Does The Space Shuttle Technically Use Real Asparagus Staging

[poopslayer78]

Based on the description from Wikipedia, it sounds like the big brown tank contains liquid Hydrogen and Oxygen, which is fed into the space shuttle's engines.  When the tank is depleted, it is detached and the shuttle operates off of the Hydrogen and Oxygen contained in the (full) shuttle.  The shuttle's hydrogen engines run from the beginning of the launch combined with the SRBs.

This sounds like real life asparagus staging to me, which is awesome.  My impression was that asparagus staging isn't ever done in real life since pumping fuel around with turbopumps is really difficult, but I guess it works here.

[Geonovast]

34 minutes ago, poopslayer78 said:

it is detached and the shuttle operates off of the Hydrogen and Oxygen contained in the (full) shuttle. 

I don't know where you read this, but it is not the case.

The shuttle did not store any hydrolox for the main SSMEs.  That came solely from the external tank.  The main engines would shut off, then the tank would be detached, and the main engines would not run again for duration of the mission.  It had two orbital maneuvering engines for on-orbit, but those ran on a completely different propellant.

[poopslayer78]

21 minutes ago, Geonovast said:

I don't know where you read this, but it is not the case.

Ah, I never read this I simply assumed it... and assumed incorrectly it would appear.  Oh well, my dreams of real asparagus staging will need to be fulfilled elsewhere.

[magnemoe]

8 hours ago, poopslayer78 said:

Ah, I never read this I simply assumed it... and assumed incorrectly it would appear.  Oh well, my dreams of real asparagus staging will need to be fulfilled elsewhere.

Fighter jets with drop tanks is the closes you get as the carry fuel in drop tanks and internally. the Soviet UR700 and UR900 rocket design planned to use it but they was newer build
https://en.wikipedia.org/wiki/Universal_Rocket
One major problem with asparagus fuel flow is that rocket engines has an very high fuel requirement, piping is more like an small hydro plant than even piping to huge ships, the turbo pumps also don't like gas bubbles and cavitation this makes switching between tanks is challenging unlike ships and planes who does this regularly. 

[StrandedonEarth]

12 hours ago, Geonovast said:

The shuttle did not store any hydrolox for the main SSMEs.

True, but it did store some for the fuel cells

[Geonovast]

15 minutes ago, StrandedonEarth said:

True, but it did store some for the fuel cells

Tis why I specified

[wumpus]

"Asparagus would be a great tech for spacecraft" is one of the many lies KSP teaches you.  To speed up the gameplay, Kerbin is tiny.  But to keep the difficulty with an orbital velocity 1/3rd Earth's, kerbal fuel tanks are miserably heavy when empty.  For example: the "Rockomax X200-32 Fuel Tank" (which I *think* is the classic "orange tank" or yore, I haven't play in some time) has a dry weight 11% of its wet weight.  A remotely modern space fuel tank is much closer to a can of coke (.1%?).  In other words, the fuel tanks aren't quite as critical as they seem.  On the other hand, they need enough fuel for 3 times the delta-v, and need to reduce dry weight as much as possible (no, SSTO still isn't useful).  Also don't forget that during the heyday of asparagus design in KSP,  they aerodynamic model was much more primitive: so "pancake" rockets were the rule and aero drag ignored.

I'd be curious to see the difference you'd have with an asparagus (the original idea) Falcon Heavy vs. what flies.  The biggest problem is that I doubt asparagus would buy you anything unless you expended the center booster (like they did last flight).  Giving more delta-v to the center stage means it is going to hit the atmosphere with even more delta-v coming down, and make recovery that much harder.  In any event, it showed just how difficult changing fuel tanks mid-flight would be even on an engine famous for its ability to start and restart on command.

