Author Topic: ITS Booster Return - Final Landing and Mounting  (Read 11039 times)

Offline sanman

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ITS Booster Return - Final Landing and Mounting
« on: 09/29/2016 10:14 AM »
As per Musk's presentation/animation, the returning ITS booster apparently lands on a mount, putting itself in position for quicker re-launch while also avoiding the mass penalty for onboard landing gear. Are there any other benefits to this idea?

While it's not clear whether this approach will withstand further design reviews, how robust/fault-tolerant is this approach, and how can it be made more robust/fault-tolerant (short of scrapping it altogether)?

What are the specific hazards or complicating factors that most contribute to risk of landing failure? How to avoid or prevent ground-coupled turbulence and backwash from causing problems? Would the standard flame trench/channel work?

Could air-bearings/maglev-bearings -- perhaps forming a cusp shape -- help to "funnel"/guide the rocket base onto the mount more smoothly?
You've still got some cryo-propellants in that landing booster -- could they be used to cool superconductive magnets in the rocket's aft/base to produce a suitable magnetic field for this purpose?
(Heh, sorry, still had some Hyperloop belches left in me)   ;)

Years ago, I wrote to a fellow in the UK who makes a toy called the Levitron, asking him if his idea could be adapted to making a "space-age" pen holder where the pen floats in an upright vertical orientation on your desk.
He replied to me that the idea was workable in principle, and that it would be dependent on rotation of the magnetic field for gyro-stabilization to offset any imperfections/asymmetries in the magnetic cusp. With high enough rotational speed of the field, enough gyrostabilization will be produced to keep a pen upright (and a rocket maybe?).



(Note: No actual Blue Origin tortoises were hurt in the making of that video)  ;)

Online Kaputnik

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Re: ITS Booster Return - Final Landing and Mounting
« Reply #1 on: 09/29/2016 09:18 PM »
One advantage of the plan is that the thrust of the booster even in landing mode is going to be substantial, and a flame trench with water deluge is going to be much more robust than a concrete apron.

Compared to F9, the booster will have a far wider range of thrust:weight options available, conceivably allowing it to hover or, depending on propellant, even have a wave-off and second attempt (perhaps a wave off and crash land on the beach is the best that actually realistic?)

Waiting for joy and raptor

Offline Lemurion

Re: ITS Booster Return - Final Landing and Mounting
« Reply #2 on: 09/29/2016 11:23 PM »
I see a number of trade-offs involved with the mount system vs. F9 landing legs. Without the mass limitations of flight hardware the mount system can be much more tolerant of hard landings, but less tolerant of off-center ones. Another advantage I see is that it eliminates the need to deal with taking the booster's weight off its legs and returning them to flight position. If nothing else, that can improve the launch cadence.

Offline sanman

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Re: ITS Booster Return - Final Landing and Mounting
« Reply #3 on: 09/30/2016 10:32 PM »
Can some clever geometry on the mount somehow cleverly channel the thrust of the booster to somehow force the booster to properly align itself onto the mount? Like some kind of Coanda effect?

Otherwise one bad misalignment could ruin your whole day.

Offline Bob Shaw

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Re: ITS Booster Return - Final Landing and Mounting
« Reply #4 on: 09/30/2016 11:09 PM »
Imagine a sort of dance, where the returning first stage is the elephant and the launch platform is a mouse. The elephant does what it can do, but the launch platform can scurry around, fast and agile and smart.

The first stage has a job to do, which is to get within a low value of feet from the platform. It is limited by inertia, by wind, by sloshing fluids and by power and weight constraints. The platform is solidly attached to a planet, with as many Kw of energy as required. The answer, then, is to create a platform which can move, quickly and responsively and which will find itself in exactly the right place and at the right time to welcome the booster. The intelligence and manoeverability becomes distributed between both players, with as much of the heavy lifting as possible being left on the ground.

