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Chinese Space Program (CNSA) & Ch. commercial launch and discussion


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3 hours ago, K^2 said:

The fact that there have been no repercussions for this one is only going to make them more careless.

They're really only used (relatively, compared to all the rockets they launch) sparingly though in that configuration. Initially they wanted more configurations of the LM-5 design so it would cover a lot more payload cases but apart from the 4-boostered design it has been relieved to rockets with smaller cores. Apart from the three planned, in absence of launch failures of the planned missions I don't see the manifest growing. (there really isn't a lot of reason to put a 25 tonnes object in LEO apart from stations...)

Chances that they'd correct the design and add a controlled re-entry method (like some retrorockets) isn't high.

2 hours ago, JoeSchmuckatelli said:

Perhaps not.  PRC has a low tolerance for losing face.

Looks at South China Sea and SE Asia

 

Anyway, some clues on how they might been re-entered precisely, infrasound data from CTBTO sensor :

Honestly the debris might not even reach close to the Maldives as I'll say that if you can start to detect soundwaves then it must've hit parts of the atmosphere that are dense enough to transmit it to the surface. (Also CTBTO sensors are all over the world so if they had made anything else it's most likely going to be noted as well.)

Some speculations :

And this is that video from Oman everyone is talking about. (deffo not from this account, but it has made it there - they're a group of astronomers mostly known for their work on new moon visibility - so I think it's OK to post.)

 

Edited by YNM
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There is a journalist for a Chinese domestic aerospace magazine claiming that the core stage entering orbit was well understood from the beginning of the design of the Long March-5B. They apparently think 74% (or whatever it was) chance of it hitting the ocean is safe enough.

This may have been bad publicity in the West, but it is a win for China domestically as it is giving them an opportunity to provide the population "evidence" of bias against China in Western media as compared to coverage of SpaceX's second stage.

I think NASA/Bill Nelson have made the most "correct" response to the reentry-

https://www.nasa.gov/press-release/nasa-administrator-statement-on-chinese-rocket-debris

After calling out China, he also mentions all nations and commercial entities.

In other news, Tianhe-1 is the first crewed spacecraft to be equipped with ion thrusters.

The 2nd, 3rd, and also 4th tweet (from that mentioned as "1/3")-

Quote

...further research on the LHT-100's station applis. The cause of the change, from my insight was that in 2014 there were various candidates for the CSS's EP, in which the HET-80 won the bidding eventually. In terms of tech, the HET-80 has a small plume divergence angle..(2/3)

...at 82 deg (less than 41deg each side), significantly smaller than similar products, so the thruster could be mounted at a 45deg elevation to the broadside while emerging little influence to the module. Two firing thrusters could produce 117mN effective thrust. (3/3)

Correct: 83mN, not nN

 

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6 hours ago, YNM said:

Anyway, some clues on how they might been re-entered precisely, infrasound data from CTBTO sensor :

  

On 5/4/2021 at 7:17 PM, kerbiloid said:

If pierce it with a kinetic warhead. it will be whistling, so they can hear and run away.

You see?! It works!

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3 hours ago, kerbiloid said:
On 5/4/2021 at 11:17 PM, kerbiloid said:

If pierce it with a kinetic warhead. it will be whistling, so they can hear and run away.

You see?! It works!

CTBTO infrasound sensors already routinely detects meteor re-entry and impacts. Basically the stage was a man-made one here.

5 hours ago, SunlitZelkova said:

There is a journalist for a Chinese domestic aerospace magazine claiming that the core stage entering orbit was well understood from the beginning of the design of the Long March-5B. They apparently think 74% (or whatever it was) chance of it hitting the ocean is safe enough. This may have been bad publicity in the West, but it is a win for China domestically as it is giving them an opportunity to provide the population "evidence" of bias against China in Western media as compared to coverage of SpaceX's second stage.

I think NASA/Bill Nelson have made the most "correct" response to the reentry - after calling out China, he also mentions all nations and commercial entities.

