Chang'e-4 farside landing mission Options

[A.Nemo]

Preliminary Suggestions for International Cooperation on Chang'E-4 Lunar Probe
Xu Y. (China)
http://www.unoosa.org/pdf/pres/copuos2015/...2015tech08E.pdf

An Introduction of Chang’E-4 Probe:
Probe（Lander,Rover）+ Relay Statellite
Soft-landing on lunar farside
Landing and roving exploration
Will be launched between 2018 and 2019

the probe:
Chang’E-4 probe，lander and rover have the same technical status with the Chang’E -3; but exploration will be redesigned; the payload will be reconfigered; The name of the probe might be changed.
Chang’E-4 probe is a backup spacecraft of Chang’E -3 probe. By now, all platform products of the probe have been manufactured, waiting for further AIT.
The probe will be launched by a long March 3B rocket from the Xichang Statellite Launch Center(XSLC) which is the same way with the Chang'E-3 between 2018 and 2019

The relay statellite:
will be first launched into a lunar transfer orbit about the end of 2018 in the whole mission, then starts its earth-to-moon jurnery alone, and will enter and run in a Halo orbit around the Earth-Moon L2 point; the design life is 3 years.
would provide relay service for the probe and the Earth, and carry out exploration.

Engineering objectives are as follow.
To realize the first soft landing on the lunar farside and perform exploration in human history.
To demonstrate technologies of lunar data relay, landing and roving on complicated terrains of the lunar farside, and lunar night power generation;
To perform further detailed survey on lunar environment in order to lay a foundation for subsequent lunar exploration mission.

Tentative Scientific objectives are as follow.
To study lunar surface dust features and its formation mechanism;
To perform in-situ measurement of lunar surface residual magnetism
and study its interaction with solar wind;
To study lunar surface temperature and particle radiation environment;
To perform lunar surface topology and material composition analysis,
shallow-layer structure survey and study;
To explore and study lunar interior structure of spheres;
To perform lunar based VLF astronomical observation and study

[Phil Stooke]

That's true, of course, but the distance to the ideal horizon is not as important as the height and distance of significant relief features. Von Karman is about 160 km across and up to 4 km deep (wall height varies quite a bit). A good comparison might be with Flamsteed P, the flooded crater which Surveyor 1 landed in. It is 80 km across, but mostly filled with lava and with hills 1500 m high protruding above the plains. Hills 20 km away were visible in the Surveyor 1 panorama. Scaling up, I am confident there will be some relief on the CE4 horizon. Maybe if the landing is in exactly the worst place for viewing relief there would not be much, but from many areas some features will be visible.

Phil