I love building asparagus rockets in KSP but don't see them much in real life.

[I_Killed_Jeb]

If people want to build 1000-booster asparagus rockets, who cares? Besides, as others have mentioned, as soon as proper drag is implemented most of these problems will be moot.

[magnemoe]

It would have the effect you want, but I think it would have some serious drawbacks in other situations because it doesn't matter what you're using the radial decouplers for, a 0.625 m probe or a 6.25m superbooster, it adds the same amount of drag per stack. Which means that even the perfectly normal and acceptable large center stack with two narrow solid boosters gets penalized.

If you want to use aerodynamics to kill asparagus staging (it probably won't, but it could probably kill the multi-layer asparagus abuse), then model aerodynamics to do so, don't hack up something because you don't like it. It reminds me of the old Star Trek roleplaying game, where they actually had rules for dual-wielding weapons that didn't restrict the rules to melee weapons, they just said "Sulu would never consider using two phasers at the same time."

Mass that a 7 stack 3.75m asparagus cluster wouldn't notice would be enough to ground my little Mun lander that only uses fuel lines to suck fuel from radially mounted tanks because without them, it would be too tall to land safely. Having different fuel lines (with differing masses) for different fuel flow amounts is just adding complexity to the game that would affect most designs just to stomp on one class of design, but at least it would have fewer negative consequences other than the complexity itself.

It's really these kinds of unintended consequences that you have to watch out for with ideas of how to limit asparagus staging.

Then I think of wild aspargus use its stuff like my 16 stage Jool lander who is totally unrealistic. The three stage 6+1 mainsail default will thrive well, you will probably need to switch to the radial separator without spacing and use more seperatrons.

As you say lots of legitimate use of fuel lines. We also use fuel lines between tanks to regulate fuel drain. An jet fighter on an long range bombing mission might carry 3 drop tanks and first drop the outer tanks and then the center one, however this is done with switching the tanks to drain fuel from. In KSP we would have to draw fuel lines from outer tanks to central and then to plane unless you want to transfer fuel manually who is very hard during takeoff and landing at least unless you let mechjeb do the flying.

My standard Mun lander to do science missions to Mun has two drop tanks who take it from LKO to deorbit burn. Yes I could have uses an transfer stage but I save 0.5 ton on using the 909 in the lander.

As for using two pistols at the same time, it don't work in real life at least not outside an circus show. Yes carrying multiple pistols was common then you had one or two barrels muzzle loaded pistols to give you more shots however the standard rpg idea that you can shoot with multiple weapons at once to get more firepower the same way ships has multiple cannons don't make sense, at least not for humans.

[Francesco]

How about just limiting the amount of fuel per second that can flow through the fuel line? I mean right now a single fuel line can drain an entire orange tank in a second or two if you go overboard with asparagus staging... That's hardly realistic.

That would be interesting.

Maybe have fuel lines and turbopumps of various sizes and performances.

The aforementioned Falcon Heavy, in fact, shouldn't crossfeed all of the core engines, but only 6 out of 9 (three per side booster.)

[Eric S]

As for using two pistols at the same time, it don't work in real life at least not outside an circus show. Yes carrying multiple pistols was common then you had one or two barrels muzzle loaded pistols to give you more shots however the standard rpg idea that you can shoot with multiple weapons at once to get more firepower the same way ships has multiple cannons don't make sense, at least not for humans.

So you're saying there should be a severe accuracy penalty for using two ranged weapons at the same time? Funny, that's what I said at the time. "Don't do it because I say so" reasons bother me. Even "there's a 1% chance that you'll cross the streams, causing both phasers to explode" would have been more acceptable than just "don't do it."

There are reasons that asparagus isn't used in real life yet, the biggest problem is that none of those reasons depend on something currently modeled in KSP in such a way that it adversely affects asparagus staging. Heck, just having stages dropped on the launch pad damage the launch pad which in turn causes repairs that bite into your funds would kill the deep asparagus designs because they don't get far enough away from the launchpad before they drop the first set of tanks. The "unintended consequences" is that would make disastrous launchpad failures even more expensive, but at least that can be "Revert to Vehicle Assembly Building"ed away. Hmmmm.... the more I think about it, the more I like that idea, especially given that it's something the devs have said that they want to do. The more stages you have, the bigger an issue it becomes because with asparagus staging, that means that your first staging event happens soon. Heck, I've had designs where the first staging event happened at less than 500 meters.

[magnemoe]

So you're saying there should be a severe accuracy penalty for using two ranged weapons at the same time? Funny, that's what I said at the time. "Don't do it because I say so" reasons bother me. Even "there's a 1% chance that you'll cross the streams, causing both phasers to explode" would have been more acceptable than just "don't do it."

