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  ESA - JAXA - China - International
  Tiangong-1: Viewing, comments, questions (Page 2)

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Author Topic:   Tiangong-1: Viewing, comments, questions
starhopper
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Posts: 57
From: Kathleen, GA, USA
Registered: Aug 2005

posted 11-18-2011 12:00 PM     Click Here to See the Profile for starhopper   Click Here to Email starhopper     Edit/Delete Message   Reply w/Quote
Strange - I see no evidence of re-entry burn marks on the heat shield of the craft. I wonder if it tumbed during re-entry as some of Russian capsules have? (Granted, the photos only show part of the heatshield - but it seems awfully clean doesn't it?)

Lasv3
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From: Bratislava, Slovakia
Registered: Apr 2009

posted 11-19-2011 02:06 AM     Click Here to See the Profile for Lasv3   Click Here to Email Lasv3     Edit/Delete Message   Reply w/Quote
It is unusually clean, you're right. Isn't it possible they use the deployable heat shield a la Mercury which is jettisoned shortly before touchdown? I have no idea what the reason for such an arrangement would be, the only one I can imagine is to protect the soft landing engines during the descent.

Or - the Chinese recovery crews cleaned and polished the shield to look nice for the landing photo session.

starhopper
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Posts: 57
From: Kathleen, GA, USA
Registered: Aug 2005

posted 11-19-2011 04:23 AM     Click Here to See the Profile for starhopper   Click Here to Email starhopper     Edit/Delete Message   Reply w/Quote
I've not seen anything that indicates the Chinese used a heat shield that is jettisoned before landing - I was under the impression that they used Russian Soyuz designs to build their capsule. The Soyuz uses three jets that "cushion" the capsule just before landing.

I'll bet anything that the capsule didn't reenter in the proper attitude. This has happened recently to the Soyuz capsules when they failed to properly separate from the service module. This resulted in what they called a "ballistic" reentry for the capsule and it's occupants - not a fun ride!

Anyone else have a theory as to why the heat shield seems awfully clean, and the side of the capsule seem burnt?

Lasv3
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Posts: 222
From: Bratislava, Slovakia
Registered: Apr 2009

posted 11-19-2011 11:01 AM     Click Here to See the Profile for Lasv3   Click Here to Email Lasv3     Edit/Delete Message   Reply w/Quote
To refresh my memory I looked into the book "Soyuz" by Rex D.Hall and David J. Shayler and there is a description of the Soyuz landing sequence on p. 71 saying "the thermal shield is jettisoned at 3 km (although one source states 5,5 km - immediately prior to full main chute deployment)..."

This seems to be the explanation as the Shenzhou is a younger brother of Soyuz and the soft landing system philosophy is most probably the same.

Jay Chladek
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Posts: 2211
From: Bellevue, NE, USA
Registered: Aug 2007

posted 11-19-2011 06:29 PM     Click Here to See the Profile for Jay Chladek   Click Here to Email Jay Chladek     Edit/Delete Message   Reply w/Quote
quote:
Originally posted by music_space:
10,000 mechanical parts, really?
China's system seems to be based on the APAS systems originally utilized on Apollo Soyuz and eventually refined for use on the ISS. The Apollo probe and drogue had its uses, but the thing had a few problems late in Apollo and during Skylab's missions, starting with Apollo 13. The APAS system was more complicated (maybe not quite 10,000 parts, but the final design had a lot more mechanisms to it), but even Tom Stafford even said he was more concerned with the Apollo probe and drogue possibly having another foul up on ASTP as opposed to the APAS system designed for the Soyuz side.

I hope 10,000 parts is an exaggeration as I have this line spoken by Mr. Scott from Star Trek 3 running through my head: "The more they overthink the plumbing, the easier it is to stop up the drain."

As for the heat shield, considering how clean Shenzhou looks in the rear, I would say it likely had some sort of jettisonable heat shield, like Soyuz.

If a Soyuz capsule is free by itself, the laws of aerodynamics and its center of gravity will swing it into a blunt end forward position where the thickest part of the heat shield can handle the reentry temperatures. Soyuz 5 certainly proved that with its front first reentry until the propulsion module broke away. Once the capsule was free, it immediately swung the proper direction and it did it without thrusters and the thruster fuel got exhausted at the start of reentry as the craft was trying to correct its orientation with a propulsion module still attached. Shenzhou has pretty much the same shape, so aerodynamically, I would expect it to behave exactly the same.

