Help getting into Orbit without going bankrupt

[Orc]

Greetings to all fellow Kerbal Space Explorers

 

I hope your rockets are holding to their appointed course and not exploding spectacularly (unless that is what you want today).

 

I am a noob, rookie, newbie... whatever....

 

I am trying to get into orbit and get my Kerbal home without going bankrupt.

 

FYI: I am playing the demo from the KSP website, the one that comes in a ZIP file. If that makes a difference.

 

My problem is:

 

With the VAB and launch pad upgrades I can afford a rocket that will perform the necessary mission, but I won't have the money to go any further, and without upgrading the Science Center (which is VERY expensive) I can't access the necessary technology to earn the big bucks offered by the sub-orbital tourists trade.

 

If I could build a rocket that can make orbit and safely return the Kerbal home WITHOUT the VAB and launch pad upgrade I might be able to survive long enough to make enough money on other Contracts (testing parts, surveying terrain) to afford the science center upgrade.

 

But my non-upgraded rockets keep not making orbit, or going loop da loop all over the launch pad area and making spectacular but unwanted smoke trails and ultimately explosions (I have succeeded in completely destroying the launch pad), or I can make orbit and not have enough fuel to get my kerbal-naut home.

 

Am I missing something?

 

Help please!

 

REgards

Orc

[Venusgate]

Hello and welcome to the forums!

There are many MANY guides about on rocket building design (Like this one! http://wiki.kerbalspaceprogram.com/wiki/Tutorial:Basic_Rocket_Design)

But allow me to help you in a more quick and dirty fashion.
 

First, it is definitely doable to make orbit without upgrading any buildings.

Second, consider downloading the mod Kerbal Engineering Redux (http://forum.kerbalspaceprogram.com/index.php?/topic/17833-104-kerbal-engineer-redux-v10180/)
This mod is INCREDIBLY useful for rocket building as it gives you a readout of how far your rocket is going to be able to go (in a unit called Delta V or dV here)
Whether you use that, or whip out your calculator and do all the math yourself, getting to orbit will take at the very least 3000 m/s dV

Third, on "flipping rockets." Basically what's happening is the Center of Mass of your rocket is too low and you dont have enough control to keep it behind you. Early on, consider putting a few fins or winglets toward the bottom of your rocket. This should make control much easier

Fourth, on actually flying. A good "ascent profile" (or the curved path into space your rocket takes from pointing straight up to being horizontal in space) should have you starting to turn eastward between 1km and 3km up, 45 degrees around 10km up, and slowly going to zero degrees as you go from 10km to 70km.

Hope these help!

[Streetwind]

@Venusgate: read his post carefully: he's playing the demo version. Available parts are heavily restricted (for example there are no thrust vectoring engines, period) and mods are incompatible unless you know exactly which specific outdated version to find.

At the same time, I'll echo your suggestions regarding ascent profile (gradual turning, staying very close to the prograde marker) and rocket design (heavy bits at the front, draggy bits at the rear - exactly like an arrow).

@Orc: Try the following rocket:

1x command pod, ideally with a parachute on top
1x TR-18 Stack Decoupler
3x FL-T200 (or 6x FL-T100, depending on what you have available - the result is identical)
1x Reliant engine
1x TR-18 Stack Decoupler
6x FL-T200 (or 12x FL-T100, see above)
4x winglets/fins attached as low as possible to the lowest fuel tank in the stack
1x Reliant engine

Make sure you have five stages: bottom engine, bottom decoupler, upper engine, upper decoupler, parachute. And make sure to throttle up fully on the launchpad, and keep the throttle full until you at least lost your first stage! You can fly the upper stage with less throttle, but only for improved control; throttling down during ascent does not save fuel, contrary to what most new players think. Rocket engines do not work like cars do

Aim your apoapsis to be at around 80 kilometers up. This rocket should get you into orbit with fuel to spare, and back too, provided your pod does not burn up because the demo version does not have any heatshields. Good luck!

Edited December 3, 2015 by Streetwind

[Venusgate]

23 minutes ago, Streetwind said:

@Venusgate: read his post carefully: he's playing the demo version. Available parts are heavily restricted (for example there are no thrust vectoring engines, period) and mods are incompatible unless you know exactly which specific outdated version to find.

