Asparagus Staging in Real Life?

[zxczxczbfg]

It might be possible to design a craft that, rather than relying on asparagus staging, can get to orbit non-asparagus, but then add asparagus capability to it for efficiency. If one or more pumps do fail, the rocket can just switch off crossfeed and complete the orbit normally, with the pumps simply giving an increased margin of safety.

[Rakaydos]

Or design a "bolt on" asparagus stage, designed to lift itself while fueling one other identical engine.

In the center you have 1 engine. It has 4 "bolt on" asparagi attached to it.

Asparagi pair A feed themselves and Asparagi pair B, asparagi pair B feed Center engine (at half rate because there's two sources.)

Second stage, Asparagi pair A drops empty. Asparagi pair B's "other engine tanks" are half empty, while their "self lift" tanks are full. they continue to feed the center engine. Both sets of tanks will empty at about the same time.

Third stage, Asparagi B drops away, leaving the center stack at max fuel.

[phemark]

Hi,

So from this thread I understand that asparagus staging doesnt really work in real life because of fuel pump problems. But what about air drag? Let's say that NASA managed to get perfect fuel transfer lines, would they start using asparagus staging, (building monsters like I see in KSP), or would they still not do it, because very wide rockets create a lot of air drag?

At the moment I dont like building asparagus staging wide rockets, because I think that this is not realistic and it is just "cheating" in KSP, because of loss of proper air resistance in the game (stock). So please correct me if I'm wrong.

[Ralathon]

Hi,

So from this thread I understand that asparagus staging doesnt really work in real life because of fuel pump problems. But what about air drag? Let's say that NASA managed to get perfect fuel transfer lines, would they start using asparagus staging, (building monsters like I see in KSP), or would they still not do it, because very wide rockets create a lot of air drag?

At the moment I dont like building asparagus staging wide rockets, because I think that this is not realistic and it is just "cheating" in KSP, because of loss of proper air resistance in the game (stock). So please correct me if I'm wrong.

Air drag is actually a surprisingly small dV loss as anyone with FAR will acknowledge. But they still wouldn't be using (much) Asperagus staging because of costs. Engines and turbopumps are expensive and tossing away multiple expensive boosters is bad for business.

I suspect that Asperagus staging is going to disappear in KSP when money gets implemented. Asperagus is the most efficient way up in terms of dV, but not in terms of costs.

[phemark]

Air drag is actually a surprisingly small dV loss as anyone with FAR will acknowledge. But they still wouldn't be using (much) Asperagus staging because of costs. Engines and turbopumps are expensive and tossing away multiple expensive boosters is bad for business.

I suspect that Asperagus staging is going to disappear in KSP when money gets implemented. Asperagus is the most efficient way up in terms of dV, but not in terms of costs.

Thanks for the answer. I will continue to learn to build rockets with no (or little) asparagus stagings then:)

What is the most cost effective (if we had money), or part effective (requiring least amount of parts) way to build rockets? (Sorry if this is offtopic, please reply to my inbox if it is).

[Ralathon]

What is the most cost effective (if we had money), or part effective (requiring least amount of parts) way to build rockets? (Sorry if this is offtopic, please reply to my inbox if it is).

This constantly changes as we invent new technologies. Better technology allows cheaper, stronger and more versatile engines and fuel tanks. So this isn't a question with a simple answer.

In general there are 2 main trains of thought:

Reusability. Make a very high tech rocket/spaceplane that you can use multiple times. The space shuttle and Space X's Falcon are examples of this. The problem with them is that high tech means high maintenance which drives up the costs per launch.

Big Dumb Booster. Essentially just building the simplest cheapest rocket you can, and then mass producing this to drive down costs. The Soyuz is a good example of this. The simplicity and cheap production outweigh the efficiency gains you'd get using more high tech solutions.

Right now the 'Big Dumb Booster' approach is winning. But as technology improves and materials become more expensive reusability will become more and more viable. I don't know how it is going to pan out in the short to medium term future though.

[phemark]

And if you were to answer the same answer for KSP universe? (Basically which rocket designs are closest in efficiency of asparagus, while being somelike real-world-like?

[Ralathon]

And if you were to answer the same answer for KSP universe? (Basically which rocket designs are closest in efficiency of asparagus, while being somelike real-world-like?

In KSP the physics work way different. It's relatively easy to make an SSTO and there are no random failures, making maintenance a moot point.

So in KSP the most efficient way is to build a spaceplane SSTO and keep reusing that indefinitely.

[sgt_flyer]

And if you were to answer the same answer for KSP universe? (Basically which rocket designs are closest in efficiency of asparagus, while being somelike real-world-like?

Well engineered Stages and a half can pretty efficient in KSP - and a lot of current rockets use this. Basically, boosters around a sustainer. - the sustainer + whatever is above has not enough twr to lift off by itself while the fuel tanks are full.

The sustainer burns enough fuel to be able to have a TWR > 1 when the boosters are dropped.

(IRL : soyuz, STS, SLS, Ariane, Delta rockets, etc : p)