Discussion of Optimus Prime/Octograbber Machine for F9 Securing

[mongo]

Question: what exactly does the Octograbber do? Guessing it somehow secures the upright Stage 1 on the deck so it doesn’t tip over? I’ve seen a photo of it but not I guess when it’s in use and can’t picture how it works.

BTW I did feel a bit nervous when we were waiting to hear if the satellite was in a successful orbit. Seemed like forever. Kind of like when Stage 1 is landing and the images goes out ...

View attachment 333933

and you wait to hear applause from mission control. It’s really amazing how quickly these satellites get deployed. Realize we get spoiled when then it’s something with a different orbit. I was still glued to the screen for the Roadster though and it was so worth it.

My understanding:
Watch

again. Octograbber prevents the rocket sliding all over the deck. It's heavy and sits under the rocket grabbing the legs.

 

[ecarfan]

Question: what exactly does the Octograbber do? Guessing it somehow secures the upright Stage 1 on the deck so it doesn’t tip over?

That is my understanding.

 

[Grendal]

The machine grabs onto the same hold points that the rocket has for launch hold down.

 

[SMAlset]

Thanks for the replies. I love the blooper reel. Never get tired of watching it. Like the obvious message that nothing difficult like this comes easy and makes success all the more sweet.

Grendal that's the first pic I've seen of it actually attached to the rocket. So is this octoframe somewhere on the barge out of the way until the rocket stage lands and then scoots out by remote control or some kind of programming to position itself directly underneath the middle of the rocket, extending arms up to clamp on to the rocket? I know it's not centered on the landing ring when the rocket is coming down to the drone ship. Just don't think I've ever noticed it in any live landing videos. Eyes more focused on the launch/landing and not what happens after to get it to port. I guess I haven't seen too many photos of the first stage returning to port come to think of it. Pretty fascinating piece of equipment that needed to be designed from scratch I assume since no one else had landed rockets like this before, nor on a ship on the ocean either. Would love to know more of the background on the design and manufacture of it.

 

[ecarfan]

I believe the octograbber lives in an enclosed structure at one end of the ASDS and is brought out after the stage has landed. I do not know if that process is all handled remotely or not. I assume so. SpaceX has not commented on it or released info about the octograbber. I wish they would at least tell us that the correct name for it is!

 

[skitown]

I don't understand what holds the octogabber to the deck though... (if at all) I would think that unless the octograbber was super heavy it wouldn't add enough mass/weight to keep the F9 from tipping over unless it was tethered to the decking too. Perhaps some weight is better than none. Or perhaps it creates enough surface area friction to prevent F9 from sliding around like we've seen in some rough wave footage. F9's four landing legs don't have a lot of surface area in contact with the deck by themselves; so perhaps this is the deal. Anyone have a theory they like?

 

[Electroman]

How will the Octograbber move in position automatically, and know exactly where the legs are to latch onto it precisely?

 

[Nikxice]

This is not my work, but perhaps one of the better photos of a stand alone Octograbber, along with speculative notes. I'd be surprised if we were to learn it's totally automated. Can't rule it out, but it would likely entail using several cameras to maneuver into position, then precisely latch onto the four attachment points. Brings to mind Elon describing the complex task of threading a wire harness through a new Tesla. Up to this point, some jobs can still be more efficiently accomplished by humans versus robots.

 

[SMAlset]

Given SpaceX can already develop reusable rockets, land them back on land or at sea, and put a Roadster into space in the coolest way possible and let’s not forget, connect with the ISS, I’m thinking they came up with an interesting way to anchor the rocket stage to the Octograbber and that to the deck. Never great in school with science and didn’t have to take physics so forgive me if this is totally implausible, but any chance it could be done with electromagnets or some type of vacuum force? Anyone know if that yellow beaded cord is a power source?