The burn on the side doesn't look bad at all (certainly not like it was that side which bore the brunt of reentry)and that could easily have come from rolling the capsule on a controlled reentry (done with thrusters and an offset CGI, like what Gemini and Soyuz both have done). Judging by the burns location next to a chute compartment, maybe it was a chute pyro that had a little too much of a charge packed into it. It just seems too small and localized to be reentry heating unless something caused a very small hot spot there.

Believe me, if this craft had come down front first or sideways, the side would have looked a LOT more charred then it does.

starhopper
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Posts: 57
From: Kathleen, GA, USA
Registered: Aug 2005

posted 11-20-2011 07:08 AM     Click Here to See the Profile for starhopper   Click Here to Email starhopper     Edit/Delete Message   Reply w/Quote
quote:
Originally posted by Lasv3:
"the thermal shield is jettisoned at 3 km (although one source states 5,5 km - immediately prior to full main chute deployment)"
WOW - thanks for researching that - I had never heard of the heat shield being jettisoned before - very interesting! Thanks!

SpaceKSCBlog
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Posts: 112
From: Merritt Island, FL
Registered: Nov 2011

posted 02-16-2012 08:10 AM     Click Here to See the Profile for SpaceKSCBlog   Click Here to Email SpaceKSCBlog     Edit/Delete Message   Reply w/Quote
Originally reported by Shanghai Daily, China will launch Shenzhou 9 unmanned to dock with the orbiting Tiangong-1 in June, then launch Shenzhou 10 next year to send astronauts into the module.
During the Shenzhou-9 mission in June, a channel between the unmanned Shenzhou-9 and the Tiangong-1 will open for the first time to link the air between the two spacecraft, a key step to prepare for the following manned mission, said Zhu [Yilin, a researcher on the project from the Chinese Space Technology Institute].

"The temperature, humidity and pressure will be monitored after the air is ventilated between the two spacecraft to ensure the safety of the astronauts into the Tiangong-1 on the following mission," Zhu said.

Some small animals and plant seeds will be taken aboard the Shenzhou-9 for passive experiments on the conditions of zero gravity and radiation, he said.

And one observer's commentary:
We now know, thanks to Chinese state media, that Shenzhou 9 will be launched in June, as suspected. But there will be no astronauts on board. This is probably the greatest shock that space boffins have seen from China in years.

Why the sudden change? It seems clear that there must be technical issues at work, and they must be fairly serious.

The last time China launched people was September 2008. Looks like it will be at the minimum 4+ years before they attempt it again.

Robert Pearlman
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Posts: 27328
From: Houston, TX
Registered: Nov 1999

posted 02-16-2012 08:17 AM     Click Here to See the Profile for Robert Pearlman   Click Here to Email Robert Pearlman     Edit/Delete Message   Reply w/Quote
This is probably the greatest shock that space boffins have seen from China in years.
Not quite. Since before Shenzhou 8 launched and throughout its mission, landing and recovery, Chinese space program officials said that Shenzhou 9 would only possibly fly with a crew.

Tonyq
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Posts: 150
From: UK
Registered: Jul 2004

posted 02-16-2012 01:19 PM     Click Here to See the Profile for Tonyq   Click Here to Email Tonyq     Edit/Delete Message   Reply w/Quote
Robert is right, that the Chinese stance, both before and after Shenzhou 8, was that Shenzhou 9 might, or might not, be manned. However, the apparent unqualified success of Shenzhou 8, and several statements from Chinese officials and taikonauts over the Chinese New Year period had implied that the next flight would carry a crew.

Therefore, yesterday's reports were something of a surprise, as it seemed to totally contradict the direction of travel which had been unfolding in the last few weeks.

That said, Chinese space watchers and forums are now seriously questioning the original source, which has now been removed from the internet, and People's Daily has today published a rather different version of current plans, painting a rather different picture.

Firstly, People's Daily should be a credible, semi-official source, and it is dated today, so should be fresher information than yesterday's report, so worth looking at what it says:

China will launch another spacecraft in June to dock with its Tiangong-1 space lab, and one more spaceship next year to conduct a more demanding manual docking, according to sources with the China Aerospace Science and Technology Corporation (CAST)...

