Build a plane or rocket for Kerbal high altitudes

kerbal-space-program

I currently have a contract where I'm asked to take crew reports at certain spots on Kerbal at an altitude of 18,000m. However, I've failed to build a vehicle to achieve this (without a hundred retries).

Building a rocket to fly vertical seems to be nearly impossible, in the atmosphere they tend to become unstable (or maybe I missed a trick?). I tried building a plane but can't climb higher than about 11,000m (I don't have many plane parts yet, though).

Any advices for building a vehicle for this task?

I'm in career mode and got all groups of the 45-science-cost level, except Flight Control, and additionally have Electrics, Heavy Rocketry and Fuel Systems.

Best Answer

Ideally, you'll want to avoid these contracts until you get the High-Altitude Flight tech node and the improved jet engine that comes with it. But since when do Kerbals wait for ideal conditions? Here's my example of dealing with the situation.

I started by attaching two LV-909 rocket engines to a regular low-atmosphere plane:

In this save, I don't have custom action groups yet, so I'm using the RCS control to toggle between jet and rocket modes. I also set it to enable the cockpit's reaction wheels to improve control at high altitude, and close air intakes to reduce drag. Only the fuel tanks attached to rockets have any oxidiser in them. Strictly speaking this optimisation is unnecessary, but it can win you a bit of range.

Approximately 12km up the main engines stop providing enough thrust to maintain the climb, so it's time to switch to rocket mode. In my case, it brought me to 20km up at a 45-degree angle, but it is probably not optimal. It may take some practice to hit your target area this way, because you'll be picking up additional horizontal speed, and thus it's possible to under or overshoot.

At this point the plane plummets, but as it goes deeper into the atmosphere, it regains pitch authority, and at 10km it's enough to regain control and turn it around for a safe landing.

Of course, this thing has very limited range, speed and acceleration because of the extra weight. Another problem is jet engines stealing fuel from the rockets' tanks - you may want to pump the fuel manually (requires an R&D centre upgrade) or add some pipes between them. Or try using SRBs instead.

Related Solutions

Do plugins for Kerbal Space Program work on unix

With very few exceptions, KSP mods are either parts only (and thus consist only of configuration files) or include plugins written in C# (which work on both Linux and Windows). MechJeb and Protractor specifically I can confidently say work on Linux because I'm using both right now.

All mods - parts or plugins - should be installed to the GameData directory. For example, if KSP were installed in ~/Games/KSP, with MechJeb installed you should have a directory structure that looks something like this:

~/Games/KSP/
  ...other KSP directories...
  GameData/
    Squad/
      ...base game files...
    MechJeb2/
      Parts/
        ...MJ part configurations...
      Plugins/
        ...MJ plugin DLL and PluginData files...

Bear in mind that with MechJeb you need to install a MechJeb part on your rocket to see any UI changes. Furthermore, if you're playing in career mode, you'll need to unlock it in the tech tree before it appears.

Kerbal Space Program – How to Edit Save Files for KSO

The part most interesting for you is:

    lat = -0.0708559885838229
    lon = -97.2394889192516
    alt = 2917405.7211654

To have a stable geosynchronous orbit, you need to set latitude to 0, so you are over equator. To obtain longitude, simply launch another craft, and keep it in KSC. Read lon from it's save. Proper altitude can be read from Kerbin entry at wiki. Currently it's 2,868.75 km - you are a bit too high, so update accordingly.

Now to the orbit part, you want:

ECC = 0

for exactly round orbit. Also, to avoid confusing your game, you need to set average of periapsis and apoapsis to your new-current altitude. However, when we take into account Kerbin radius, it gets 3 468.75 km, due to Kerbin's ~600km radius:

SMA = 3468750

To be sure you are on equator, nullify inclination:

INC = 0

The tricky part is MNA - Mean anomaly at epoch. If your game will decide to use it instead of lat and long set above, you may find yourself not where you wanted. Experiment with changing it a bit in one way or another.

For easier experiments always edit quicksave. That way you will be able to load updated state with one key. And always backup your persistence file.

For a video tutorial watch this Youtube video. As usual, Scott Manley is your friend.

Best Answer

Related Solutions

Do plugins for Kerbal Space Program work on unix

Kerbal Space Program – How to Edit Save Files for KSO

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