Is Asparagus obsolete with SLS?

[Jarin]

No way is asparagus staging dead. I use it for my latest SLS lifter which can get a 500 ton payload into LKO.

Those look a bit odd for the standard SLS S3-KS engines, what are they?

[Redshift OTF]

2 x S3 KS engines clipped in a way to make a hexa-nossel design plus 1 x KR 2L slightly extended so you can stage under it if you wish.

[Killerdude8]

SLS makes what formerly required a Mainsail Asparagus setup, Obsolete, But, SLS parts now also allow for Even larger payloads when you Asparagus them together.

Imagine the possibilities!!

[pauix]

The only thing that can kill asparagus staging is a proper aerodynamic model. Bigger engines will only result in bigger asparagus.

[r4pt0r]

The only thing that can kill asparagus staging is a proper aerodynamic model. Bigger engines will only result in bigger asparagus.

/thread. this sums it all up.

[Red Iron Crown]

Fuel line flow limitations would put a serious damper on asparagus staging, too. The better question is, do we want asparagus staging to go away? It's the most efficient staging we have so it gets used a lot, but if it was eliminated wouldn't the next best staging method just supplant it? I guess I don't see anything inherently undesirable in asparagus staging.

[Kasuha]

The only thing that can kill asparagus staging is a proper aerodynamic model. Bigger engines will only result in bigger asparagus.

Delta IV Heavy and Falcon Heavy are real-life rockets which resemble KSP asparagus design (Falcon is even planned to use it) and don't have any aerodynamic problems. So nope, proper aerodynamics would just mean end to "pancakes" but asparagus staging would still be viable approach. Remember, even with two stages it can still be asparagus.

Fuel line flow limitations would put a serious damper on asparagus staging, too.

Fuel flow limitation is in my opinion almost impossible to implement with current way how fuel flow is handled. It seems simple at first glance but the more you're looking at it, the harder it gets. Up to complete rework of fuel feeding system. Besides, who would prevent you to install ten fuel lines if one was not enough?

The better question is, do we want asparagus staging to go away? It's the most efficient staging we have so it gets used a lot, but if it was eliminated wouldn't the next best staging method just supplant it? I guess I don't see anything inherently undesirable in asparagus staging.

There's no reason to try to get rid of it if real life rockets are trying to go that way. Should we get rid of SSTOs because they don't exist in real world? I think the game would just be way less fun without either.

[Jouni]

I would like asparagus staging to go away, or at least it should be reduced to niche applications like Eve landers. I dislike game-specific knowledge in general, and especially in sandbox games like KSP. When something works in the game but not in the real world, it feels like a bug in the physics simulation.

[Red Iron Crown]

Fuel flow limitation is in my opinion almost impossible to implement with current way how fuel flow is handled. It seems simple at first glance but the more you're looking at it, the harder it gets. Up to complete rework of fuel feeding system. Besides, who would prevent you to install ten fuel lines if one was not enough?

I'll take your word on the difficulty of implementation, I know you're intimately familiar with fuel flow in KSP. Abuse of fuel lines could be curtailed by having the part have mass. If I understand how fuel lines (and struts) are implemented, the mass would all be concentrated in the first half of the part placed, which would be a reasonable approximation of a pump and associated hardware.

[Starwhip]

Delta IV Heavy and Falcon Heavy are real-life rockets which resemble KSP asparagus design (Falcon is even planned to use it) and don't have any aerodynamic problems. So nope, proper aerodynamics would just mean end to "pancakes" but asparagus staging would still be viable approach. Remember, even with two stages it can still be asparagus.

I think you don't know what asparagus staging is. It's the 3+ layers of fuel tank-engine combos that are around 7 Rockomax-64's in width. Those are pancakes. The Delta IV Heavy uses a smaller version: from what I remember it has 2 side boosters that have their own engines but also feed to the core stage, not 35 other engines that stage every 2.5 seconds.

[Red Iron Crown]

I think you don't know what asparagus staging is. It's the 3+ layers of fuel tank-engine combos that are around 7 Rockomax-64's in width. Those are pancakes. The Delta IV Heavy uses a smaller version: from what I remember it has 2 side boosters that have their own engines but also feed to the core stage, not 35 other engines that stage every 2.5 seconds.

You can do asparagus with as few as 5 tanks, even 3 by some definitions. The critical characteristics are all engines burning and two tanks drained and dropped at a time.

[NecroBones]

You can do asparagus with as few as 5 tanks, even 3 by some definitions. The critical characteristics are all engines burning and two tanks drained and dropped at a time.

As far as I'm concerned, at 5+ tanks, it can still be asparagus. With only 3, it's technically the same idea, but it's just crossfeeding from radial boosters into the center without being daisy-chained anymore, so it's a bit of a judgment call there.

[Red Iron Crown]

^^ Yeah, that's what I meant with "by some definitions".

Does anyone have a link about Delta IV Heavy using crossfeed? As I understood it, they just throttle the center stage down so it has fuel left after the side boosters are expended. I thought SpaceX's Falcon Heavy was to be the first seriously-sized attempt at crossfeed.

[AngusJimiKeith]

^^ Yeah, that's what I meant with "by some definitions".

