New SLS vs Asparagus

[RocketPilot573]

Asparagus is too unrealistic, I'm already starting to not use it...

[Temstar]

SERV was 96ft in diameter and 83ft tall. In comparison the Saturn V was 33ft in diameter.

It's not the only time that tubby shape has come up either. JRS once proposed the Kankoh-maru:

On the less extreme end there's the Delta Clipper:

[Red Iron Crown]

Temstar, it's not the width per se that is the problem with asparagus. All those examples you post are wide but streamlined, they taper to a nice tip at the top and stay roughly conical. Asparagus rockets tend to get away from that nice conical shape, even if the individual stacks have nosecones. That's why they don't make sense aerodynamically.

Also, good job digging up pictures of those rocket concepts, hadn't seen some of them before.

[magnemoe]

There's tubby and then there's tubby. A rocket with 2 or 4 lateral mounted booster (whether asparagus or not) can still be pretty sleek. Otoh some asparagus designs are 2 or 3 layers deep and may be wider than they are tall - that's tubby. That Chrysler vehicle is hardly more tubby than the Saturn V.

Yes however more than 1+6 setups are unusual, has used them but only a couple times.

More common to build booster around the interplanetary stage, say four LV-N+orange tank with crew quarters and landers on top, now you add 4 boosters around the orange tank.

This is far more stable than putting the interplanetary stage on top of the rocket.

[Temstar]

Temstar, it's not the width per se that is the problem with asparagus. All those examples you post are wide but streamlined, they taper to a nice tip at the top and stay roughly conical. Asparagus rockets tend to get away from that nice conical shape, even if the individual stacks have nosecones. That's why they don't make sense aerodynamically.

The point is that aerodynamic drag is not a big factor in preventing rockets from reaching orbit, at least here on Earth. It takes around 9,200 m/s to reach LEO. Out of that, around about 150 m/s is usually the amount spent in overcoming aerodynamic drag. 1500 - 2000m/s is spent overcoming the gravity drag and rest goes into your orbital velocity. In other words aerodynamic drag accounts for less than 2% of the launch to orbit delta-V budget.

That's the real reason why people do design tubby rockets in real life - aerodynamic drag is just not a big deal. If we are to have a better aerodynamic model that more closely mimic Earth than wide rockets is still viable as ever.

[Red Iron Crown]

In other words aerodynamic drag accounts for less than 2% of the launch to orbit delta-V budget....

....of a properly streamlined rocket. Careful streamlining is why the loss to drag is so low.

The dV lost to drag mostly occurs early in the launch, too, where every m/s is costly.

[magnemoe]

....of a properly streamlined rocket. Careful streamlining is why the loss to drag is so low.

The dV lost to drag mostly occurs early in the launch, too, where every m/s is costly.

Yes radical streamlined designs like the space shuttle http://upload.wikimedia.org/wikipedia/commons/2/2a/Space_Shuttle_Atlantis_launches_from_KSC_on_STS-132_side_view.jpg

No they probably used loads of time in the wind tunnel too reduce drag and aerodynamic is not entirely intuitive however nobody can say it look aerodynamic at launch. Far less than the Russian N1 alternative who looks like its made in KSP.

[Wahgineer]

Actually, I don't think it's aerodynamics that could kill asparagus/payload-specific rockets: it would be the introduction of money. Modular, common core launch systems that launch smaller, more compact, more thought out payloads would be more economical than the " I have a massive ship i threw together in 10 minutes or so, lets build an asparagus rocket capable of launching it" approach.

[BMBender]

My 2 bits. Even with a realistic aerodynamic model you won't see a major die-off of asparagus use. As far as "WIDE LOAD" applications the big difference between RW and KSP isn't aero dynamics, it fuel pumping. In the real word the equivalent of a "yellow fuel line" would cost almost as much as the rest of the lifter vehicle, and break, often, usually catastrophically.

[ScallopPotato]

I don't get why people think realistic aerodynamics would kill asparagus. I play with FAR and single-layer asparagus isn't noticeably less aerodynamic.

Multiple layers of asparagus aren't optimal, but one ring of boosters is fine as long as they all have nosecones. Multiple rings won't be needed anyway due to reduced dV requirements (an aerodynamic rocket cuts quickly and swiftly through the lower atomsphere) and larger diameter parts. I have yet to set an upper limit on what I can put into LKO with the 3.75m KW parts in a one ring asparagus, but I do believe it's somewhere around... 300 tons or so.

