Maneuvers Not Being Performed

[Popestar]

I recently picked up KSP, and I am having a blast just creating rockets and launching them into space.  If this game had existed when I was much younger, this would have probably pushed me on a path towards aerospace engineering.  :D

Anyhow, I decided to go through the game on Science, to get a feel for how things are upgraded and what's available when.  So I can launch stuff into space, and I can run the experiments (right click, log temp, etc.), and that's all fine and dandy.  But I for some reason cannot get anything to actually orbit the planet.  I can right click and set a maneuver, I can alter the path/trajectory of the maneuver, and I've got SAS turned on.  But when the craft gets to the node and I cut the thrust (X)...nothing.  It continues on its current trajectory, reaching the apoapsis and then starting its descent back to Kerbin.

I've gone through the Orbiting tutorial in the game multiple times, and during the tutorial I can get the ship into orbit around Kerbin.  But if I do this outside the tutorial, I just can't get a ship to orbit the planet.

Am I doing something wrong?  What am I missing here?  Is there some special engine I need to have and engage once I hit the node?  Some keypress I'm not familiar with?

[Snark]

Hello, and welcome to the forums! 

1 hour ago, Popestar said:

But I for some reason cannot get anything to actually orbit the planet.  I can right click and set a maneuver, I can alter the path/trajectory of the maneuver, and I've got SAS turned on.  But when the craft gets to the node and I cut the thrust (X)...nothing.  It continues on its current trajectory, reaching the apoapsis and then starting its descent back to Kerbin.

That's correct, and it's perfectly normal and expected behavior.

1 hour ago, Popestar said:

What am I missing here?

It's because maneuver nodes are just indicators that show in what direction (and by how much) to burn-- they don't actually do the burn for you.

Maneuver nodes do not control your ship. 

1 hour ago, Popestar said:

Is there some special engine I need to have and engage once I hit the node?  Some keypress I'm not familiar with?

No special engine, no special keypress.  All you do is just manually fly your ship, using the same WASD rotation controls and the same throttle controls that you use all the time.

Here's the deal:

After you place a maneuver node, go take a look at your navball.  Somewhere on the navball you'll see a marker that looks like this:

(If you don't see it, that just means you're pointing away from it; there should be a little blue arrow at the rim of the ball, pointing in the direction where it can be found.  Try rotating the ship in that direction and you should see it come into view pretty soon.)

That little marker on the navball shows you what direction you need to point in order to do the burn-- i.e. it points in the direction of the maneuver vector.  If you've got a high-level pilot or probe core on board, your SAS may have the option of pressing a little button labeled , which will automatically point you in that direction.  If your pilot or probe core isn't high enough level, then you just need to manually rotate the ship until the navball crosshairs are centered on that marker.

Then, watch the burn display next to the navball (it displays any time there's a maneuver node set).  It will tell you how long the estimated burn will be (i.e. "60 seconds" or whatever).  It will also tell you how much time remains until you arrive at the maneuver node.

So, all you need to do is:

1. Place a maneuver node.
2. Line up your ship so it's pointing at on the navball.
3. Note the length of the burn you'll need.
4. Watch the countdown display for "time until node".
5. When the time-until-node is about half of the burn length, max your throttle.
6. Watch the burn indicator count down as you thrust.  When it reaches zero, cut your throttle.

 

[Popestar]

So, I did all that, and the estimated burn time is 30 days.  And time to node is like 2 minutes.  What did I do wrong?

[Tyko]

27 minutes ago, Popestar said:

So, I did all that, and the estimated burn time is 30 days.  And time to node is like 2 minutes.  What did I do wrong?

Can you take a screen shot of your ship?  Just the part of the ship that you're trying to maneuver.

[bewing]

26 minutes ago, Popestar said:

So, I did all that, and the estimated burn time is 30 days.  And time to node is like 2 minutes.  What did I do wrong?

(Depending on the game version) the game tries to estimate your burn time based on your last burn with that craft. And sometimes it just gets it wrong.

But if it's telling the truth, then you either have your main engine deactivated, or you have the "thrust limiter" turned way down for your engine, or your main engine is really tiny.

 

[Popestar]

1 minute ago, bewing said:

(Depending on the game version) the game tries to estimate your burn time based on your last burn with that craft. And sometimes it just gets it wrong.

But if it's telling the truth, then you either have your main engine deactivated, or you have the "thrust limiter" turned way down for your engine, or your main engine is really tiny.