I was under the impression that the drone ship was unmanned and controlled remotely from a safe distance. Especially in light of the past early crashes onto or into it, which the risk of is still present should something go wrong. If so, that would mean that there isn’t a manned crew onboard to maneuver the Octograbber in place and of course there’s never any guarantees where exactly on the deck the Stage will set down, just hopefully somewhere within the targeted landing circle. I think in that case it’s likely it’s also remotely controlled or has some built in intelligence that can hone in on the underbelly of the booster rockets and set about clamping on to the rocket and whatever else it does to secure it in place.

 

[mongo]

Given SpaceX can already develop reusable rockets, land them back on land or at sea, and put a Roadster into space in the coolest way possible and let’s not forget, connect with the ISS, I’m thinking they came up with an interesting way to anchor the rocket stage to the Octograbber and that to the deck. Never great in school with science and didn’t have to take physics so forgive me if this is totally implausible, but any chance it could be done with electromagnets or some type of vacuum force? Anyone know if that yellow beaded cord is a power source?

I was under the impression that the drone ship was unmanned and controlled remotely from a safe distance. Especially in light of the past early crashes onto or into it, which the risk of is still present should something go wrong. If so, that would mean that there isn’t a manned crew onboard to maneuver the Octograbber in place and of course there’s never any guarantees where exactly on the deck the Stage will set down, just hopefully somewhere within the targeted landing circle. I think in that case it’s likely it’s also remotely controlled or has some built in intelligence that can hone in on the underbelly of the booster rockets and set about clamping on to the rocket and whatever else it does to secure it in place.

All supposition:
I like electromagnets, but probably something more mundane like high coefficient of friction pads on the bottom that deploy after attaching the Falcon 9. Could even be the treads themselves. Plenty of rocket mass to use for friction. Anything better than the ends of the landing legs (which are likely designed to slide during leg compression) is an improvement.

Cable wise: command and power cable from it to the garage. Remote control with real time camera feeds.

 

[ecarfan]

I'd be surprised if we were to learn it's totally automated.

I can’t say for sure, but my speculation is that it is fully automated or at least partially automated and remotely controlled by humans.

We know that there are no humans on the ASDS during booster landing, obviously, and that the support vessels are at least several kilometers away. When seas are calm, there is no need to quickly anchor the stage to the ASDS deck. But when seas are rough the need is urgent, yet it would be hazardous to transfer humans to the ASDS under those conditions; the deck is moving vertically 5 to 15+ feet in a few seconds. In that situation the octograbber has to move into position and do its job as quickly as possible.

My Teslas can parallel park themselves and maneuver with an accuracy of about +/- 4 inches. It seems plausible that the SpaceX octograbber can do even better.

 

[ggr]

I believe the octograbber lives in an enclosed structure at one end of the ASDS and is brought out after the stage has landed. I do not know if that process is all handled remotely or not. I assume so. SpaceX has not commented on it or released info about the octograbber. I wish they would at least tell us that the correct name for it is!

I believe its name is "Optimus Prime".
SpaceX debuts 'Optimus Prime' Robot, successfully recovers Falcon 9 1029 for the second time

 

[bxr140]

All supposition:
I like electromagnets, but probably something more mundane like high coefficient of friction pads on the bottom that deploy after attaching the Falcon 9. Could even be the treads themselves. Plenty of rocket mass to use for friction.

Completely agree.

There are two very simple objectives of the octo—keep The Thing from tipping over and keep The Thing from sliding around—which can be satisfied by the most basic of KISS solutions.

—Wider effective footprint than the three landing legs better resists tipover
—Heavier octo+rocket system mass lowers the system cg which better resists tip over
—Heavier system mass increases friction force which better resists sliding around
—As @mongo notes, the material properties of the octo ‘feet’ (whatever the are) will certainly result in a higher friction coefficient than the landing pads which are likely designed for slippage on impact

 

[mongo]

Completely agree.

There are two very simple objectives of the octo—keep The Thing from tipping over and keep The Thing from sliding around—which can be satisfied by the most basic of KISS solutions.