To be fair I guess that comparing between uncontrolled re-entry and leaving your stage around forever and opening up chances to have close encounters with other 'dead' bodies is ever so sliightly better - but it's not significantly better.

Even controlled re-entry procedures using the stage's own engines can fail, and at that point you're left to rely on the nature to provide you the brakes you need.

Maybe we need something like range safety that'd explode when re-entry is passively detected, to minimize the reach of debris onto the ground...

5 hours ago, SunlitZelkova said:

In other news, Tianhe-1 is the first crewed spacecraft to be equipped with ion thrusters.

Would they be continuously operated ? Does it have any effect on sensors on-board ? It is interesting development however for LEO stations, not really useful elsewhere (yet)...

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12 hours ago, SunlitZelkova said:

There is a journalist for a Chinese domestic aerospace magazine claiming that the core stage entering orbit was well understood from the beginning of the design of the Long March-5B. They apparently think 74% (or whatever it was) chance of it hitting the ocean is safe enough.

This may have been bad publicity in the West, but it is a win for China domestically as it is giving them an opportunity to provide the population "evidence" of bias against China in Western media as compared to coverage of SpaceX's second stage.

So - as a poker player, I would definitely throw money at any situation where I thought I'd win 74% of the time.

But this wasn't poker - and it could have gone badly.

Problem is, for PRC at least,  is that they want to showcase 'top tier' space capabilities and then make a blunder like this (rookie move, as others have pointed out).  But the PRC also cannot or will not admit fault - which we've seen Elon do without losing face (to the point of both making fun of himself / SpaceX and admitting mistakes).  The PRC wants it both ways: 'we are equals' and 'people are mean to us' followed by, 'if we don't acknowledge a mistake, it never happened'.

They'd have been far better off simply saying, 'yeah, we goofed up... but the odds are in our favor and we will do everything we can to help identify and minimize risk to others now and moving forward'.  Even then, they could have pointed at the Washington farm impact and said, 'this happens occasionally in this industry, and we try to not do stuff like this, but it still happens,' rather than trying to play the bias card.

 

Bad look all around.

Edited by JoeSchmuckatelli
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16 hours ago, YNM said:

They're really only used (relatively, compared to all the rockets they launch) sparingly though in that configuration. Initially they wanted more configurations of the LM-5 design so it would cover a lot more payload cases but apart from the 4-boostered design it has been relieved to rockets with smaller cores. Apart from the three planned, in absence of launch failures of the planned missions I don't see the manifest growing. (there really isn't a lot of reason to put a 25 tonnes object in LEO apart from stations...)

Chances that they'd correct the design and add a controlled re-entry method (like some retrorockets) isn't high.

It would take more than just retrorockets. If you look up the design report for the YF-77, the integrated IMU loop and control unit is routed directly to the engine gimbal and nothing else. There is no AOCS at all. The observed high rotation rate of the boosters means that there was a significant amount of undamped torque on the rocket body at staging and during engine shutdown/outgassing and tank passivation.

Without a functioning AOCS and cold-gas thrusters to control attitude, the retrorockets would just be firing in a useless spiral as the stage tumbled. They would have to totally redesign the control software code too. Obviously they SHOULD but they clearly WON'T.  

Quote
And this is that video from Oman everyone is talking about. (deffo not from this account, but it has made it there - they're a group of astronomers mostly known for their work on new moon visibility - so I think it's OK to post.)

Looks authentic. Only likely authentic video we have seen so far. Too bad it is so short and grainy.

I did a review of all the fake rocket breakup videos circulating on social media:

 
There were a lot of them.
 
12 hours ago, SunlitZelkova said:

There is a journalist for a Chinese domestic aerospace magazine claiming that the core stage entering orbit was well understood from the beginning of the design of the Long March-5B. They apparently think 74% (or whatever it was) chance of it hitting the ocean is safe enough.

This may have been bad publicity in the West, but it is a win for China domestically as it is giving them an opportunity to provide the population "evidence" of bias against China in Western media as compared to coverage of SpaceX's second stage.

So frustrating.