 

Main engine?  From the top down:

• Mk16 Parachute
• Mk1 Command Pod
• Sciency Stuff on the Command Pod
• TD-12 Decoupler
• RT-5 Flea Solid Fuel Booster
• TD-12 Decoupler
• FL-T100 Fuel Tank (x4)
• Basic Fin (2) on tanks 3/4
• LV-T45 Swivel Liquid Fuel Engine
• TD-12 Decoupler
• RT-10 Hammer Solid Fuel Booster
• Basic Fin (2) near bottom of RT-10

At launch, I've got throttle set to max (Z), and I'm trying to enter space at ~30 degrees (maybe a little more, maybe a little less; sometimes I blow up due to heat and have to revert, but that's not my issue here).  I burn through the Hammer, then the Swivel, then the Flea; this gets me into space.  I set the node as above, trying to keep the initial trajectory into that maneuver so I'm not trying to go perpendicular to it but rather parallel into orbit.  I cut the throttle to nothing (X), and then watch as the burn time sets in days while time to node is in minutes.

So what main engine am I missing?  This is the second craft being built as, again, I'm just going through the Science mode to get a feel for everything.  Do I need to unlock something else or add something else to my ship to be able to orbit the planet?  I've only got 3 things unlocked in Science, which I believe are Start, Basic Rocketry, and Basic Engineering.

What am I missing here?  Am I not advanced enough in the game to get a stable orbit on a craft yet?  Am I just trying to do too much too early, and need to just relax and keep doing sciency stuff to unlock more junk?

[Snark]

Okay, here's your ship, sitting on the launchpad.  I've colored green the engines that can actually make your ship do stuff, and grayed out anything that's not an engine.

1 hour ago, Popestar said:

• Mk16 Parachute
• Mk1 Command Pod
• Sciency Stuff on the Command Pod
• TD-12 Decoupler
• RT-5 Flea Solid Fuel Booster
• TD-12 Decoupler
• FL-T100 Fuel Tank (x4)
• Basic Fin (2) on tanks 3/4
• LV-T45 Swivel Liquid Fuel Engine
• TD-12 Decoupler
• RT-10 Hammer Solid Fuel Booster
• Basic Fin (2) near bottom of RT-10

3... 2... 1... Launch! 

1 hour ago, Popestar said:

I burn through the Hammer

Gotcha.  So now your ship looks like this:

1 hour ago, Popestar said:

• Mk16 Parachute
• Mk1 Command Pod
• Sciency Stuff on the Command Pod
• TD-12 Decoupler
• RT-5 Flea Solid Fuel Booster
• TD-12 Decoupler
• FL-T100 Fuel Tank (x4)
• Basic Fin (2) on tanks 3/4
• LV-T45 Swivel Liquid Fuel Engine

Hammer burns out, you're a few kilometers up and climbing fast.  Next?

1 hour ago, Popestar said:

then the Swivel

Okay, so now your ship is going higher and faster, still climbing.  It burns out and you stage it away.  Now your ship looks like this:

1 hour ago, Popestar said:

• Mk16 Parachute
• Mk1 Command Pod
• Sciency Stuff on the Command Pod
• TD-12 Decoupler
• RT-5 Flea Solid Fuel Booster

Then,

1 hour ago, Popestar said:

then the Flea; this gets me into space

I assume that by "get me into space" you mean that when the Flea burns out, you're on a climbing suborbital trajectory whose Ap is outside the atmosphere, yes?

So, you burn out the Flea and eject it, still suborbital, and now your ship looks like this:

1 hour ago, Popestar said:

• Mk16 Parachute
• Mk1 Command Pod
• Sciency Stuff on the Command Pod

...You see the problem?  There's no engine left.  You've burned all your fuel and ejected all your engines.  What's left is basically just an inert cannonball-- it's got nothing left with which to burn.

Note that SRBs (like the Flea) are tricky to use as orbital engines, because you can't control them-- once you turn 'em on, there's no way to turn 'em off until they burn out, which means that they're very tricky to use for controlled burns.  So even though you can put it on an upper stage... most people don't.

It's worth noting, too, that SRBs have a very low Isp, i.e. they're high-thrust but low efficiency.  For complicated math reasons that I won't go into unless you're interested, it's not very "dV-efficient" to put low-Isp stages at the top of the rocket.  In other words, if you're having trouble designing a rocket that has enough dV to get to orbit... you probably shouldn't be using an SRB in an upper stage.  You can certainly do that if you find it fun and challenging ... just be aware that you're making life more difficult by doing so.

So, the general rule of thumb for maximizing your dV is:  burn the low-Isp fuel before the high-Isp fuel.  And SRBs are best used off the pad, rather than as an upper stage.

Suggestion:  Take off on the SRB, then have a middle stage with a Swivel with a few tons of fuel, then an upper stage with a Terrier if you can manage it.  If you haven't unlocked the Terrier, maybe take off with two radial SRB Hammers and put more fuel on your second stage with the Swivel.

