Seeking expert on LAR and sep systems 1

[Calvin Murphy]

Hello everyone,
I'm new to this site, and I'm hoping to find anyone who has experience with launch adapter rings (LAR) or their installation.
If you can answer any of the questions below, please reply or message me.

• How common is it for components on the satellite to be located within the inner diameter of the LAR?
• Are there consistent guidelines for where those components can be located within the LAR on the satellite?
• How common is it for LARs to be insulated with MLI or foil, and how much of the LAR is guaranteed to be exposed?
• During installation, are they coated in any lubrication that might still be present in space?
• Are the LAR's manufactured by launch providers and left to clients to install, or are clients responsible for designing their own LARs that will interlock with the one on the rocket?
• Is there a way to track which LAR shapes and sizes are in space currently?

Ultimately, this information will be used to help clean up space debris.


All pictures are from publicly available payload user interface guides.
Picture of LAR pair and clamp-band for context:


Cross sections of some sizes of LAR:

 

[rb1957]

• How common is it for components on the satellite to be located within the inner diameter of the LAR?
  Do you mean "does the satellite fit within the cylinder made by the LAR ?" ... no, how many blistered fairing are there ? (lots) or
  "does the satellite have components that stick down through the LAR separation plane ?" ... don't know, something I'd expect the launch vehicle would define.
  
  
• Are there consistent guidelines for where those components can be located within the LAR on the satellite?
  Arh, I think you're focusing on option 2 above. I'd expect these would be controlled by the launch vehicle.
  
  
• How common is it for LARs to be insulated with MLI or foil, and how much of the LAR is guaranteed to be exposed?
  I'd expect that the LAR would not be covered by foil, as in your example, but this would be controlled by the launch vehicle.
  
  
• During installation, are they coated in any lubrication that might still be present in space?
  I'd suspect not, fluids would probably misbehave in space; your example looks like anodised Aluminium.
  
  
• Are the LAR's manufactured by launch providers and left to clients to install, or are clients responsible for designing their own LARs that will interlock with the one on the rocket?
  Either/Or ... I'd suspect the the launch vehicle would provide the LAR, or alternatively some interface geometry between the launch vehicle and the satellite client. The satellite client may be allowed to install a permanent fixture on the launch vehicle (something that would stay with the launch vehicle after satellite deployment), and build the satellite separation plane somewhere else.
  I think it is unlikely that a launch vehicle manufacturer would want you messing with their structure below some defined geometry.
  But, because your sentence runs on, the satellite will have some interface with the LAR, which I'd've thought would be fixed to the satellite
  
  

 

[Calvin Murphy]

I'm really not sure why you decided to waste your time answering each question with basically, "I don't know."
I'm going to assume your intentions were good, although FYI you did come off somewhat snide here and there.

Here's a few things you should know:
Dry lubricants exist and are commonly used in space applications.
Fluids definitely misbehave in space, not probably.
There's a difference between a run-on sentence and a complex sentence.
Postulating is not helpful and can even have negative consequences if someone mistakes it for fact and acts on it.
Your mention of blistered fairings was a non-sequitur, and to imply that there are lots of them seems illogical. If they are blistered enough to impinge on the payload volume, they have severe defects in the composite layup and should not be flown, which means there should not be lots of them.

I'm new to this site, but judging by the numbers under your name, you've been doing this for a concerningly long time.

 

[rb1957]

so glad I could help.

if you are working with a launch vehicle, then they will have a manual defining what you ask. If you haven't chosen a launch vehicle, then I suggest "there is a cart and a horse, and you're putting the cart before the horse".

Have a nice day.

 

[IRstuff]

If you are truly interested in the subject, I suggest that you search for "ESPA ring" and "ESPA Grande ring" You can tack on "manual" and get information such as https://www.moog.com/content/dam/mo...tructures/moog-espa-users-guide-datasheet.pdf which would have answered most of your questions

 

[Calvin Murphy]

so glad I could help.

if you are working with a launch vehicle, then they will have a manual defining what you ask. If you haven't chosen a launch vehicle, then I suggest "there is a cart and a horse, and you're putting the cart before the horse".

Have a nice day.

Well, I am not working with any singular launch vehicle, so there is no cart being put before any horse. The problem I have to solve is agnostic to launch vehicle selection.
I also made it clear that I already know about payload user interface guides. That's where I got my pictures from, as I stated.

 

[Calvin Murphy]

If you are truly interested in the subject, I suggest that you search for "ESPA ring" and "ESPA Grande ring" You can tack on "manual" and get information such as https://www.moog.com/content/dam/mo...tructures/moog-espa-users-guide-datasheet.pdf which would have answered most of your questions

I have already read this manual along with many others. The images in my initial post are from a few of them, as I stated. Also, the question was about LARs, not ESPA rings.

 

[Ng2020]

It's engtips.com not engfreebindingadviceforsafetycriticalapplications.com.

 

[Calvin Murphy]

It's engtips.com not engfreebindingadviceforsafetycriticalapplications.com.

This is totally based. I completely agree.

 

[Calvin Murphy]

It's engtips.com not engfreebindingadviceforsafetycriticalapplications.com.

Do you have a specific recommendation for a real website or service that would be better for this kind of question?

 

[3DDave]

Try the companies that supply LARs.

 

[Calvin Murphy]

Try the companies that supply LARs.

Thank you, 3DDave. That is a good idea. I will try to reach out to them. The only reason I have not already is because large space companies are often difficult to get information from if you are not already a high value customer. Still, I will try.

 

[rb1957]

apologies, but I have no idea how you can apply whatever it is you'll do with this if you don't have a target launch vehicle. You can't design something that'll fit all rockets.

