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Handful of assembly and pre-launch questions: payload weight, cut power, etc.


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Knewb here trying to better grok the process...

  1. Is there any way to see the payload weight? I just constructed a satellite and I want to know if the launch vehicle I used earlier has the power to get it into orbit, how can I compare weights of payloads?
  2. How can I see what DeltaV my launch vehicle or any stage in my launch vehicle will produce?
  3. Is there a way to have my payload power turned off during launch? So when I hit the launch button it automatically runs some kind of Launch Action that turns off all the power of non-essential pods?
  4. Is there any way to see what total electrical consumption the parts currently in assembly consume? So I know how many panels or batteries to add?
  5. What is a gimbal? I see in the action group for my engine a Toggle Gimbal option... what does this do exactly?
  6. Why does everything talk about a 2 stage rocket to get things into orbit? Why not just a single stage?

Thanks!

Edited by Oddible
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1) mods (mechjeb, enegnier, ect.)

2) see #1

3) no

4) not really, maybe mechjeb. else 1 generator powers 20+probes indeffanetly

5) gimbal is tilt in the engine nossle, used to control direction

6) 2 stages tend to me more efficient since you drop some dead weight mid flight.

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Actually, you can see mass without mods, launch the payload by itself and go into the map screen and it'll tell you the mass of the vessel. You can also use this to calculate delta-v, by getting wet and dry mass (after burning all the fuel on the launch pad), and using the rocket equation.

The electricity thing is a bit trickier, with some of the rates in the VAB being listed as per minute and some per second, but the Resources menu in flight can help. A lot of these things require test flights, I suppose.

As for stage separation, I usually end up separating above 20 kilometres, but it depends heavily on the design. Parallel stages tend to be dropped earlier, while serial stages tend to be separated later.

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There really isn't going to be any hard set altitude for when you want to stage. It all depends on the performance of the rocket you are building. My, very light, probe launchers usually only have an ascent stage and on orbit stage. So i don't drop anything until i get to orbit. However, some of my much bigger payload lifters have 4 or 5 stages that all drop at different times before i even get to orbit.

I highly recommend you watch Scott Manley's tutorial videos on youtube. He starts with the very basics and explains things in an easy to understand manner. Good luck and have fun!

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Wow, wow, wow, just found the SpacePort! Got MechJeb and Engineer. Any other info / status / stats addons I should get? (Not super interested in adding a bunch of part mods or functionality mods yet, but I'd like MORE INFO!).

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Well, either MechJeb or Engineer is usually enough. Both is kind of data overkill. ;)

Kerbal Alarm Clock is not really info on your ships... but it's INCREDIBLY useful for running multiple missions, especially long-duration missions. You set game alerts for events (SOI changes, maneuver nodes, etc), and it will bring you out of time warp, even if you're on another mission, and remind you, so you don't miss it.

"RCS Build Aid" - very useful in the VAB for ensuring that you place RCS thrusters around the Center of Mass equally, or as evenly as possible (fuel burn changes COM)

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Other people've handled the first few questions well enough :).

Gimballing refers to your rocket engine's ability to swivel it's nozzle a small amount to assist in steering. Real rockets do do this. It's one of the features that the ASAS unit (a type of autopilot, though just for holding a steady heading) will use to try to maintain course. However, on large ships many people would recommend setting the outer rocket engine's gimballing off because the ASAS has a tendency to overcompensate; the vibration can cause unintended damage.

Single-stage-to-orbit craft are possible but trickier. For rockets in real life they offer the possibility of much easier and quicker turn-around on usage. In game, it's less efficient as you're commiting yourself to carrying a lot of extra dead weight as opposed to trimming it as much as possible as you go up.

Edited by Lheim
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As for staging, I tend to drop the first stage right before I begin my gravity turn. Depending on the rocket, my second stage is dropped after I circularize my orbit. I find that this makes planning maneuver nodes more effective, because a projected burn can be way off if you have to drop a stage mid-burn.

If I find I don't have quite enough fuel to complete a necessary maneuver before destaging, it's likely a sign that my rocket design may need a mall improvement.

Edited by HeadHunter67
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At what altitude do you usually do your gravity turn? 10K? Do you shift to a 45 degree trajectory outright or move through notches along the curve? (Wouldn't that consume more fuel?)

I prefer doing it gradually. In fact, doing 45 degrees all at once can cause problems if you install FAR.

As far as efficiency goes, from my testing, gradual seems slightly better, but by a small enough amount that it gets overshadowed by other factors. if you turn gradually, you need to make sure you don't do it too gradually, otherwise you hit your desired apoapsis before you're close to your desired orbital velocity, and that can cause some major inefficiency.

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In my experience I have had better experience waiting till my apogee reaches 10k then begin to slowly following the progade marker on the navball then stop at 45 degrees untill the navball switches to orbital speed then move there continue until at desired altitude then burn sideways. Best case scenario is that you complete in one burn but that is unlikely.

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In my experience I have had better experience waiting till my apogee reaches 10k then begin to slowly following the progade marker on the navball then stop at 45 degrees untill the navball switches to orbital speed then move there continue until at desired altitude then burn sideways. Best case scenario is that you complete in one burn but that is unlikely.

It might be easier to control your altitude that way, but it's not as fuel efficient. You burn more fuel by waiting until your Ap to turn horizontal. It's best to be horizontal by the time you reach the upper atmosphere, then just increase your orbital speed until your Ap is where you want it. Coast to the Ap then do a short prograde circulation burn.

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