I assumed basic fins were part of the demo, which is what I meant. Didn't know about mod incompatibility.

[Warzouz]

For new players, SCIENCE game mode is best to discover the game and get used to it's mechanics

[jros83]

Aaaaaaand right away someone jumped right to "get a mod."

[cephalo]

36 minutes ago, jros83 said:

Aaaaaaand right away someone jumped right to "get a mod."

You can probably get into orbit without a mod with much trial and error, but if you don't know your dv, failures will become intolerable. Some mods are absolutely necessary. This is just one of those games that relies heavily on the community.

[jros83]

4 minutes ago, cephalo said:

You can probably get into orbit without a mod with much trial and error, but if you don't know your dv, failures will become intolerable. Some mods are absolutely necessary. This is just one of those games that relies heavily on the community.

That's debatable.

[cephalo]

18 minutes ago, jros83 said:

That's debatable.

Kerbal Engineer Redux... NOW.

[jros83]

With no malice towards Squad, the more we inflate the importance and "necessity" of mods, the less inclined Squad will be to include decent additions in future updates. 

[Snark]

@Orc: Welcome to the forums!

As Streetwind pointed out, your options will be rather limited by the demo.  If it's an option for you, I'd strongly recommend just buying the full version, it's not all that expensive and you'll have so much fun with it.  Hundreds of hours of enjoyment for US$27 is a pretty good deal.

Aside from being a lot more fun with it, you'll also have much better luck asking questions in the forums.  Very few people here are playing the demo, they're using the full version.  I would guess that the large majority of them don't even know exactly what is or isn't included in the demo (I know I sure don't), which means you're likely to get lots of answers that will be unhelpful to you because they will reference parts that you don't have.

Streetwind has given a demo-compatible recipe for getting into orbit.  If you have the full game, it's even easier than that, because there's another engine (the Terrier) that is perfectly suited as an upper-stage, get-into-Kerbin-orbit engine.  High fuel efficiency, weighs only half a ton.  With the full game, you can build a very cheap rocket with just a few parts that will get you into orbit with no problem.  From top to bottom:  parachute, Mk1 command pod, 2-ton fuel tank, Terrier engine, stack decoupler. Two more 2-ton fuel tanks, Swivel engine, stack decoupler.  Hammer SRB on the bottom.  Some basic fins on the bottom for stability.

In any case:  whether you stick with the demo or buy the full version, best of luck, and welcome to our worlds!

[jros83]

Orc when you have the chance, KSP is definitely worth the buy. And I am massively critical of most modern games. I can't find any viable reason to pass up KSP. At all. If you enjoy this sort of thing, you will enjoy KSP immensely.

[GarrisonChisholm]

3 hours ago, jros83 said:

Orc when you have the chance, KSP is definitely worth the buy. And I am massively critical of most modern games. I can't find any viable reason to pass up KSP. At all. If you enjoy this sort of thing, you will enjoy KSP immensely.

I will echo this.  It is stunning that so many hours of enjoyment can be found- even when you are trying to solve a similar problem, the ability to tinker and experiment with something new is immensely enjoyable.  It is so easy to sacrifice sleep to this marvel, and I am a middle aged guy who should know better.

 

You're not buying a game.  You're investing in joy.

[Waxing_Kibbous]

Just want to add a +1 to buying it- I very rarely buy games, as in maybe once a year, but this one is too good to pass up. I also recommend if you do buy it to stay away from mods for the beginning, you can do Mun landings without them no problem, and if there is something you think is missing after a bit of play look it up, chances are it exists already.

[Venusgate]

14 hours ago, jros83 said:

Aaaaaaand right away someone jumped right to "get a mod."

I agree that KSP is fun without mods, but I'm not about to give a newbie a math homework assignment before he or she starts liking the game in the first place. 

[Warzouz]

16 hours ago, jros83 said:

With no malice towards Squad, the more we inflate the importance and "necessity" of mods, the less inclined Squad will be to include decent additions in future updates. 

You're true. KER and KAC (in a simpler design) should definitely be stock. Without KAC you can't really play multiple missions or you're probably miss node while time warping.