6 hours ago, YNM said:

Even controlled re-entry procedures using the stage's own engines can fail, and at that point you're left to rely on the nature to provide you the brakes you need.

I believe the Falcon upper stage has four ways to ensure a safe disposal:

  1. Final Merlin engine relight to target disposal trajectory
  2. Propulsive vent to target disposal trajectory
  3. Cold-gas ullage thruster impulse to target disposal trajectory
  4. Active cold-gas attitude control to control drag and re-entry profile

And of course they also typically use a fairly low-altitude parking orbit to try and ensure the fastest possible deorbit. Obviously 3 and 4 are mutually exclusive; if you blow all your ullage gas then you can no longer control drag, so if your ullage reserves don't give you enough dV to get the disposal orbit that you want, you don't want to waste it. That's what happened back in March...the relight failed and (presumably) the propulsive vent wasn't quite enough to get a good disposal orbit, so they just went with active drag control to try and get re-entry as close to the water as possible.

But there is a huge difference between having multiple safety measures and having those safety measures partially fail...and having no safety measures at all and flipping a coin on every launch, like the Long March 5B.

Quote

Maybe we need something like range safety that'd explode when re-entry is passively detected, to minimize the reach of debris onto the ground...

You typically do have an FTS, but once you are in a stable orbit that FTS is irreversibly disarmed (usually a physical pin or arm that is dropped into place with a spring to prevent the FTS from firing and cannot be remotely removed). That's the callout you always hear during Falcon 9 webcasts right before SECO: "FTS is safed." You disarm your FTS once you're in orbit because the risk of a Kessler-initiating debris cloud on orbit from an armed FTS is much much higher than risks of ground impact.

Also the biggest issue with the Long March 5B booster was those two stinking engines. Each YF-77 is the size of four-wheeler but weighs as much as a pickup truck. FTS is great for unzipping a stage and dumping propellants in midair to prevent a fireball on ground impact, but it does nothing to reduce the impact of a three-tonne chunk of flaming metal.

Edited by sevenperforce
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2 minutes ago, sevenperforce said:

You typically do have an FTS, but once you are in a stable orbit that FTS is irreversibly disarmed (usually a physical pin or arm that is dropped into place with a spring to prevent the FTS from firing and cannot be remotely removed). That's the callout you always hear during Falcon 9 webcasts right before SECO: "FTS is safed." You disarm your FTS once you're in orbit because the risk of a Kessler-initiating debris cloud on orbit from an armed FTS is much much higher than risks of ground impact.

I had wondered about this... and figured that if they lost control because of a comms glitch they could not fire it.  Did not think about the fact that 'best practices' would be to disarm any FTS in orbit because of what you describe.  Thanks for this!

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I will say that US Space Command's prediction of CZ-5B R/B's re-entry point was wildly impressive.

The Space Force made its final prediction just before 5 PM EDT on Saturday: re-entry at 10:11 PM EDT plus or minus 60 minutes. At that point in time, Aerospace Corporation still had a four-hour window centered at 11:40 PM EDT, which only had a small overlap with the Space Force window. I was nervous about trusting such a narrow prediction made relatively early.

And then...it came down at 10:14 EDT. Literally three minutes later than the prediction. Like, that is GOOD. Really validates our abilities in that area and, to some degree, the whole idea of having a "US Space Command" as an independent entity. Not to get all nationalistic or anything...it's just very impressive.

Also, today in poorly-written space headlines:

"With no landing pad"?!?! What in the world.

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1 hour ago, JoeSchmuckatelli said:

Problem is, for PRC at least,  is that they want to showcase 'top tier' space capabilities and then make a blunder like this (rookie move, as others have pointed out).  But the PRC also cannot or will not admit fault - which we've seen Elon do without losing face (to the point of both making fun of himself / SpaceX and admitting mistakes).  The PRC wants it both ways: 'we are equals' and 'people are mean to us' followed by, 'if we don't acknowledge a mistake, it never happened'.

