How to NOT use asparagus?

[Renaissance0321]

I'm not sure if my designs actually qualify as asparagus staging but I tend to make a large center rocket, usually 3.75m and then have two fuel tanks on the side with fuel lines going to the center tanks which fall off during ascent. Even for very small payloads this seems to be the only solution and this is the only way I've been able to get to the Mun, land and have enough dV to come back. Is there something flawed with this design or is this how its done?

[Taki117]

If you are using 3.75m parts with a small payload to get anywhere something is flawed. what does your ascent profile look like?

[Renaissance0321]

Get to 7-10km turn 45 degrees, go until apoapsis is 85km then coast and circularize?

[Taki117]

Get to 7-10km turn 45 degrees, go until apoapsis is 85km then coast and circularize?

Ok, so pretty standard, now I'll ask for a couple of pics of your rocket to see how much fuel/thrust you have vs how large your payload is. if you are trying to lift a couple hundred tons to Mun, then 3.75m parts are the way to go, but if you are lifting less than 50 you should probably think about your flight profile after you achieve Kerbin orbit.

should help.

Edited April 24, 2014 by Taki117

[Renaissance0321]

8600kg payload Lander

- - - Updated - - -

10,000kg Station Tower and Habitat

[Renaissance0321]

30,000kg heavy transport

[FREEFALL1984]

Generally a munar mission can be performed with 8000m/s which is achieved with a fairly basic rocket with pretty standard low tech parts.

I normally account for

5km/s into LKO

850m/s to mun

500m/s to circularize into munar orbit and change inclination for targeted landing

1000m/s for safe targeted landing

1000m/s to return to kerbin.

This is generally grossly overestimated, leaving me with plenty of DV after landing. also this can easily be achievable with a standard easy to build rocket and I often end up landing on my transfer stage, the only thing I can think is that your phasing is incorrect or your fuel lines are back to front, because the rocket you've described should be able to achieve a low circular munar orbit before you even detach your lander. I also noticed you refer to the tanks on the sides as tanks and not liquid boosters, they do have engines on them dont they?

[Renaissance0321]

They all pretty much follow the same design no matter how heavy the payload is.

[FREEFALL1984]

That smaller payload has a total of 10km/s Dv, you should be able to land on the mun, then take off fly to minmus, then land and take off again and return to kerbin in a single mission. the only possible issue is that you're using mainsails (unless im mistaken), your heavy lifter should be able to insert to munar orbit without issue, but your 10ton station might struggle since the second stage T/W is only 1.2, and the whole thing only has 6.5km vac to begin with. you'll likely struggle getting that into orbit due to gravity drag

[Renaissance0321]

That smaller payload has a total of 10km/s Dv, you should be able to land on the mun, then take off fly to minmus, then land and take off again and return to kerbin in a single mission. the only possible issue is that you're using mainsails (unless im mistaken), your heavy lifter should be able to insert to munar orbit without issue, but your 10ton station might struggle since the second stage T/W is only 1.2, and the whole thing only has 6.5km vac to begin with. you'll likely struggle getting that into orbit due to gravity drag

Ok I see ...

[Dkmdlb]

Get to 7-10km turn 45 degrees, go until apoapsis is 85km then coast and circularize?

Instead, go to 8-10km and then pitch over a few degrees at first, and then slowly continue pitching over a few degrees at a time until you are horizontal at about 50-60km. You should be going about 250m/s at 10km and 700m/s at 20km. If you are going faster or much slower than that you're wasting energy and you need to adjust your engine choice accordingly. Try not to use the throttle at all (just keep it at 100%) - you don't want to carry a heavy engine up only to use it at 50% throttle. Swap it for a lighter engine with half the power and leave it at 100% throttle.

[KerikBalm]

Freefall mentioned the use of mainsails:

I don't see any mainsails, tbh, I don't recognize half the parts, he's using mods, some parts I recognize as mod parts even though I don't use that mod.

[FREEFALL1984]

Freefall mentioned the use of mainsails:

I don't see any mainsails, tbh, I don't recognize half the parts, he's using mods, some parts I recognize as mod parts even though I don't use that mod.

Ah ok, I thought the engines under the huge side tanks where perhaps mainsail, which would lower the thrust to weight since a mainsail on its would only just be able to lift the side stack, replacing them with KR-L2 engines would reduce the gravity drag and help get into orbit faster

[MartGonzo]

I'm with Scott Manley on this, never use it

the gain over just feeding all the external tanks into the centre is negligible and it makes for messy symmetry.

[Kasuha]

I'm not sure if my designs actually qualify as asparagus staging but I tend to make a large center rocket, usually 3.75m and then have two fuel tanks on the side with fuel lines going to the center tanks which fall off during ascent.

I think that's exactly the essence of asparagus. You run all available engines and every time you stage, you're left with rocket full of fuel.

Edited April 24, 2014 by Kasuha

[Pecan]

I'm with Scott Manley on this, never use it

the gain over just feeding all the external tanks into the centre is negligible and it makes for messy symmetry.

In the OP and illustrations it is clear there are two side-tanks feeding into the centre. Are you happier if this is called 'onion' staging?

How does asparagus make for messy symmetry? What is 'messy' symmetry anyway? What gains do you consider significant?

Have you tested and checked this or are you with Manley just on principal? Can we have your design figures for comparison?

@OP: Yes, I've found core + two boosters to be about the most useful and flexible design for many uses too. The most common alternative is serial (stack) staging - you may like to check mhoram's recent tutorial: http://forum.kerbalspaceprogram.com/threads/75669-Staging-Methods-Overview

There are simpler - and certainly lower-mass/smaller - ways to build your ships but if they work for you they're not 'flawed' to any great extent.