There are reasons that asparagus isn't used in real life yet, the biggest problem is that none of those reasons depend on something currently modeled in KSP in such a way that it adversely affects asparagus staging. Heck, just having stages dropped on the launch pad damage the launch pad which in turn causes repairs that bite into your funds would kill the deep asparagus designs because they don't get far enough away from the launchpad before they drop the first set of tanks. The "unintended consequences" is that would make disastrous launchpad failures even more expensive, but at least that can be "Revert to Vehicle Assembly Building"ed away. Hmmmm.... the more I think about it, the more I like that idea, especially given that it's something the devs have said that they want to do. The more stages you have, the bigger an issue it becomes because with asparagus staging, that means that your first staging event happens soon. Heck, I've had designs where the first staging event happened at less than 500 meters.

Yes and the accuracy penalty would be so high you would do less damage than using one weapon except on very close ranges.

For the asparagus you simply make the first stage larger, no need for them to be of same size.

This is an typical asparagus abuse. it lift almost 5 orange tanks to orbit, it drops the trashcans before the first booster stage at around 3000 meter and the large solid fuel afterwards at around 5000 meter.

[magnemoe]

That would be interesting.

Maybe have fuel lines and turbopumps of various sizes and performances.

The aforementioned Falcon Heavy, in fact, shouldn't crossfeed all of the core engines, but only 6 out of 9 (three per side booster.)

Yes, however then we should also get fuel values who could be staged, so I did not start drawing from tank2 until I activated the valve at the same time I dropped tank1. The pipe through an row of tanks do the same in the game but is unrealistic.

The 3+3+3 engines are done to simplify piping perhaps they do 4+4+1 with the new engine setup they switched to, you can anyway vary the trust from different engines

[Eric S]

Yes and the accuracy penalty would be so high you would do less damage than using one weapon except on very close ranges.

Exactly. A realistic penalty that makes it not worth doing except under specific circumstances instead of a flat "Don't do that" rule.

This is an typical asparagus abuse. it lift almost 5 orange tanks to orbit, it drops the trashcans before the first booster stage at around 3000 meter and the large solid fuel afterwards at around 5000 meter.

Actually, I'd disagree on "typical asparagus abuse." Five asparagus stages (counting the center stack) to me is just into what I'd consider abusive. It's the 10 stage asparagus stacks I was thinking of, and even stacking fuel tanks that high, you'd be looking at dropping the tanks in half the time in that case. Still, a valid counterpoint to my idea that would have to be kept in mind during balancing.

The 3+3+3 engines are done to simplify piping perhaps they do 4+4+1 with the new engine setup they switched to, you can anyway vary the trust from different engines

I had read somewhere that they were at least considering the 4+4+1 plan with the new engine setup.

Edited October 24, 2013 by Eric S

[hobbsyoyo]

Actually, I'd disagree on "typical asparagus abuse." Five asparagus stages (counting the center stack) to me is just into what I'd consider abusive. It's the 10 stage asparagus stacks I was thinking of, and even stacking fuel tanks that high, you'd be looking at dropping the tanks in half the time in that case. Still, a valid counterpoint to my idea that would have to be kept in mind during balancing.

I think maybe you misread him. He meant that it could lift 5 orange tanks to orbit (presumably full), not that it had 5 booster stages.

[Eric S]

I think maybe you misread him. He meant that it could lift 5 orange tanks to orbit (presumably full), not that it had 5 booster stages.

That's not where I got that number from. I counted the stacks, double checked the number of liquid engines in the staging bar, etc. Unless he's doing something wrong and not firing all of his asparagus stacks at the same time, that ship has 9 asparagus stacks, which means two branches of four stages, coming together at one central stage. The SRBs are another stage, but has nothing to do with the asparagus staging.

[doggie015]

Add reliability to the list. If your engines are clustered tight together you can compensate for one of the engine failing and simply burn longer. With asparagus setups you will need every engine to burn, doubling, tripling or even quadrupling the chances of failure. And RL engines are fare less reliable than the KSP ones...

Case in point: The Apollo 13 ascent. The inboard engine shut down two minutes early but they were able to burn the outboards longer and still get into normal orbit.

[magnemoe]

That's not where I got that number from. I counted the stacks, double checked the number of liquid engines in the staging bar, etc. Unless he's doing something wrong and not firing all of his asparagus stacks at the same time, that ship has 9 asparagus stacks, which means two branches of four stages, coming together at one central stage. The SRBs are another stage, but has nothing to do with the asparagus staging.

