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[alway]

http://en.wikipedia.org/wiki/Falcon_Heavy
So there's that.
The other thing you need to worry about with liquid props is sloshing. One of the early tests of the Falcon 1 rockets failed when the propellant started sloshing around in the tanks, causing a steadily worsening harmonic motion that ended up causing an abort. In the most recent Falcon 9 flight, they tested their ability to land the used stage 1 rocket safely. It nearly worked, but the low remaining propellant was centrifuged along the outside of the container, preventing proper thrusting. All these are solvable (the first was fixed, and the second is probably fixed by now), but they do require additional testing.

[forsaken1111]

http://en.wikipedia.org/wiki/Falcon_Heavy
So there's that.
The other thing you need to worry about with liquid props is sloshing. One of the early tests of the Falcon 1 rockets failed when the propellant started sloshing around in the tanks, causing a steadily worsening harmonic motion that ended up causing an abort. In the most recent Falcon 9 flight, they tested their ability to land the used stage 1 rocket safely. It nearly worked, but the low remaining propellant was centrifuged along the outside of the container, preventing proper thrusting. All these are solvable (the first was fixed, and the second is probably fixed by now), but they do require additional testing.

Good thing we don't have to worry about that in KSP...?

[ank]

God dammit I want .22 so bad right now!
GIVE EET!
NOAW!
FOR !!SCIENCE!!

[BigD145]

Sorry, it appears you have to be a socially inept person to be a tester (judging by the streams). Do you talk to Yoda?

[ank]

Sorry, it appears you have to be a socially inept person to be a tester (judging by the streams). Do you talk to Yoda?

They are looking for more streamers, so I'd say give it a shot if you think you are better than the current ones.
Oh, and they aren't testers, they are streamers. Testers test stuff before the streamers get their hands on it.

[Girlinhat]

The streamers effectively can't give bug reports.  Squad has testers, streamers, and customers.  Testers stumble on bugs.  Customers shouldn't deal with bugs.  Streamers get told "gtfo" if they report a bug.

[10ebbor10]

http://en.wikipedia.org/wiki/Falcon_Heavy
So there's that.
The other thing you need to worry about with liquid props is sloshing. One of the early tests of the Falcon 1 rockets failed when the propellant started sloshing around in the tanks, causing a steadily worsening harmonic motion that ended up causing an abort. In the most recent Falcon 9 flight, they tested their ability to land the used stage 1 rocket safely. It nearly worked, but the low remaining propellant was centrifuged along the outside of the container, preventing proper thrusting. All these are solvable (the first was fixed, and the second is probably fixed by now), but they do require additional testing.

And that's about the only rocket system that tried that, from what I know off. Additionally, it's pretty unique in it's payload capacity too. Simply said, it's not efficient to do aspergus in real life save for gigantic rockets.

[Sean Mirrsen]

http://en.wikipedia.org/wiki/Falcon_Heavy
So there's that.
The other thing you need to worry about with liquid props is sloshing. One of the early tests of the Falcon 1 rockets failed when the propellant started sloshing around in the tanks, causing a steadily worsening harmonic motion that ended up causing an abort. In the most recent Falcon 9 flight, they tested their ability to land the used stage 1 rocket safely. It nearly worked, but the low remaining propellant was centrifuged along the outside of the container, preventing proper thrusting. All these are solvable (the first was fixed, and the second is probably fixed by now), but they do require additional testing.

And that's about the only rocket system that tried that, from what I know off. Additionally, it's pretty unique in it's payload capacity too. Simply said, it's not efficient to do aspergus in real life save for gigantic rockets.

Not cost-efficient or not complexity-efficient? Because the principle of the asparagus staging is perfectly valid and very effective. You're basically taking a rocket that can already fly by itself, and then you're giving it extra fuel, but sidestep the rocket equation by also giving it engines that will carry that extra fuel until it runs out - at which point you're left with the same rocket that can fly by itself, but it is already some few dozen kilometers off the ground and going at a decent clip.

Also, the Falcon Heavy isn't merely the "only" rocket system that tried that.

It's the "first".

