How to get fat heavy things into orbit with stick kerbal and only 30% science tech

[jpinard]

I know I'm doing thing wrong, as I'm building the most massive monstrosities trying to get a good gescybchronous orbit, and they all fall apart. Can someone post some design for getting heavy stuff into space in a decent orbit with fuel to spare?

Thanks!

[RSwordsman]

May I ask what you're doing with the fat heavy thing that makes you want a synchronous orbit?

I will advise without knowing though that you can try putting a bunch of fuel tanks in your lifter and using cubic struts to cluster LV-T45s. Using this method to put 5-7 engines on the bottom of a 2.5m stack, you can get almost as much power (and a teensy bit better Isp) than with a Mainsail. Coupled with asparagus staging (not sure if you have the fuel pipe yet) I still use this method for my heavy lifter.

[RatchetinSpace]

It helps to have an efficient design for your launch stage. Make sure you are doing your gravity turn at a good altitude (10,000m is my preffrence)

I have uploaded to Kerbal Space Port 2 heavy lift vehicles that should be well and truly enough to get yourself into geostationary orbit: http://kerbalspaceprogram.com/glenospaceheavyliftvehicles/

Of course, this assumes that you have mainsails. I suggest Scott Manley's beginners guide to getting science if you want budget launchers.

[ksbes]

Men has onli 30% of science. So it is a long way to "cubic struts". A lot of LV-T45 bp VERY laggy (they all trying to keep rocket oncorse, but with little laggs to each other wich makes rocket wobbling). It is better mix LV-30 and LV-45 in 2-to-1 proportion.

The best solution is to use orbital building, or low orbit refueling (at space station). Intercepting is not as hard as it seems even in vanilla. With MehJeb it's a child play.

[Phafor]

Try keeping it simple, use LV909 ones you hit space, don't be like if you have a ship that doesn't have enough thrust. MOAR do, because more boosters means that your rocket is less stable which means more moving parts which means more lagg. And for some reason in KSP you waste more fuel when you are lagging i find.

[SpaceGremlin]

Strut everything together. For big rockets I like to run some struts along the entire length of it to reduce loading on the middle connections. If my weak joint is a tank-decoupler-engine-tank sequence, I'll place small cubic octagonal struts on the fuel tanks above and below and strut them together. Or if I haven't unlocked the small cubic strut I'll just strut both tanks to the decoupler.

[RSwordsman]

Men has onli 30% of science. So it is a long way to "cubic struts"

I might be wrong but I think it gives you the bigger frame struts on the first science node. And I was able to use clusters totaling over a dozen gimbaling engines without an annoying amount of lag.

[Vanamonde]

It would help if you posted pictures of your payload.

[nala2624]

What tonage are we talking about? If you have radial decouplers, almost anything is possible. Also consider using a mod to find your terminal velocity and stay under that during accent. I recommend engineering redux or, even better, FAR.

[Skorpychan]

More fuel, more rockets, asparagus staging, and lots of decouplers to ditch things you don't need.

Otherwise, why do you need to lift fat heavy things into space in one piece? Unless it's your mother, disassemble and use on-orbit assembly. Or just build smaller.

[jpinard]

Wrote this while falling asleep last night hence all the typos. I'm trying to do two different things:

#1 - Get a Communications Satellite into geosynchronous orbit at 310,000 meters for remotetech 2. I don't have RCS thrusters, so I need to launch with a manned capsule attached (and because I don't have a network yet). I watched a good video that said to go straight up, then do your orbital burn when you hit your apoapsis. Then you can get a really good orbit right in sync. Problem is I run out of fuel before I get the proper orbit, and also not enough fuel to deorbit the manned capsule.

#2 - I want to get Scansat satellite in a North-South pole orbit to start scanning the whole world of Kerbin. So I need fuel to not only get into a vertical orbit, but also to move the probe around a bit to continue scanning at different longitudes.

My craft have gotten entirely out of control build-wise. You can see I'm using a few KW Rocketry parts, but I figured there's got to be a way to do this stock and/or I'm building really inefficiently.

http://imgur.com/a/rsVvO#0

Edited February 9, 2014 by jpinard

[7499275]

For 1, your orbit of 310,000 meters won't be a geo sync. It has to be at 2,868,000 meters and an orbital speed of 1009.8 Meters per second.

[jpinard]

Here's a direct link to an album showing the rockets I built, the satellite payload, and the science I've researched. http://imgur.com/a/rsVvO#0

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Edited February 9, 2014 by jpinard

[nala2624]

From looking at your pictures, you're trying to haul too much fuel into orbit with you. Your payload doesn't look too heavy. Try shortening your rocket by having most of your thrust lower in the rocket. To get my comsat system into a geo-sync orbit, my setup was pretty simple and I only used LV-T45 engines with a modded LFO tank that's equal to about 3 FL-T800 tanks. My footprint was about 29 LV-T45s with varying amounts of tank stack sizes. All in all, the bottom stage was about the width of 11 LV-45 tanks while the top was kept in the diameter of one. Use onion or asparagus staging to get the most dV out of your rocket. Maybe even shorten your mid and upper stages. Each stage should be shorter than that last, generally speaking.