Shenzhou-9 and Shenzhou-10 are part of the program to establish a manned space station, earlier reports only said the two would be launched in the first and second half of this year, and no information about crew was released.

The Shenzhou-9 mission will still focus on docking, separating and docking with Tiangong-1 to ensure safety in the coming manned mission...

Shenzhou-9 will try opening the passageway linking the spaceship and Tiangong-1 when they dock, a move not carried out in the Shenzhou-8 mission...

However, Pang Zhihao, a researcher from CAST, said it has not been decided whether the Shenzhou-9 mission will be manned or not.

Clearly, there is still no official clarity here, but, on balance this report looks more credible, and still leaves the option of a manned, automated docking in June, as a possibility.

In any event, can anyone explain how the 'passageway link' connecting the vehicles could be opened without a crew there to do it?

Robert Pearlman
Editor

Posts: 27328
From: Houston, TX
Registered: Nov 1999

posted 02-17-2012 07:36 AM     Click Here to See the Profile for Robert Pearlman   Click Here to Email Robert Pearlman     Edit/Delete Message   Reply w/Quote
Xinhua is now reporting that Shenzhou 9 will launched with a three-person crew.
China will launch the manned Shenzhou 9 spacecraft between June and August this year and achieve space rendezvous and docking mission with the orbiting Tiangong-1 space lab module, a spokesman for China's manned space program said Friday.

The new space docking mission will be realized by astronauts' manual operation, another chance for China to test its docking technology, he spokesman said.

The three crew members of Shenzhou-9 will enter Tiangong-1 vehicle to live and work there, conducting space science experiments.

Jay Chladek
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Posts: 2211
From: Bellevue, NE, USA
Registered: Aug 2007

posted 02-17-2012 07:54 AM     Click Here to See the Profile for Jay Chladek   Click Here to Email Jay Chladek     Edit/Delete Message   Reply w/Quote
Whether Shenzou 9 flies manned or not, China will likely need to gather data on how long their craft can remain in orbit to certify its on orbit storage life if they are going to attempt something like Salyut's long duration stays in the not too distant future.

Plus, as small as Tiangong is, I figure they would need to probably come up with a Shenzou version of a Progress craft as well to send up supplies and discard trash buildup since those are the biggest keys to a space station. And three crewmembers can generate A LOT of trash.

Robert Pearlman
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Posts: 27328
From: Houston, TX
Registered: Nov 1999

posted 02-17-2012 08:36 AM     Click Here to See the Profile for Robert Pearlman   Click Here to Email Robert Pearlman     Edit/Delete Message   Reply w/Quote
Tiangong-1 is not intended to be a Salyut-like space station. Rather, it is a test article for the deployment of a multi-module station in the 2020 time frame.

Crew visits to Tiangong-1 are expected to be short in duration.

Tiangong-1 is also a testbed for a Progress-like resupply vehicle to service the future station.

SkyMan1958
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Posts: 355
From: CA.
Registered: Jan 2011

posted 02-18-2012 02:38 PM     Click Here to See the Profile for SkyMan1958   Click Here to Email SkyMan1958     Edit/Delete Message   Reply w/Quote
I was intrigued to see in today's People's Daily Online some of the physical requirements for the first two batches of taikonauts. They must be 25 to 35 years old. They must weigh 55 to 70 kilograms (about 122 to 154 pounds). They must be 1.6 to 1.72 meters (about 5'3" to 5'8") tall. I'm surprised at how small they must be. Even the Mercury 7 could be significantly larger than this.

SkyMan1958
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From: CA.
Registered: Jan 2011

posted 06-09-2012 02:24 PM     Click Here to See the Profile for SkyMan1958   Click Here to Email SkyMan1958     Edit/Delete Message   Reply w/Quote
China will launch the Shenzhou 9 spacecraft in mid-June according to the People's Daily Online.
China will launch its Shenzhou-9 manned spacecraft sometime in mid-June to perform the country's first manned space docking mission with the orbiting Tiangong-1 space lab module, a spokesperson said here Saturday.

By 10:30 a.m. Saturday, the spacecraft and its carrier rocket, the Long March-2F, had been moved to the launch platform at the Jiuquan Satellite Launch Center in northwest China, a spokesperson with the country's manned space program said.

In the next few days, scientists will conduct functional tests on the spacecraft and the rocket, as well as joint tests on selected astronauts, spacecraft, rocket and ground systems, according to the spokesperson.


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