If you have a novel concept, then design for a fictitious rocket if you can't get real data. I have downloaded the Ariane6 user manual from somewhere ... here are a couple of relevent pages from the index.

 

[Calvin Murphy]

apologies, but I have no idea how you can apply whatever it is you'll do with this if you don't have a target launch vehicle. You can't design something that'll fit all rockets.

If you have a novel concept, then design for a fictitious rocket if you can't get real data. I have downloaded the Ariane6 user manual from somewhere ... here are a couple of relevent pages from the index.

Thank you, and my apologies for not explaining better earlier. I am designing grippers for a satellite servicer that will grab onto the remnant LARs of other satellites. Once docked, the servicer can take over maneuvering for satellites that are low on fuel or unresponsive, towing them to a better orbit. This is part of a real project my company has been developing over the past few years.

The previous gripper design was developed by another company overseas, but it performed poorly in simulations. As a result, we’re starting over from scratch, including redefining the solution space, as the assumptions and reasoning behind the previous design weren’t well documented. A key challenge in this effort is determining where we can reliably and safely grab a LAR, given the variety of cross-sectional profiles and satellite designs.

From reviewing numerous launch vehicle user guides, I’ve found that internal keep-out zones within LARs are extremely rare. In theory, this suggests payload developers could use the entire internal space up to the separation plane (and often beyond) for thrusters, sensors, or other components, potentially obstructing more favorable grasping features inside. However, I’ve yet to see pictures of actual satellite designs that do so. Interestingly, I have come across two physical prototype LAR grippers from research projects that utilized the inner rim of the LAR, which interacts with actuators during deployment. I’ve tried reaching out to the authors of these projects to understand what gave them the confidence to grab the LAR in this way, but I’ve been unable to get responses from the limited contact information available.

Grabbing only the outer rim is far from ideal, as it protrudes only 10mm and often has minimal clearance (around 50mm). Moreover, I recently learned that molybdenum disulfide dry lubricant is often used during clamp-band installation, which makes friction on this already difficult feature an additional concern.

My asking questions without clear or readily available answers has been frustrating, particularly when I’m tasked with leading the design effort. It can feel daunting to face situations where expertise is rare or answers are prohibitively expensive to obtain. That said, I now realize that you and others here have been genuinely trying to help, even if I initially misinterpreted your tone. I apologize for being abrasive earlier and appreciate the time and effort you’ve taken to respond.

 

[rb1957]

hey, NP ... all grist for the mill !

I think it is going to be hard to figure out a generic interface. Particularly an attachment that will allow you to control the satellite.

what are you planning on doing with these re-captured things ? oh, you want to refuel them and keep using them ? That sounds much easier to say than do ! Satellites fail for many reasons. And fuel tanks are not made (or accessible) to be easily refilled. If you were going to de-orbit the thing, then just harpoon it ... that is easier said than done too ... since you have to create the reaction loadpath that'll allow the harpoon to sink in.

If the LAR ring was clear you could insert an expandable ring (the opposite of a jubilee clip) but doing anything beyond gripping the thing is very difficult ... I don't think refueling is a viable idea ... unless the satellite was designed to be refueled (most aren't). Restarting the satellite is another "doomed" mission. The most you might to is transport it to a space station where people can get hands on and diagnostics. But even transporting an unknown mass and CG is difficult ... but not impossible.

 

[SWComposites]

Seems like you are going to need a gripper that simulates the original attachment configuration, somehow, which might not be consistent between vehicles.

Also seems like you should be searching on LinkedIn or similar for retired experts in LARs that you could hire part-time for advice.

Does your company have any connections to the various rocket and satellite manufacturers? Seems like you are going to need very specific detailed info.

And yeah, posting the info in your last post at the start would have got the discussion onto a much better track.

 

[Calvin Murphy]

Our current mission does not aim to refuel the satellite, just take over maneuvering like a jet pack. That way, we can get more usefulness out of satellites that are already up there. Northrop Grumman previously proved the concept with the MEV-1 in 2020 by docking with the thruster bell of a stranded satellite. https://en.wikipedia.org/wiki/Mission_Extension_Vehicle We're not Northrop, but we do plan on taking it a step further than they did by accommodating a larger variety of satellites by docking with launch adapter rings instead, which are more common.

Most progress in the space industry happens in small incremental steps. I'm sure some day we'll refuel a satellite by some means. First, we need customers to see the usefulness of satellite servicing before anyone decides to incorporate a purpose-built refueling port.

Since you mentioned harpoons, you might enjoy knowing that Airbus has actually tested this concept: https://www.surrey.ac.uk/news/harpoon-successfully-captures-space-debris Unfortunately, the idea has faced a lot of criticism, some warranted, some not.

 

[Calvin Murphy]

Seems like you are going to need a gripper that simulates the original attachment configuration, somehow, which might not be consistent between vehicles.

Also seems like you should be searching on LinkedIn or similar for retired experts in LARs that you could hire part-time for advice.

Does your company have any connections to the various rocket and satellite manufacturers? Seems like you are going to need very specific detailed info.

And yeah, posting the info in your last post at the start would have got the discussion onto a much better track.

Looking on LinkedIn is a very interesting idea. Thank you.

I don't have much insight into our companies connections, but I will see if any of them might be worth asking. Thank you for the idea.

And yeah... I will use this feedback to fine tune my internet navigation protocols.

 

[GregLocock]

A large ring containing an inflatable collar that goes round the outside of the LAR, textured to pierce the dry coating. It won't fit every size obviously.

 

[Calvin Murphy]

Inflatable collar that goes round the outside, textured to pierce the dry coating. It won't fit every size obviously.

Thank you for the reply. This and similar ideas have come up a few times, and it's one I enjoy. Unfortunately, it isn't possible with our current system.