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China lands Chang'e-4 on far side of Moon

planetary.org

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Re: China lands Chang'e-4 on far side of Moon

#31

Post by djsumdog »

ericye16 wrote: post #29
taneq wrote: post #22

Earlier quoted context omitted.

It wasn't in TFA, but here's a source: https://www.bbc.com/news/science-environment-46724727 > The lander carries a 3kg (6.6lb) container with potato and arabidopsis plant seeds - as well as silkworm eggs - to perform biological studies. The "lunar mini biosphere" experiment was designed by 28 Chinese universities. (Source for the silkworms, at least. I must confess that giant mutant moonworms are only conjecture...…

Hm, doesn't this violate the prime directive (or planetary protection guidelines)?

I think they'd have to dump something on the surface, but even if they did, who's going to enforce it? The moon's not Antarctica.

Re: China lands Chang'e-4 on far side of Moon

#32

Post by A2017U1 »

sowbug wrote: post #13
A2017U1 wrote: post #4

Copying earlier comment: Wikipedia seems to say the rover mission duration is 3 months, yet the previous rover traveled for a year and transmitted a bit longer. The Chinese seemed quite coy about it failing last time (as with many things) so perhaps underpromising in this case? This all preparation for China's planned permanent radio telescope on the far side which would be a huge boon for astronomers by escaping Ear…

I'd interpret the stated duration as a criterion for whatever budget they came up with. Building something that'll last 90 days in a harsh environment is a lot less expensive than one that needs to last at least a year. And assuming the folks monitoring the rover aren't working for free, the budget needs to include their cost of employment for a fixed amount of time.

Fair point, guess when you have specs and failure rates to meet the effort/cost goes up dramatically.

Fair chance this rover can last a while though. Good luck to them.

Re: China lands Chang'e-4 on far side of Moon

#33

Post by jetison_out_to_ »

Noticed this is the same day as NASA got the Ultima-Thule photos. Was this announced today to overshadow it, like how Uber announced their IPO basically a day after Lyft's?

Want to avoid going off about conspiracy theories or who's more patriotic, just curious how the announcements actually lined up.

This (wikipedia-sourced) AP wire from Oct 22, 2015 when the Pluto flyby happened said they had re-pointed the probe for this flyby, scheduled for Jan 1, 2019, which it did exactly that. So we knew at least 3 years ago the exact date of Ultima-Thule -- spacework requires very good precision*. http://apnews.excite.com/article/20151022/us-sci--pluto-next...

The Chang'e 4 wikipedia page says it was launched Dec 7, 2018, only about a month ago.

So I get launches are well-planned in advance so wheels have been spinning a long time there too, but even so, they clearly must have known the two events would occur right around the same time, the Chinese one just a day or two after the American one.

Is this what a space race feels like?

Re: China lands Chang'e-4 on far side of Moon

#34

Post by ggm »

skilled wrote: post #25

Can someone explain how are these types of devices safe from hackers? I mean, it talks back to the space agency, right? Just curious is all. Haven't seen anything related to this question.

Feels like a state actor risk in the main. I can't think of a state actor without significant volumes of more attackable assets in earth orbit, and that's without considering their options for eg A one time cipher stream or other serious protection of the uplink signal.

I doubt it's using open comms and a diginotarencrypt certificate.

Re: China lands Chang'e-4 on far side of Moon

#35

Post by jetison_out_to_ »

taneq wrote: post #22
hyperpallium wrote: post #14

Earlier quoted context omitted.

Where's that? I couldn't fimd it in the linked article. Sounds like Elon Musk's original idea for a greenhouse on Mars, to inspire via realtime cam. Is there any indication they'll have a public cam for it?

It wasn't in TFA, but here's a source: https://www.bbc.com/news/science-environment-46724727 > The lander carries a 3kg (6.6lb) container with potato and arabidopsis plant seeds - as well as silkworm eggs - to perform biological studies. The "lunar mini biosphere" experiment was designed by 28 Chinese universities. (Source for the silkworms, at least. I must confess that giant mutant moonworms are only conjecture...…

Any bio nerds know why silkworms?

There's an obvious reference to Chinese culture in that one, curious what are the biological reasons to choose that creature over any other.

Re: China lands Chang'e-4 on far side of Moon

#36

Post by adventured »

jetison_out_to_ wrote: post #33

Noticed this is the same day as NASA got the Ultima-Thule photos. Was this announced today to overshadow it, like how Uber announced their IPO basically a day after Lyft's? Want to avoid going off about conspiracy theories or who's more patriotic, just curious how the announcements actually lined up. This (wikipedia-sourced) AP wire from Oct 22, 2015 when the Pluto flyby happened said they had re-pointed the probe fo…

> Is this what a space race feels like?

No.

New Horizons capturing Ultima Thule is not a large enough event to warrant the Chinese feeling like they need to compete with it. Spectator wise, it's a nice event for anyone that likes astronomy. It will be ignored by most of the people on the planet, just as the Chinese landing on the far side of the moon will be. These are not seminal moments in space history.

Re: China lands Chang'e-4 on far side of Moon

#37

Post by Rebelgecko »

skilled wrote: post #25

Can someone explain how are these types of devices safe from hackers? I mean, it talks back to the space agency, right? Just curious is all. Haven't seen anything related to this question.

A lot of satellites and probes "back in the day" more or less depended on security through obscurity. You would need to know what frequency (or frequencies) to use, and how to encode the commands. Your ground station also needs a bigass antenna, and a good idea of where to point it.

Now most if not all satellites use encryption and/or authentication for command and control, but I wouldn't be surprised if some space programs don't bother. With something like the New Horizons, why waste precious CPU cycles with encryption/decryption when it takes such a tremendous effort to communicate with it. The Deep Space Network costs something upwards of $1,000/hour, and requires huge dishes and lots of land.

Re: China lands Chang'e-4 on far side of Moon

#38

Post by [deleted] »

adventured wrote: post #36
jetison_out_to_ wrote: post #33

Noticed this is the same day as NASA got the Ultima-Thule photos. Was this announced today to overshadow it, like how Uber announced their IPO basically a day after Lyft's? Want to avoid going off about conspiracy theories or who's more patriotic, just curious how the announcements actually lined up. This (wikipedia-sourced) AP wire from Oct 22, 2015 when the Pluto flyby happened said they had re-pointed the probe fo…

> Is this what a space race feels like? No. New Horizons capturing Ultima Thule is not a large enough event to warrant the Chinese feeling like they need to compete with it. Spectator wise, it's a nice event for anyone that likes astronomy. It will be ignored by most of the people on the planet, just as the Chinese landing on the far side of the moon will be. These are not seminal moments in space history.

[deleted]

Re: China lands Chang'e-4 on far side of Moon

#40

Post by Rapzid »

XorNot wrote: post #19
golfer wrote: post #15

From the NYT article [0] on the topic: "We Chinese people have done something that the Americans have not dared try.” -- someone associated with the Chinese space agency Why so insecure? Not a good look. [0] https://www.nytimes.com/2019/01/02/world/asia/china-change-4...

I'm pretty happy if China wants to throw shade at the US over space program accomplishments. I'd prefer a measuring contest over space accomplishments then building more earth-bound weapons systems.

No need to choose, you'll get both!
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