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It's possible, but not as easy in real life as it is in KSP.

To maintain proper tank pressurization, the crossfeeds have to be pump-driven; the fuel and oxidizer crossfeed lines have to be pretty large to move the required amount of propellant (i.e. abouton the order of the same power as the core section's engine turbopumps). All this increases weight and complexity.

In your proposed design, a minor issue is that the pumping direction of the outer tanks produces a rolling torque on the rocket which has to be countered (via gimbaled engines or other attitude-control mechanisms). No torque is produced by the S2->S1 feeds in your design, so a single-level N-to-1 crossfeed, like Falcon Heavy's proposed 2-to-1, doesn't have to worry about it.

It turns out to be possible to get some of the benefits of asparagus crossfeed by throttling the core engines down while the boosters are running -- the outer tanks thus empty first because they're consuming propellant faster. This is much easier to engineer -- no crossfeed plumbing, just throttlable engines. This is what Falcon Heavy actually does. Installing more or larger engines on the outer boosters would be generally equivalent, as well.

It's possible, but not as easy in real life as it is in KSP.

To maintain proper tank pressurization, the crossfeeds have to be pump-driven; the fuel and oxidizer crossfeed lines have to be pretty large to move the required amount of propellant (i.e. about the same power as the core section's engine turbopumps). All this increases weight and complexity.

In your proposed design, a minor issue is that the pumping direction of the outer tanks produces a rolling torque on the rocket which has to be countered (via gimbaled engines or other attitude-control mechanisms). No torque is produced by the S2->S1 feeds in your design, so a single-level N-to-1 crossfeed, like Falcon Heavy's proposed 2-to-1, doesn't have to worry about it.

It turns out to be possible to get some of the benefits of asparagus crossfeed by throttling the core engines down while the boosters are running -- the outer tanks thus empty first because they're consuming propellant faster. This is much easier to engineer -- no crossfeed plumbing, just throttlable engines. This is what Falcon Heavy actually does. Installing more or larger engines on the outer boosters would be generally equivalent, as well.

It's possible, but not as easy in real life as it is in KSP.

To maintain proper tank pressurization, the crossfeeds have to be pump-driven; the fuel and oxidizer crossfeed lines have to be pretty large to move the required amount of propellant (i.e. on the order of the same power as the core section's engine turbopumps). All this increases weight and complexity.

In your proposed design, a minor issue is that the pumping direction of the outer tanks produces a rolling torque on the rocket which has to be countered (via gimbaled engines or other attitude-control mechanisms). No torque is produced by the S2->S1 feeds in your design, so a single-level N-to-1 crossfeed, like Falcon Heavy's proposed 2-to-1, doesn't have to worry about it.

It turns out to be possible to get some of the benefits of asparagus crossfeed by throttling the core engines down while the boosters are running -- the outer tanks thus empty first because they're consuming propellant faster. This is much easier to engineer -- no crossfeed plumbing, just throttlable engines. This is what Falcon Heavy actually does. Installing more or larger engines on the outer boosters would be generally equivalent, as well.

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source | link

It's possible, but not as easy in real life as it is in KSP.

To maintain proper tank pressurization, the crossfeeds have to be pump-driven; the fuel and oxidizer crossfeed lines have to be pretty large to move the required amount of propellant (i.e. about the same power as the core section's engine turbopumps). All this increases weight and complexity.

In your proposed design, a minor issue is that the pumping direction of the outer tanks produces a rolling torque on the rocket which has to be countered (via gimbaled engines or other attitude-control mechanisms). No torque is produced by the S2->S1 feeds in your design, so a single-level N-to-1 crossfeed, like Falcon Heavy's proposed 2-to-1, doesn't have to worry about it.

It turns out to be possible to get some of the benefits of asparagus crossfeed by throttling the core engines down while the boosters are running -- the outer tanks thus empty first because they're consuming propellant faster. This is much easier to engineer -- no crossfeed plumbing, just throttlable engines. This is what Falcon Heavy actually does. Installing more or larger engines on the outer boosters would be generally equivalent, as well.