[Harry Rhodan]

4 hours ago, Popestar said:

But when the craft gets to the node and I cut the thrust (X)...nothing.

 

1 hour ago, Popestar said:

  I cut the throttle to nothing (X), and then watch as the burn time sets in days while time to node is in minutes.

What am I missing here?

You need to step on the gas when you reach the node and not hit the brake. And to do that you need an engine and fuel like Snark already said.

Edited November 1, 2018 by Harry Rhodan

[Snark]

By the way, @Popestar, in case it's not clear from the lots-of-words I just threw in your direction, here's the fundamental problem with your design:

Your rocket doesn't have enough dV to get to orbit.  That is, not enough "oomph"-- it simply can't go fast enough.

Here's your description of the rocket:

1 hour ago, Popestar said:

• Mk16 Parachute
• Mk1 Command Pod
• Sciency Stuff on the Command Pod
• TD-12 Decoupler
• RT-5 Flea Solid Fuel Booster
• TD-12 Decoupler
• FL-T100 Fuel Tank (x4)
• Basic Fin (2) on tanks 3/4
• LV-T45 Swivel Liquid Fuel Engine
• TD-12 Decoupler
• RT-10 Hammer Solid Fuel Booster
• Basic Fin (2) near bottom of RT-10

Here's my attempt at reconstructing this in the VAB:

...this is basically what you described, but without any of the "sciency stuff".

Then I did the math, and this rocket is well short of what it needs to get to orbit.  It has about 900 m/s of dV from the Flea, about 1200 m/s from the Swivel, and about 600 m/s from the Hammer.  Add 'em up, and we get around 2700 m/s total dV for your rocket.

That's roughly 700 m/s not enough.  (Exact dV to get to Kerbin orbit depends on ascent trajectory, piloting skill, launchpad TWR, etc., but broadly speaking I think you need around 3400 m/s, something like that.  Certainly you need considerably more than 2700.)

So, there's basically nothing you can do with this rocket to get to orbit-- it simply doesn't have enough oomph.  Also, the fact that you've got an SRB as your top stage would make setting up an orbit pretty tricky even if you did have enough dV, since you can't throttle an SRB in flight.

So, basically what you need to do is to design a rocket which,

• has at least 3400 m/s of dV
• doesn't use an SRB in its top stage (to make life easier for you)

If you're interested in seeing some alternate rocket designs, just say the word. 

 

[Popestar]

EDIT:  Working on this.  I may have figured it out.

Edited November 1, 2018 by Popestar

[Popestar]

And nope.  I got nothing.  I think I need more fuel and just trial and error on this, but whatever I got going right now isn't working.

[Snark]

If you want an example of a design that does have enough oomph to put a Mk1 command pod into Kerbin orbit, with a fair amount of dV left over as a safety margin:

• First stage:  Two Hammer SRBs, attached with radial decouplers (stick a nosecone on each one)
• Second stage:  A Swivel with four tons of LFO
• Third stage:  A Terrier with two tons of LFO
• Payload is a Mk1 command pod with typical accessories such as parachute, decoupler, science, batteries, yadda yadda.

Not claiming that's the "best" or "ideal", just that it's a straightforward design that gets the job done reasonably well, while staying under 30 parts and under 18 tons.

If you don't have the Terrier unlocked yet, then you can get to orbit with nothing available to you besides Hammer and Swivel, but the designs get a bit clunkier.  The Terrier is fantastic as an upper-stage engine for getting to orbit.  Very good Isp, and the engine itself is pretty lightweight (only half a ton).

[Gargamel]

3 hours ago, Popestar said:

I think I need more fuel and just trial and error on this,

And that, my friend, is the heart of KSP.    

Well that one blew up.... let's try the other way!

[GoatRider]

As Scott Manley says, "Failure is an option!"

[Popestar]

So I spent a lot of time yesterday toying with different designs and trajectories and all, and I got close.  The last time I tried I was within 5 seconds of total burn time before running out of fuel.  Now, I must say that when I started I had 60 seconds of burn time, so I fired up with 30 seconds to maneuver and got to 55 seconds of burn time, which was close but not enough!  So my first issue here now is having enough fuel to make the burn time.  My biggest concern, then, is being light enough to make sure I don't make that burn time too long once again.  And so the story goes on!

I should mention that this is all done so far with just the 3 science nodes unlocked that I mentioned above.  I've got enough science points to unlock a few more, but again, I'm doing the science thing to get a true feel for the game before pushing myself into career or missions.

