Chang'e-4 lunar operations

[JimO]

Also, autonomous hazard avoidance needs to, well... *see* the terrain below.

Is that a feature of this vehicle?


Power, I can appreciate. And the desire to get early TV of the surrounding terrain. Is there a time constraint on the deployment of the rover?

[ugordan]

Also, autonomous hazard avoidance needs to, well... *see* the terrain below.

Is that a feature of this vehicle?

It was a feature on Chang'e 3, I can only assume it's used here as well.

[Dalhousie]

Also, autonomous hazard avoidance needs to, well... *see* the terrain below.

Unless using active sensors such as radar and/or lidar

[ugordan]

Also, autonomous hazard avoidance needs to, well... *see* the terrain below.

Unless using active sensors such as radar and/or lidar

Chang'e 3 used optical imagery for things like large boulder identification.

[Galactic Penguin SST]

Seems like the landing will be on January 3 at perhaps early morning GMT.
That is, "seems" - I hope someone else tangentially involved can confirm this. 

[mcgyver]

Also, autonomous hazard avoidance needs to, well... *see* the terrain below.

Is that a feature of this vehicle?

Is autonomous navigation really needed on a spacecraft just 3 lightseconds away going down at 3m/s?

[Phillip Clark]

Is autonomous navigation really needed on a spacecraft just 3 lightseconds away going down at 3m/s?

Remember that the Chinese are testing procedures for landing on Mars and operating a rover there.

[woods170]

Is autonomous navigation really needed on a spacecraft just 3 lightseconds away going down at 3m/s?

Remember that the Chinese are testing procedures for landing on Mars and operating a rover there.

Correct. The ultimate target for China is not the Moon. The Moon is just the "sandbox" environment to get their act together. China is aiming for Mars.

[Blackstar]

Is autonomous navigation really needed on a spacecraft just 3 lightseconds away going down at 3m/s?

Remember that the Chinese are testing procedures for landing on Mars and operating a rover there.

Correct. The ultimate target for China is not the Moon. The Moon is just the "sandbox" environment to get their act together. China is aiming for Mars.

That's misleading. They have several other Moon landings planned, and they may even send humans there. This is not just a dress rehearsal for Mars.

[ugordan]

That's misleading. They have several other Moon landings planned, and they may even send humans there. This is not just a dress rehearsal for Mars.

Still, gaining more experience with autonomous hazard avoidance is useful. We'll see if their 2nd attempt is as successful.

I realize it's not necessarily as simple with Mars landings given the constraints direct entry trajectories to Mars give you (early afternoon-ish local time landing for Hohmann-type transfers?) so shadows will not be as pronounced and the atmosphere will further reduce contrast for any large boulders on the surface. It's kind of a shame that so far we only got MSL MARDI descent imagery to "train" future Mars lander algorithms, Phoenix would have been a nice additional data set. I wonder if HiRise imagery can be useful in this respect even though hazardous objects just smaller than 1/3 meter would be difficult to resolve from orbit.

[vjkane]

That's misleading. They have several other Moon landings planned, and they may even send humans there. This is not just a dress rehearsal for Mars.

I think that the Chinese are using their lunar missions to build capabilities for both their lunar and Martian programs.  An example of the latter is that their lunar sample return has the ascent vehicle rendezvous with a co-launched orbiter.  Based on the Moonrise proposals to NASA, a simpler direct-to-Earth return from the moon is possible.  However, the Chinese have stated that they are using the automated rendezvous and sample transfer to develop technologies for Martian sample return where direct-to-Earth is not practical.

It will be interesting to see who gets the first samples back from Mars.

[Blackstar]

https://www.scientificamerican.com/article/with-first-ever-landing-on-moons-farside-china-enters-luna-incognita/

[Josh_from_Canada]

We should be around 24 hours away from the attempted landing. 

[Taxidermista]

We should be around 24 hours away from the attempted landing. 

Any info about live coverage outside China?

[Phil Stooke]

As far as I can tell, we don't even have info about live coverage in China.

[mcgyver]

Landing time prediction from another forum, by  Thorsten Denk:
02 January, 00:00 UTC (midnight) at 178.1° East.

[Phillip Clark]

BBC's preview of the landing.

https://www.bbc.co.uk/news/science-environment-46724727

[lcs]

The Thorsten Denk predicted time has already passed.  According to 'the Sun' article:

https://www.thesun.co.uk/tech/8101134/china-probe-landing-dark-side-of-moon/

"China's National Space Administration reportedly said the craft will land around 1:00am GMT on Thursday."

Based on Denk's analysis the 24 hour delay would mean the orbital plane would have rotated beyond Van Karman crater.

[tdenk]

I see that my modest prediction starts to be cited here and on Twitter.
For reference, it can be found here:
http://www.unmannedspaceflight.com/index.php?s=&showtopic=8057&view=findpost&p=242821

The idea is simply that
(1) the orbital plane at LOI was perpendicular (normal vector pointing to Earth) and then
(2) remained fix in space. The Moon rotates below until the trajectory goes over the Von-Kármán crater.
Apparently, one or both of the assumptions were wrong.

Thorsten

[tdenk]

The third assumption of course is that they really land
in the eastern part of the Von-Kármán crater
and did not change the landing zone without notification. 

Thorsten