There are already examples of smart platforms: 3D printers. BAE Systems looked at a smart ship-borne Harrier recovery system some time ago (see also 1930s USAF airship parasite fighters and the 1950s Goblin parasitic escort jet fighter).
« Last Edit: 09/30/2016 11:10 PM by Bob Shaw »

Offline Saabstory88

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Re: ITS Booster Return - Final Landing and Mounting
« Reply #5 on: 09/30/2016 11:10 PM »
One advantage of the plan is that the thrust of the booster even in landing mode is going to be substantial, and a flame trench with water deluge is going to be much more robust than a concrete apron.

Compared to F9, the booster will have a far wider range of thrust:weight options available, conceivably allowing it to hover or, depending on propellant, even have a wave-off and second attempt (perhaps a wave off and crash land on the beach is the best that actually realistic?)

A wave off and crash would be the least destructive as the booster could burn to prop depletion.

Offline Patchouli

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Re: ITS Booster Return - Final Landing and Mounting
« Reply #6 on: 10/01/2016 05:16 AM »
Can some clever geometry on the mount somehow cleverly channel the thrust of the booster to somehow force the booster to properly align itself onto the mount? Like some kind of Coanda effect?

Otherwise one bad misalignment could ruin your whole day.

Maybe something like the hook and cable set up that was used for the X-13 Vertijet might be more tolerant of misalignment.
But still if something goes wrong you'll have a very bad day.
« Last Edit: 10/01/2016 05:18 AM by Patchouli »

Offline sevenperforce

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Re: ITS Booster Return - Final Landing and Mounting
« Reply #7 on: 10/02/2016 07:23 PM »
Given that the fully-loaded and fully-fueled ITS only has a SL TWR of around 1.007 (given that the RVacs can't be used safely at SL), I'd anticipate the addition of a compact secondary LES inside the interstage. In an AMOS-6 style RUD, the LES would push the ITS clear of the fireball to give the SL raptors enough time to spin up, but on nominal launches, the LES would remain with the booster and return for reuse. That way you aren't lifting the LES all the way to orbit for no reason each time.

If that was the case, then it's conceivable that the LES could be configured to pull the booster free of the pad in a Very Bad Day situation. Moreso if it was a hypergolic LES rather than a SF one.

Offline sanman

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Re: ITS Booster Return - Final Landing and Mounting
« Reply #8 on: 10/02/2016 11:41 PM »
Given that the fully-loaded and fully-fueled ITS only has a SL TWR of around 1.007 (given that the RVacs can't be used safely at SL), I'd anticipate the addition of a compact secondary LES inside the interstage. In an AMOS-6 style RUD, the LES would push the ITS clear of the fireball to give the SL raptors enough time to spin up, but on nominal launches, the LES would remain with the booster and return for reuse. That way you aren't lifting the LES all the way to orbit for no reason each time.

If that was the case, then it's conceivable that the LES could be configured to pull the booster free of the pad in a Very Bad Day situation. Moreso if it was a hypergolic LES rather than a SF one.

Not that this has anything do with mount landings - but is it a given that there's no LES for Mars-side launches then?

Offline sevenperforce

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Re: ITS Booster Return - Final Landing and Mounting
« Reply #9 on: 10/03/2016 12:16 AM »
Not that this has anything do with mount landings - but is it a given that there's no LES for Mars-side launches then?
Right. Elon said something to the effect that "if something goes wrong on the Mars launch you're screwed anyway."

Online Lars-J

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Re: ITS Booster Return - Final Landing and Mounting
« Reply #10 on: 10/03/2016 12:40 AM »
Not that this has anything do with mount landings - but is it a given that there's no LES for Mars-side launches then?
Right. Elon said something to the effect that "if something goes wrong on the Mars launch you're screwed anyway."