EDIT: side note, I wouldn't use boosters on any other stage beside the first one.

[jpinard]

What tonage are we talking about?

Also consider using a mod to find your terminal velocity and stay under that during accent. I recommend engineering redux or, even better, FAR.

I have both FAR and Engineering Redux, but admit I don't really know how to use Engineer.

How do I find my terminal velocity during launch?

Is my weight the 4,000 kg number or the 6,000 kg?

Edited February 10, 2014 by jpinard

[Pecan]

How do I find my terminal velocity during launch?

Is my weight the 4,000 kg number or the 6,000 kg?

Terminal velocity is what it is according to the atmosphere, whether your vehicle reaches or exceeds it during any stage is determined by the TWR (Thrust to Weight Ratio) displayed. The weight (surface mass) of your vehicle is 6.03 tonnes (4.359 just for stage 3) but since none of these stages have engines your TWR is 0 - you will not be going to space today.

Of course you know that last bit, which is why you add a launch vehicle underneath it. With that attached the TWR and deltaV figures in KER will update and you'll be able to see how far and how fast the thing will go. 4,500m/s deltaV required to reach orbit. TWR 1.6 - 1.8 generally recommended at the start of each stage - as that stage burns through its fuel the mass decreases but thrust stays the same so TWR increases - so you roughly follow a TWR = 2 curve through the atmosphere.

[DrMonte]

1. What does it mean "straight up"? I have no idea how much more fuel you'll need if you would not start your orbital turn at 10km.

2. I think you know that stationary orbits are only at equator? You should go either equator way or pol way from the start. Changing inclination by 90deg costs a lot lot of fuel (even maneuver over the Mun sometimes is used to save some). Although Ion engines would be forgiving here.

[KSK]

It does look like you're overbuilding things. I don't know how heavy your payload is but for comparison, I have a basic stock comsat (because roleplaying ) that's basically an OKTO plus antenna, with Round-8 tank and an LV-1 on the back for propulsion. It's quite possible to get that to kerbostationary orbit using the big Rockomax SRB as a first stage and then an FLT-400 + LV909 second stage. All nice low tech parts!

Couple of other points.

From your tech tree screenshot it looks like you've unlocked the Stayputnik, so you might not need to include the command pod. Getting a synchronous orbit will be still be difficult without RCS, or a small engine to make fine adjustments though.

For polar orbits, it's far easier to just launch straight into the orbit. you do need a little more delta-V for that but its only around 200-250m/s extra, which is much less than you'll need to make the required plane change from an equatorial orbit.

If you post the mass of your two satellites, I could have a go at designing a suitable launch vehicle if you'd like.

Edited February 10, 2014 by KSK

[Taki117]

That's a lot of batteries. Also, you have KW installed, so why not use those fuel tanks? I've noticed they hold a tad more fuel than the stock tanks (You could also use those engines) I assume you are not using KIDS (Kerbal Isp Difficulty Scaler) meaning it's only going to take you about 3.5-4 km/s dV to get to an 80kmx80km orbit. You also have a lot of SRBs that are nothing more than dead weight until that stage, I suggest dropping these and going for an all liquid rocket. Contrary to popular belief you don't need to build tall spindly rockets with FAR, you just need to make them aerodynamic (Control surfaces help here) You are using Remote tech, so it might be best to launch into LKO, then do a Hohmann Transfer to KSO while your above the KSC so that you don't need to bring along the command pod. Also, the 4kg number is the weight of the stage, the 6kg is the total weight of the craft, the same is true for dV. You don't need that many Omni antennas, the dipoles are only good to about 100km, great for getting you into orbit, not so much for anything else. The communotron-16 is good to about 2.5Mm, which is less than KSO so you can ditch those. I assume you have 2 of the Comms DTS-M1 those are great for pointing at the next and previous satellites in orbit. If you have the Communotron-32 (Which judging from your tech tree you should) I would use that if you want an Omni antenna on your craft. Also, while you don't need to turn the Dipole on, you can turn it off once you are in flight and have your longer range Omni deployed. You really don't need all those tiny batteries. If you have the round ones use those instead. You can also swap the shielded panels at the top for the lighter, but no less efficient, unshielded solar panels. Not sure if I have said this already, but that engineer part is blocking the hatch, you will not be able to EVA your kerbal.

Sorry for the wall of text, but I have a feeling that it will help.

So, In order to prove that this can be done I decided to try it myself.

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Edited February 10, 2014 by Taki117
Tried it!

[jpinard]

Yea you guys did it! Not only did I put packages up in a proper orbit, but you helped me finally "actually" understand what's going on.

One of the biggest issues I've had is with stability. I'm using FAR and I've yet to conquer large, powerful ships angling for orbit at 10,000 m as they just want to wobble or flip over.

* Pecan - thanks for the numbers. Those help tremendously.

* Dr Monte - straight up meant no use of Kerbin's orbit to help with the orbital insertion. So straight up to 300,000 m, then did a 90* burn to hit an equatorial orbit. I'd used the 300,000 because that's just far enough up that 3 satellites in perfect triangular orbit from each other can see each other around the width of the planet.