[alway]

Yeah, it adds a bunch of systems complexity, which prior to fully automated, error-tolerant nav systems like SpaceX uses, would have been practically impossible. Typically, you also would reduce plumbing complexity to a bare minimum, since that's one of the single biggest fault locations for a rocket. If an engine goes out, or a rocket is lost, it's pretty much always because of some issue with the plumbing.

http://en.wikipedia.org/wiki/N-1_rocket#Problems

Complex plumbing was needed to feed fuel and oxidizer into the clustered arrangement of rocket engines. This proved to be extremely fragile, and was a major factor in the design's launch failures

Doing crossfeed also increases the number of engines firing at any given stage. Which means you will have more engines fail. SpaceX nav AI has experimentally verified its ability to fly well after losing an engine (it lost one during a trip to the ISS) and can theoretically fly to its target trajectory even when it loses nearly half its engines, at which point physics says no. But it also increases the chances of engine failure specifically for the later stage engines: they are now firing for multiple stages; for a much longer sum of time. Or in short, you simply couldn't do crossfeed up until... now, really. You needed the vast advances in both materials science and computing before systems would become tolerant enough to do so.

[Putnam]

Whenever I crossfeed multiple engines, I end up with one tank that drains quicker than the rest and predictable results from there unless I manually stop and start the fuel from that tank.

[forsaken1111]

Whenever I crossfeed multiple engines, I end up with one tank that drains quicker than the rest and predictable results from there unless I manually stop and start the fuel from that tank.

Use TAC fuel balancer. You can set which tanks to keep full and which to balance out or draw from. Its useful for drop tanks.

[forsaken1111]

Just 'landed' my fuel depot on Jool. It hangs in the atmosphere via 4 large balloons while processing the hydrogen in the atmosphere for fuel then rockets back into orbit to deliver the fuel to ships. I'll probably end up setting up a base around one of the moons.

It also has a science module generating science to upgrade some parts later on.

Spoiler (click to show/hide)

[ank]

As I said before, KSPTV is looking for more streamers, to apply follow this link:
http://bit.ly/KSPTVApp

I would love someone from B12 to show them how it's done!

[10ebbor10]

http://en.wikipedia.org/wiki/Falcon_Heavy
So there's that.
The other thing you need to worry about with liquid props is sloshing. One of the early tests of the Falcon 1 rockets failed when the propellant started sloshing around in the tanks, causing a steadily worsening harmonic motion that ended up causing an abort. In the most recent Falcon 9 flight, they tested their ability to land the used stage 1 rocket safely. It nearly worked, but the low remaining propellant was centrifuged along the outside of the container, preventing proper thrusting. All these are solvable (the first was fixed, and the second is probably fixed by now), but they do require additional testing.

And that's about the only rocket system that tried that, from what I know off. Additionally, it's pretty unique in it's payload capacity too. Simply said, it's not efficient to do aspergus in real life save for gigantic rockets.

Not cost-efficient or not complexity-efficient? Because the principle of the asparagus staging is perfectly valid and very effective. You're basically taking a rocket that can already fly by itself, and then you're giving it extra fuel, but sidestep the rocket equation by also giving it engines that will carry that extra fuel until it runs out - at which point you're left with the same rocket that can fly by itself, but it is already some few dozen kilometers off the ground and going at a decent clip.

Also, the Falcon Heavy isn't merely the "only" rocket system that tried that.

It's the "first".

Neither cost nor complexity efficient at the moment, for anything smaller than the Falcon Heavy. Point is, in order to the crossfeed to work you need to use liquid fuel boosters, which are significantly harder and more expensive to handle than solid ones, hence not worth the effort for any smaller craft (Also, liquid fuel has a higher failure rate).

Additionally, in order to make the crossfeed worth the effort, you need to delay the separation of the sideboosters. Meaning that you have to use alternate systems to get the booster to land safely and be reuseable.

People have thought of it before. The N-1 had fuel crossfeeding, and was a massive failure.

[Sean Mirrsen]

SpaceX are kind of pioneering the "alternate systems" for landing liquid fuel boosters specifically, so I guess them using the crossfeed as well makes sense. I lack the general knowledge required to have a say on how complexity scales with size, but isn't "Asparagus staging" innately an easily scalable system? I.e. once you have a rocket system that can work with it, changing payload size is a matter of changing booster size.