How to play without asparagus staging?

[Foxster]

I suppose it depends where you want to draw the line. 

If you want to impose the restriction on yourself of not doing any cross-feeding of fuel then you will have to take the hit of lower dV and compensate accordingly with more fuel+engines. 

If, however, you are OK with a single cross-feed then many ships become more workable. For instance, here is a current Eve science-base delivery rocket I have been toying with...

 

The first stage tanks keep the second stage topped up and all six of the non-nuke engines fire at launch. So it is asparagus staging - of a limited sort. 

Edited December 31, 2015 by Foxster

[Whackjob]

I always went the route of, "More boosters is never as good as bigger boosters.  Because you can always have more bigger boosters."

[GoSlash27]

Alshain,

 I knocked together a similar table a while back and never released it. I can expand on your recommendations.

These recommendations were generated using my engineering spreadsheet. They are optimized for cost to orbit.

payload range vs. recommended stack

0-0.12t	LV-1 "Ant" a,b	48-7S "Spark" a
0.13-1.1t	48-7S "Spark" a	LV-T30 "Reliant" b
1.2t-2.2t	LV-909 "Terrier" a	LV-T30 "Reliant" b
2.4-4.0t	LV-909 "Terrier" a	RE-I5 "Skipper"
4.2-7.0t	RE-L10 "Poodle"	RE-I5 "Skipper"
7.5-17t	RE-L10 "Poodle"	RE-M3 "Mainsail"
18-24t	RE-I5 "Skipper"	KR-1x2 "Twin Boar"
25-45t	RE-I5 "Skipper"	KS-25x4 "Mammoth"

Notes:

a: Warning, this part does not generate electric charge

b: Warning, this part does not have thrust vectoring.

I like to use SRB lowers to cut down on costs. In the above chart everything from the Reliant to the Twin Boar can be replaced by SRBs for substantial savings, but the reader should keep in mind that SRBs have no throttle, no alternator, and no thrust vectoring. This makes them somewhat tricky to work with.

Best,

-Slashy

Edited December 31, 2015 by GoSlash27

[Grenartia]

3 hours ago, Foxster said:

I suppose it depends where you want to draw the line. 

If you want to impose the restriction on yourself of not doing any cross-feeding of fuel then you will have to take the hit of lower dV and compensate accordingly with more fuel+engines. 

If, however, you are OK with a single cross-feed then many ships become more workable. For instance, here is a current Eve science-base delivery rocket I have been toying with...

 

The first stage tanks keep the second stage topped up and all six of the non-nuke engines fire at launch. So it is asparagus staging - of a limited sort. 

I find myself intrigued by what those intakes are for.

 

[luizopiloto]

Aspargus is not a impossible thing in RL... we just need better fuel pumping tech for this...

[cantab]

Yeah, I've rarely found the need for asparagus staging. Just look at real life rockets for some inspiration, you'll see a few common approaches.

[NecroBones]

If you're trying to avoid Asparagus staging, another option is to do what the Delta IV Heavy does. That is, there's no fuel crossfeed, and even though the strap-on boosters have the same engine and fuel capacity as the center stack's lower stage, they still burn out and discard faster. What they do is run the center engine at about 57% throttle. When the side boosters are almost out of fuel, they stage off, using the remaining small amount of fuel to steer away from the center stack. Then the center, which has maybe 45% (roughly) of its fuel remaining, will throttle up to 100%. If you're working with just one center engine in this configuration, you can right-click and use the thrust limiter to throttle just the one engine.

[Foxster]

2 hours ago, Grenartia said:

I find myself intrigued by what those intakes are for.

 

They are better nose cones than "nose cones". 

[luizopiloto]

I only need aspargus staging for compact returning vehicles for Eve and Laythe...

[Pecan]

Exotic alternatives to asparagus on Kerbin:

• SSTOs.  Rockets are easier to build and fly on the way up, 'planes are easier on the way down.
• Twisted candle staging.  Even more efficient than asparagus but even more complicated/expensive to build.

 

[Eric S]

13 hours ago, 5thHorseman said:

THAT is what is not super realistic for at LEAST the reason that it would introduce torque in the ship, pumping fuel around in a circle like that.

That's not as true as you'd think.  Except for when the fuel lines are filling or draining, there's always the same amount of fuel being accelerated into the pipe as there is being decelerated when it comes out of the pipe.  Generating torque out of that situation would be the same as being able to push against yourself.

