SpaceX Tuesday...

[Eric Mc]

Absolutely. The barge was just a preliminary device whilst they ensured they could get the stage to within a few hundred meters of its landing point. The plan was always to eventually have them return to solid ground.

Even though none of the barge landings were completely successful, they had obviously satisfied themselves and the FAA that they could target the return accurately enough so that the rocket stage would not end up in a car park in downtown Cocoa Beach.

[MartG]

ash73 said:

Where were the launch and landing sites? Did it turn around and come back, or follow a ballistic trajectory?

Landing site was just a few miles down the coast from the launch site - they refurbished an old Atlas launch pad LC13 for use as the landing pad

Edited by MartG on Tuesday 22 December 10:42

[Eric Mc]

ash73 said:

Depends if they can reuse it economically. If you funded a $1 billion satellite would you want it sitting on top of that used rocket stage? It needs a second flight to prove it's robust.

Absolutely. That's where the Shuttle concept failed. Yes, elements of the system were reusable - but at a massive cost - which completely wiped out the perceived economic advantage of the reusability.

But I certainly have more optimism for the SpaceX way of doing things.

[callmedave]

Even if the recoverable section can only be re-used say 4/5 before it is decommissioned, it must still be more financially viable due to the relatively low initial cost of Falcon 9 (compared to a shuttle for example)

There is a heavier version of the Falcon 9 (think it has 2 solid boosters strapped on) I wonder if they can achieve the same results for this?

[Eric Mc]

We do know that solid boosters can be recovered and re-used. Although it is very interesting that NASA has chosen to make the Shuttle system derived solid boosters for the SLS NON recoverable.

[Scuffers]

callmedave said:

Even if the recoverable section can only be re-used say 4/5 before it is decommissioned, it must still be more financially viable due to the relatively low initial cost of Falcon 9 (compared to a shuttle for example)

There is a heavier version of the Falcon 9 (think it has 2 solid boosters strapped on) I wonder if they can achieve the same results for this?

Falcon 9 heavy is effectively 3 first stages.

[callmedave]

Scuffers said:

callmedave said:

Even if the recoverable section can only be re-used say 4/5 before it is decommissioned, it must still be more financially viable due to the relatively low initial cost of Falcon 9 (compared to a shuttle for example)

There is a heavier version of the Falcon 9 (think it has 2 solid boosters strapped on) I wonder if they can achieve the same results for this?

Falcon 9 heavy is effectively 3 first stages.

Yes, what I meant was how much of it can be recovered, as a percentage of the initial cost.

[Eric Mc]

I doubt if any more than the first stage could be recoverable. By the time a second or third stage has been expended, the craft is hundreds for miles from the launch site travelling at many thousand miles an hour.

[Gandahar]

How much money does it save? How long does the refurbishment take also?

Landing rockets like this is very funky though and good to see.

[Toaster]

This is good video of the shuttle launch and boosters returning https://youtu.be/527fb3-UZGo

With sound

[SpeedyDave]

Eric Mc said:

I doubt if any more than the first stage could be recoverable. By the time a second or third stage has been expended, the craft is hundreds for miles from the launch site travelling at many thousand miles an hour.

Distance from launch is a non issue, no need to land where you launch from. Ideally still land at alternative base where you have facilities though & avoid the cost & complexity of return ground transport.

Getting back down from high and fast is the tricky bit.

And then you also need to add the weight of a complete second set of landing legs, grid fins etc further eating into payload capacity. A payload capacity that is already significantly less than in expendable format.

[annodomini2]

Eric Mc said:

ash73 said:

Depends if they can reuse it economically. If you funded a $1 billion satellite would you want it sitting on top of that used rocket stage? It needs a second flight to prove it's robust.

Absolutely. That's where the Shuttle concept failed. Yes, elements of the system were reusable - but at a massive cost - which completely wiped out the perceived economic advantage of the reusability.

But I certainly have more optimism for the SpaceX way of doing things.

The Space Shuttle was only economically viable with around 30 Shuttles at 10 launches/year each.

This is why the US Air Force backed out.

[annodomini2]

Scuffers said:

callmedave said:

Even if the recoverable section can only be re-used say 4/5 before it is decommissioned, it must still be more financially viable due to the relatively low initial cost of Falcon 9 (compared to a shuttle for example)

There is a heavier version of the Falcon 9 (think it has 2 solid boosters strapped on) I wonder if they can achieve the same results for this?

Falcon 9 heavy is effectively 3 first stages.

It's not 3 stages, the 3 main boosters that are strapped together are the 1st stage.

[Scuffers]

annodomini2 said:

It's not 3 stages, the 3 main boosters that are strapped together are the 1st stage.

that's what I said?

3 first stages (or cores as they call them)

http://www.spacex.com/falcon-heavy

[annodomini2]

Eric Mc said:

I doubt if any more than the first stage could be recoverable. By the time a second or third stage has been expended, the craft is hundreds for miles from the launch site travelling at many thousand miles an hour.

The 2nd stage achieves orbit, albeit a low unstable one.

So go round and come back down.

[Eric Mc]

annodomini2 said:

The Space Shuttle was only economically viable with around 30 Shuttles at 10 launches/year each.

This is why the US Air Force backed out.

I'd be inclined to say that the Shuttle would never have been economically viable - no matter how many there were or how often they flew.

Of course, defining what is "economic" or not is actually a rather arbitrary measurement.

[CrutyRammers]

annodomini2 said:

The 2nd stage achieves orbit, albeit a low unstable one.

So go round and come back down.

It's not the navigation, it's the amount of energy required to decelerate it back to rest. And the amount of energy required to lift that amount of fuel into orbit in the first place.

[Eric Mc]

annodomini2 said:

The 2nd stage achieves orbit, albeit a low unstable one.

So go round and come back down.

I wasn't talking Falcon specifically. Depending on the rocket and/or the payload, some second stages make it into orbit, some don't.

[Toaster]

ash73 said:

Eric Mc said:

...maybe even more important than the Space Shuttle or even Apollo.

I think that's over-egging it a bit.

Glad someone else pointed that out

and similar work was done in 1995 see the DC-X https://youtu.be/wv9n9Casp1o

Oops https://youtu.be/Kk-gGtC7xZ4

How about the Xaero 444m https://youtu.be/UpH3u3hizOc

and of course Blue Origin https://youtu.be/9pillaOxGCo 100km+ altitude and then lands.......


Musk is just building on others ideas and it clearly not a 'big' first i would suggest however he does have pretty good Marketing though

I am not decrying its clever but can it really claim to be the first landing?

Edited to say this is from 2009 and you can see the amount of control that can be had in the challenge

https://youtu.be/ALKvai4p7OE

Edited by Toaster on Tuesday 22 December 13:35

[Scuffers]

Toaster said:

Glad someone else pointed that out

and similar work was done in 1995 see the DC-X https://youtu.be/wv9n9Casp1o

Oops https://youtu.be/Kk-gGtC7xZ4

How about the Xaero 444m https://youtu.be/UpH3u3hizOc

and of course Blue Origin https://youtu.be/9pillaOxGCo 100km+ altitude and then lands.......


Musk is just building on others ideas and it clearly not a 'big' first i would suggest however he does have pretty good Marketing though

I am not decrying its clever but can it really claim to be the first landing?

it can in terms of it being a 100% commercial customer launch that then recovered the first stage as opposed to being a simple recovery test.