Klopchuck

Yeah yeah the family is away for Easter weekend - so free time for geeking out on KSP. Has anyone adapted this to their larger launch vehicles and gotten better performance? Please let me know if this is helpful.

Hello! I found a description of something called 'Ed Keith\'s Innovative Asparagus-Stalk Booster' in Tom Logsdon\'s 'Orbital Mechanics: Theory and Applications' (1998). BTW, if you want to learn the maths and rocket sciences, this is a fun textbook. Anyway, Ed Keith developed a concept that might be familiar to many of your designs: 1) seven cylindrical rockets mated side-by-side 2) all seven engines burning in parallel at lift-off Please see attached photo of page 144 of the textbook. However, he also proposed automatically pumping propellant from some of the rockets first, so two of the rockets could be discarded as soon as possible, followed by the next two, and so on, until you are left with the center rocket. So this may not be new to some of you, but I thought I would take it to the next level with some comparisons of two comparable 21-tank designs: [list type=decimal] [li]'Simple' design with an inner-core of 3 fuel tanks and the gimbled liquid engine; the outer six boosters have 3 fuel tanks each, and the LV-T30 liquid engines. Core and boosters are activated immediately upon launch for max thrust; the outer boosters are expended at approximately 187 seconds of full-throttle. The core expends shortly thereafter, at approximately 214 seconds of full-throttle. Average Thrust/Mass is 31.29 for 215 seconds. [/li] [li]'Asparagus' design with same configuration, except fuel-lines added to pump fuel from boosters 1 and 4 to boosters 2 and 5; from boosters 2 and 5 to boosters 3 and 6, and from 3 and 6 to the inner core. The first two boosters are empty and can be dropped at about 55 seconds, the next stage at about 131 seconds, and the last boosters at about 262 seconds. Then you have the core, with all its fuel, still available for about another 214 seconds of full-throttle. Average Thrust/Mass is 22.99 for 476 seconds.[/li] What is the proper comparison of spacecraft performance? If I multiply the average thrust/mass times the duration, the Asparagus is 162% of the simple design. All from adding 6 fuel lines and some more-complicated staging! (see attached .pdf for graphs) Also, I tested the two designs with MechJeb set to ascend to KSO orbit, about 2870km. The 'simple' design without fuel lines and more than two-stages used about 98% of the fuel to get to KSO. By comparison, the 'asparagus' design only used about 84% of the fuel. More than six times as much fuel remaining - much more efficient! [table] [tr] [td]Design[/td][td]Starting Fuel[/td][td]Engines[/td][td]Fuel Remaining in KSO (~2870km)[/td] [/tr] [tr] [td]Simple[/td][td]21 x FL-T500[/td][td](1) LV-T45 (6) LV-T30[/td][td]<0.5 FL-T500[/td] [/tr] [tr] [td]Asparagus[/td][td]21 x FL-T500[/td][td](1) LV-T45 (6) LV-T30[/td][td]~3.4 FL-T500[/td] [/tr] [/table] A .pdf comparison chart of Thrust and Mass is attached, along with screenshots of Keo-synchronous orbit. Please note, MechJeb was used to get the two spacecraft into the same orbit with minimal operator error. A stock-version of Asparagus is attached for your enjoyment.

Great post - putting it to work right now rescuing some stranded kerbonauts. When you get close to another ship, does it get designated on the screen or the navball? If so, how close do you need to be?

Awesome mission description - definitely shows how much you can do with a basic system. Can you post a youtube video? Or at least some guidance on when and how to get into LKO with good fuel economy?