HELP! getting this into orbit.

[Dewm]

So I have these 5 fuel tanks I would like to get into orbit... and after hours... no luck, I get it to around the 60,000 meter mark and about half way around kerbin..and then run out of juice. So help and/or suggestions would be great!

7 Mainsail engines. Drop offs in pairs of 2, fuel lines feeding so I drop off two, then another two etc...

At the very top you can see a smaller fuel tank with a small engine, so I can maneuver while in orbit.

Suggestions would be great!

thanks

[painking]

Replace the center Mainsail engine with a Skipper, since 6 of them are more than enough thrust. It's higher lSP should give you enough fuel leftover to get into a circular orbit.

Also, gravity turns if you aren't doing them yet.

[Dewm]

Replace the center Mainsail engine with a Skipper, since 6 of them are more than enough thrust. It's higher lSP should give you enough fuel leftover to get into a circular orbit.

Also, gravity turns if you aren't doing them yet.

the 6 "surrounding" mainsails get me to aroun the 40k meter mark, I think if I replaced the middle one with a skipper I wouldn't have enough thrust to reach a circular orbit..

And as far as my gravity turns. I get to 10k-13k meter mark, swing it down to 45 degree's and burn the rest like that.. is that correct?

[Rassa Farlander]

Try making that upperstage bigger with an orange tank and use more solids on the lower stage Go Jeb Kerman with it! Moar Boosters!! :D good luck!

[Tripzter]

Add another line of tanks outside. Very simple.

[astropapi1]

May I ask, what is that payload for?

You should never, ever, need that much RCS.

[Dashman]

I recon I can answer the rcs question...

Its a refuelling station?

Have you tried asparagus staging?

with that amount of Delta V it should get up with heaps to spare!

I commomly put 4 full orange tanks into orbit without blinking now.

it is like riding a bike...get it the first time and you'll feel like a pro!

[Johnno]

Suggestions would be great!

I think you're simply trying to lift too much mass. Your 'orbital manouvering' stage is almost dead weight in my opinion, you've got 22 tons of extra payload just for a few hundred extra delta-v, you'd be better off dropping that stage entirely and focusing on having your core carry it all the way into the desired orbit.

I'm not sure how good those solid boosters are that you're using (don't know the mod/stats), but double orange tank core + 6 boosters can lift around 100 tons to orbit. You're trying to lift around 130 tons. My advice would be to slim down your payload, remove your 'orbital manouvering' stage and 2-3 of the large RCS tanks. Even if you're to use it as a refuelling station core or such you won't need that much RCS fuel.

If you're dead set on that specific payload, you need more boosters. Try adding one more pair. Also it'd be wise to put a Rockomax X200-8 tank (thinnest stock 2.5m tank) between the orange tanks and the mainsails, so they don't overheat easily.

[Dashman]

...and as always, go to the share ship section in the forums...

download a couple of other peoples lifters and you'll get some great design ideas and help.

I did that when I first started and did a forehead slap and an "of course!" when I realized

what other people had done. lol

[Dewm]

I recon I can answer the rcs question...

Its a refuelling station?

Have you tried asparagus staging?

with that amount of Delta V it should get up with heaps to spare!

I commomly put 4 full orange tanks into orbit without blinking now.

it is like riding a bike...get it the first time and you'll feel like a pro!

Thanks for the reply. First, nice 4 orange tanks? care to share a pic?

Second.. what isasparagus staging?

Thanks!

[capi3101]

Asparagus staging - a clever method of setting up radial decouplers and fuel lines in a manner that extends the usable lifespan of the inboard engines while chucking dead weight as you go. Somewhat controversial as there's debate as to whether or not it's physically realistic. Specifics here.

Payload looks almost identical to one of my Barn Burner Superheavy 7s - five X200-32 tanks and a quad of big RCS tanks. You know, if you run fuel lines from the outboard tanks to the centerline tank, you can lose the seniors on the outboard tanks...unless you're going for a super-strong connection between whatever you call your supply module and the tug. I recognize this - its a supply module for an interplanetary rocket, right? String two or three of these things together, slap a heavy booster on one end and an excursion module on the other and you can go anywhere. Pack some extra LV-Ns; that's all I'm gonna say about that.

