Superheavy landing mechanism

[Lars-J]

SpaceX still taking my ideas away like the grid-fins from 10 years back ...

Didn't the Soviet RSD-10 Pioneer (AKA SS-20 Saber in NATO countries) have grid fins? That one went into service back in 1976.

Getting off topic, but N1 also had grid fins in the late 1960s IIRC.

Right, but that was for a fundamentally different reason. (not steering) They were added for the same reason the Saturn V fins were added... To make an abort safer by making the rocket more aerodynamically stable.

[JamesH65]

SpaceX still taking my ideas away like the grid-fins from 10 years back ...

Didn't the Soviet RSD-10 Pioneer (AKA SS-20 Saber in NATO countries) have grid fins? That one went into service back in 1976.

Getting off topic, but N1 also had grid fins in the late 1960s IIRC.

Right, but that was for a fundamentally different reason. (not steering) They were added for the same reason the Saturn V fins were added... To make an abort safer by making the rocket more aerodynamically stable.

These are for steering.

https://en.wikipedia.org/wiki/GBU-43/B_MOAB

[Slarty1080]

SpaceX still taking my ideas away like the grid-fins from 10 years back ...

Didn't the Soviet RSD-10 Pioneer (AKA SS-20 Saber in NATO countries) have grid fins? That one went into service back in 1976.

Getting off topic, but N1 also had grid fins in the late 1960s IIRC.

I don't remember any grid fins on the N1

[Lars-J]

SpaceX still taking my ideas away like the grid-fins from 10 years back ...

Didn't the Soviet RSD-10 Pioneer (AKA SS-20 Saber in NATO countries) have grid fins? That one went into service back in 1976.

Getting off topic, but N1 also had grid fins in the late 1960s IIRC.

Right, but that was for a fundamentally different reason. (not steering) They were added for the same reason the Saturn V fins were added... To make an abort safer by making the rocket more aerodynamically stable.

These are for steering.

https://en.wikipedia.org/wiki/GBU-43/B_MOAB

Yes but these (the N1 in question) are not:

[Rocket Science]

SpaceX still taking my ideas away like the grid-fins from 10 years back ...

Didn't the Soviet RSD-10 Pioneer (AKA SS-20 Saber in NATO countries) have grid fins? That one went into service back in 1976.

Getting off topic, but N1 also had grid fins in the late 1960s IIRC.

Right, but that was for a fundamentally different reason. (not steering) They were added for the same reason the Saturn V fins were added... To make an abort safer by making the rocket more aerodynamically stable.

These are for steering.

https://en.wikipedia.org/wiki/GBU-43/B_MOAB

Correct James 10 years back I was inspired by the larger MOAB when the light went on...
https://forum.nasaspaceflight.com/index.php?topic=21923.msg787578#msg787578

[pubanthony]

a French university, within the framework of the PERSEUS project (The European Space Research Student Project) worked on a concept of launcher recovery: The Smartcatcher concept consists of catching the launcher a few meters before touching the ground using a system of cables that would enclose it in a kind of polygon

[Skyway]

The Soviet/Russian missile AA-12 Adder was designed in the 80s with grid fins for steering.

[DigitalMan]

a French university, within the framework of the PERSEUS project (The European Space Research Student Project) worked on a concept of launcher recovery: The Smartcatcher concept consists of catching the launcher a few meters before touching the ground using a system of cables that would enclose it in a kind of polygon

I was thinking of something similar to that in my post upthread, but with two towers. I think it has issues compared to other ideas, but it allows a lot of space for the target area, plus, double or triple redundancy would not be hard.

[agray5]

There are all sorts of interesting ideas here. Personally, I am team 4 arms with active capture mechanisms and independent damping, but we shall see.

The one aspect of this system I would feel comfortable constraining is that there will be no structure fully surrounding the SH at any point. I believe there are two limiting factors here:

1. Those offshore platforms are small, especially when you are 9 meters wide. There just isn't the real-estate on an offshore system for any of the multi tower/large footprint systems discussed here. Additionally, those platforms are explicitly built to take their primary vertical loads/greatest moments via the derrick/down pipe areas already present. Substantially changing the CG/moments applied to the platform would negate the benefits of starting with a second hand platform in the first place.