Also, some kind of tool to help finding transfer windows is definitively necessary. Maybe someone at the observatory could warn us of those windows ! that you be RP.

External tools and mods are nice to expand the gameplay. But when we need them to play, that means the game is not complete.

 

[Orc]

Hi All

 

Orc is back. 

 

Many thanks for all the answers.

I've tried the configuration StreetWind suggested, thanks StreetWind. It seems to offer the best chance of success. I also tried another configuration (1 capsule, 8 FL-T200  and one  Reliant engine). I can see how it would work in Theory but my rocket flying skills are not yet up to Theory's standards. 

My success rate with getting into orbit has improved (2 versus 0 for certain value of success). One of my kerbal-nauts is doomed to endlessly circle Kerbal in his Mk1 capsule. The Periapsis of his orbit is +- 55K meters an I hoped the minimal atmosphere at that altitude would eventually cause him to slow down enough to re-enter but after a few dozen orbits the numbers don't seem to have changed by more than a couple of meters. My other Kerbal-naut got to walk away alive.

That all said it still takes me ten for fifteen attempts to getting into orbit.

For those who suggested I buy the game, I would in heart beat (or in significantly less time than a heart beat) but I am currently unemployed so I'm stuck with demo, which is still more fun than I've had with a computer game in probably a decade.

That said can anyone point me toward the mods that will work with the Demo version?

Thank you all.

Take care. May your rockets fly true and Kerbal-nauts not puke in their helmets when your rockets go loop da loop, unless of cause that is something you want today.

 

Kind regards,

Orc

 

 

 

[Streetwind]

1 hour ago, Orc said:

One of my kerbal-nauts is doomed to endlessly circle Kerbal in his Mk1 capsule. The Periapsis of his orbit is +- 55K meters an I hoped the minimal atmosphere at that altitude would eventually cause him to slow down enough to re-enter but after a few dozen orbits the numbers don't seem to have changed by more than a couple of meters. My other Kerbal-naut got to walk away alive.

*snip*

That said can anyone point me toward the mods that will work with the Demo version?

That periapsis should indeed be low enough to let the orbit decay. If you're not seeing any decay happening, there's something wrong...

...unless you are looking at it in the tracking station. In order to save on CPU load, KSP only fully simulates objects that you are currently flying, or within ~2.5 km of an object you are currently flying (called the "physics bubble"). All other objects are placed "on rails" and are no longer affected by things like passing through atmospheres - unless they get below a certain altitude, at which point the object is flat-out deleted.

That means: you should take control of your stranded Kerbal's pod, even though it has no propulsion left. Stay with the pod as it encounters the atmosphere. If you have battery power left, orient the pod so the big, flat bottom side faces forwards - though if you simply turn SAS off and do nothing, the pod should automatically orient itself into that direction due to atmospheric drag and the special way it is shaped. You should now be able to watch in map mode how your aposapsis and periapsis are slowly decaying. It may take a loop around or two, but eventually it should dip down deep enough that it won't come back up again.

 

As for mods, I believe you need to look for mod downloads that work with KSP version 1.0.0 (as opposed to the current version, which is 1.0.5). I'm not sure how many you will be able to find, because there were two patches relatively soon after the release of 1.0.0, and most mods went straight for supporting 1.0.2 instead. You can try those, too, but there were a lot of changes and some things may not work right.

You can find these downloads on KerbalStuff or Curse when looking for past versions.

Edited December 4, 2015 by Streetwind

[Warzouz]

And BTW, heavier rockets are sometime easier to launch to orbit than small ones (especially those 1.25m)

[MrOsterman]

On 12/3/2015, 3:31:08, Streetwind said:

throttling down during ascent does not save fuel, contrary to what most new players think. Rocket engines do not work like cars do

Like at all?  Or is this a case of "you can throttle back, but it'll just take you just as long to push out of the atmosphere and thus use just as much fuel?"  I've thought that pulling back to half throttle does reduce my fuel use and I'm still pretty loosey goosey with my design that I find that I've got a lot more push than I can use at the lift stage.  I hit 300 m/s pretty fast while still in the thicker air so I don't want to burn too much gas trying to up that speed while fighting terminal velocity on the way up.