Exactly. But the ITS lander/ship has a lot of excess thrust capacity on Mars, so it could lose several engines and likely still make orbit.
« Last Edit: 10/03/2016 12:40 AM by Lars-J »

Offline rakaydos

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Re: ITS Booster Return - Final Landing and Mounting
« Reply #11 on: 10/03/2016 12:53 AM »
Given that the fully-loaded and fully-fueled ITS only has a SL TWR of around 1.007 (given that the RVacs can't be used safely at SL), I'd anticipate the addition of a compact secondary LES inside the interstage. In an AMOS-6 style RUD, the LES would push the ITS clear of the fireball to give the SL raptors enough time to spin up, but on nominal launches, the LES would remain with the booster and return for reuse. That way you aren't lifting the LES all the way to orbit for no reason each time.

If that was the case, then it's conceivable that the LES could be configured to pull the booster free of the pad in a Very Bad Day situation. Moreso if it was a hypergolic LES rather than a SF one.

Not that this has anything do with mount landings - but is it a given that there's no LES for Mars-side launches then?
Where would you abort to?

Offline envy887

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Re: ITS Booster Return - Final Landing and Mounting
« Reply #12 on: 10/03/2016 02:54 AM »
To survive an AMOS type anomaly the LAS has to separate the crew from the upper stage. There is no reason or feasible way to abort full 2000 tonne methalox tanks off a pad

Such a LAS would be of little use in returning the booster.

I heard that SpaceX is working on 10-tonne class pressure-fed gaseous methalox thrusters for the ITS orbiter RCS. A set of those might be useful for fine control of the returning booster. Similar to how N2 thrusters are used on F9, but 100s of times more powerful.

Online Robotbeat

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Re: ITS Booster Return - Final Landing and Mounting
« Reply #13 on: 10/03/2016 03:16 AM »
Given that the fully-loaded and fully-fueled ITS only has a SL TWR of around 1.007 (given that the RVacs can't be used safely at SL), I'd anticipate the addition of a compact secondary LES inside the interstage. In an AMOS-6 style RUD, the LES would push the ITS clear of the fireball to give the SL raptors enough time to spin up, but on nominal launches, the LES would remain with the booster and return for reuse. That way you aren't lifting the LES all the way to orbit for no reason each time.

If that was the case, then it's conceivable that the LES could be configured to pull the booster free of the pad in a Very Bad Day situation. Moreso if it was a hypergolic LES rather than a SF one.

Not that this has anything do with mount landings - but is it a given that there's no LES for Mars-side launches then?
Where would you abort to?
Surface or orbit. In either case, you'll have a budding which could send a rescue mission to you.

Remember, this isn't Apollo. There would be hundreds or thousands of people on Mars.
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Online Lars-J

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Re: ITS Booster Return - Final Landing and Mounting
« Reply #14 on: 10/03/2016 04:25 AM »
Given that the fully-loaded and fully-fueled ITS only has a SL TWR of around 1.007 (given that the RVacs can't be used safely at SL), I'd anticipate the addition of a compact secondary LES inside the interstage. In an AMOS-6 style RUD, the LES would push the ITS clear of the fireball to give the SL raptors enough time to spin up, but on nominal launches, the LES would remain with the booster and return for reuse. That way you aren't lifting the LES all the way to orbit for no reason each time.

If that was the case, then it's conceivable that the LES could be configured to pull the booster free of the pad in a Very Bad Day situation. Moreso if it was a hypergolic LES rather than a SF one.

Not that this has anything do with mount landings - but is it a given that there's no LES for Mars-side launches then?
Where would you abort to?
Surface or orbit. In either case, you'll have a budding which could send a rescue mission to you.

Remember, this isn't Apollo. There would be hundreds or thousands of people on Mars.

Yes, but the point is that the *whole* ship either aborts to orbit or lands downrange. There is nothing in the middle. Any detachable cabin essentially has to be a mini-ITS inside an ITS. Mars is not Earth, it is not practical.

Remember, this is an architecture to start colonization of Mars. Once a colony exists, there will be other (perhaps safer?) crew vehicles available, and they might have more abort options.