2. Much more importantly, there is no way SH will descend into this catch system vertically. Why constrain the guidance/control problem any more than necessary? The booster will come in to a point laterally separated from the offshore installation/onshore tower and pad and then ~horizontally translate into the catch system before settling onto it. As the program matures the angle of that traverse might get a bit steeper, but the 'initial point' of the recovery will always be off to the side. It is massively simpler to harden a launch and recovery structure to failures if the possibility of taking a hit from a booster from above is entirely eliminated, the maximum velocity of said hit is greatly reduced, and the general direction from which said hit might come is limited. This aspect becomes even more crucial in the offshore setting. There are going to be people and equipment on that platform. The prospect of crashing or tipping a booster on any of that is to be avoided at all costs. As with the latest offshore rigs, I'm guessing there will be a 'hot' side located to be downwind of the 'cold' side of the platform as much as possible, and both the SH and Starships will make their landing approach from the hot side. If/when something goes wrong, ideally the vehicle goes straight into the water/dirt, the wind is never pushing towards the tower/platform, and if you do have a fire, the fire is downwind of the people onboard.

We can already see the second consideration illustrated in Boca Chica. The GSE bunkers and protection berms for both the orbital and suborbital pads are only hardened from the front. You really don't want to have to harden things from all sides, even if you can just throw concrete at the problem until it goes away, which is not an option offshore.

[robot_enthusiast]

There are all sorts of interesting ideas here. Personally, I am team 4 arms with active capture mechanisms and independent damping, but we shall see.

The one aspect of this system I would feel comfortable constraining is that there will be no structure fully surrounding the SH at any point. I believe there are two limiting factors here:

1. Those offshore platforms are small, especially when you are 9 meters wide. There just isn't the real-estate on an offshore system for any of the multi tower/large footprint systems discussed here. Additionally, those platforms are explicitly built to take their primary vertical loads/greatest moments via the derrick/down pipe areas already present. Substantially changing the CG/moments applied to the platform would negate the benefits of starting with a second hand platform in the first place.

2. Much more importantly, there is no way SH will descend into this catch system vertically. Why constrain the guidance/control problem any more than necessary? The booster will come in to a point laterally separated from the offshore installation/onshore tower and pad and then ~horizontally translate into the catch system before settling onto it. As the program matures the angle of that traverse might get a bit steeper, but the 'initial point' of the recovery will always be off to the side. It is massively simpler to harden a launch and recovery structure to failures if the possibility of taking a hit from a booster from above is entirely eliminated, the maximum velocity of said hit is greatly reduced, and the general direction from which said hit might come is limited. This aspect becomes even more crucial in the offshore setting. There are going to be people and equipment on that platform. The prospect of crashing or tipping a booster on any of that is to be avoided at all costs. As with the latest offshore rigs, I'm guessing there will be a 'hot' side located to be downwind of the 'cold' side of the platform as much as possible, and both the SH and Starships will make their landing approach from the hot side. If/when something goes wrong, ideally the vehicle goes straight into the water/dirt, the wind is never pushing towards the tower/platform, and if you do have a fire, the fire is downwind of the people onboard.

We can already see the second consideration illustrated in Boca Chica. The GSE bunkers and protection berms for both the orbital and suborbital pads are only hardened from the front. You really don't want to have to harden things from all sides, even if you can just throw concrete at the problem until it goes away, which is not an option offshore.

Elon specifically stated that it would not translate into the catcher.
https://twitter.com/elonmusk/status/1344462159560904706?s=20

[Slarty1080]

There are all sorts of interesting ideas here. Personally, I am team 4 arms with active capture mechanisms and independent damping, but we shall see.

The one aspect of this system I would feel comfortable constraining is that there will be no structure fully surrounding the SH at any point. I believe there are two limiting factors here:

1. Those offshore platforms are small, especially when you are 9 meters wide. There just isn't the real-estate on an offshore system for any of the multi tower/large footprint systems discussed here. Additionally, those platforms are explicitly built to take their primary vertical loads/greatest moments via the derrick/down pipe areas already present. Substantially changing the CG/moments applied to the platform would negate the benefits of starting with a second hand platform in the first place.

