China's Space Program News Thread

[FairAndUnbiased]

Are you sure? The outer structure with the dome shaped hatch/door is the pressure resistant structure. The inner cylindrical struct is only for mounting the instrument. You can see that there is no air seal to the inner structure, meaning no pressure difference between the outer and inner struct, both zero in a vacuum chamber.

Another example is the submarine pressure hull all have domes at both end.

uh I know that. Where did I say that the outer structure was not the pressure resistant structure? I simply said it is not an exaggerated egg shape, the curvature of the dome is relatively small, the rest of the chamber is a cylindrical tube section.

why is this even an argument, it is clear that the chamber is a tube from looking at it. I never said that this specific vacuum chamber was 100% completely flat at the end. The chamber is clearly not an egg. It's a cylinder with a small curvature dome, not an exaggerated egg shape, at the end.

Tube sections simply does not result in the loss of useful volume the way an exaggerated egg shape would and are simpler to produce. this is evidenced by the fact that real world vacuum chambers and yes, submarines, are all tube sections except the ends.

 

[FairAndUnbiased]

Further evidence that may suggest that an egg shape is shit:

Here's CVD chambers operated under high vacuum. Not egg shaped.

Please, Log in or Register to view URLs content!

Here's a plasma etch system also operated under high vacuum. Not egg shaped.

Please, Log in or Register to view URLs content!

Here's Tiangong. Not egg shaped.

All the egg shaped structure proposals I've seen were for shitty CGI ads about how some revolutionary new space company is going to build a 1 million person city on Mars.

And if you were going to build an egg, because of pressure resistance, just build a god damn sphere which is just as structurally difficult but at least is the most pressure resistant, and if you're worried about rolling, put a strut on the bottom or something.

 

[escobar]

CN commercial sat imagery reach 30cm resolution!!

Please, Log in or Register to view URLs content!

SuperView Neo-2 1&2 SAR sats launched

https://twitter.com/i/web/status/1548106102654394368

 

[gadgetcool5]

Please, Log in or Register to view URLs content!

1. The "no limits" partnership was declared before the war started. At that time, Germany was still going forward with Nord Stream 2. Actions from that time cannot have any bearing on policy today. It is not even clear what this so-called partnership specifically consists of. As far as we know it is just rhetoric.

2. There is no evidence that China "signed off" or even knew what Russia was planning to do. The fact that Russia seeks Chinese support does not mean China will agree.

3. The Uyghur and other controversies have been going on for years. They are not new.

Basically, all of the reasons given in this article are either not new, or BS. Nor is it explained why a purportedly sovereign continent of 27 nations and 500 million people have to listen to a Senator from Florida. But if they want to push China into Russia's arms go ahead. The Russian army could use some Chinese hardware

 

[iantsai]

7月16日6时57分，长征二号丙运载火箭在太原卫星发射中心点火升空，以“一箭双星”的方式成功将四维高景二号01、02星送入预定轨道，发射任务取得圆满成功。

四维高景二号01、02星是中国航天科技集团有限公司所属中国四维测绘技术有限公司的两颗高分辨率商业遥感卫星，由航天科技集团五院研制。卫星主要服务于城市安全、实景三维、城市信息模型、数字农业等新兴市场，以及国土测绘、防灾减灾、海事监测等传统领域，为用户提供高时效、高性能的时空信息服务。

本次发射是长征系列运载火箭第427次发射。

China launched Siwei Gaojing-2/-01, -02 twin satellites by a CZ-3C rocket from Taiyuan Satellites Launch Center at 06:57 UTC+8, July 16, 2022.

Siwei Gaojing-2 are a group of high-res commercial imaging satellites serving emerging markets such as urban security, real scene 3D, urban information model and digital agriculture surveying, as well as traditional fields such as landscape surveying and mapping, disaster prevention and mitigation, maritime monitoring, and provide users with time-lapse and high-performance space-time information services.

This is the 427th CZ series rocket launch mission.

 

[luosifen]

 

[sunnymaxi]

Latest -

Scientists at Huazhong University of Science and Technology are proposing to use lunar soil to make buildings at the moon. The egg-shaped design provides a living area on top and a work area below. The team produced the first model using 3D printing technique recently.