They'd have been far better off simply saying, 'yeah, we goofed up... but the odds are in our favor and we will do everything we can to help identify and minimize risk to others now and moving forward'.  Even then, they could have pointed at the Washington farm impact and said, 'this happens occasionally in this industry, and we try to not do stuff like this, but it still happens,' rather than trying to play the bias card.

This assumes, however, that their target audience is the Anglophone space enthusiast community. "If we don't acknowledge a mistake, it never happened" works very well against a domestic audience, who will dismiss any claims of "this supposed mistake" with the aforementioned bias argument - whereas an admission would, indeed, be a loss of face.

The CCP/mainland nationalist Chinese absolutely do, however, want to get to a point where this trick works on the international community - because they believe the US/"Collective West" has this privelege already, that part of being a superpower is being able to make people shut up about your failures (or at least strangle the headlines and then turn the information into a historical footnote), and dismiss criticism of you as ill-willed bigotry and misinformation.

Edited by DDE
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1 hour ago, sevenperforce said:

But there is a huge difference between having multiple safety measures and having those safety measures partially fail...and having no safety measures at all and flipping a coin on every launch, like the Long March 5B.

Yeah I get it. Putting in actual safeguarding that might fail is not the same as not even trying at all in the first place. Tumbling is definitely sign that it wasn't even designed into the stage itself for it to be able to do anything after engine shutoff. I was referring to if it's possible to design a last-effort option that means however large your stage is it'll never end up with some roofs pierced with a pipe or a surprise tank in your lawn.

1 hour ago, sevenperforce said:

I did a review of all the fake rocket breakup videos circulating on social media:

There were a lot of them.

Yeah, honestly one thing that I was concerned when following the events was the amount of reference to a certain 'media network' with certain naming and certain meanings. (not the place to discuss them here really.) There were videos claimed from Latin America but since that was then somehow re-posted as claiming from Europe it's definitely not it.

46 minutes ago, sevenperforce said:

The Space Force made its final prediction just before 5 PM EDT on Saturday: re-entry at 10:11 PM EDT plus or minus 60 minutes. At that point in time, Aerospace Corporation still had a four-hour window centered at 11:40 PM EDT, which only had a small overlap with the Space Force window. I was nervous about trusting such a narrow prediction made relatively early.

And then...it came down at 10:14 EDT. Literally three minutes later than the prediction. Like, that is GOOD. Really validates our abilities in that area and, to some degree, the whole idea of having a "US Space Command" as an independent entity. Not to get all nationalistic or anything...it's just very impressive.

You should see Roscosmos' prediction as well as the prediction made by the last TLE from 18-SPCS/CSpOC (which is later than their last public prediction). Honestly I'm wondering about the SBIRS that the major space nations have when they called it actually re-entering, wouldn't surprise me if all three have it.

8 minutes ago, DDE said:

The CCP/mainland nationalist Chinese absolutely do, however, want to get to a point where this trick works on the international community - because they believe the US/"Collective West" has this privelege already, that part of being a superpower is being able to make people shut up about your failures (or at least strangle the headlines and then turn the information into a historical footnote), and dismiss criticism of you as ill-willed bigotry and misinformation.

I'm kinda wondering actually about this attitude... AFAIK for the most part of our interaction (and by that I mean like, from the silk road age) they're not really interested too much in showing that they're ahead by a lot and the last properly nationalistic stuff ended when the 'founder of the party' died. If this attitude were to change it is kinda concerning since we have a lot of relations regardless of the actual political situation.

Edited by YNM
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29 minutes ago, YNM said:

I'm kinda wondering actually about this attitude... AFAIK for the most part of our interaction (and by that I mean like, from the silk road age) they're not really interested too much in showing that they're ahead by a lot and the last properly nationalistic stuff ended when the 'founder of the party' died. If this attitude were to change it is kinda concerning since we have a lot of relations regardless of the actual political situation.

Knowing what an actual mess post-Soviet Russian ideology is, I feel very careful about venturing into Chinese state ideology - especially as it seems to be in flux with an apparent rise in the role of the cult of personality, and all the schizoid mess of ideas that turning random quotes into scripture entails. However, most observers point to the CCP incorporating a strong nationalist and revanchist element into its rhetoric - not to the degree of racial supremacism posited by Juche, but still. There are certainly lines of thought under which China must act tough and expansionist in order to avoid another Century of Humiliation.

