenge that has never been faced before the Chang’E-3 mission in China.
There are three parts in his chapter based on telemetry/telecommand and telecommunication instruments onboard the Chang’E-3 lunar lander. The first one is
analysis of the characteristics of telemetry/telecommand and telecommunication
technology for the lunar lander. Then the design and key technology principles
of telemetry/telecommand and telecommunication subsystem are described based
on the analysis. The second one is the latest development of new technologies
in telemetry/telecommand and telecommunications for deep space exploration in
China. The third one is design and verification of the Chang’E-3 lunar lander.
10.2 Development Status
In early space missions, the carriers of tracking, telemetry and telecommand were
independent. From 1950s to mid of 1960s, it was found that more carrier frequencies were easy to interfere with each other and there were difficulties in spacecraft configuration, while the ground facilities were large and complex, difficult to
operate. In the mid of 1960s, the unified carrier telemetry/telecommand system was
come up. Only one uplink carrier and one downlink carrier were required to realize
the telemetry/telecommand of spacecraft [3]. In 1980s, along with application of
spacecraft, different carriers were used in spacecraft telemetry/telecommand and
telecommunication. A unified carrier telemetry/telecommand system was applied in
the telemetry/telecommand. Generally, suppressed carrier modulation was applied
for telecommunication and the baseband signal was directly modulated to the carrier
[1].
Since Luna 1 was launched by the Soviet Union in January 1959, the United States,
Russia, Japan, ESA, China and India had successfully launched lunar probes up to
date. The telemetry/telecommand and telecommunication subsystem used by lunar