Kerbal Space Program: get GDLV3 into low Kerbin orbit, release payload and deorbit booster (works but needs tuning: final orbit of payload was 72720m/118675m), tested in LINQPad

KSP_kRPC_GDLV3_KEO.cs

// fetch Google.Protobuf and KRPC.Client from nuget gallery
// namespace imports:
//KRPC.Client
//KRPC.Client.Services.SpaceCenter
//System
// removed due to ambiguity with linq expressions: KRPC.Client.Services.KRPC

class GDLV3_To_KEO
{
	public static readonly System.Net.IPAddress kspKrpcServer = System.Net.IPAddress.Parse("ipv4/ipv6 of KSP with kRPC");
	const String VesselName = "GDLV3";
	
	public static void Main()
	{
		using (var conn =
			//new Connection("Sub-orbital flight",IPAddress =  kspKrpcServer);
			new Connection("kspRpcSpike", kspKrpcServer))
		{

			var vessel = conn.SpaceCenter().ActiveVessel;
			// Assert script matches the vessel it was designed for, or at least a revision/mod thereof
			if(!vessel.Name.Contains(VesselName))
			{
				Console.WriteLine($"Script is for '{VesselName}' but active vessel is '{vessel.Name}', aborting launch sequence.");
				return;
			}
			else
			{
				Console.WriteLine($"Found vessel '{vessel.Name}' in biome {vessel.Biome}.");
				// todo: check biome is kerbin/launch pad (well, actually, it's Shores)
				// todo: check not moving relative to kerbin
			};
			// don't ever hurt kerbals
			if(vessel.CrewCount>0){
				Console.WriteLine($"Vessel contains {vessel.CrewCount} crew members. Launch script not permitted to be applied on living beings. Aborting launch sequence.");
				return;
			}
			
			vessel.AutoPilot.TargetPitchAndHeading(90, 90);
			vessel.AutoPilot.Engage();
			vessel.Control.Throttle = 1;
			System.Threading.Thread.Sleep(1000);
			
			Console.WriteLine("Launch!");
			vessel.Control.ActivateNextStage();
			
			{
				var solidFuel = Connection.GetCall(() => vessel.Resources.Amount("SolidFuel"));
				var expr = KRPC.Client.Services.KRPC.Expression.LessThan(
					conn, 
					KRPC.Client.Services.KRPC.Expression.Call(conn, solidFuel), 
					KRPC.Client.Services.KRPC.Expression.ConstantFloat(conn, 0.1f)
				);
				var evnt = conn.KRPC().AddEvent(expr);
				lock (evnt.Condition)
				{
					evnt.Wait();
				}
			}
	
			Console.WriteLine("Booster separation");
			vessel.Control.ActivateNextStage();
	
			{
				var meanAltitude = Connection.GetCall(() => vessel.Flight(null).MeanAltitude);
				var expr = KRPC.Client.Services.KRPC.Expression.GreaterThan(
					conn, 
					KRPC.Client.Services.KRPC.Expression.Call(conn, meanAltitude), 
					KRPC.Client.Services.KRPC.Expression.ConstantDouble(conn, 10000)
				);
				var evnt = conn.KRPC().AddEvent(expr);
				lock (evnt.Condition)
				{
					evnt.Wait();
				}
			}
	
			Console.WriteLine("Gravity turn");
			vessel.AutoPilot.TargetPitchAndHeading(45, 90);
	
			{
				var apoapsisAltitude = Connection.GetCall(() => vessel.Orbit.ApoapsisAltitude);
				var expr = KRPC.Client.Services.KRPC.Expression.GreaterThan(
					conn, 
					KRPC.Client.Services.KRPC.Expression.Call(conn, apoapsisAltitude), 
					KRPC.Client.Services.KRPC.Expression.ConstantDouble(conn, 80000) //75k inteded plus 5k safety margin (drag)
				);
				var evnt = conn.KRPC().AddEvent(expr);
				lock (evnt.Condition)
				{
					evnt.Wait();
				}
			}

			Console.WriteLine("Wait for Apoapsis");
			vessel.Control.Throttle = 0;

			{
				var meanAltitude = Connection.GetCall(() => vessel.Flight(null).MeanAltitude);
				var expr = KRPC.Client.Services.KRPC.Expression.GreaterThan(
					conn,
					KRPC.Client.Services.KRPC.Expression.Call(conn, meanAltitude),
					KRPC.Client.Services.KRPC.Expression.ConstantDouble(conn, 75000)
				);
				var evnt = conn.KRPC().AddEvent(expr);
				lock (evnt.Condition)
				{
					evnt.Wait();
				}
			}

			Console.WriteLine("Circuralize Orbit");
			vessel.AutoPilot.TargetPitchAndHeading(0, 90);
			Thread.Sleep(2500);// hope we manage to change attitude in that time
			vessel.Control.Throttle = 1;

			{
				var apoapsisAltitude = Connection.GetCall(() => vessel.Orbit.PeriapsisAltitude);
				var expr = KRPC.Client.Services.KRPC.Expression.GreaterThan(
					conn,
					KRPC.Client.Services.KRPC.Expression.Call(conn, apoapsisAltitude),
					KRPC.Client.Services.KRPC.Expression.ConstantDouble(conn, 72000) //70k+ inteded plus 2k safety margin (we may want to rendevouz to that vessel!)
				);
				var evnt = conn.KRPC().AddEvent(expr);
				lock (evnt.Condition)
				{
					evnt.Wait();
				}
			}

			Console.WriteLine(@"Achieved Orbit! \o/");
			vessel.Control.Throttle = 0;
			Thread.Sleep(5000);// let vessel stabilize 
			Console.WriteLine($"Releasing payload into Orbit: Apo={vessel.Orbit.ApoapsisAltitude}m, Peri={vessel.Orbit.PeriapsisAltitude}");// todo: argument of periapsis
			vessel.Control.ActivateNextStage();
			
			Thread.Sleep(10000);// gain enough distance to payload
			Console.WriteLine("deorbitting booster");
			vessel.AutoPilot.TargetPitchAndHeading(180, 90);
			Thread.Sleep(5000);// turn retrograde and let vessel stabilize
			Console.WriteLine("final deorbit burn");
			vessel.Control.Throttle = 1;

			{
				var apoapsisAltitude = Connection.GetCall(() => vessel.Orbit.PeriapsisAltitude);
				var expr = KRPC.Client.Services.KRPC.Expression.LessThan(
					conn,
					KRPC.Client.Services.KRPC.Expression.Call(conn, apoapsisAltitude),
					KRPC.Client.Services.KRPC.Expression.ConstantDouble(conn, 30000) //deorbit fast, burn in atmosphere
				);
				var evnt = conn.KRPC().AddEvent(expr);
				lock (evnt.Condition)
				{
					evnt.Wait();
				}
			}
			
			Console.WriteLine("deactivating control");
			vessel.Control.Throttle = 0;
			vessel.AutoPilot.Disengage();
			
			//autodispose since where in a using-environment: conn.Dispose();
		}
	}
}

Designed for GDLV3. Uses kRPC.