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1 hour ago, YNM said:
1 hour ago, sevenperforce said:

The Space Force made its final prediction just before 5 PM EDT on Saturday: re-entry at 10:11 PM EDT plus or minus 60 minutes. At that point in time, Aerospace Corporation still had a four-hour window centered at 11:40 PM EDT, which only had a small overlap with the Space Force window. I was nervous about trusting such a narrow prediction made relatively early.

And then...it came down at 10:14 EDT. Literally three minutes later than the prediction. Like, that is GOOD. Really validates our abilities in that area and, to some degree, the whole idea of having a "US Space Command" as an independent entity. Not to get all nationalistic or anything...it's just very impressive.

You should see Roscosmos' prediction as well as the prediction made by the last TLE from 18-SPCS/CSpOC (which is later than their last public prediction). Honestly I'm wondering about the SBIRS that the major space nations have when they called it actually re-entering, wouldn't surprise me if all three have it.

temp.png

$%&@#~!

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4 hours ago, DDE said:

There are certainly lines of thought under which China must act tough and expansionist in order to avoid another Century of Humiliation.

We hit them back hard when they tried to scare us though. (granted by confusing them through dividing ourselves into two, but still.)

Still think that it's not really their way to raise up publicity of the strongest person ever to live. Have always thought that for a leader if you're never noticed by anyone but you notice everyone then you're doing it right, and I thought that's what they held as well (until they enclosed themselves and the west came up with more advanced technologies... but seriously I think they're now the ones at the tip of things again).

Edited by YNM
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On 5/10/2021 at 1:31 AM, YNM said:

Would they be continuously operated ? Does it have any effect on sensors on-board ? It is interesting development however for LEO stations, not really useful elsewhere (yet)...

Unfortunately not much is available on it in English as far as I can see at the moment beyond it existing. Everyone seems to have been distracted by the core stage reentry. There is a CGTN video that explains the solar arrays and the ion thrusters in very simple terms, but the actual purpose behind its use is currently unknown.

We will likely hear more once people actually get on board in the summer.

18 hours ago, sevenperforce said:

"With no landing pad"?!?! What in the world.

A CNN "expert" apparently claimed that the booster weighs 22000 tons, while some British tabloid's live stream claimed that the core stage was "one of the largest objects to reenter Earth's atmosphere since the Mir space station, launched in the 1960s".

I think that unfortunately, the majority of media organizations are only interested in the core stage's reentry for the ad revenue, not actually conveying useful information.

19 hours ago, JoeSchmuckatelli said:

So - as a poker player, I would definitely throw money at any situation where I thought I'd win 74% of the time.

But this wasn't poker - and it could have gone badly.

Problem is, for PRC at least,  is that they want to showcase 'top tier' space capabilities and then make a blunder like this (rookie move, as others have pointed out).  But the PRC also cannot or will not admit fault - which we've seen Elon do without losing face (to the point of both making fun of himself / SpaceX and admitting mistakes).  The PRC wants it both ways: 'we are equals' and 'people are mean to us' followed by, 'if we don't acknowledge a mistake, it never happened'.

They'd have been far better off simply saying, 'yeah, we goofed up... but the odds are in our favor and we will do everything we can to help identify and minimize risk to others now and moving forward'.  Even then, they could have pointed at the Washington farm impact and said, 'this happens occasionally in this industry, and we try to not do stuff like this, but it still happens,' rather than trying to play the bias card.

 

Bad look all around.

I don't think the bias card is meant as a defence against their decisions with the core stage as much as it was intended to be used as part of the broader effort to discredit the West as both a source of information and role model for the Chinese people.