* KSK - No RCS thrusters has been a huge pain. The mass is a couple of screenshots up. They're kinda heavy fully equipped with everything needed.

* Taki117 - Thank you!! I'm going to rebuild with that construction and see if I can hit a true geosynchronous orbit.

[Taki117]

* Taki117 - Thank you!! I'm going to rebuild with that construction and see if I can hit a true geosynchronous orbit.

If you want the craft file you can have it. (Pretty sure the batteries on the fuel tank are KW) Also, you could swap out the Communotron-16's for the Comms DTS-M1 to provide connectivity to your other satellites.

[jpinard]

If you want the craft file you can have it. (Pretty sure the batteries on the fuel tank are KW) Also, you could swap out the Communotron-16's for the Comms DTS-M1 to provide connectivity to your other satellites.

Yes please to the craft file. Also, what's the difference between satellite dish vs. the other 2 basic antennas you get early in the game and how many do I need of each and for what reason?

[Taki117]

https://docs.google.com/file/d/0BzOU_F85Qj0YRFJBblV5Tmg1dlk/edit

There's the Craft file.

Also, the biggest difference is the Range. The Dipole (little black box with two wires coming out) is good to 500km. The communotron 16 is good to 2.5Mm, both are Omnidirectional antenna meaning that they will connect with everything within range. Dishes have to be pointed. Generally I use the DTS-M1 to talk to other satellites in the same orbit and the other dish to cover everything else. I would put 2 of the large dishes on, one pointing at Kerbin and the other at the Mun. The DTS-M1 one should point at the next satellite in the series, and one should point at the previous satellite. (i.e if you have 3 satellites in a triangle you should have one DTS-M1 pointed at each other satellite) You really don't need the Communotron-16 at all if you do it right. With my launch profile I circularized at 80km (Still within the range of the Dipole) and then turned one of the dishes to Kerbin and activated it. Once I got out of range of the Dipole ( >500km) it automatically switched over to using the dish, at that point I didn't need anything else.

Oh poop, I need to remove a couple of things...Namely the Parachutes from Realchute and the Radiators from KSP Interstellar Totally forgot about those!

Fixed! Everything there is either Stock or KW. Also, Action group 1 toggles all solar panels, and action group 2 jettisons the fairing.

Edited February 11, 2014 by Taki117
Added Craft File

[thereaverofdarkness]

Just yesterday I had an 80 ton payload I wanted to get into orbit. I remembered the payload fraction challenge and decided I was going to need a minimum 400 ton launcher, but probably more like 600 to 800 tons. I put a strong square base together with girders and struts, and attached twelve 2.5m tank stacks with 4200/5400 fuel each and a mainsail engine. That was 60 tons per stack, or more than 720 tons considering extra bits to attach them together plus fins and reaction wheels. Even though it was a single stage unit, it got my rocket into orbit.

Another consideration I took into account was the number of tons that the payload and rocket weigh. Sometimes I add this up by counting each part from heaviest down (and estimate once I get to the little stuff), or I use Kerbal Engineer to tell me. You have to be careful with Kerbal Engineer though because it wont tell you the total weight including the bottom stage if you have it set to show stages and the bottom stage has no rockets yet. You want at least 20kN thrust per ton. An 800 ton rocket needs therefore 16,000+kN. Twelve Mainsails gives 18,000kN.

The most important part after that was lots and lots of struts, carefully placed because I didn't want to overwhelm my computer. Then I put a bunch of canards on the bottom and a few in the middle and near the top. I forgot the RCS thrusters and that was problematic once I got into the upper atmosphere--I had to link each tank across the stacks and down to the engines with fuel pipes because the structural connections between tanks kept breaking and causing them to stop emptying. I got a setup that allowed every engine to draw fuel from anywhere in the stack, but it didn't empty evenly. The powerful Canards kept it straight through the atmosphere but once my lift was gone, almost 100 units of torque were not enough to make that giant thing turn in any reasonable amount of time and the engine thrust was off balance to the mass.

[KSK]

OK, here goes with the promised design, although it's a bit redundant now.

LV-T30s on the first stage, LV-T45s on the second, LV909 on the third. Small SRBs to get it off the pad. Otherwise just uses FLT800 tanks, FLT400 tanks and a wee bit of strutting to hold the stages together. Flies OK, although you need to be a bit careful with the gravity turn. As soon as you lose the SRBs you'll start to decelerate but it'll pick up again at around 70 m/s. First stage should get you to about 10km up, second stage will probably get you to orbit with care, or not far off it. I still needed about 250m/s delta-V out of the third stage to hit orbit but my ascent profile probably wasn't optimal.

Third stage in above kerbostationary orbit, using cupola module and Mk 1 lander can as approximate mass dummy payload.

Apoapsis value didn't get captured but you can hopefully tell from the velocity that we're comfortably past stationary orbit. With fuel left to spare for plane changes and fiddling with orbital parameters. Or probably a one-way trip to Munar orbit!