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SpaceX Will Catch Super Heavy Booster With Launch Tower Arm

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Elon Musk tweeted that SpaceX will try to catch the Super Heavy Booster with the launch tower arm. Large grid fins will take the load.

This will save the cost of legs and enable the booster to be ready for re-launch in under one hour.

The landing legs on the Falcon 9 weigh about 2000 kilograms. The Falcon Heavy landing legs are about 3000-4000 kilograms and Super Heavy Booster would need landing legs that weigh about 6000-8000 kilograms.

The Super Heavy Booster will be able to hover. This will make it easier for a precise docking style landing.

Ercxspace has a rendering of what it a tower arm catch of the Super Heavy booster would look like.

SOURCES- Scott Manley, Marcus House, Elon Musk , Ercxspace
Written By Brian Wang, Nextbigfuture,com

54 thoughts on “SpaceX Will Catch Super Heavy Booster With Launch Tower Arm”

  1. This is actually a brilliant way to save weight.
    There is much to gain by making it work, so I expect Elon will make it work.

  2. Extra fuel for a safe landing/safety margin can be whittled down as they perfect the landings. Extra weight for legs will always be there.

  5. I doubt it could land in high winds, particularly when empty. It's basically an empty coda can when it is landing.

  6. They won't be launching in gale force winds. They know the wind conditions at launch and the booster will be back in ~5-7 minutes.

  7. The booster is not designed to do 90 deg flip maneuvers. That was the 2nd stage (Starship), and that too was while falling (or moving sideways), not while hovering. The booster's flight path should be much more similar to the F9 1st stage.

    Also, while it has the potential for multi-G when it's somewhat empty, at that point you have a lot less fuel, so you don't want to spend more than you have to. You also don't want to make sharp movements, because they're more difficult to control. So don't expect more than 1-2 G in practice, probably less than that.

    Btw, the thrust-to-weight of the full stack when fully fueled is ~1.35 by my calculations with Wikipedia's numbers. So lift-off acceleration is less than 1 G.

  8. We tend to think of large things as sluggish things (fraction of a G acceleration, seconds to respond). But the SH booster has multiple G vertical acceleration, fractional second response time. It can also execute the flip maneuver (90 deg pitch change) in about 1.5 seconds…so it has lots of lateral power and control compared to the wind trying to move something that weights many tons. F9 appears to land within a 10 ft circle and it has not ability to hover and correct. SH booster should be able to do much better.

    The arms that move to catch the thing will have powerful electric motors that can move them very rapidly and with precise control

    We are used to seeing things that move fast enough for a 1G environment. Fast sensors, fast motors, fast control loops will result in big mechanical systems that move with 10G acceleration.

  9. The ugly issue is a pad landing with legs allows for some slop. Getting grabbed by an arm, or landing directly on the launch mount, means you need ludicrous amounts of RCS thruster power for control due to wind gusts during landing/hover. There's also the existential risk of damage to launch infrastructure from a bad landing, whereas a pad landing with legs can be mostly be corrected with a bulldozer and a concrete mixer.

    Even on Elon Time, I find it hard to imagine the speed of reflight being so high that arm grabbing to allow faster stacking really improves the operational aspects, compared to hauling the booster over on SPMT's to the launch tower crane after landing.

  11. Standing there with my mouth open* would result in my catching just as many fish as my usual technique.

    *Note, that is not me in the photo. My mouth is not that big.

  13. I'll gladly eat crow if I am wrong on this.

    But as I said elsewhere: let them try.

    It's 0 risk for everyone but E. Musk's funds (unless you are standing below it on a test). And as you said, it might actually work.

  14. Ten years back, the idea of landing a first stage for reuse was ludicrous. Landing on a pitching, rolling barge? Even more so.

    Musk has done the ludicrous and impossible, and made it commonplace.

    If he's going to try this – I'd say he's got a 90% chance of getting it right on the second try.

  15. They currently have 3 types of F9 launch, no fuel/burn up, less fuel land on barge down range, enuf fuel to return to launch site. But that is dependent on sat mass and orbit, so perhaps SH is so big they won't hit the limit or will just use two (very cheap!) launches instead. Or, huge barge that can take whole launch complex to sea and not have to return the booster, just land a SS there too.

  17. I recall suggesting this (here) as an option for the Falcon 9 about 5 or 6 years ago.

    Essentially, four towers connected by 4 cables to form a box/square.

    Have two moving cables stretched between the north-south, and east-west stationary cables.

    Wherever the rocket comes down within the square, the moving cables converge to intersect under hooks; here, the grids.

    Move rocket to the launch tower, built next to the north-South outside cable.

    This thing is so massive though! Might need to be trusses or beams.

  18. If they want to land it in the ocean, They will probably have to launch from Florida or Texas and and land it on a rock they lease respectively either by the Bahamas or in the Gulf. They may not be able to make a barge big and stable enough for the 1st stage landing on the tower arms.

  21. "Launching rockets trump Power Point and in-development ones any time." How about rocket engines? BO has an apparently bigger than Raptor gas engine just into productioin, plus very small very variable H for landing on Moon, plus mid range H for second stage, Space tug to be? These are timed to be ready according to a rational plan of incremental bootstrapping of development into real economic might. I hope Musk cargo biggie makes this all easier!

  22. "everyone will dance with whatever polka Elon Musk composes." I like his rockets, but he is not quite the only one with ideas in the world. O'Neill ideas predate Musk, do not rely on better rockets, altho they certainly help. We waited to do O'Neill because we are collectively slow thinkers, no other reason. We should have been doing simple (compared to Mars) rovers on Moon in 70s, not *soon*.

  23. Launching rockets trump Power Point and in-development ones any time.

    Which so far means everyone will dance with whatever polka Elon Musk composes.