Does anyone have a link about Delta IV Heavy using crossfeed? As I understood it, they just throttle the center stage down so it has fuel left after the side boosters are expended. I thought SpaceX's Falcon Heavy was to be the first seriously-sized attempt at crossfeed.

Yeah, your understanding is correct. There have been studies with D-IV H crossfeed, but none too serious. More likely they'll put srb's on all three cores to get extra performance. I'll see if I can dig up the source for that.

Even Falcon Heavy won't use crossfeed at first.

[Shna_na]

You can go "SUPER ASPARAGUS" quite easily with the new update. Though I never use asparagus staging, I do use external tanks. I tend to just treat the SLS parts the same way I treat any other propulsion part - by following these 5 simple steps:

1. Put a bunch of fuel tanks on a powerful engine
   
2. "That looks like it'll fly!"
   
3. Launch
   
4. ???
   
5. Profit!
   

[Moar Boosters]

^^ Yeah, that's what I meant with "by some definitions".

Technically it's onion staging unless you've got boosters feeding boosters. The whole reason it was named asparagus is because the rockets look like a bundle of asparagus sticks.

I kinda question the purpose of building giant asparagus monsters with the new SLS fuel tanks. It's not necessarily going to be the most efficient way to launch because the new fuel tanks have an inferior dry mass ratio. They're also too big to really bring the efficiency. Generally the more regularly you drop empty tanks, the more efficient the design..... so it's not going to be hugely efficient waiting for these big tanks to empty. That's why people normally use the 1.25m tanks for Eve landers. Even the 2.5m ones result in you carrying more empty fuel tanks that is optimal.

[Kasuha]

Definition of asparagus staging is older than KSP. And if we look at that definition, then nothing there says that more than two boosters need to be involved. The matter is the fuel feed. Falcon Heavy is officially referred to be using "asparagus staging".

But if we return to the matter of aerodynamics, I still don't think there are any real obstacles in using more stages, as long as the whole body is kept reasonably aerodynamic. The difference is not in asparagus or non-asparagus, it is in pancake, or aerodynamic.

For instance Kerbal-X craft would in my opinion pass aerodynamics test with flying colors.

[R0cketC0der]

Definition of asparagus staging is older than KSP. And if we look at that definition, then nothing there says that more than two boosters need to be involved. The matter is the fuel feed. Falcon Heavy is officially referred to be using "asparagus staging".

But if we return to the matter of aerodynamics, I still don't think there are any real obstacles in using more stages, as long as the whole body is kept reasonably aerodynamic. The difference is not in asparagus or non-asparagus, it is in pancake, or aerodynamic.

For instance Kerbal-X craft would in my opinion pass aerodynamics test with flying colors.

Could you please show me a source that is older than ksp that refers to this kind of staging as asparagus? Also a source where SpaceX calls it asparagus staging would be nice. Because from my understanding, the name asparagus staging is made up by the ksp community.

[sal_vager]

You want Ed Keith's Innovative Asparagus Stalk Booster concept, the oldest source of which that we know of is Tom Logsdons Orbital Mechanics, Theory and Applications.

[Kasuha]

Could you please show me a source that is older than ksp that refers to this kind of staging as asparagus? Also a source where SpaceX calls it asparagus staging would be nice. Because from my understanding, the name asparagus staging is made up by the ksp community.

Likewise: could you please show me a source that proves that the name was inventented by the KSP community?

I can remember a post here on forums that showed a 30+ years old document mentioning asparagus staging. But of course I have no idea how to find it now. There's the Search function for both of us.

Edit: I found this, this, and this. Sadly the last link does not show me any content.

Edit 2: and this

So much for KSP origin.

Then, there's the fact that Falcon Heavy is referred to use Asparagus staging, too. See Wikipedia entry for Falcon Heavy, I don't think it's made by KSP fans.

Edited May 7, 2014 by Kasuha

[sal_vager]

The old thread.

I used to call this daisy chaining, never knew the term asparagus when I started playing KSP, but yeah the term pre-dates the game by a fair bit.

[Moar Boosters]

Likewise: could you please show me a source that proves that the name was inventented by the KSP community?

I can remember a post here on forums that showed a 30+ years old document mentioning asparagus staging. But of course I have no idea how to find it now. There's the Search function for both of us.

Edit: I found this, this, and this. Sadly the last link does not show me any content.

Here is the missing page.

The original concept backs up what I said. You've gotta have boosters feeding boosters and them dropping off in pairs when empty. Otherwise it's not asparagus, it's onion staging (I have no idea if the term onion staging pre-dates KSP or not).

http://m.radd.it/r/KerbalSpaceProgram/comments/1uyx29/any_publications_on_asparagus_staging/

[Jas1126]

There is, however, no need to be insulting about it.

I realized after I made the post that it needed to be sugar coated. Self expression has to be faked with smiley faces and kittens. I should have done so. Sorry.

[NecroBones]

You want Ed Keith's Innovative Asparagus Stalk Booster concept, the oldest source of which that we know of is Tom Logsdons Orbital Mechanics, Theory and Applications.

Awesome, so it goes back at least as far as 1997 (Library of Congress date at the beginning of the book).

[R0cketC0der]

Ok thanks for the sources, really didn't know this.