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There are actual concepts of catching Starship without using rockets at all? That seems more insane than propulsion landing. 

I think most risks associated with landing under rocket power can and will get ironed out I think its fine. If Falcon 9 boosters can do it under more strict requirements, Starship should be able to do the same. 

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9 minutes ago, MKI said:

There are actual concepts of catching Starship without using rockets at all? That seems more insane than propulsion landing. 

I think most risks associated with landing under rocket power can and will get ironed out I think its fine. If Falcon 9 boosters can do it under more strict requirements, Starship should be able to do the same. 

Without propulsion it just isn't feasible, yeah. I agree that powered landings will get ironed out pretty well after a while, especially with the dozens/hundreds of starships that will fly before it carries crew. Precision aside, nearly all the other aspects have a much greater margin in starship compared to the falcon 9

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16 minutes ago, zolotiyeruki said:

What's wrong with the idea of catching a bellyflopping Starship in a gigantic net? What is its terminal velocity with empty tanks?

Starship terminal velocity is around 65 m/s (for comparison, for the falcon 9 it is about mach 0.8 or 275 m/s)

Edited by Beccab
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42 minutes ago, MKI said:

There are actual concepts of catching Starship without using rockets at all? That seems more insane than propulsion landing

If by 'concepts' you mean Elon idly musing on Twitter, then sure. I doubt it's something that's been seriously considered, as it doesn't sound practical at all.

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8 hours ago, JoeSchmuckatelli said:

Halon too? It's what we used for military applications.  Breaks the fire triangle.  Don't know how it would work with something that large and open air... But maybe? 

Halon is very difficult to get. It has not been manufactured for many years, because of the Montreal Protocol.

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7 minutes ago, mikegarrison said:

Halon is very difficult to get. It has not been manufactured for many years, because of the Montreal Protocol.

And firefighting foam is unfortunately carcinogenic.

3 hours ago, Beccab said:
3 hours ago, zolotiyeruki said:

What's wrong with the idea of catching a bellyflopping Starship in a gigantic net? What is its terminal velocity with empty tanks?

Starship terminal velocity is around 65 m/s (for comparison, for the falcon 9 it is about mach 0.8 or 275 m/s)

That would wreck the tiles. Remember that the tiles can be broken with your bare hands (even though they’re stronger than the Shuttle orbiter’s tiles).  65 m/s is 145 mph; the steel MIGHT survive hitting the net at that speed but the tiles will be crushed to dust.

The only way to make it work would be to build a gigantic net mounted on rails on four different towers hundreds of meters in the air, and have those rail mounts accelerate downward to 145 mph to match the speed of the descending Starship, then hit the brakes. Let us suppose that each of these towers is 828 meters high, the height of the Burj Khalifa. Let us suppose that the rail mounts have electromagnetic accelerators able to accelerate the net downward at 64 m/s/s (the same as the extremely buggy EMALS system intended to replace steam catapults on aircraft carriers). The net will need at least 63 meters to accelerate, meaning that it meets Starship at 765 meters ASL.

765 meters seems like a lot of travel distance. But even so, the net will need to exert a constant deceleration of 1.3 gees on the belly of Starship in order to slow it to a stop within that distance. A truly empty Starship (since we are ditching landing burn propellant) has a mass of at least 85 tonnes. So the requisite force will be 1.84 megaNewtons.

Using a net to distribute 1.84 MN of force across 707 square meters of tessellated tiles fragile enough to be shattered with bare hands will be left as an exercise for the reader. 

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8 hours ago, Kerwood Floyd said:

Is Halon heavier than air? Is there anything comparable that is heavier than air? If so (and money is no object :lol:). build a giant "bathtub", fill it with whatever, and land your rocket in the bathtub. 

Radon should work great. It's chemically inert (it's a noble gas) and much heavier than air. Too bad it's radioactive ...

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17 hours ago, Beccab said:

Starship terminal velocity is around 65 m/s

Horizontally? But it needs a vertical landing, and thus should start rotating at safe altitude, decreasing the cross-section and increasing the terminal speed to probably falconian value.

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17 minutes ago, kerbiloid said:

Horizontally? But it needs a vertical landing, and thus should start rotating at safe altitude, decreasing the cross-section and increasing the terminal speed to probably falconian value.

...how. You have seen the reentry profile multiple times, literally all the SN did that. It's the whole reason behind the bellyflop, when it isn't completely horizontal it is either already thrusting or in the uppermost parts of the atmosphere

Starship starts the bellyflop at roughly 500 meters, which means that even if after that point both drag and the atmosphere magically dissapeared and starship never started thrusting, it would reach almost 165 meters per second by the time it hit the terrain

Edited by Beccab
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18 hours ago, Codraroll said:

Radon should work great. It's chemically inert (it's a noble gas) and much heavier than air. Too bad it's radioactive ...

Half-life of 3.8 days.  Forget about using it in place of xenon in your ion thruster, let alone using it for fire suppression.

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22 hours ago, cubinator said:

Maybe a couple whiteboard sketches.

Yes, now an net is an none starter but its theoretical possible. 
So is if flight refueling at hypersonic velocity instead of staging :)

I think grabbing the booster is wild enough. 
And yes I'm pretty sure they will start testing grabbing starship. 

Then this works they probably grab most of them.  The cargo version will have legs even if they prefer to catch simply as starship has more abort modes than the shuttle who is nice if you want to launch something expensive, on the other hand the flipover might be hard on the cargo.

 

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9 hours ago, RealKerbal3x said:

 

 

8 hours ago, magnemoe said:

Yes, now an net is an none starter but its theoretical possible. 
So is if flight refueling at hypersonic velocity instead of staging

Fairings halves have a terminal velocity of 20 m/s and weight less than a ton, so that seems unlikely:P

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Guest The Doodling Astronaut
2 hours ago, RealKerbal3x said:

Definitely looking cleaner than 20 did at this stage of construction.

That's a good thing, if they can start making a routine out of this. I can see the heat tiles actually being a good idea instead of a limiting factor.

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33 minutes ago, The Doodling Astronaut said:

That's a good thing, if they can start making a routine out of this. I can see the heat tiles actually being a good idea instead of a limiting factor.

Given a bit of iteration - as is SpaceX's modus operandi - I think they'll be able to work out the kinks. The concept of a heat shield composed of thousands of individual tiles is already proven, and the implementation on Starship has a number of advantages over how it was done on the Shuttle. All they need to do is install them securely and minimise any gaps, which they already seem to be doing pretty well.

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1 minute ago, RealKerbal3x said:

Given a bit of iteration - as is SpaceX's modus operandi - I think they'll be able to work out the kinks. The concept of a heat shield composed of thousands of individual tiles is already proven, and the implementation on Starship has a number of advantages over how it was done on the Shuttle. All they need to do is install them securely and minimise any gaps, which they already seem to be doing pretty well.

I wonder if we will ever see the transpirational cooling shield make a return, the ceramic heat shield seems to be quite good for starship already

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