2. Much more importantly, there is no way SH will descend into this catch system vertically. Why constrain the guidance/control problem any more than necessary? The booster will come in to a point laterally separated from the offshore installation/onshore tower and pad and then ~horizontally translate into the catch system before settling onto it. As the program matures the angle of that traverse might get a bit steeper, but the 'initial point' of the recovery will always be off to the side. It is massively simpler to harden a launch and recovery structure to failures if the possibility of taking a hit from a booster from above is entirely eliminated, the maximum velocity of said hit is greatly reduced, and the general direction from which said hit might come is limited. This aspect becomes even more crucial in the offshore setting. There are going to be people and equipment on that platform. The prospect of crashing or tipping a booster on any of that is to be avoided at all costs. As with the latest offshore rigs, I'm guessing there will be a 'hot' side located to be downwind of the 'cold' side of the platform as much as possible, and both the SH and Starships will make their landing approach from the hot side. If/when something goes wrong, ideally the vehicle goes straight into the water/dirt, the wind is never pushing towards the tower/platform, and if you do have a fire, the fire is downwind of the people onboard.

We can already see the second consideration illustrated in Boca Chica. The GSE bunkers and protection berms for both the orbital and suborbital pads are only hardened from the front. You really don't want to have to harden things from all sides, even if you can just throw concrete at the problem until it goes away, which is not an option offshore.

I mostly agree, but suspect that the platform crew will evacuate before the landing. Not sure why they would need to be on site.

[rakaydos]

There are all sorts of interesting ideas here. Personally, I am team 4 arms with active capture mechanisms and independent damping, but we shall see.

The one aspect of this system I would feel comfortable constraining is that there will be no structure fully surrounding the SH at any point. I believe there are two limiting factors here:

1. Those offshore platforms are small, especially when you are 9 meters wide. There just isn't the real-estate on an offshore system for any of the multi tower/large footprint systems discussed here. Additionally, those platforms are explicitly built to take their primary vertical loads/greatest moments via the derrick/down pipe areas already present. Substantially changing the CG/moments applied to the platform would negate the benefits of starting with a second hand platform in the first place.

2. Much more importantly, there is no way SH will descend into this catch system vertically. Why constrain the guidance/control problem any more than necessary? The booster will come in to a point laterally separated from the offshore installation/onshore tower and pad and then ~horizontally translate into the catch system before settling onto it. As the program matures the angle of that traverse might get a bit steeper, but the 'initial point' of the recovery will always be off to the side. It is massively simpler to harden a launch and recovery structure to failures if the possibility of taking a hit from a booster from above is entirely eliminated, the maximum velocity of said hit is greatly reduced, and the general direction from which said hit might come is limited. This aspect becomes even more crucial in the offshore setting. There are going to be people and equipment on that platform. The prospect of crashing or tipping a booster on any of that is to be avoided at all costs. As with the latest offshore rigs, I'm guessing there will be a 'hot' side located to be downwind of the 'cold' side of the platform as much as possible, and both the SH and Starships will make their landing approach from the hot side. If/when something goes wrong, ideally the vehicle goes straight into the water/dirt, the wind is never pushing towards the tower/platform, and if you do have a fire, the fire is downwind of the people onboard.

We can already see the second consideration illustrated in Boca Chica. The GSE bunkers and protection berms for both the orbital and suborbital pads are only hardened from the front. You really don't want to have to harden things from all sides, even if you can just throw concrete at the problem until it goes away, which is not an option offshore.

Elon specifically stated that it would not translate into the catcher.
https://twitter.com/elonmusk/status/1344462159560904706?s=20

There will probably be SOME translation for saftey reasons, but  certianly not a blue origin style "hover and translate to the pad".

[agray5]

There are all sorts of interesting ideas here. Personally, I am team 4 arms with active capture mechanisms and independent damping, but we shall see.

The one aspect of this system I would feel comfortable constraining is that there will be no structure fully surrounding the SH at any point. I believe there are two limiting factors here:

1. Those offshore platforms are small, especially when you are 9 meters wide. There just isn't the real-estate on an offshore system for any of the multi tower/large footprint systems discussed here. Additionally, those platforms are explicitly built to take their primary vertical loads/greatest moments via the derrick/down pipe areas already present. Substantially changing the CG/moments applied to the platform would negate the benefits of starting with a second hand platform in the first place.