[Dewm]

Asparagus staging - a clever method of setting up radial decouplers and fuel lines in a manner that extends the usable lifespan of the inboard engines while chucking dead weight as you go. Somewhat controversial as there's debate as to whether or not it's physically realistic. Specifics here.

Payload looks almost identical to one of my Barn Burner Superheavy 7s - five X200-32 tanks and a quad of big RCS tanks. You know, if you run fuel lines from the outboard tanks to the centerline tank, you can lose the seniors on the outboard tanks...unless you're going for a super-strong connection between whatever you call your supply module and the tug. I recognize this - its a supply module for an interplanetary rocket, right? String two or three of these things together, slap a heavy booster on one end and an excursion module on the other and you can go anywhere. Pack some extra LV-Ns; that's all I'm gonna say about that.

Thats pretty much exactly what I want to do. I know you can travel to planets cheaper etc etc etc... but this is more for the build experience then anything.

After looking at the asparagus staging I realized its the staging I used on this rocket. I would like to build this so I can design similar modules but with slight weight variations (take the rcs off, add solar panels.. living modules etc)

So it would be nice if I could get this into orbit with a fair amount of extra fuel. so I don't have to redesign the whole lifter system.

[Johnno]

So it would be nice if I could get this into orbit with a fair amount of extra fuel. so I don't have to redesign the whole lifter system.

I'm usually not much for asparagus staging, but thought I'd help you out (plus I get some practice doing asparagus since I normally don't touch it).

So here's how I tweaked the one you showed in your initial post:

-Removed solid boosters

-Added a large reaction wheel to the payload

-Swapped solar panels for RTGs

-Removed 'orbital manouvering' stage

Now here is where it gets interesting, the actual lifter design. I added rockomax x200-32 tanks below the bottom jumbos, mainsails on all 6 outer tanks. The core however got a makeover; engine cluster with a central T45 engine surrounded by 8 T30 engines.

Ascent profile is pretty simple, 100% thrust the whole way. Wait with gravity turn until second pair of boosters has dropped (around 12-13km or somesuch), do a 45° gravity turn, drop third pair of boosters when they run out, chase the prograde marker while monitoring your AP, cut thrust when your AP is as desired, do your circularization at AP.

I launched it several times while tweaking it, 100x100km orbit is no problem, I overshot a bit doing a sloppy circularization and ended up at 100x117km with a bit of fuel to spare. The lifter could probably be tweaked/optimized some more, I'll leave that up to you.

A few pics that'll be helpful:

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[capi3101]

Hey Johnno, thanks for that. Subassembly's jacked up in 0.21 and it's playing merry hell with Temstar's Zenith booster subassemblies...haven't had a successful Barn Burner mission in 0.21 yet.

17.6% of the total thrust in the centerline stage is a bit less than what's recommended for asparagus, but if it works, who cares? Right?

[Dewm]

Thanks for the help Johnno, I will have to try this later after work.

Whats the advantage of the rocket cluster pack? more thrust? or better isp?

Thanks!

[Johnno]

Whats the advantage of the rocket cluster pack? more thrust? or better isp?

Both. Thrust is 1920 vs Mainsail's 1500, ISP is 320/370 vs Mainsail's 280/330.

Downside is more parts and more hassle of building it.

Edit: Oh and mass. The engine cluster weighs more.

[Dkmdlb]

If this is going to be a refueling station, you ought to use some of the fuel from the payload to get to orbit. Put a couple of fuel lines in there to feed the final stage. Then, you can send smaller refueling ships up to it to refuel it while its just sitting in LKO.

[Motokid600]

Whatever mod your using for those boosters ( is it KW? ) should be utilized. I recognise them I just forget what mod. And I remember those SRB's are very week. Stronger boosters will get the job done. If you use KW's most powerful booster you'd have more DV left then you'd know what to do with.

[zanzibar196]

You are WAY over-thinking things here... something like this should EASILY get you into orbit:

[annallia]

If this is going to be a refueling station, you ought to use some of the fuel from the payload to get to orbit. Put a couple of fuel lines in there to feed the final stage. Then, you can send smaller refueling ships up to it to refuel it while its just sitting in LKO.

