China's Space Program News Thread

[ougoah]

I'm told, although I haven't found a video of this: the Canadarm on ISS can in fact walk end over end like this too, and it did so in early days of ISS construction. Some time later ISS got a system where the arm has one end planted on a little rail mounted cart which can move around on the ISS quickly, saving the need for walking.

Can anyone confirm?

Having a closer look at it (it's a quick google!) for the rails, yes it currently rides on rails for movement. So I'm wrong on Canadarm being fixed!

I'm not sure about it using the same system for movement as the Chinese one. Canadarm is actually mobile and quite a lot more modular than the ESA and JAXA ones which I don't think have been made mobile... mostly because their tasks don't require them to be whereas the ISS is the largest station and all associated equipment equivalents (compared to JAXA and ESA projects) obviously have more funding and the arm itself needs to be more capable to deal with the size of the station - modular and mobile.

 

[Richard Santos]

I'm told, although I haven't found a video of this: the Canadarm on ISS can in fact walk end over end like this too, and it did so in early days of ISS construction. Some time later ISS got a system where the arm has one end planted on a little rail mounted cart which can move around on the ISS quickly, saving the need for walking.

Can anyone confirm?

I think you are right. According to NASA, the Canadarm 2 on ISS is arranged exactly like the arm on the Chinese space station. It has identical hands and wrists on both ends. The hands are called latching end effectors(LEE). The arm can walk end over end from mounting point to mounting point just like the Chinese arm. The mounting points are called power data grapple fixtures(PDGF). many PDGFs are distributed over the external surfaces of main ISS modules. In early days of ISS inching between PDGFs was its only means of relocation for the Canadarm 2. Later a external rail mounted trolley with a PDGF was added. The arm can latch onto the trolley and travel the entire 100 meter length of the station main truss without having to detach and walk around.

So it looks like ISS has had a more thorough implementation of the same idea since 2001.

however, the schematic of LEE and PDGF shows the interface is not androgynous. So two Canadarms can not shake hands or grasp one another to extend their reach. If the Chinese arm can do that, then that would still be a new feature.

The Canadarm 2 was installed in 2000, so it must have been designed in the early to middle 1990, before universal aerial bus was a thing. So the concept of connecting arms end to end and supplying power and signal to each section probably would have been electrically more challenging using likely methods of that time.

 

[Temstar]

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[horse]

I'm told, although I haven't found a video of this: the Canadarm on ISS can in fact walk end over end like this too, and it did so in early days of ISS construction. Some time later ISS got a system where the arm has one end planted on a little rail mounted cart which can move around on the ISS quickly, saving the need for walking.

Can anyone confirm?

I think that is total bullshit.

If that thing was able to do that, we still be hearing about that in Canada.

No.

Just another case of butt hertz.

 

[ougoah]

I think that is total bullshit.

If that thing was able to do that, we still be hearing about that in Canada.

No.

Just another case of butt hertz.

Nope only denying reality is the surest form of butthurt. Some of us weren't aware that Canadarm was mobile. It is and has always been. It might be slightly different to the Chinese one and did not benefit from more modern electronics technologies when it was designed in the 1990s but it's certainly mobile as a matter of fact and it's certainly engineered to be modular.

 

[horse]

Nope only denying reality is the surest form of butthurt. Some of us weren't aware that Canadarm was mobile. It is and has always been. It might be slightly different to the Chinese one and did not benefit from more modern electronics technologies when it was designed in the 1990s but it's certainly mobile as a matter of fact and it's certainly engineered to be modular.

I never seen the Canadian space arm "walk" like the Chinese are planning to do.

To read something like this, 2 decades later, that is butt hurt, disguised as disinformation.

Why even bring it up, something a couple decades old?

They could not stand the Chinese building a better space arm?

They could not do it back then, but insists that the Canadian arm was modular.

What is the point of that?

Mobile is mobile. Modular is modular. Butt hurt is butt hertz.