At its heart, asparagus simply allows you to fire all engines simultaneously, thus ignoring the mass of engines yet to be staged.  And this was yet another issue old-KSP left out, you could use vacuum optimized nozzles without worry.  In practice, and even moreso for a rocket designed for re-use, I'd suggest simply adding additional stages.  Have the lowest stage return to launch site (preferably with air-augmentation).  Have the next stage get to at least 1/2 orbital velocity (a lot depends on the amount of thrust needed after stage 1 is staged, and also on surviving atmospheric re-entry).  Using side booster with significant thrust (not the little guys that ring some main boosters) is apparently a significantly hard problem.

[magnemoe]

14 hours ago, wumpus said:

"Asparagus would be a great tech for spacecraft" is one of the many lies KSP teaches you.  To speed up the gameplay, Kerbin is tiny.  But to keep the difficulty with an orbital velocity 1/3rd Earth's, kerbal fuel tanks are miserably heavy when empty.  For example: the "Rockomax X200-32 Fuel Tank" (which I *think* is the classic "orange tank" or yore, I haven't play in some time) has a dry weight 11% of its wet weight.  A remotely modern space fuel tank is much closer to a can of coke (.1%?).  In other words, the fuel tanks aren't quite as critical as they seem.  On the other hand, they need enough fuel for 3 times the delta-v, and need to reduce dry weight as much as possible (no, SSTO still isn't useful).  Also don't forget that during the heyday of asparagus design in KSP,  they aerodynamic model was much more primitive: so "pancake" rockets were the rule and aero drag ignored.

I'd be curious to see the difference you'd have with an asparagus (the original idea) Falcon Heavy vs. what flies.  The biggest problem is that I doubt asparagus would buy you anything unless you expended the center booster (like they did last flight).  Giving more delta-v to the center stage means it is going to hit the atmosphere with even more delta-v coming down, and make recovery that much harder.  In any event, it showed just how difficult changing fuel tanks mid-flight would be even on an engine famous for its ability to start and restart on command.

At its heart, asparagus simply allows you to fire all engines simultaneously, thus ignoring the mass of engines yet to be staged.  And this was yet another issue old-KSP left out, you could use vacuum optimized nozzles without worry.  In practice, and even moreso for a rocket designed for re-use, I'd suggest simply adding additional stages.  Have the lowest stage return to launch site (preferably with air-augmentation).  Have the next stage get to at least 1/2 orbital velocity (a lot depends on the amount of thrust needed after stage 1 is staged, and also on surviving atmospheric re-entry).  Using side booster with significant thrust (not the little guys that ring some main boosters) is apparently a significantly hard problem.

Yes, in KSP tanks and engines are much heavier than in real life, I also add that in early KSP version connections was also much weaker, so you needed to make an pyramid if you wanted to make an very heavy rocket. the 3.75 meter pars mostly solved this issue and an 2.5 stages rocket is much more practical, this is realistic as 2.5 stages seems optimal for an disposable rocket. 
SSTO rocket planes is also much easier in KSP as we has the rapier who can reach 5000 km/h who is more than half the orbital velocity around Kerbin. 

Now I found asparagus very nice for very high dv nuclear rockets mostly used for rescuing kerbals in retrograde orbits. 
Also for stuff like Eve accent from sea level. 

[radonek]

On 11/20/2022 at 1:03 PM, magnemoe said:

…
One major problem with asparagus fuel flow is that rocket engines has an very high fuel requirement, piping is more like an small hydro plant than even piping to huge ships, the turbo pumps also don't like gas bubbles and cavitation this makes switching between tanks is challenging unlike ships and planes who does this regularly. 

What if you don't pipe that extra fuel directly into engine, but top-off center tank, using it as a buffer?

One reason for using asparagus that I don't see mentioned is that it allows me to use beefier center engine. With center tank full, there is less of a TWR jump through staging, without need to throttle down. I know that bigger engine is not called for at LEO missions, but for heavier cargo at TLI or farther burns… 

 

[wumpus]

1 hour ago, radonek said:

What if you don't pipe that extra fuel directly into engine, but top-off center tank, using it as a buffer?