 

[Streetwind]

40 minutes ago, MrOsterman said:

Like at all?

 

Yes, at all.

Terminal velocity runs away from you fast. If your rocket is reasonably shaped - i.e. it has a pod with a parachute on top, as opposed to a lander can with a flat uncovered end - then you need TWRs in excess of maybe 4 to have a chance to keep up with it, and you'll hit orbital velocity while still in the lower half of the atmosphere. After all, terminal velocity approaches infinite (not orbital velocity) as atmospheric density approaches zero, and atmospheric density drops exponentially with altitude. As such, you can pretty much forget about terminal velocity altogether. You will never hit it unless you overengineer to absurd levels. (Which some people do, but hey, they have fun with it )

Also, as you can imagine from the description above, if you are approaching terminal velocity during ascent, you're going to have much more serious problems than the risk of wasting one or two m/s of dV. Namely, you're probably going to overheat whatever part acts as your nosecone, unless you took special precautions. Now this is a valid reason for throttling down during ascent. You want to keep your structural integrity after all.

The dV cost of reaching orbit breaks itself down thus, very over-the-thumb, for a typical and suitably pointy rocket:
- 70% goes to accelerating to orbital velocity
- 22% goes to gravity losses
- 7% goes to aerodynamic losses
- 1% goes to steering losses (when your engines gimbal away from thrusting straight forward in order to steer)

This vey much illustrates the fallacy of trying to throttle down to reduce aerodynamic losses. Not only are they an incredibly minor position in the first place, which makes almost no difference either way; but you are also increasing gravity losses by accelerating more slowly - and gravity losses eat a far larger share of the dV pie. That means as you throttle down, you lose far more to gravity than you gain from aerodynamics.

Why is that so? Because gravity is negative acceleration. Every second you spend thrusting straight upwards, gravity gobbles up 10 m/s² of your engine output. If you want to accelerate at a steady pace of 2G, then your engines have to put out 3G worth of acceleration - and 33% of the fuel you expend is just plain wasted. Now imagine you want to reduce drag losses, and you throttle down so that you are only accelerating at 1G, not 2. Now your engines have to put out 2G of acceleration, and 50% of the fuel they consume is wasted to gravity. You could continue this game of throttling down all the way to a standstill in the air: now the engines have to put out 1G, and 100% of the fuel spent is wasted to gravity. This is why I often refer to this as the "hovering component", or "maintaining the status quo". You don't want to hover or maintain the status quo. You want to change your velocity and altitude! So kick that pedal to the metal and go full burn to space!

Now of course this applies to flying straight up. The more you turn over towards the horizon, the lower the percentage of thrust gets that must be expended to maintain the status quo. So throttling down hurts less and less as you approach being horizontal. And when you do burn horizontal, there is no gravity component at all - 100% of your fuel goes towards changing your forward velocity. This is why upper stages get away with very low TWRs for orbital insertion: it simply stops mattering at that point. However, at the same time, aerodynamic losses have also long since ceased to matter by the time you are fully horizontal. So there's nothing to save here by going slowly either. The only reason you bring a small engine here is because it saves weight, not because going slow is a good idea.

Hope this helped you!

Edited December 4, 2015 by Streetwind

[Plusck]

On 3/12/2015 16:31:23, cephalo said:

You can probably get into orbit without a mod with much trial and error, but if you don't know your dv, failures will become intolerable. Some mods are absolutely necessary. This is just one of those games that relies heavily on the community.

What? No way. With the "revert" option it is relatively simple to trial multiple variants of a basic design without losing any cash and with losing relatively little time.

I was playing the demo just a month or so ago. SRBs and throttle limiting make a simple combination that lets you go suborbital with minimal cost, minimal unlocking of the science tree and no upgrading of any of the buildings. Admittedly my early craft were horrendously inefficient before I found out about asparagus design...
 

 

6 hours ago, Streetwind said:

...

This vey much illustrates the fallacy of trying to throttle down to reduce aerodynamic losses. Not only are they an incredibly minor position in the first place, which makes almost no difference either way; but you are also increasing gravity losses by accelerating more slowly - and gravity losses eat a far larger share of the dV pie. That means as you throttle down, you lose far more to gravity than you gain from aerodynamics.