    Which is fine, we really need better, cheaper reusable launchers for whatever we plan to do in space.

  24. A hovering booster is most definitely a part. A claw grabbing the booster is most definitely a part.

  25. The launch tower is a bit high value to risk, are the savings from the lack of landing legs justifiable. The need for a 1hr reuse is a silly proposition for a few decades, de-risk the whole thing and just have a second booster on hand while you reposition the first.

  27. The plan for some time now has been that SS/SH will launch and land from a barge facility. The idea being that the barge launch/landing facilities could be positioned a few miles offshore of any coastal area while avoiding hazards and nuisances to the nearby inhabited areas on land, such as accidents and sound.

  28. That's correct, it can't. The reason it can't is that even at lowest throttle setting on one engine it produces too much thrust to hover. That's the primary reason for the "hover-slam" landing procedure F9 employs, not merely to save fuel.

  29. I still have my doubts about the degree of control and precision they can have with the landing spot.

    But I guess we will see. They have shown they can adapt quickly to whatever situation arises.

    For example, they will re-add helium tank pressurization after the SN8 landing R.U.D. due to a loss of fuel pressure, after stating they didn't have nor wanted that (helium is an expensive and finite resource). And this a few weeks after said R.U.D.

    I guess they will fix that problem and remove helium later. Or not. They tend to go with whatever works.

  30. I think this is just E. Musk doing his by now usual "setting the bar high" for his engineering crew.

    Something that ends up with them delivering something still amazing, but not as miraculous.

  31. I wasn't under the impression that boosters are designed to be grabbed by "The Claw". Obviously SpaceX has a good idea of what they are doing but this seems error prone.

    Put another way you need to design a system that works 10/10 times, not 9/10 times. The economics of space access now revolve around guaranteed reuse but reuse is only as likely as the most failure prone part of the launch. This looks failure prone and the cost to replace a booster is really high.

    A chain is only as strong as its weakest link and this looks like the weakest link.

  32. We will get to In Space Resource Use and In Space Manufacturing soon after we start doing what I and O'Neill have been demanding since 1977, long before Musk. Bezos has the right plan, NASA getting closer as they ponder whether to do stuff on Moon or ship stuff to Gateway Halo for ISM. People like Musk have rights, but planet gravity prisons are wrong, esp ones like Mars where we are not even there!

  33. That's not Musk's concern at this point in time. His concern is build and operate the launchers, so that others can get the equipment in place, and do the ISRU. So don't complain that Musk is going with launching. We won't get ISRU any other way.

  34. Yes, I actually knew that. The question is about all launches, not just the first few. Check out the plans! Getting to greater growth curve than linear based upon launch is a biggie.

  35. Can't do In-Situ-RU if you can't get the equipment to the Situ. Gotta launch the first stuff from Earth – no way around that.

  36. BO has a fast moving very large ship for New Shep booster. It has vanes that interact with the *passing* water to very quickly adjust level, far faster than by pushing on a stationary barge with water thrusters. And the rocket uses less fuel slowing down to the moving ship.

  40. O'Neill sez the best launch is no launch. ISRU instead. Musk has launched refuel. Sigh.

    "Is the surface of a planet the right place for an expanding tech civilization?" Please attempt a definitive answer based only upon KISS principle.

  41. The very small BO rocket they are testing this on looks much like Musk F9 booster coming down, but stops for a few seconds several meters up, then down in a few more secs. Also, they perhaps will use any extra fuel on the way up afterwords, from the Moon usu. Don't know if BO New Shep will hover or not? May be that any hover uses fuel that would be overall safety margin, but is avail once you are *almost* there, know you want to land, still have the fuel, and would crash if did not use!

  43. How much extra fuel does this manouver require? The booster has to hoover and move laterally into position. Will this be less fuel than the weight they save by not having legs?

    Also, I thought that the landing barge was a great advantage..? Allowing them to catch the booster anywhere in the world, but now they will be limited to the launcing pad(s) only?

  45. Well, to their advantage in controlling this, the steel construction booster is extremely heavy even when empty; Despite of the large surface exposed to the wind this could be enough to cancel out wind effects in reasonable weather conditions short of a full gale. It is not a light zeppelin but a heavy lump.

  46. But hover cost fuel, for a 110 ton super heavy booster with 330 Isp it is 330 kg pr second. If you trade the legs weighing 7000 kg for fuel, you have 20 seconds to dance around, or break the rocket.

  49. It's actually easier to be more precise and accurate with Super Heavy than the F9 first stage because of the larger mass and throttlability of the Raptors.

  50. If the idea would be to hover and laterally translate into position next to the tower, I'd be a bit concerned that there'd be a ground effect increase in effective lift that would change when it moves over the significantly higher launch platform.

    They could test this out with a hopper that hovers back and forth over a launch platform. Might be possible to handle it dynamically.

  51. "The Super Heavy Booster will be able to hover. This will make it easier for a precise docking style landing." Hover is also the key to BO/NASA landing system for unprepped lunar surface. SH could get besides the tower and waltz on into its arms.

  52. Poor Erc X. His work in life is to get the Musk attention by digitally illustrating everything that he tweets.

  53. The super heavy will need to position itself to somewhat lower accuracy of spot either for getting caught by an arm than landing on a pad . It is pure advantage that with the arm there is no need for legs. Launching and landing can still happen in different spots. Will need a bigger and more stable platform for sea landing though. Another or an additional option is to give the tower the ability to tilt to counter the sea platform movement.

  54. I'll believe it when I see it.

    I can perfectly see them launching and returning Superheavy several times.

    But it will most likely be in a flat landing pad prepared for it. Not in the same tower that launched it.

    Sorry, but wind and other weather and machinery imponderables ensure there is some degree of noise on the landing.

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