What is true is that if the craft starts rotating and goes unchecked, there will be a force trying to cause it to rotate faster.  That would be conservation of angular momentum from the fuel that is getting transferred to the center core.

On the other hand, what kills asparagus staging IRL is the fact that it's heavily reliant on turbopumps, and from what I've seen, those are probably the most common non-human cause of rocket launch failure going.  That said, it's going to take about 70 years for the single layer concept to go from conception to practical application (conceived in 1947, if I remember correctly, and a practical application in the F9H which hasn't actually flown yet), so I wouldn't be surprised if it takes another 50 years for us to develop turbopumps that are reliable enough for asparagus usage.  After all, KSP players didn't invent asparagus staging, we just live in a world with perfectly reliable infinite-fuel-flow turbopumps so it was easier for us to implement the concept.

 

Edited December 31, 2015 by Eric S
hit post too soon.

[Fleb]

I just spent some time watching real rocket videos on Youtube, and then tried copying the designs. Most of my lifters now consist of a central core stage with a TWR around 1-1.1 and then enough boosters to get it up to speed. Probably not as efficient as asparagus staging, but it's much easier to build and get to orbit without any fuel tank collision incidents.

[Beowolf]

11 hours ago, Grenartia said:

Honestly, I just let MechJeb do it for me.

It's worth learning. I let MechJeb teach me, but these days I dock manually, with help from navyfish's docking indicator, and quickly got much, much faster than MJ.

Once I had a lander stuck on Mun, terribly short on fuel. I burned straight up, got an apo of 20 km. Switched to my mothership 60 km away and managed rendezvous, docking, and turn-and-burn to miss the ground in 2 minutes 20 seconds (less really, as that was the lander's time-to-impact). It did take a several quickloads to get the rendezvous right, as it required an absurd burn with a 180-degree flip at 6Gs to end up at the right spot at the right time and speed for docking.  But I nailed that docking first time, at a concussion-inducing 3m/s. Those ports will never be the same!

Naturally Murphy's Law was in-effect, and now the mothership was running on fumes, but they managed a 10km orbit to await help.

[Choctofliatrio2.0]

I rarely use it. Lots of effort, and I often do it wrong. I just add more boosters.

[Geschosskopf]

16 hours ago, GunnDawg said:

Anyways, lets hear your tips and pointers on building rockets that DO NOT use asparagus staging. I'm talking some SpaceX or Soyuz rocket style designs I guess.

Well, I don't use asparagus myself at all, except maybe once or twice early in a career game before I have enough big rocket parts to lift my payloads on single stacks (although often with some initial SRB help).  See, the thing is, a given payload mass to a given orbit altitude requires the same dV no matter how you slice it.  So you basically have a choice:  slice it up into lots of small small-diameter asparagus stacks or fewer, wider, non-asparagus stacks.  IOW, without sacrificing payload mass, if you don't want to do asparagus, you need a wider rocket and the more powerful engines that come with them.

So, bottom line is, the mass of your payload is limited by the diameter of your biggest rocket parts.  To put heavier payloads in space, you either need to send them up in pieces for orbital assembly or get bigger rocket parts.  Stock only goes to 3.5m so if you need anything bigger than that, you'll need a mod.  My current big lifter mod of choice is Space-Y Lifters which goes to 5m.  There's an extension for that which goes to 7m but so far I've never needed to use it.

The cool thing about Space-Y is that it comes with many very useful SRBs in all sizes up to 3.5m.  I use these much more than the 5m rocket parts themselves.  Usually, I can build a 3.5m rocket with enouth TWR to lift my payloads but it only has about 2500m/s.  So I just put a few big SRBs on it to give it that extra 1000m/s.  IOW, my "standard" lifter is a philosophy, not necessarily the same parts all the time.  It's a single LFO stage with a starting TWR of about 2.0 and about 2500m/s in the tanks.  This is rigged as the 2nd stage after launch.  The 1st stage is SRBs with about 1000m/s dV and an initial TWR of about 1.5.  I do this for all sizes of rockets from 1.25m probe launchers to massive 3.5m and 5m things hefting large stations and bases to the outer planets.  Occasionally, the numbers work out so that the LFO part of the lifter is in 2 stages but usually that's not worth messing with.