You are right, its an 8+1 design, looks weird as its highly tuned and I wanted an easy to operate refueler who carried lots of fuel so an short design with one center and four side tanks made sense.

As I tuned it to use less and less of the 5 tanks I found I could easy increase the size of first stage if I used more SRB

[roosterr]

.. and to your point OP, I dont like to build asparagus rockets (but still must to get anywhere in KSP).

[Moar Boosters]

.. and to your point OP, I dont like to build asparagus rockets (but still must to get anywhere in KSP).

You don't have to use asparagus. Being efficient isn't the only way. Building stupidly big also works. This ship gets to Tylo and back using simple pancake staging and no atomic engines.

[Tokay Gris]

And RL engines are fare less reliable than the KSP ones...

Well.... Engines ok. They never fail.

But the rockets.... (My) KSC its littered with the remains of a lot of quite interesting fireworks. Especially since I am trying to get a 200 ton interplanetary tanker in orbit.

The problem with this is not the actual lifting stage but keeping the payload (the tanker) together during liftoff.

Sometimes it works, sometimes one of the tanks or more just drop of and destroys the rest. Leading to more debris around KSC.

But well.... it's unkerbaled. Lets try again!

;-)

[Moar Boosters]

Well.... Engines ok. They never fail.

But the rockets.... (My) KSC its littered with the remains of a lot of quite interesting fireworks. Especially since I am trying to get a 200 ton interplanetary tanker in orbit.

The problem with this is not the actual lifting stage but keeping the payload (the tanker) together during liftoff.

Sometimes it works, sometimes one of the tanks or more just drop of and destroys the rest. Leading to more debris around KSC.

But well.... it's unkerbaled. Lets try again!

;-)

Big ships can be unpredicable when physics kick in. Sometimes they fall apart, sometimes they don't. TBH I have no idea how the Kerbals manage to move some of my rockets from the VAB to the launch pad in one piece.

I think in real life they probably do calculations to test the integrity of their designs before even starting construction. The Kerbal way is to do it kinda in reverse. Build the rocket however you feel like, and then keep applying duct tape (struts) until it stops falling apart.

[magnemoe]

yes and structural issues is another major benefit with asparagus, most interplanetary cargoes tend to be long, nuclear engines, fuel, reaction wheels, rcs, crew compartment, control cabin, probe and then the lander or landers, even an small duna mission tend to be more than an orange tank long my huge Jool mission is over two.

Putting the lower stages around it makes it easy for it to survive launch as the boosters support each other, and you can use the LV-N to increase trust and ISP.

[hobbsyoyo]

That's not where I got that number from. I counted the stacks, double checked the number of liquid engines in the staging bar, etc. Unless he's doing something wrong and not firing all of his asparagus stacks at the same time, that ship has 9 asparagus stacks, which means two branches of four stages, coming together at one central stage. The SRBs are another stage, but has nothing to do with the asparagus staging.

Sorry, I thought you were saying he had 5 asparagus stacks.

Case in point: The Apollo 13 ascent. The inboard engine shut down two minutes early but they were able to burn the outboards longer and still get into normal orbit.

The problem is that in KSP, unless it is the central engine in a cluster that goes out, your mission is over. Even if you have gimbaled engines, the SAS cannot adjust the vectoring to make up for assymetrical thrust and your rocket will flip over.

Big ships can be unpredicable when physics kick in. Sometimes they fall apart, sometimes they don't. TBH I have no idea how the Kerbals manage to move some of my rockets from the VAB to the launch pad in one piece.

I think in real life they probably do calculations to test the integrity of their designs before even starting construction. The Kerbal way is to do it kinda in reverse. Build the rocket however you feel like, and then keep applying duct tape (struts) until it stops falling apart.

Unfortunately, when you get into making huge rockets, adding more struts at best doesn't help or even makes the problem worse. Like you said, the physics engine acts up when you launch big rockets and will break them at randome points even if they are properly strutted. Adding more struts to compensate means more physics calculations which makes for more errors in the physics engine and more random break-downs.

This is an issue my Laythe science base mission has had: I can desigb launchers for the heavier components but they all explode at random points due to the physics engine walking off the job.

Edited October 25, 2013 by hobbsyoyo

[SRV Ron]

This is one design that worked well. The ring of braces on the eight SRBs support it well. The LV-N is not used in launch as it overheats badly.

[boomerdog2000]

The problem is that in KSP, unless it is the central engine in a cluster that goes out, your mission is over. Even if you have gimbaled engines, the SAS cannot adjust the vectoring to make up for assymetrical thrust and your rocket will flip over.