2. Much more importantly, there is no way SH will descend into this catch system vertically. Why constrain the guidance/control problem any more than necessary? The booster will come in to a point laterally separated from the offshore installation/onshore tower and pad and then ~horizontally translate into the catch system before settling onto it. As the program matures the angle of that traverse might get a bit steeper, but the 'initial point' of the recovery will always be off to the side. It is massively simpler to harden a launch and recovery structure to failures if the possibility of taking a hit from a booster from above is entirely eliminated, the maximum velocity of said hit is greatly reduced, and the general direction from which said hit might come is limited. This aspect becomes even more crucial in the offshore setting. There are going to be people and equipment on that platform. The prospect of crashing or tipping a booster on any of that is to be avoided at all costs. As with the latest offshore rigs, I'm guessing there will be a 'hot' side located to be downwind of the 'cold' side of the platform as much as possible, and both the SH and Starships will make their landing approach from the hot side. If/when something goes wrong, ideally the vehicle goes straight into the water/dirt, the wind is never pushing towards the tower/platform, and if you do have a fire, the fire is downwind of the people onboard.

We can already see the second consideration illustrated in Boca Chica. The GSE bunkers and protection berms for both the orbital and suborbital pads are only hardened from the front. You really don't want to have to harden things from all sides, even if you can just throw concrete at the problem until it goes away, which is not an option offshore.

Elon specifically stated that it would not translate into the catcher.
https://twitter.com/elonmusk/status/1344462159560904706?s=20

There will probably be SOME translation for saftey reasons, but  certianly not a blue origin style "hover and translate to the pad".

Oh, totally, I agree a hover is very unlikely, so there will absolutely be a vertical component throughout the procedure. but any system that fully boxes in the booster. thereby requiring a purely vertical translation to capture, also seems very unlikely. 

I think the aspect of the Smallstars concept Elon is referencing is that whatever the rig looks like it will not have anything directly above the booster at touchdown. I think the cradle Smallstars designed is a perfectly viable concept, I just think it is unlikely to be hung from the tower from above as they show.

[agray5]

There are all sorts of interesting ideas here. Personally, I am team 4 arms with active capture mechanisms and independent damping, but we shall see.

The one aspect of this system I would feel comfortable constraining is that there will be no structure fully surrounding the SH at any point. I believe there are two limiting factors here:

1. Those offshore platforms are small, especially when you are 9 meters wide. There just isn't the real-estate on an offshore system for any of the multi tower/large footprint systems discussed here. Additionally, those platforms are explicitly built to take their primary vertical loads/greatest moments via the derrick/down pipe areas already present. Substantially changing the CG/moments applied to the platform would negate the benefits of starting with a second hand platform in the first place.

2. Much more importantly, there is no way SH will descend into this catch system vertically. Why constrain the guidance/control problem any more than necessary? The booster will come in to a point laterally separated from the offshore installation/onshore tower and pad and then ~horizontally translate into the catch system before settling onto it. As the program matures the angle of that traverse might get a bit steeper, but the 'initial point' of the recovery will always be off to the side. It is massively simpler to harden a launch and recovery structure to failures if the possibility of taking a hit from a booster from above is entirely eliminated, the maximum velocity of said hit is greatly reduced, and the general direction from which said hit might come is limited. This aspect becomes even more crucial in the offshore setting. There are going to be people and equipment on that platform. The prospect of crashing or tipping a booster on any of that is to be avoided at all costs. As with the latest offshore rigs, I'm guessing there will be a 'hot' side located to be downwind of the 'cold' side of the platform as much as possible, and both the SH and Starships will make their landing approach from the hot side. If/when something goes wrong, ideally the vehicle goes straight into the water/dirt, the wind is never pushing towards the tower/platform, and if you do have a fire, the fire is downwind of the people onboard.

We can already see the second consideration illustrated in Boca Chica. The GSE bunkers and protection berms for both the orbital and suborbital pads are only hardened from the front. You really don't want to have to harden things from all sides, even if you can just throw concrete at the problem until it goes away, which is not an option offshore.

I mostly agree, but suspect that the platform crew will evacuate before the landing. Not sure why they would need to be on site.

Yea, I keep kicking that issue around as well. For any early launches I am sure you are dead on. But if you look at the evacuation options, eg boat or helicopter, they aren't pretty either, so as the cadence increases I am guessing we will see personnel staying on board. 