Thus, I have very simply rockets with very few thing to go wrong, which can lift anything I want.  I like the simplicity and reliability of this philosophy in its own right and would do things this way even if I didn't think asparagus was an exploit.

[Grenartia]

6 hours ago, Foxster said:

They are better nose cones than "nose cones". 

I'm actually surprised by that.

5 hours ago, Pecan said:

Exotic alternatives to asparagus on Kerbin:

• SSTOs.  Rockets are easier to build and fly on the way up, 'planes are easier on the way down.
• Twisted candle staging.  Even more efficient than asparagus but even more complicated/expensive to build.

 

I know I should probably lose my Kerbal Kard for this, but I've never successfully built an SSTO. At least a reuseable one. Or a plane.

Twisted candle?
 

4 hours ago, Beowolf said:

It's worth learning. I let MechJeb teach me, but these days I dock manually, with help from navyfish's docking indicator, and quickly got much, much faster than MJ.

Once I had a lander stuck on Mun, terribly short on fuel. I burned straight up, got an apo of 20 km. Switched to my mothership 60 km away and managed rendezvous, docking, and turn-and-burn to miss the ground in 2 minutes 20 seconds (less really, as that was the lander's time-to-impact). It did take a several quickloads to get the rendezvous right, as it required an absurd burn with a 180-degree flip at 6Gs to end up at the right spot at the right time and speed for docking.  But I nailed that docking first time, at a concussion-inducing 3m/s. Those ports will never be the same!

Naturally Murphy's Law was in-effect, and now the mothership was running on fumes, but they managed a 10km orbit to await help.

I just find the whole process a little too tedious for my personal tastes. I'm more of an engineer than a pilot, truth be told. Although I could probably do it in a pinch, watching MJ has taught me the basics.

Also, holy crap.

 

2 hours ago, Geschosskopf said:

Well, I don't use asparagus myself at all, except maybe once or twice early in a career game before I have enough big rocket parts to lift my payloads on single stacks (although often with some initial SRB help).  See, the thing is, a given payload mass to a given orbit altitude requires the same dV no matter how you slice it.  So you basically have a choice:  slice it up into lots of small small-diameter asparagus stacks or fewer, wider, non-asparagus stacks.  IOW, without sacrificing payload mass, if you don't want to do asparagus, you need a wider rocket and the more powerful engines that come with them.

So, bottom line is, the mass of your payload is limited by the diameter of your biggest rocket parts.  To put heavier payloads in space, you either need to send them up in pieces for orbital assembly or get bigger rocket parts.  Stock only goes to 3.5m so if you need anything bigger than that, you'll need a mod.  My current big lifter mod of choice is Space-Y Lifters which goes to 5m.  There's an extension for that which goes to 7m but so far I've never needed to use it.

The cool thing about Space-Y is that it comes with many very useful SRBs in all sizes up to 3.5m.  I use these much more than the 5m rocket parts themselves.  Usually, I can build a 3.5m rocket with enouth TWR to lift my payloads but it only has about 2500m/s.  So I just put a few big SRBs on it to give it that extra 1000m/s.  IOW, my "standard" lifter is a philosophy, not necessarily the same parts all the time.  It's a single LFO stage with a starting TWR of about 2.0 and about 2500m/s in the tanks.  This is rigged as the 2nd stage after launch.  The 1st stage is SRBs with about 1000m/s dV and an initial TWR of about 1.5.  I do this for all sizes of rockets from 1.25m probe launchers to massive 3.5m and 5m things hefting large stations and bases to the outer planets.  Occasionally, the numbers work out so that the LFO part of the lifter is in 2 stages but usually that's not worth messing with.

Thus, I have very simply rockets with very few thing to go wrong, which can lift anything I want.  I like the simplicity and reliability of this philosophy in its own right and would do things this way even if I didn't think asparagus was an exploit.

This is my general approach, more or less. Though I usually budget 4km/s to LKO instead of 3.5.
 

Edited December 31, 2015 by Grenartia

[Geschosskopf]

48 minutes ago, Grenartia said:

This is my general approach, more or less. Though I usually budget 4km/s to LKO instead of 3.5.

Deranged minds have similar nightmares

 

[Pecan]

42 minutes ago, Grenartia said:

...Twisted candle?...

