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SpaceX Falcon rocket explodes on landing after delivering satellite to space

bbc.com

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Re: SpaceX Falcon rocket explodes on landing after delivering satellite to space

#151

Post by jraines »

cbhl wrote: post #82
Medox wrote: post #29

The landing could be made safer by something like cushioned walls that deploy towards the rocket after touchdown, to avoid such explosions. Think of a giant Christmas Tree stand like this: http://www.christmastreeland.co.uk/product_images/v/428/761_... . but with cushioned hooks on the barge. You can't always hope for all 4 legs to be in perfect condition, or that there aren't high waves in the ocean. That rocket is…

SpaceX eventually wants to land vehicles on Mars, where such landing infrastructure won't exist (at first). (The Dragon cargo capsule has windows, despite cargo not needing to be able to look outside into space -- the windows are there because the capsule is designed to eventually carry humans some day.)

Seems like it would save money in the interim though, and they'd still have the data of whether it fell or not.

Re: SpaceX Falcon rocket explodes on landing after delivering satellite to space

#152

Post by tempestn »

Havoc wrote: post #149

Why is the barge landing part so important to them? Seems unnecessarily difficult. Big world out there...surely some suitable location can be found that is less wobbly for a start.

They have a limited number of launch sites available to them, and the landing site is based on trajectory and fuel. Depending on the mass being launched, there will often not be enough fuel to turn around, and if you keep going, there's not much but ocean for a long way. Also, not any land will do. You need a pretty big, purpose-built space to land a rocket. With a barge, they can put that space where they need it.

Re: SpaceX Falcon rocket explodes on landing after delivering satellite to space

#153

Post by drchiu »

myth_buster wrote: post #133
smegel wrote: post #104

> explodes on landing This is a pretty unfair characterization. It actually made the landing for most purposes, then a specific failure occurred - a leg failed to lock and it fell over. And yes, when a rocket falls over it will often explode.

As someone mentioned on Reddit Succeeded to land. Failed to stand.

Haha... Made me think the Olympics. What if they had a rocket landing event.

Re: SpaceX Falcon rocket explodes on landing after delivering satellite to space

#154

Post by LewisJEllis »

Havoc wrote: post #149

Why is the barge landing part so important to them? Seems unnecessarily difficult. Big world out there...surely some suitable location can be found that is less wobbly for a start.

Launches which send the payload beyond low earth orbit require too much velocity for the first stage to then turn around and make it all the way back to the launch site.

They put the barge downrange so less fuel will be needed to turn around and land, enabling first stage landings on beyond-low-earth-orbit launches.

Re: SpaceX Falcon rocket explodes on landing after delivering satellite to space

#155

Post by LewisJEllis »

codecamper wrote: post #131

This is the second time something like this happened. Why not put 4 tall posts up - equidistant from each other - a square. Then a wire net between the posts. When it tips over, it can just fall into the wire net.... they could even have motors to unwind a little while it leans over on them to allow "soft catching" the rocket. Foam over the wires would help here. Actually... why not skip the barge & the dramatic land…

Rockets are more fragile than one might think, but even assuming that would work, it's significantly more useful to be able to land just about anywhere that's flat.

Also, we don't have giant posts and nets waiting for us on Mars.

Re: SpaceX Falcon rocket explodes on landing after delivering satellite to space

#156

Post by ansible »

codecamper wrote: post #131

This is the second time something like this happened. Why not put 4 tall posts up - equidistant from each other - a square. Then a wire net between the posts. When it tips over, it can just fall into the wire net.... they could even have motors to unwind a little while it leans over on them to allow "soft catching" the rocket. Foam over the wires would help here. Actually... why not skip the barge & the dramatic land…

Anything other than a perfect vertical landing is likely to result in damage to the structure and components. Thus negating most of the value in landing the 1st stage.

Sea water is also highly corrosive to many materials.

Re: SpaceX Falcon rocket explodes on landing after delivering satellite to space

#157

Post by mmcconnell1618 »

tempestn wrote: post #150
ctdonath wrote: post #115

Earlier quoted context omitted.

There's a pragmatic difference between recovering the booster over some period of time, vs literally parking the booster right where it took off & ready to re-launch within hours/minutes.

I can't see re-launching withing hours any time in the foreseeable future. Even once they're proven reusable each booster will need significant inspection and likely maintenance before being ready to re-launch.

The same stage probably won't be ready to relaunch but imagine an assembly line of reusable stages that land at the same facility where they take off and then head right into a service center. With enough stages in rotation you can have a near continuous stream of launches.

Re: SpaceX Falcon rocket explodes on landing after delivering satellite to space

#158

Post by ansible »

dchesterton wrote: post #65
el_zorro wrote: post #39

Earlier quoted context omitted.

The utility here is not really landing on other planets, but instead the order of magnitude decrease in launch costs if they don't have to build a new first stage for every launch.

This could theoretically be achieved by either means. The question was specifically why a vertical landing is favoured over a cushioned inflatable landing. Musk has stated in the past that they're looking to eventually use this tech to create rockets which can be used on Mars, hence why parachutes and inflatables are out of the question.

Parachutes also have the problem that you can't as easily control the landing point.

Re: SpaceX Falcon rocket explodes on landing after delivering satellite to space

#159

Post by usrusr »

codecamper wrote: post #131

This is the second time something like this happened. Why not put 4 tall posts up - equidistant from each other - a square. Then a wire net between the posts. When it tips over, it can just fall into the wire net.... they could even have motors to unwind a little while it leans over on them to allow "soft catching" the rocket. Foam over the wires would help here. Actually... why not skip the barge & the dramatic land…

My initially reaction were similar ideas, but thinking about it some more i am not sure if the empty tank could tolerate the stresses from getting caught in a net. And with a landing strut failure like today, you would probably lose the engines even with the tank not completely tipping over.

But SpaceX seem to be exceptionally good at control systems, fast and precise automated planning. Maybe they will just skip the level of passive rocket catcher structures and intend to move directly to a three-axis actuated landing table? A system like that that could take responsibility for a tiny little amount of deceleration (think extra suspension) and a fair bit of balancing completely outside of the mass budget of the rocket.

Re: SpaceX Falcon rocket explodes on landing after delivering satellite to space

#160

Post by codecamper »

usrusr wrote: post #159
codecamper wrote: post #131

This is the second time something like this happened. Why not put 4 tall posts up - equidistant from each other - a square. Then a wire net between the posts. When it tips over, it can just fall into the wire net.... they could even have motors to unwind a little while it leans over on them to allow "soft catching" the rocket. Foam over the wires would help here. Actually... why not skip the barge & the dramatic land…

My initially reaction were similar ideas, but thinking about it some more i am not sure if the empty tank could tolerate the stresses from getting caught in a net. And with a landing strut failure like today, you would probably lose the engines even with the tank not completely tipping over. But SpaceX seem to be exceptionally good at control systems, fast and precise automated planning. Maybe they will just skip the…

3 axis table? Do you mean that the platform would be able to shift either way to keep it from wobbling over? That seems hard given that a rocket is tall & skinny.

How about a massive electromagnet underneath?

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