View attachment 93280View attachment 93281View attachment 93282

[Bricklaying on the moon] Another proposal of the same team is to manufacture bricks on the moon and then use a robot to construct the building. Learn more details in this paper.

here is the link -

Please, Log in or Register to view URLs content!

 

[FairAndUnbiased]

Keep in mind that in space, you are dealing with internal pressure which places the pressure vessel into tension - something that concrete is NOT good at. This means that while a conventional pressure vessel design works on earth when made out of high tensile strength steel, it likely won't be good enough when using lunar concrete. I'm sure they will use micro-fibers in the mix to increase tensile strength, but even that isn't going to get you near the performance of steel.

The real problem here is

Please, Log in or Register to view URLs content!

- a spherical pressure vessel will outperform cylindrical all day every day and is why high pressure COPV's in space applications are ALWAYS round. Sure they have some that are cylindrical, but those aren't the highest pressure ones (and again carbon overwrap has way more tensile strength than lunar concrete).

Egg shape gets you somewhere in between a spherical and a cylindrical pressure vessel and reduces stress and therefore needed wall thickness and safety factors. Many are researching using this shape for similar applications with minimal safety margin, for example

Please, Log in or Register to view URLs content!

.

Thanks for reminding me that the lunar "concrete" is under tension. I am still highly skeptical of egg shape as it is common to see in bullshit CGI from scam companies.

One thing to note is that wall thickness isn't necessarily bad. You need thick walls to block radiation anyways. I would think that digging underground is the obvious solution and using a tunnel wall melter to leak seal/harden the tunnel would be the solution to use. It also provides thermal insulation as the subsurface of the moon has much lower temperature swings.

 

[tankphobia]

Thanks for reminding me that the lunar "concrete" is under tension. I am still highly skeptical of egg shape as it is common to see in bullshit CGI from scam companies.

One thing to note is that wall thickness isn't necessarily bad. You need thick walls to block radiation anyways. I would think that digging underground is the obvious solution and using a tunnel wall melter to leak seal/harden the tunnel would be the solution to use. It also provides thermal insulation as the subsurface of the moon has much lower temperature swings.

It takes so much energy to melt lunar regolith I'm not sure it'll ever be practical to melt it and use it as a structural material unless you have access to nuclear/fusion power. Perhaps an inflatable module with steel frame then scoop some moon dirt on top as radiation shielding would be achievable with current technologies. All those CGI of melting lunar/mars surface to build things always seemed a bit scammy to me. On another note Mars is so much better than the moon for colonization efforts since it's a less harsh environment without razor sharp dust and insane temperature fluctuations, but due to its distance that's not practical in the near future either.

 

[FairAndUnbiased]

It takes so much energy to melt lunar regolith I'm not sure it'll ever be practical to melt it and use it as a structural material unless you have access to nuclear/fusion power. Perhaps an inflatable module with steel frame then scoop some moon dirt on top as radiation shielding would be achievable with current technologies. All those CGI of melting lunar/mars surface to build things always seemed a bit scammy to me. On another note Mars is so much better than the moon for colonization efforts since it's a less harsh environment without razor sharp dust and insane temperature fluctuations, but due to its distance that's not practical in the near future either.

The moon is more energy and oxygen rich, and closer to earth for resupplying, and has less extreme temperature difference subsurface. Below the lunar surface the temperature stays relatively constant at -30C or so.

Please, Log in or Register to view URLs content!

You have permanent illuminated regions at the poles and places of permanent shadow in craters near the poles. This means you can build a heat engine using the temperature gradient or use solar panels. Unlike Mars which is poor in energy resources and where all the energy you have is energy sources that you bring with you, you can in-situ generate alot of energy on the moon.

There's also far less limitation to shipping people and material from Earth to moon, with deltaV required to land (6 km/s) only a small portion that of landing on Mars (~11 km/s) and with ~3 days travel time vs. ~9 months.

Please, Log in or Register to view URLs content!

With sufficient energy you can vacuum refine metals and oxygen from lunar regolith. Thanks to the above-mentioned you can have sufficient energy.

Please, Log in or Register to view URLs content!