I'm sorry, I intended to include a link to it in my post above: http://forum.kerbalspaceprogram.com/index.php?/topic/68532-staging-methods-overview/

The general idea is that you have a single stack of tanks in several stages, with radial engines on several stages (some may be left slack) and fuel lines such that fuel is consumed from the bottom tank up.  The single tank is used-up faster than asparagus's two so can be staged earlier and is more efficient, at least in theory.  When a tank is staged any attached radial engines go with it, of course, much like the engines in asparagus stages.  The arrangement is called twisted candle because the engines have to be offset so they don't get hit by the exhaust from ones above, eg; N/S in one stage, NW/SE in the next, E/W in the next and so on.

[Grenartia]

1 minute ago, Geschosskopf said:

Deranged minds have similar nightmares

 

Well, that, and it cuts down on fuel requirements for other stages.

I have noticed a fair amount of debris buildup in orbit, though. I think I might have to make and deploy some kinetic kill missiles.

[Geschosskopf]

3 minutes ago, Grenartia said:

Well, that, and it cuts down on fuel requirements for other stages.

I have noticed a fair amount of debris buildup in orbit, though. I think I might have to make and deploy some kinetic kill missiles.

I use TAC Self-Destruct on all stages that won't re-enter by themselves.  No debris accumulation and launches punctuated by gratuitous explosions.  What's not to love?

[Grenartia]

3 minutes ago, Geschosskopf said:

I use TAC Self-Destruct on all stages that won't re-enter by themselves.  No debris accumulation and launches punctuated by gratuitous explosions.  What's not to love?

I mean, I know you can destruct debris in stock, But I just want to make something that will do it. Just to say I can and I did.

[Hysterrics]

Your lifter should be what puts your payload into orbit. Your payload is what gets you places. That's how you should organize. Make an upper stage that has the DeltaV to go where you need to go(Minus ~4000 m/s for the ascent) then build a lifter which can carry your payload to orbit(Your lifter needs ~ 4000m/s DeltaV)

[cantab]

6 hours ago, Fleb said:

Most of my lifters now consist of a central core stage with a TWR around 1-1.1 and then enough boosters to get it up to speed.

This is a common approach for me as well. Simple, like a real rocket, and burning the core engine from the start (sometimes throttled back) gives me crucial thrust-vectoring for control, since KSP doesn't have vectored SRBs.

13 minutes ago, Sequinox said:

Your lifter should be what puts your payload into orbit. Your payload is what gets you places. That's how you should organize. Make an upper stage that has the DeltaV to go where you need to go(Minus ~4000 m/s for the ascent) then build a lifter which can carry your payload to orbit(Your lifter needs ~ 4000m/s DeltaV)

Well I'd say it's not quite so cut-and-dried. Most real rockets feature two payload ratings - one for LEO, and a second lower rating for Geostationary Transfer Orbit. Sometimes other configurations are used too, like Saturn V where the third stage put the spacecraft on Trans-Lunar-Injection. Or New Horizons, where the Atlas V's second stage reignited in low orbit to start the ejection burn (that was completed by a Star 48 solid motor which you can argue was part of the payload).

What I think is more generally the case is the launcher is doing its burns around or below low orbit. Sometimes there's a wait and reignition in low orbit, but once you start thinking about the burn to enter geostationary orbit or the burn to capture at your destination planet or moon, that's definitely something that's the job of the payload. Though since KSP lacks fuel boiloff and part reliability concerns, if I have excess delta-V in my launcher I'm probably gonna keep it with me anyway!

[Superfluous J]

7 hours ago, Eric S said:

That's not as true as you'd think.  Except for when the fuel lines are filling or draining, there's always the same amount of fuel being accelerated into the pipe as there is being decelerated when it comes out of the pipe.  Generating torque out of that situation would be the same as being able to push against yourself.

No, it's as true as I think. If you ever get the chance alone on a merry-go-round, get on the edge and slowly make your way around it. You'll notice that the Merry-go-round more slowly (but perceptibly) goes the other way.

Even though there is no outside force on the two of you, your force on it (or more easily imagined the shifting of the center of mass of you two as a pair) causes - when one of you moves relative to the COM - for the other to move to compensate.

[razark]

So, what if boosters 1 and 2 each drained into both 3 and 4, which then fed into the core?

Of course, it would complicate the plumbing and double the pumps (would it?  Can the one pump feed two different fuel lines?) so I don't see it happening.