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China's Jade Rabbit lunar rover dies on moon

cbc.ca

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Re: China's Jade Rabbit lunar rover dies on moon

#41

Post by 1morewebdev »

lutusp wrote: post #2

This is a shame, but most people -- even in space programs -- don't appreciate how cold the Moon's shaded areas become. It's now estimated that these areas get to 26 Kelvins -- that's 26 degrees above absolute zero. To get a sense of how cold this is, Pluto's average surface temperature is seven degrees warmer . Also consider that, because of the specifics of the Moon's orbit, a given area stays shaded for just over…

Suppose China were to send another Rover up in the next 5 years, and it found this one. In theory, could this one be repaired? Or will the "electronics self-destruct" be thorough by then?

Re: China's Jade Rabbit lunar rover dies on moon

#42

Post by SEJeff »

TrainedMonkey wrote: post #40
SEJeff wrote: post #20

Earlier quoted context omitted.

I wish the Chinese space program the best. Every success pushes mankind (all nationalities) forward in our understanding of the universe.

That. Hopefully we can get another space race this time against China. Sending people to Mars or establishing moon colony for example.

I suspect Elon Musk will win that one and as a result America :)

SpaceX is doing quite well thusfar.

Re: China's Jade Rabbit lunar rover dies on moon

#43

Post by 1morewebdev »

TrainedMonkey wrote: post #9

Chinese space program had come a long way. Interesting test would be how they handle this failure. Will they go assigning blame and scapegoats. Or will they learn from this mistake and improve quality control/redundancy for future missions.

I expect the latter, they aren't known to give up big dreams so easily. Consider for instance that India and Russia have had numerous failed launches for various rockets and / or space probes and both countries continue to try again and eventually succeed. Why would China not try again? I pray they do. Chinese or American or Russian or Indian, I want to see a minimal human habitat on the moon in my lifetime. Our species deserves that much, for all the work done so far.

Re: China's Jade Rabbit lunar rover dies on moon

#45

Post by jonknee »

reuven wrote: post #29

I found it quite appropriate that the referenced CBC article referred to it as a moon "buggy." More seriously, I'm excited to see more countries, and more people in general, involved in space exploration. I also think that instead of pointing to the rover's failure, we shout point to its success: Launching a rover to the moon and getting it to work in any way, shape, or form, is a pretty amazing triumph. Sure, the US…

To be fair that's also what the US called the Lunar Rover:

http://en.wikipedia.org/wiki/Lunar_Roving_Vehicle

Re: China's Jade Rabbit lunar rover dies on moon

#46

Post by fallinghawks »

oftenwrong wrote: post #21
lutusp wrote: post #2

This is a shame, but most people -- even in space programs -- don't appreciate how cold the Moon's shaded areas become. It's now estimated that these areas get to 26 Kelvins -- that's 26 degrees above absolute zero. To get a sense of how cold this is, Pluto's average surface temperature is seven degrees warmer . Also consider that, because of the specifics of the Moon's orbit, a given area stays shaded for just over…

>To get a sense of how cold this is, Pluto's average surface temperature is seven degrees warmer. That doesn't give me a good sense because I have no idea how Pluto's average surface temperature compares to typical on-Earth temperatures that I have experienced. This gives me a better sense: 26 K = -247.2 C

Oh, so something like Canadian winter. ;)

Re: China's Jade Rabbit lunar rover dies on moon

#47

Post by jccooper »

Hard to say what happened from the sketchy reports, but there's been some mention of "mechanical problems" due to lunar dust, and hibernation problems. I guess they have some mechanical movement involved in hibernation mode. Pre-positioning solar arrays, maybe? Storing instruments?

Lunar dust is notoriously abrasive, having formed in a non-erosive setting. It's a well known problem for lunar exploration, and NASA's done a lot of work on it. Not a lot of recent practical experience, of course.

The Chang'e designers must have known about the problem. Apparently they underestimated it, or just missed. Hopefully there's some good lessons learned for future missions. Getting there and working for a lunar day is a pretty good job in itself.

Re: China's Jade Rabbit lunar rover dies on moon

#49

Post by mpyne »

unspecified wrote: post #38
Pxtl wrote: post #33

Earlier quoted context omitted.

That said, temperature works differently in hard vacuum - with no air to conduct/convect the heat away, isolated objects don't actually get "cold" the way they would in a pool of liquid nitrogen or something. Notice you don't hear about the ISS freezing at night.

The ISS is only in shade for 45 minutes at a time, which is orders of magnitude less than a lunar night. But speaking of that: how long is too long to spend at 26K in a vacuum? Are there any good articles/videos that talk about what happens to various materials at such extreme temperatures in a vacuum?

I think the point of the parent comment was that simply being in a cold vacuum doesn't make you instantly cold. That still requires a process of heat transfer, which occurs in a fluid via conduction, convection, and radiation.

When immersed in a vacuum the conduction and convection heat transfer paths are sharply reduced, so the question then becomes how fast do you cool off via radiation alone?

I'm not a physicist so I don't know, but it's certainly nowhere near as fast as conduction/convection (in fact I believe heat dissipation was actually problematic for many spacecraft designs).

Re: China's Jade Rabbit lunar rover dies on moon

#50

Post by sliverstorm »

cygwin98 wrote: post #25
bane wrote: post #22

Earlier quoted context omitted.

It even made the Daily Show with Patrick Stewart hilariously dressed up as the rover, slowly dying. http://www.thedailyshow.com/watch/tue-february-4-2014/who-fr...

Not surprised. He has been bashing China for a while, which is the trending topic in the mainstream media anyway. Though I do wish some of the media agencies strike out of the group-thinking, and examine what NASA has been up to for the past decade, and what needs to be improved in terms of space exploration.

He is a comedian, whose "bit" is being critical. He takes jabs at just about everything he covers.
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