China's Space Program News Thread

[by78]

EDIT: Removed the last image per correction from @Kejora.

 

[Blitzo]

Spotted by the Americans:

I presume the first two photos are colourized versions of the black/white photos from the hazard navigational cameras?

 

[by78]

I presume the first two photos are colourized versions of the black/white photos from the hazard navigational cameras?

Yep, indeed they are.

 

[Kejora]

Spotted by the Americans:

I think this is US' Curiosity rover not Zhurong

 

[winword]

I think this is US' Curiosity rover not Zhurong

I think you are right.

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[by78]

I think this is US' Curiosity rover not Zhurong

Thank you, and corrected.

 

[siegecrossbow]

Two things I want to note/ask (because I couldn't find relevant information)

1. Do the Lander have any scientific instruments? It seems like a judicious use of space to put some scientific instruments on the lander (even though it's stationary). The ground right under and around the lander is Martian too (much Martian dirt would've been displaced on landing - which is great).


2. Do the Zhurong rover have twin sources of power - RTG and Solar Power (Just like Yutu)?
I understand that the rover was the product of a decade long development but its a must that China explores the enhanced application of RTG (Just like US).

The lander only has cameras to the best of my knowledge. It probably has sensors for temperature, air pressure, etc.

Zhurong relies exclusively on solar panels. Temperature difference on Mars isn’t as drastic as it is on the moon. RTG on Yutu was used to keep the rover warm instead of generating power.

 

[taxiya]

Two things I want to note/ask (because I couldn't find relevant information)

1. Do the Lander have any scientific instruments? It seems like a judicious use of space to put some scientific instruments on the lander (even though it's stationary). The ground right under and around the lander is Martian too (much Martian dirt would've been displaced on landing - which is great).


2. Do the Zhurong rover have twin sources of power - RTG and Solar Power (Just like Yutu)?
I understand that the rover was the product of a decade long development but its a must that China explores the enhanced application of RTG (Just like US).

1. No. I suspect the reason is payload constraint as always. The space available is only one issue, for any device to work for prolonged time, there must be source of electricity, another mass and space demand. The lander has non-rechargeable batteries to power the landing radars today.
2. No RTG on Zhurong. To be clear, Yutu uses RTG primarily for heating during moon night, not much for power source. The moon night is 14 days long and as cold as to minus 173 degrees Celsius. Mars night is only 12 hours and as cold as minus 80 Celsius near equator where Zhurong is. RTG heater is really unnecessary. It is also much heavier, another no-no for payload constraint.

Note, RTG itself is not difficult, the problem is the radioactive source, commonly Plutonium 238. Even NASA's rovers so far use Russian Plutonium 238 taken from the decommissioned warhead. Yutu's RTG is the same. So I don't think technology is a stopper.

 

[taxiya]

The only disadvantage of the RTG power source is its low output. The Perseverance's RTG is only rated at 110W at launch (declining slightly per year) and would have to rely on its batteries anytime the scientific instruments require more power.

That sounds similar to Sterling engine on the AIPS sub.

 

[gelgoog]

A Sterling engine is basically an external combustion heat engine. It is a mechanical engine. An RTG uses thermocouples to convert the heat energy of radioactive decay into electricity. It is solid state. It is lower power but way more reliable because it has no moving parts. Sterling engines can be relatively high power but can be finicky to design to work properly. Both typically generate way less energy than an internal combustion engine per unit of weight with Stirling engines being more power efficient than thermocouples.