As much as people have been voicing their concerns across the world, I don't think anyone that China is targeting with the propaganda aspect of their space program- people who make decisions, whether they be the Chinese people choosing to tolerate communist rule or third world countries considering doing business with China- really care about the core stage, because nothing happened. None of those people think its a blunder because nothing bad happened. Of course if the core stage were to hit a populated area, that changes everything. But I think even if it were to impact land, so long as no one is hurt, "no one" (the targets of the propaganda aspect of their space program) will care enough to impact China's "operations" (doing business internationally, maintaining stability and the power of the CPC at home, etc.).

Of course stating they knew it would happen from the beginning while making claims of safety only further backs up that result.

15 hours ago, YNM said:

We hit them back hard when they tried to scare us though. (granted by confusing them through dividing ourselves into two, but still.)

Still think that it's not really their way to raise up publicity of the strongest person ever to live. Have always thought that for a leader if you're never noticed by anyone but you notice everyone then you're doing it right, and I thought that's what they held as well (until they enclosed themselves and the west came up with more advanced technologies... but seriously I think they're now the ones at the tip of things again).

I think the purpose of their space program is to show that they can match the West, rather than show that they are better. If they do happen to do something first, then that's a bonus, but it is not the main priority, in comparison with the nature of the Voskhod or Apollo programs.

Interestingly, it seems the Lunar Gateway was in a very preliminary stage in 2014, and it was not decided that it would have electric propulsion. Whereas in 2014 it had already been decided that the Core Module for the Chinese modular space station would have electric propulsion and development of the thrusters themselves was already well underway. So the prize of "first crewed spacecraft to have a propulsion system other than chemical rockets" was not a deliberate design decision (at least not one in response to something someone else was going to do).

So just as NASA did not fly Ingenuity because they wanted to be the first (they did it because drones on Mars may be useful in the future), I think China's space program is not dictated by "trying to be the first/best" as much as it is doing useful things, while in the process showing everyone their society is *as* innovative as the West is.

It will be interesting to see what the use of electric propulsion leads to in the long term. There are rumors NTR development has begun in China (the only evidence is diagrams that could have been made with MS paint so I have not posted about it yet). Electric propulsion is probably on the table for use in a crewed Mars spacecraft though.

EDIT- Just to clarify, NTR development and electric propulsion on Tianhe leading to or being part of crewed Mars spacecraft development is purely my idea. There is still no detailed information on China's plans for humans on Mars, not even any academic studies of mission architecture.

Edited by SunlitZelkova
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2 hours ago, SunlitZelkova said:

Interestingly, it seems the Lunar Gateway was in a very preliminary stage in 2014, and it was not decided that it would have electric propulsion. Whereas in 2014 it had already been decided that the Core Module for the Chinese modular space station would have electric propulsion and development of the thrusters themselves was already well underway. So the prize of "first crewed spacecraft to have a propulsion system other than chemical rockets" was not a deliberate design decision (at least not one in response to something someone else was going to do).

I mean stationkeeping in NRHO is supposed to be small to nonexistent... Continuous stationkeeping (esp. prograde boosting) is only really useful in LEO.

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3 hours ago, YNM said:

I mean stationkeeping in NRHO is supposed to be small to nonexistent... Continuous stationkeeping (esp. prograde boosting) is only really useful in LEO.

I'm pretty sure it is a hard requirement in GSO.  Especially if you have a lot of fixed antennae pointing at the thing.  They get batted around by the moon, even if they don't need any prograde boosting.

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19 minutes ago, wumpus said:

GSO

Geostationary ? Geosynchronous ?

19 minutes ago, wumpus said:

Especially if you have a lot of fixed antennae pointing at the thing.  They get batted around by the moon, even if they don't need any prograde boosting.

Well NRHO is supposed to be less 'difficult' to maintain than most LLOs (apart from the frozen orbits I suppose).

Also AFAIK most ion engine usage has been to do the last orbital entry into proper GEO from GTO as well as longitude movements rather than stationkeeping... but idk. Tidal effects and perturbations are definitely a thing everywhere.

Edited by YNM
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In that case, it could also be related to their space based solar power program. Obviously not actually connected to development of SPS directly, but gaining experience with electric propulsion on another space station would help.

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