 

[SimaQian]

I wonder how the Chinese engineers validate the design and testing of the robotic arm. Nothing tangible evidence has come up so far to indicate it is working. A 10 meter robotic arm here on earth has a significant weight, let alone can carry 20 tonnes load. With a detachable base with less than 0.5 sq meter of base area, thats difficult to put up without a static support elements.

Let us see if this is really working. If this really works, this would be probably the template for space robotic arms in the future.

 

[Temstar]

I wonder how the Chinese engineers validate the design and testing of the robotic arm. Nothing tangible evidence has come up so far to indicate it is working. A 10 meter robotic arm here on earth has a significant weight, let alone can carry 20 tonnes load. With a detachable base with less than 0.5 sq meter of base area, thats difficult to put up without a static support elements.

Let us see if this is really working.

Yes the arm does get tested on the ground, there's a special setup with wheels and wire harness for this purpose:

 

[ougoah]

I wonder how the Chinese engineers validate the design and testing of the robotic arm. Nothing tangible evidence has come up so far to indicate it is working. A 10 meter robotic arm here on earth has a significant weight, let alone can carry 20 tonnes load. With a detachable base with less than 0.5 sq meter of base area, thats difficult to put up without a static support elements.

Let us see if this is really working. If this really works, this would be probably the template for space robotic arms in the future.

The design is obviously well tested and validated if they've decided to use it and presumably have the actual thing already built with plenty of prototypes built and tested in the past well before the space station arm is sent up (no doubt the actual arm to be used is completed already).

How do they validate the design and engineering? Many processes too difficult and complex to simply guess at but they exist. How do they build those underwater tunnels that deal with seismic activity between Macau and HK/ mainland? I don't know but the methods and testing exists and the experts do know. Same with this. They don't need to broadcast the details on how it's tested. No one does that and when they do, it's usually for entertainment or education. The vast majority of humans can barely do simple maths, they won't understand the beginning of the technical aspects behind testing a space arm.

The tangible evidence to show that it's working isn't just in the prototypes shown but the fact they've openly stated this is the case. CPC don't openly state anything they know isn't true and can't be backed up if challenged... not that something like this would be challenged or worth challenging as opposed to political nonsense being thrown around all the time across the world.

They showed the animations and reported officially this is the planned arm and how it is planned to function. This is confirmation everything to do with design and testing has been done years ago and the actual unit itself is probably also completed and basically the station is being constructed with the second module just sent up and docked. The arm itself will be transported in some future launch.

The differences between testing environment here on earth and in space is no doubt accounted for. This would be apparent to a high school kid failing physics, not a question or doubt to give the engineers at CNSA and contractors. You also should realise that earth conditions are much more "difficult" in terms of load. For one thing the arm being tested on earth has to deal with self weight which I would imagine is substantial. I could "propel" a 100KT object in space but it would be impossible to do that on earth. Every question pertaining to loading is FAR easier in space. The arm could be designed to work with the weight of a 10kg object here on the surface but could manipulate a 10T object in space. I think you have it the other way around.

 

[Richard Santos]

Yes the ends are androgynous, besides the walking this point is also demonstrated in the video when they showed that the big arm on Tianhe and the small arm on Wentian is in fact capable of being joined together to form one super long arm.

This also means options like "dextre" style fingers and oh say a scissor style attachment are possible.

looking more closely at the video, I think the hands are not androgynous, Clearly it is a male connection of the space station hull, and a female connection on each robot hand. Moreover, superficially the male connectors on the station hull looks very similar to the power data grapple fixture (PDGF) on the ISS hull that Canadarm 2 uses, and the female connection on the hand looks very similar to the Latching Ednd Effector (LEE) of the Canadarm2. So I am thinking this arm is more similar to Canadarm 2 than I first thought.

we know the Chinese adopted some ISS standards such as the the International Docking system Standard (IDSS) androgynous docking system for their own next generation manned space craft and the tianwen space station. I wonder if the connectors on the Chinese arm is also built to an ISS standard.

Also I realized it is can still be possible for two female hands to grasp together by using a back to back double male connector between them. Maybe that is how the Tiamhe and Wentian arms are linked together.