Offline RobLynn

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Re: ITS Booster Return - Final Landing and Mounting
« Reply #15 on: 10/03/2016 09:20 AM »
Imagine a sort of dance, where the returning first stage is the elephant and the launch platform is a mouse. The elephant does what it can do, but the launch platform can scurry around, fast and agile and smart.

The first stage has a job to do, which is to get within a low value of feet from the platform. It is limited by inertia, by wind, by sloshing fluids and by power and weight constraints. The platform is solidly attached to a planet, with as many Kw of energy as required. The answer, then, is to create a platform which can move, quickly and responsively and which will find itself in exactly the right place and at the right time to welcome the booster. The intelligence and manoeverability becomes distributed between both players, with as much of the heavy lifting as possible being left on the ground.

There are already examples of smart platforms: 3D printers. BAE Systems looked at a smart ship-borne Harrier recovery system some time ago (see also 1930s USAF airship parasite fighters and the 1950s Goblin parasitic escort jet fighter).

I like this.  Could be done with a barge floating on a shallow pool with a few high-powered winches arrayed around it to rapidly position it.  Or perhaps a really big air-bearing supported cradle positioned by winches.

How about shooting high pressure jets of water up into the unused-at-landing outer ring of engine nozzles? very fast to steer the water nozzles, 'soft', and makes use of existing thrust structure to take peak landing deceleration loads.
I'm a "glass is twice as big as it needs to be" kinda guy

Offline Ludus

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Re: ITS Booster Return - Final Landing and Mounting
« Reply #16 on: 10/04/2016 04:12 PM »
It would let a sea platform handle the entire workflow. ITS spaceport platforms could be built in shipyards like big oil platforms and towed into position. Tankers would land on the platform along with boosters for rapid reuse. Cargo or Passenger variants might be processed on shore and floated out to be lifted into place by the crane.

A spaceport might have several launch/landing platforms off the coast.

Offline jsgirald

Re: ITS Booster Return - Final Landing and Mounting
« Reply #17 on: 10/04/2016 06:17 PM »
Clearly this is the most insane part of the plan.
I mean, what's wrong with a reinforced landing pad, a large flatbed and a very big crane?
Clearly Musk has heard about risk reduction, and strongly disapproves ...  :)
"For every expert, there is an equal and opposite expert".

Offline Jim

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Re: ITS Booster Return - Final Landing and Mounting
« Reply #18 on: 10/04/2016 06:19 PM »
Imagine a sort of dance, where the returning first stage is the elephant and the launch platform is a mouse. The elephant does what it can do, but the launch platform can scurry around, fast and agile and smart.

The first stage has a job to do, which is to get within a low value of feet from the platform. It is limited by inertia, by wind, by sloshing fluids and by power and weight constraints. The platform is solidly attached to a planet, with as many Kw of energy as required. The answer, then, is to create a platform which can move, quickly and responsively and which will find itself in exactly the right place and at the right time to welcome the booster. The intelligence and manoeverability becomes distributed between both players, with as much of the heavy lifting as possible being left on the ground.

There are already examples of smart platforms: 3D printers. BAE Systems looked at a smart ship-borne Harrier recovery system some time ago (see also 1930s USAF airship parasite fighters and the 1950s Goblin parasitic escort jet fighter).

I like this.  Could be done with a barge floating on a shallow pool with a few high-powered winches arrayed around it to rapidly position it.  Or perhaps a really big air-bearing supported cradle positioned by winches.

How about shooting high pressure jets of water up into the unused-at-landing outer ring of engine nozzles? very fast to steer the water nozzles, 'soft', and makes use of existing thrust structure to take peak landing deceleration loads.

None of that is viable in the real world

Offline Kansan52

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Re: ITS Booster Return - Final Landing and Mounting
« Reply #19 on: 10/04/2016 06:34 PM »
Clearly this is the most insane part of the plan.
I mean, what's wrong with a reinforced landing pad, a large flatbed and a very big crane?
Clearly Musk has heard about risk reduction, and strongly disapproves ...  :)

Maybe the launch site is built to handle the landing and the tower crane does a final position after landing.

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