In KSP though if one of your engines cuts out, it is most likely a structural issue (engine/fuel tank separation) rather than an engine one and you probably have bigger problems at that point.

[WafflesToo]

How about just limiting the amount of fuel per second that can flow through the fuel line? I mean right now a single fuel line can drain an entire orange tank in a second or two if you go overboard with asparagus staging... That's hardly realistic.

Not a bad idea, better than band-aiding a solution. Does anyone know if the fuel duct adds mass or is it ignored like struts are?

Another thing to think about is the torque problem. I build small and I have seen fuel flow rates in excess of 2 tons per second. Think about that much mass moving in a clockwise direction 2.5m from center.

[numerobis]

As Eric S points out, think of that much mass moving in a clockwise direction *and stopping* -- you get no angular momentum from just moving mass around.

Where you might get into trouble is that if something exterior (i.e. the atmosphere) imparts angular momentum upon your rocket, and then you draw mass inwards. That makes you spin faster.

[Moar Boosters]

Unfortunately, when you get into making huge rockets, adding more struts at best doesn't help or even makes the problem worse. Like you said, the physics engine acts up when you launch big rockets and will break them at randome points even if they are properly strutted. Adding more struts to compensate means more physics calculations which makes for more errors in the physics engine and more random break-downs.

This is an issue my Laythe science base mission has had: I can desigb launchers for the heavier components but they all explode at random points due to the physics engine walking off the job.

Struts don't make stresses go away, they just transfer them to different places. The trick is to place them correctly so they're distributing the stresses onto the strongest structural parts on the ship. Most of the time when ships break out it's not the physics engine spazzing out, it's simply because some part becomes over-stressed and the main difficult is determining where the stress is.

That rocket I posted as an example weighs 4000tons, is the full height of the VAB and doesn't break apart randomly. It DID..... but after many failed troubleshooting launches.... Its got struts in all the right places and is now nice and solid.

[Ruedii]

First, for asparagus staging. These huge pancake shaped ships are what doesn't work. Obviously, you only want a couple side stages, instead of dozens of them.

Second, as of getting large interplanetary tankers, I recommend building them and/or filling them in orbit. It doesn't hurt to empty them on the way up if you bring up loads of fuel to fill them.

Furthermore, rather than landing your entire ship on a planet or moon, just bring down a lander module, then have it dock back up with the mother-ship in orbit. This way the module doesn't need enough fuel to return to Kerbin, just to return to orbit. You can even carry multiple lander modules if you like.

[Nao]

Adding some flames to the discussion

Asparagus staging in KSP is so good because people are lazy and design their rockets more by visuals rather than actual mission requirements. Even in KSP it's possible to make no fuel cross feed rocket to be almost as good as asparagus one. (For standard designs of course. For the ones stretching engine efficiency as hard as possible, cross feed will be much better.)

For example this rocket that was designed to as a Tylo land and return mission: Last three stages are the same, both rockets have the same engines and the same amount of fuel. There are no fuel lines in firsts pic, and there is asparagus staging on the first 3 stages in the second pic. The difference is only 8146m/s to 8327m/s and the asparagus has 0,01 more TWR on second stage.

8146m/s No fuel lines8327m/s asparagus with the same engines, launch mass and TWR.

[Azivegu]

I think, money is the main factor IRL. Every design needs to be financed. If a Delta IV Heavy works with normal staging, why to develop much more complex systems for the same job. If more starts go to private firms like SpaceX, money will even more be the factor for design.

Didn't said Von Braun something like "Keep it simple and test it."?

Thats my main concern with the orion capsule. They said literally: We have a million lines of code to get to the moon, and when we are there we'll have a million lines more." I also like the comparison Neil DeGrasse Tyson made between the Soyuz and the Space Shuttle. The shuttle was described as the most complicated machine man ever has designed, so naturally many things can go wrong. The Soyuz is dead simple. Just short of point and fire actually. Its a good work horse that has redundancy. So it is no surprise that Soyuz 5 survived a disastrous fall from space while the shuttle lost some wing tiles and disintegrated (I know it isnt right to downplay it, but I am describing the complexity of the Space Shuttle right now) I would rather have a sturdy and reliable workhorse of a craft then something that has a million and one ways to fail.

Don't get me wrong, I have full faith in the engineers working at and for NASA. There are SOOOOOOOO many success stories (lets not even get started on voyagers and Opportunity/Spirit,) but a complicated craft is not necessarily a good craft. If you don't have to deal with dangerous fuel lines IRL, then don't do it. Often times it is even more expensive and doesn't give you a net benefit (in costs and safety.) But it is good that somebody is trying it out IRL.