Staging Methods Overview

[Kerbart]

On 4/20/2014 at 7:39 AM, mhoram said:

And that is exactly the reason why I think that they are not used in the best way possible (main diffrence to Asparagus staging).

Except that in serial staging you can use high-efficiency engines that have an I_sp that absolutely blows at ground level, where at ground level you might be willing to use low-performance engines with a very good thrust-to-weight ratio.

If you're launching a small satellite, an FLT-400 with a LV-909 as the upper stage might be all you need to push the payload to  90x0km orbit (from where, no garbage left into orbit, the thruster on the payload circularizes). Sticking to LV-909's for my entire rocket is not a good idea as their sealevel performance blows. But sticking to LV-T45's for the entire rocket.. it weighs 3× that of the LV-909. Now I'm going to need a FLT-800 tank. Now I'm carrying 3× the mass to a high altitude. Knowing the rocket equation we know what that means.

Most designs are likely to be a mix of serial/parralel. Using the same stage that got you off the pad to get out of the atmosphere is generally not efficient; you'll rarely see that approach in real life.

 

 

[Pecan]

On 6/28/2016 at 5:45 PM, Kerbart said:

...Sticking to LV-909's for my entire rocket is not a good idea as their sealevel performance blows. But sticking to LV-T45's for the entire rocket.. it weighs 3× that of the LV-909...

Nothing in the definition of asparagus says you have to have the same - or any - engine(s) on every stage.  If it's core plus lots of drop tanks linked by fuel lines in an asparagus arrangement, it's still asparagus.

[max_creative]

I use pancake staging a lot. If you run fuel lines back and forth so the fuel goes to one tank, which has a fuel line that sends the fuel back to the first tank, it balances the fuel so even if there is one tank bigger than another they all burn for the same time. Very useful for pancake staging where the sides tanks are smaller than the central tank. 

[Red Iron Crown]

19 minutes ago, Pecan said:

Nothing in the definition of asparagus says you have to have the same - or any - engine(s) on every stage.  If it's core plus lots of drop tanks linked by fuel lines in an asparagus arrangement, it's still asparagus.

I don't think of cores without engines being dropped as asparagus, that's more of a drop tank arrangement. Part of asparagus' efficiency is it sheds unneeded engine mass as well as tank mass quickly.

At least by my definition, I'm not sure there is a canonical definition.

[Kerbart]

33 minutes ago, Pecan said:

Nothing in the definition of asparagus says you have to have the same - or any - engine(s) on every stage.  If it's core plus lots of drop tanks linked by fuel lines in an asparagus arrangement, it's still asparagus.

But you'd still be lifting off using an engine that has an I_sp close to zero and burning fuel without getting anything substantial for it. Of course you can choose to light up those engines later on, but that's serially staged again (just not serially mounted).

[Pecan]

19 hours ago, Kerbart said:

But you'd still be lifting off using an engine that has an I_sp close to zero and burning fuel without getting anything substantial for it. Of course you can choose to light up those engines later on, but that's serially staged again (just not serially mounted).

Yours and RIC's are good points and, in particular, the fact that there is no canonical definition.  In practice *grin* whatever works, works.

[Kerbart]

3 hours ago, Pecan said:

Yours and RIC's are good points and, in particular, the fact that there is no canonical definition.  In practice *grin* whatever works, works.

Well, truth to be told, canonical definition would be more appropriate for space flight Jules Vernes style, right?

[DaMachinator]

You forgot the most important kind: explosive decoupling, where stages blow the previous stage up. This saves money on decouplers and special effects.  

[mhoram]

10 hours ago, DaMachinator said:

You forgot the most important kind: explosive decoupling, where stages blow the previous stage up. This saves money on decouplers and special effects.  

Well ... you can use explosive decoupling with all available staging methods ;-)