This is what I was thinking. Below is my super tank, it weighs 150 tons (just the tank) and an extremely simple launcher to get it in space (mind you I use a few mods).

No asparagus staging, just raw power. The 6 boosters were jettisoned when they ran out (no fuel crossfeed) which was around 32,000m The core stage used the fuel in the tank first, it made it to 80k orbit with enough fuel left in the core stage to not only refill the tank, but to de-orbit itself as well (and top off my tug...)

Edit- by 6 boosters I meant the stage that the liquid fuel boosters from nova punch are sitting on, I forgot about those boosters so in effect I had 12.

That said despite the mods this can be done with the stock game or KW. I simply prefer novapunch parts.

[ZenithRising]

I think the guy who suggested a skipper is right on. Your design is all thrust and no specific impulse (efficiency). You're running out of fuel part way up. As you get higher, you won't need as much thrust because you are shedding weight, the air resistance is dropping, and you are also coasting off the momentum of previous stages. Skippers are a great choice. They still have a ton of thrust and use much less fuel then the mainsails. I've also had some success with using a few aerospikes in a stage, as they have great specific impulse (though poor thrust).

Also, terminal velocity is an issue. Your thrust is giving you diminishing returns once you hit it. You may find that all of those Mainsails aren't actually helping much more than four or so would.

I'm far from an expert, but I would jam some extra solid boosters on there to get that early thrust you need (best thrust to mass ratio in the game), cut down on the Mainsails, and replace them with Skippers.

[Respawn]

I made a pretty similar thing for my mun base. (106 tonn payload).

I just launched it into orbit around kerbin in my test save as proof of concept.

The launch vehicle ended up looking pretty shabby but hey it worked.

4x boosters,

4x mainsails with 2 orange tanks each (+ 1 flat grey tank each)

6x skippers with 1 orange tank each

1 x skipper for the last stage also with only 1 orange tank.

Something like this should work for you.

Here's a undramatic video of the my 2 launches.

(raw footage + some fancy elevator music.) XD

2 launches..

1'st launch failed as i didn't pay attention to the over heating.

after adding the small grey tanks in between as heat buffer the second launch worked great.

even wasted lots of fuel with a terrible ascent profile

Hehe..

Hope this helps.

[Dashman]

there ya go. 1 tank in the middle and 3 in the outside. also full at launch.somewhere round 150 ton from memory.

https://www.dropbox.com/s/ks4envjkkrm47ke/station90.jpg

ok, still cant inbed a pic...just go to the link. sry bout that.

I know theres posts and tuts on asparagus staging.

In fact, do a search on utube for asparagus staging in KSP and a gazillion vids will pop up!

(silghtly over the top but you get me drift)

It pretty simple once ya understand it....and very effective.

[Dewm]

I made a pretty similar thing for my mun base. (106 tonn payload).

I just launched it into orbit around kerbin in my test save as proof of concept.

The launch vehicle ended up looking pretty shabby but hey it worked.

4x boosters,

4x mainsails with 2 orange tanks each (+ 1 flat grey tank each)

6x skippers with 1 orange tank each

1 x skipper for the last stage also with only 1 orange tank.

Something like this should work for you.

Here's a undramatic video of the my 2 launches.

(raw footage + some fancy elevator music.) XD

2 launches..

1'st launch failed as i didn't pay attention to the over heating.

after adding the small grey tanks in between as heat buffer the second launch worked great.

even wasted lots of fuel with a terrible ascent profile

Hehe..

Hope this helps.

Thanks for the help. I'll sure give this a try. I've been working on this for days now, and its bothering me XD.

[Dewm]

So what am I doing wrong?

Can't get this thing to work worth anything

So I burn everything at 100% until the outer tanks start to over heat. then I dial it back to about 90%. I run at 90% until I hit 10-13k meters, then I begin my gravity turn, (turn around 30-40 degrees) and I burn (dropping tanks) until around 75-80k meters. then I drift until the apoapsis then I burn until I am out of fuel (following a course I set) and its still not enough to get a full stable orbit. Not to mention having any fuel left for maneuvers etc...

Why am I so bad at this game?!?!