For the boat, doing any kind of transfer from a platform to a vessel is a non-trivial operation, especially in any but the absolute flattest of sea states. Typically today it involves a crane lift in a basket down to the deck of the support vessel, which is dangerous and takes time. Then the vessel needs to get out of the exclusion zone, which even with a pretty fast ship takes a fair bit of time. Double that to get back, and add another tricky ship to platform transfer with all the risks entailed. Even if you are only talking a launch a day and only 20 crew on the platform,  the amount of time and cumulative risk built up gets ugly. This becomes doubly true when there are humans on the Starship. If something goes wrong, even just a weird abort mode or a stuck crew arm or something, your closest people to help are distanced from the situation by time and the difficulty of the transfer.

For the helicopter option the issues are similar. An at sea landing or takeoff on a platform is inherently risky and complicated, made all the more so by doing them in the vicinity of a cocked and locked SH and Starship stack and coordinating around SH and Starship traffic. Just suiting up in the gear oil platform crews wear on a helicopter takes a fair bit. Again, asking the platform crew to do this multiple times a week, let alone day, is a lot. Doubly so when something weird goes down. Now you have to land a helo on a platform next to an off norminal Starship, probably venting methane, etc etc.

My guess is we will see helicopter crew and passenger transfers, if only because the amount of time there is a vessel in the exclusion zone is shorter than for a boat, but that the crew are probably on something like a 2 weeks on 2 weeks off oil rig schedule, and the passengers nominally only ride out once. Even that might change to the passengers loading on the Starship ashore and doing a point to point out to the rig.

Or Elon builds a fleet of submarines. Which, now that I have said it, seems pretty on brand.

[Rocket Science]

The Soviet/Russian missile AA-12 Adder was designed in the 80s with grid fins for steering.

Yes, AFAIK as well...

[Nascent Ascent]

If the Starship was unable hit the catcher bullseye, for whatever reason, could it survive an attempted soft landing in the ocean?  At the last moment do a divert maneuver. They might have a loss of vehicle but perhaps the crew would be OK?  Maybe the oil platform would make this last ditch effort viable?

[xvel]

If the Starship was unable hit the catcher bullseye, for whatever reason, could it survive an attempted soft landing in the ocean?  At the last moment do a divert maneuver. They might have a loss of vehicle but perhaps the crew would be OK?  Maybe the oil platform would make this last ditch effort viable?

you're confusing the booster with the ship, booster is landing on catcher, starship is landing on legs, no humans on booster.

[KariK]

Hi,

Haven't seen this method discussed, so had to draw a sketch. I think this would be cheaper and more reliable than catch towers. Also a lot easier to replace in event of mishap.


Superheavy would have 6 landing "pins"  60deg apart. Top of landing platform has 6 sockets with locking mechanism to capture. Pins are 60cm in diameter in photo. Rather large, but gives more leeway for targeting.

Upper platform resides on airbags/lifts that cushion the landing. They release air and are empty when landing completed. Damping distance is only 30cm in picture.  Lateral movement is captured by blue clamps ( or rather some better system ).

Lower platform is wider to give support. 16-18m in diameter at picture. Trolleys support is slightly above ground until weight of heavy collapses it to ground.

Platform is moved by 6 static winches at the edges. This configuration allows translation in X/Y and rotation of +/-60deg in Z so it should easily compensate to any rotational orientation.

Br,
Kari Knuuttila

[Stan-1967]

This concept will have to absorb the rocket blast of multiple raptors during landing.  That negates a lot of its apparent simplicity when it has to withstand that environment

[Doom2pro]

Hi,

Haven't seen this method discussed, so had to draw a sketch. I think this would be cheaper and more reliable than catch towers. Also a lot easier to replace in event of mishap.


Superheavy would have 6 landing "pins"  60deg apart. Top of landing platform has 6 sockets with locking mechanism to capture. Pins are 60cm in diameter in photo. Rather large, but gives more leeway for targeting.

Upper platform resides on airbags/lifts that cushion the landing. They release air and are empty when landing completed. Damping distance is only 30cm in picture.  Lateral movement is captured by blue clamps ( or rather some better system ).

Lower platform is wider to give support. 16-18m in diameter at picture. Trolleys support is slightly above ground until weight of heavy collapses it to ground.

Platform is moved by 6 static winches at the edges. This configuration allows translation in X/Y and rotation of +/-60deg in Z so it should easily compensate to any rotational orientation.

Br,
Kari Knuuttila

That landing would have to be "pinpoint"... Pun Intended.