One reason for using asparagus that I don't see mentioned is that it allows me to use beefier center engine. With center tank full, there is less of a TWR jump through staging, without need to throttle down. I know that bigger engine is not called for at LEO missions, but for heavier cargo at TLI or farther burns… 

 

No idea.  Falcon Heavy was the only rocket I ever heard of that was planned to use asparagus staging, although only NASA and Spacex typically publish their iterative design process so there may be plenty others.  Ask them why it didn't work.

[magnemoe]

2 hours ago, radonek said:

What if you don't pipe that extra fuel directly into engine, but top-off center tank, using it as a buffer?

One reason for using asparagus that I don't see mentioned is that it allows me to use beefier center engine. With center tank full, there is less of a TWR jump through staging, without need to throttle down. I know that bigger engine is not called for at LEO missions, but for heavier cargo at TLI or farther burns… 

That is how asparagus works in KSP but as the center tank is full and you tap from the bottom you will need to lift the fuel, yes you could do that with the turbo pump using an separate pump and an pipe going to the top, you will loose the fuel in the pipe however, it the pipe and the extra pump adds weight.  Had been interesting in how SpaceX and the UR-700 rocket planned to solve this. 
Still think an switch valve in the piping would work better.
Note that  falcon heavy could have the option to shut down the 6 core who got feed from the side tanks during the switch. 
Shut down engines, close pipes and the open flow from the core tank and restart eliminating this problem, but probably not how they planned to do it.  

[kerbiloid]

1 hour ago, magnemoe said:

Had been interesting in how SpaceX and the UR-700 rocket planned to solve this. 

Easily.

http://nick-stevens.com/2017/03/04/chelomeis-ur-700/

Spoiler

The triple central core and three twin lateral blocks are similar, but the laterals are extended with a nose cone containing additional propellant tanks which are replenishing the central core booster by gravity and acceleration.

When the laterals are jettisonned, the central ones are still full.

[magnemoe]

22 hours ago, kerbiloid said:

Easily.

http://nick-stevens.com/2017/03/04/chelomeis-ur-700/

  Hide contents

The triple central core and three twin lateral blocks are similar, but the laterals are extended with a nose cone containing additional propellant tanks which are replenishing the central core booster by gravity and acceleration.

When the laterals are jettisonned, the central ones are still full.

Now that is genial and it explains the weird top tanks. As an bounus you can use pressure on the now disconnected top tanks for separation .
Mirror an KSP tricks of adding fuel tanks on top of SRB for cross feed. 

Here is a bit more about this http://www.astronautix.com/u/ur-700.html
Can not come over how Kerbal this rocket is, 
First stage with cross feed from boosters, then an second stage who take this almost to orbit, it looks a bit like a Proton with 3 side tanks.
But then it get wilder, the trans lunar injecting is done by 3 side boosters to the 3rd stage, 3rd stage then get into moon orbit and is an crashing stage during landing. 
It reuses the engine for accent from the moon but leaves behind the legs and an module like Apollo. Not sure if it was fuel tanks in this module but would not be surprised. 
One option here would be to  move fuel from the leg module to the accent module after landing. 
And unless you missed it, its direct landing. 

Edited November 22, 2022 by magnemoe

[Beamer]

The Otrag ( http://www.astronautix.com/o/otrag.html ) was designed to use parallel staging, making it look a lot like a KSP asparagus creation, however afaik it was never intended to pump fuel between the stages. Although its engines racked up an impressive 1 million plus seconds of static firing and there were over a dozen successful test launches, the project was eventually cancelled. It was meant to have its stages in concentric squares so that each square further out would have enough trust to lift the whole thing. Once the outermost square of boosters was discarded, the next square would take over and the staging would work its way to the inner core like that. The way it would have discarded its stages would have made it at least appear very much like a KSP asparagus staged rocket.

Spoiler