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Wentian Long March 5B Core Stage Reentry Update and Discussion Thread


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This is a thread to share updates on the status of the core stage of the Long March 5B LV that launched the Wentian module on July 24th, 2022.

This has been created because sharing of news has picked up quite a bit on the CNSA thread compared to when Tianhe was launched, and therefore the core stage merits a separate thread to avoid losing Wentian and other CNSA related news in the flood of core stage updates- it took 10~ days or so for the core stage to reenter last time and attracted quite a bit of discussion.

EDIT- I’ll go first

 

Edited by SunlitZelkova
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Although in purely probabilistic, "theoretical" terms, it is unlikely to hit anyone and the fuel probably was already discharged. But there is something on this planet called Murphy's law…

Probably we need more Tsinghua University’s atmosphere research probes.

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11 minutes ago, steve9728 said:

Although in purely probabilistic, "theoretical" terms, it is unlikely to hit anyone

The simple solution would be to properly dispose of it. Insert into a low perigee orbit, and have the module raise the perigee itself (or with a much smaller kick stage that will randomly—but safely—reenter).

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8 minutes ago, tater said:

The simple solution would be to properly dispose of it. Insert into a low perigee orbit, and have the module raise the perigee itself (or with a much smaller kick stage that will randomly—but safely—reenter).

Retro-vent (or use small pressure-fed retromotors) leftover propellants at the right time to drop it into the ocean. But do Chinese launches pass over the "spacecraft graveyard (South Pacific) within a few orbits of lift-off? all depends on inclination, of course, but...

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18 minutes ago, tater said:

The simple solution would be to properly dispose of it. Insert into a low perigee orbit, and have the module raise the perigee itself (or with a much smaller kick stage that will randomly—but safely—reenter).

But that means there’s more weight for the engines or fuel on it. You know, every gram is count up there. So I’m thinking could de-orbit sail helps in this case.

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1 minute ago, steve9728 said:

But that means there’s more weight for the engines or fuel on it. You know, every gram is count up there. So I’m thinking could de-orbit sail helps in this case.

Except that you want to dispose of it in the exact location you select, a sail makes reentry happen sooner, but not more predictably I think.

Regarding mass to LEO? Yeah, the module has to be smaller/lighter, that's the price you pay for responsibly disposing of stages.

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2 hours ago, StrandedonEarth said:

The core makes it to orbit? 

I finally realized that the Chinese Space Agency has copied my KSP habits.

(Of course the core makes it to orbit!  The only way to build a core is MOAR!!!)

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24 minutes ago, tater said:

Except that you want to dispose of it in the exact location you select, a sail makes reentry happen sooner, but not more predictably I think.

Regarding mass to LEO? Yeah, the module has to be smaller/lighter, that's the price you pay for responsibly disposing of stages.

Yup. Separating the Shuttle external tank before reaching orbit and doing the final m/s with the OMS is not nearly as efficient than just continuing to fire the SSME, but it was still done in every single STS flight in order to have it reenter in the first orbit

Edited by Beccab
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14 minutes ago, steve9728 said:

Or to make the rocket more susceptible to ablation within a certain temperature range while maintaining safety: It's fine when everything is burnt.

It's impossible to burn everything. The engines in particular are made to resist to those temperatures, and every COPV inside the vehicle is extremely likely to resist as well

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Just now, Beccab said:

It's impossible to burn everything. The engines in particular are made to resist to those temperatures, and every COPV inside the vehicle is extremely likely to resist as well

Yeah, so thinks that’s why it’s hard to graduate from Materials Science subject:ph34r:

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4 hours ago, tater said:

Regarding mass to LEO? Yeah, the module has to be smaller/lighter, that's the price you pay for responsibly disposing of stages.

That is the frustrating part, I think. Everyone else seems prepared to pay this price. A deorbiting mechanism weighs a bit, but it's a small margin on the large weight of a rocket stage anyway. That little bit of sacrificed payload capacity is generally considered to be worth it for a "guaranteed" safe deorbit of the rocket stage, judging by how common they are.

But whoever designed this rocket stage apparently didn't concern themselves with such trivial things as the safety of other people. There might be some merit to the idea that the world is big and mostly empty, and that the overwhelming odds are in favour of it not landing anywhere near people. But unlike everyone else, they did not bother to do that little extra effort to make sure. That makes them come across as quite reckless and not very emphatic. 

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CMS (China Manned Space Program) official Weibo: As of 16:00 Beijing time on 27 July 2022, the orbit of the remnants of the upper stage (the core stage) of the CZ-5B Y3 launch vehicle was 176.6km perigee, 263.2km apogee, with an inclination of 41.4°.

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On 7/24/2022 at 11:25 PM, Codraroll said:

That is the frustrating part, I think. Everyone else seems prepared to pay this price. A deorbiting mechanism weighs a bit, but it's a small margin on the large weight of a rocket stage anyway. That little bit of sacrificed payload capacity is generally considered to be worth it for a "guaranteed" safe deorbit of the rocket stage, judging by how common they are.

But whoever designed this rocket stage apparently didn't concern themselves with such trivial things as the safety of other people. There might be some merit to the idea that the world is big and mostly empty, and that the overwhelming odds are in favour of it not landing anywhere near people. But unlike everyone else, they did not bother to do that little extra effort to make sure. That makes them come across as quite reckless and not very emphatic. 

Well China has an practice of dropping spent boosters with very toxic fuel and oxidizer on their own villages, yes they was evacuated but in the danger zone, as an indication about how much they care.  And this is not an fail its just standard dropping of side boosters. 
 

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Spoiler
3 hours ago, magnemoe said:

dropping spent boosters with very toxic fuel and oxidizer on their own villages

Maybe, after bargaining with the local villagers in their market, everyone would be doing that, too.

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