—Wider effective footprint than the three landing legs better resists tipover
—Heavier octo+rocket system mass lowers the system cg which better resists tip over
—Heavier system mass increases friction force which better resists sliding around
—As @mongo notes, the material properties of the octo ‘feet’ (whatever the are) will certainly result in a higher friction coefficient than the landing pads which are likely designed for slippage on impact

I'm with you on CG lowering and anti-sliding aspects, but I don't think Octo/ Optimus Prime provides a wider footprint. It fits in the gap between the legs and as @Grendal 's post #38 shows, it's smaller than the tri-QUAD-leg footprint.

EdIt: 4 not 3, 5 is right out.Thanks for the correction @Nikxice

 

[Nikxice]

Believe there has always been 4 landing legs on SpaceX's booster rockets.

 

[bxr140]

EdIt: 4 not 3, 5 is right out.Thanks for the correction @Nikxice

Yeah, total duh moment on that one!!!

 

[SMAlset]

I believe its name is "Optimus Prime".
SpaceX debuts 'Optimus Prime' Robot, successfully recovers Falcon 9 1029 for the second time

Thanks for the article. However the article says that Optimus Prime is one of the names given to it by fans. It would be nice to know what SpaceX uses. Suprised the press hasn't asked Elon or Gwen yet.

 

[scaesare]

I believe its name is "Optimus Prime".
SpaceX debuts 'Optimus Prime' Robot, successfully recovers Falcon 9 1029 for the second time

I still prefer "Roomba".

 

[SMAlset]

I'm with you on CG lowering and anti-sliding aspects, but I don't think Octo/ Optimus Prime provides a wider footprint. It fits in the gap between the legs and as @Grendal 's post #38 shows, it's smaller than the tri-QUAD-leg footprint.

EdIt: 4 not 3, 5 is right out.Thanks for the correction @Nikxice

From the photos yes we can see that it is narrower and would have to be to insert itself inbetween the landing legs and position itself underneath Stage 1. Once clamped on though it does provide a solid base for Stage 1 to make it anti-tip. I wonder what the type of calculations are to determine how to achieve this. LOL here's a realworld situation that comes to mind related to the holidays coming up -- halloween or christmas. If you want to stablize a standing prop in the yard from wind forces, how would you design the base. In the octograbber's case in addition to wind force there's what...tilt and roll from the ocean's wave action. It's not done with legs on it that extend beyond the footprint of the standing piece as we've seen. Weighted piece for sure, and wonder how much the shape of it plays into it (how tall to make it as well).

 

[mongo]

From the photos yes we can see that it is narrower and would have to be to insert itself inbetween the landing legs and position itself underneath Stage 1. Once clamped on though it does provide a solid base for Stage 1 to make it anti-tip. I wonder what the type of calculations are to determine how to achieve this. LOL here's a realworld situation that comes to mind related to the holidays coming up -- halloween or christmas. If you want to stablize a standing prop in the yard from wind forces, how would you design the base. In the octograbber's case in addition to wind force there's what...tilt and roll from the ocean's wave action. It's not done with legs on it that extend beyond the footprint of the standing piece as we've seen. Weighted piece for sure, and wonder how much the shape of it plays into it.

It's only a solid base if it also attaches itself to the deck. Otherwise, the lines of stability are still connecting the ends of the Falcon's landing legs (no extension legs on Octo). If the static+ dynamic forces so outside that square, it will tip. The weight and low position of octo makes it more stable, but if you took the legs off, it would be way tippy. If where ever the combined CG of the Falcon + Octo is went outside the Octo perimeter (due to barge tipping), over she goes.

In addition, the lever arm that the wind gets on the top of rocket vs half the width of Octo is huge and a much worse setup compared to height vs landing leg mid span (minimum distance to the contact square 0.71 of horizontal leg distance).

For outside decoratations, I use guy wires, or a really heavy base.