And I'm off to take a conference call, followed by more KSP.  Oh, and on the topic of blowing up:  Anybody else feel bad for those poor Kerbals that end up dying majestically upon impact? 

[Xd the great]

27 minutes ago, Popestar said:

So I spent a lot of time yesterday toying with different designs and trajectories and all, and I got close.  The last time I tried I was within 5 seconds of total burn time before running out of fuel.  Now, I must say that when I started I had 60 seconds of burn time, so I fired up with 30 seconds to maneuver and got to 55 seconds of burn time, which was close but not enough!  So my first issue here now is having enough fuel to make the burn time.  My biggest concern, then, is being light enough to make sure I don't make that burn time too long once again.  And so the story goes on!

I should mention that this is all done so far with just the 3 science nodes unlocked that I mentioned above.  I've got enough science points to unlock a few more, but again, I'm doing the science thing to get a true feel for the game before pushing myself into career or missions.

Anybody else feel bad for those poor Kerbals that end up dying majestically upon impact? 

1. No. No one feels bad for them. Because they respawn.

2. A simple solution to getting to orbit (which i assume to be your goal) will be what is called a gravity turn. Experts please help here.

3. Or MOAR BOOSTERS. You can turn a blind eye on funds, unless you are playing career.

[Rocket In My Pocket]

Basic orbital rocket construction 101:

3 stages.

1. SRB's for high thrust, low efficiency to get us out of the thickest part of the atmosphere.
2. A medium thrust/medium efficiency engine like the Reliant to raise our AP to 70+
3. A low thrust/high efficiency engine like the Terrier to circularize our orbit in Vacuum.

A proper rocket looks like an arrow; Mass at the tip, long sturdy shaft, fins at the rear for stability.

Basic gravity turn 101.

1.  Rotate your rocket in the VAB so it faces the door, you want to head out over the ocean, it's the cheapest way. (You benefit from the spin of the planet.)
2. Once you clear the pad start dipping your nose very slowly towards 45 degrees, this should be completed before 10k.
3. Hold your nose at 45 degrees and burn till Ap is 70k+
4. Cut engines, drift towards Ap, till time to Ap is 30 seconds.
5. Burn prograde, keeping time till Ap between 10-30 seconds. Nose up to increase time, nose down to decrease time.
6. Cut engines when Pe is 70k+

Congrats, gravity turn accomplished, and your orbit should be nice and circular.

 

[Popestar]

I did it!  I did it!  I got a manned craft into orbit!  Just needed to take my time, get some more science points, research a couple new things, and voila!  Orbiting Kerbin!  Now I just hope I have enough fuel to make another burn to get poor Jebediah home!

Edited November 2, 2018 by Popestar

[Cavscout74]

6 minutes ago, Popestar said:

I did it!  I did it!  I got a manned craft into orbit!  Just needed to take my time, get some more science points, research a couple new things, and voila!  Orbiting Kerbin!  Now I just hope I have enough fuel to make another burn to get poor Jebediah home!

Congrats!!!  The first time is always the hardest.    And worst case, Jeb can get out and push (with his suit RCS) - I think we've all had to do that at some time.   As soon as Pe is below 70 km, it'll eventually land.

[Snark]

55 minutes ago, Popestar said:

I did it!  I did it!  I got a manned craft into orbit!  Just needed to take my time, get some more science points, research a couple new things, and voila!  Orbiting Kerbin!  Now I just hope I have enough fuel to make another burn to get poor Jebediah home!

Congratulations!    "First orbit" is a major milestone for a new KSP player.  Welcome to the club!

Getting home is a lot easier than getting up there in the first place.  If you're in a low orbit, you only need to make a fairly small burn to lower your Pe down inside the atmosphere.  Around 30 km is a good altitude, in my experience.  Should take hardly any fuel at all.

(And if perchance you do end up completely out of fuel, then Jeb could always get out and push, as @Cavscout74 suggests above.)

[Pecan]

4 hours ago, Popestar said:

I did it!  I did it!  I got a manned craft into orbit!  Just needed to take my time, get some more science points, research a couple new things, and voila!  Orbiting Kerbin!  Now I just hope I have enough fuel to make another burn to get poor Jebediah home!

Congratulations and welcome to the Society of Spacetravellers ^^.

Remember your failure, frustration, persistence and ultimate success.  Remember how good it feels to know you have learnt a real thing, not just pressing the "take me to orbit" button.  If you wish to do more with KSP these things will become very familiar.  Expect re-entry, rendezvous, docking, powered landings and interplanetary transfers to be challenging and rewarding in a similar way.  KSP makes you work (and learn) for your successes but having done so you know you have truly earnt them.  Being able to recite the Tsiolkovsky equation on demand is just an additional benefit ^^.