[JedTech]

Asparagus was invented by KSP fans for KSP. Plus asparagus is really fun to design and fly. I'd be sad if they changed KSP physics so as to exterminate asparagus staging.

[Twreed87]

My 2 bits. Even with a realistic aerodynamic model you won't see a major die-off of asparagus use. As far as "WIDE LOAD" applications the big difference between RW and KSP isn't aero dynamics, it fuel pumping. In the real word the equivalent of a "yellow fuel line" would cost almost as much as the rest of the lifter vehicle, and break, often, usually catastrophically.

I know that the Falcon Heavy will be using propellant crossfeed, but does any rocket currently use anything like that? Anyone know?

[The Jedi Master]

I saw the SLS parts, those things are huge. The problem is, they are so huge that it would be impractical to launch them into space. Asparagus remains.

Asparagus was invented by KSP fans for KSP. Plus asparagus is really fun to design and fly. I'd be sad if they changed KSP physics so as to exterminate asparagus staging.

Asparagus staging is actually based off real plans for efficient rockets made by SpaceX. It's not impossible, just easier said than done.

[Rakaydos]

Isnt the "Yellow fuel line" from the shuttle external to the shuttle the part that had the falling foam that killed Columbia?

[Red Iron Crown]

I know that the Falcon Heavy will be using propellant crossfeed, but does any rocket currently use anything like that? Anyone know?

The Shuttle had an external tank, so it must have used crossfeed. No engine on the tank, though, so not exactly asparagus.

[Thiel]

AFAIK the term itself comes from an old paper from the fifties.

[NecroBones]

I saw the SLS parts, those things are huge. The problem is, they are so huge that it would be impractical to launch them into space.

That's why we'll never land on the moon in the real world. It would require a rocket 350 feet tall, generating 7.5 million pounds of thrust.

[mellojoe]

If I can reduce the part count of my heavy lifter and still get the same payload to orbit, I'll be happy enough.

But that won't stop me from trying to go bigger and bigger. I mean, whats a few extra thousand struts, anyway?

[Aardvark]

I saw the SLS parts, those things are huge. The problem is, they are so huge that it would be impractical to launch them into space. Asparagus remains.

Asparagus staging is actually based off real plans for efficient rockets made by SpaceX. It's not impossible, just easier said than done.

Tsiolkovsky had something very similar in the '20s.

[Daze]

That's why we'll never land on the moon in the real world. It would require a rocket 350 feet tall, generating 7.5 million pounds of thrust.

Do you believe in moon hoax?

[The Jedi Master]

Do you believe in moon hoax?

It is a joke! It is a joke! A counterpoint to my argument! Don't start a fight!

[Daze]

It is a joke! It is a joke! A counterpoint to my argument! Don't start a fight!

The only ironic part of his post is the ending ";)", so i was asking, just a question, nothing else... The only one who want to start a fight seems to be you...

[lincourtl]

Asparagus staging is actually based off real plans for efficient rockets made by SpaceX. It's not impossible, just easier said than done.

Quoth the wiki:

"In the real world there might be one craft, the Falcon Heavy by 2014/2015 which uses this type of staging, although only with one level. ... In 1947, Mikhail Tikhonravov developed this kind of staging which he called “packet rocketsâ€Â. This lead to the development of the R-7 Semyorka. Later developments of this rocket became then the R-7 rocket family. But all those rockets never used the original “packet rocketsâ€Â/asparagus staging. ... The application of the term "asparagus" to a form of rocket staging predates Kerbal Space Program and is not a creation of the players. The "Asparagus-Stalk Booster" was described by aerospace engineer Ed Keith on page 144 of Tom Logsdon's "Orbital Mechanics: Theory and Applications" in 1997."

Ref: http://wiki.kerbalspaceprogram.com/wiki/Asparagus_staging

[UmbralRaptor]

Asparagus was invented by KSP fans for KSP. Plus asparagus is really fun to design and fly. I'd be sad if they changed KSP physics so as to exterminate asparagus staging.

Of course, getting the fuel pumps to work as well as they do in KSP is non-trivial...

[Red Iron Crown]

http://i26.photobucket.com/albums/c128/raptor_87/Textbook-Source.jpg

Of course, getting the fuel pumps to work as well as they do in KSP is non-trivial...

I would imagine each stage would pump fuel into the core and adjacent stage, as necessary. It wouldn't make sense to pump fuel through a bunch of tanks to the core.