...
 

While everything Streetwind said is absolutely true, it doesn't necessarily help for the demo, since you have no gimbal-able engine and no decent automatic pod. And your pilot sucks 'cos he's a noob.

That leaves you with fins - but in the latest demo (I think, the version I have dates from spring 2015) that is towards the end of the available science tree.

This is a problem because when you have several stages in your stack, the top of the stack is heavy with fuel as the bottom is emptying. A top-heavy rocket with poor torque control and no fins WILL flip at the first chance. And this is a valid reason for throttling back because the faster you go through the lower atmosphere, the greater the aerodynamic forces on the nose as soon as you turn in the slightest.

 

So I went back to the demo and had a try with fairly basic parts (not the final level in the science tree). It is a bit touch-and-go at times due to poor control options, but you can get into orbit and back fine (just) with:

stage 0: parachute - pod - materials bay

stage 1: stack decoupler

stage 2: FL-T200 + reliant

stage 3: stack decoupler

bottom of centre stack: 3x FL-T200 + reliant (activated in stage 5)

stage 4: 2x radial decoupler

2x radial stacks: nosecone + 4xFL-T200 + reliant + fuel lines and struts to central stack

29 parts, so you only need to upgrade the launchpad.

Although you should definitely start at max throttle ( T,  Z,  space), you have to be extra careful and slow before you hit about 12km. Just accelerate fast to 100m/s then go third throttle to get to about 200m/s at 10km. Turn a tiny amount when you leave the pad then just stay centred on prograde until you can start turning more at around 14-18km. When you can turn significantly without flipping, then you can raise throttle to 100% and watch your Ap. Shut off engines at 71km, then circularise at Ap.

But of course, if you DO have the fins available, and can build more than 30 parts, add four to the bottom of each of the vertical stages and go faster. I didn't try it but I'm sure you'll have a ton more fuel on reaching orbit.

Edited December 4, 2015 by Plusck
eror in fuel tanks

[Streetwind]

42 minutes ago, Plusck said:

This is a problem because when you have several stages in your stack, the top of the stack is heavy with fuel as the bottom is emptying. A top-heavy rocket with poor torque control and no fins WILL flip at the first chance. And this is a valid reason for throttling back because the faster you go through the lower atmosphere, the greater the aerodynamic forces on the nose as soon as you turn in the slightest.

Fair point, although I was answering a question about fuel efficiency Besides, aggressive steering is something you ought to learn to avoid as early as possible!

[Snark]

1 hour ago, Plusck said:

This is a problem because when you have several stages in your stack, the top of the stack is heavy with fuel as the bottom is emptying. A top-heavy rocket with poor torque control and no fins WILL flip at the first chance.

Agreed, lack of fins = flip-worthy.

Also, lack of gimbaled engine = flip-worthy.

However, top-heavy isn't a problem.  Top-heavy is good for aero stability.  You want your rocket as top-heavy as possible, with its CoM as high as you can manage.

The important distinction is between "heavy" and "draggy".  Top-HEAVY rockets are good, top-DRAGGY rockets are bad.  If you stick something massive up at the front of your rocket, you'll bring the CoM forward, which is good... but depending on its size and shape, it will add some amount of drag as well, which will also bring your center of drag forward.

The question is which it brings forward more, center of mass or center of drag.  As long as it brings center of mass farther forward than it brings center of drag, you're good.

Multi-stage rockets tend to do fine, if they keep to a good, slender/pointy profile, and if they don't put something big and not-very-dense at the front end.  This is one reason why SRBs are nice to launch with:  as they burn, they become lighter and lighter (a nearly empty SRB weighs very little, much less than a liquid-fuel engine does), but not smaller, so they effectively move the CoM for your ship upward by quite a lot as they burn, without raising the center of drag.

[Plusck]

Hmmm. You're right (of course).

Now I think about it, the most delicate part of getting to orbit in the demo is actually when you discard the bottom stage. So yes, it's discarding the light bit at the back which suddenly changes the relative centres of drag/thrust/mass and make control a nightmare.

hmmm...