Like Principia? Want contracts utilizing Lagrange points? Now you can have them. This mod extends Contract Configurator to let you configure contracts that can make sure your within a range of distances between two celestial bodies (a parent and a child), as well as an angle between the child body's prograde vector, and the line between the vessel and the child body (useful for differentiating between L4 and L5).

The best way to explain this is probably with some sample configs.

CONTRACT_TYPE
{
    # put your standard contract stuff here
    PARAMETER
    {
        name = vesselGroupLaunch
        type = VesselParameterGroup # generally, we'll want to make sure that you can maintain this Lagrange point,
                                    # so we'll combine this with a duration
        title = Reach L1

        PARAMETER
        {
            name = L1
            type = Lagrange           # This is our new paramater type
            childBodyName = Mun       # The smaller of the two bodies involevd in the Lagrang point
            parentDistance = 10000000 # The desired distance to the larger body
            parentTolerance =  100000 # The tolerance from the desired distance allowed
            childDistance = 2080000   # The desired distance to the smaller body
            childTolerance =  20000   # The tolerance from the desired distance allowed
        }
        PARAMETER
        {
            name = Duration
            type = Duration
            duration =  5d
            preWaitText = Reach L1
            waitingText = Maintaining...
            completionText = Congrats!
        }
    }
}

CONTRACT_TYPE
{
    # more standard contract stuff would go here
    
    PARAMETER
    {
        name = vesselGroupLaunch
        type = VesselParameterGroup
        title = Reach L4
        
        PARAMETER
        {
            name = L4
            type = Lagrange
            childBodyName = Mun
            childDistance = 12000000
            childTolerance =  500000
            parentDistance = 12000000
            parentTolerance =  500000
            angle = 30                # Here you can see that we have an angle of 30
                                      # This makes us ahead of the Mun
            angleTolerance = 5
        }
        PARAMETER
        {
            name = Duration
            type = Duration
            duration =  30d
            preWaitText = Reach L4
            waitingText = Maintaining...
            completionText = Congrats!
        }
    }
}
CONTRACT_TYPE
{
    
    PARAMETER
    {
        name = vesselGroupLaunch
        type = VesselParameterGroup
        title = Reach L5
        
        PARAMETER
        {
            name = L5
            type = Lagrange
            childBodyName = Kerbin       # Here you can see the child is Kerbin, 
                                         # so the parent would be the Sun
            childDistance = 13600000000
            childTolerance =  500000000
            parentDistance = 13600000000
            parentTolerance =  500000000
            angle = 150                  # A value of 150 here means that we're behind Kerbin
            angleTolerance = 5
        }
        PARAMETER
        {
            name = Duration
            type = Duration
            duration =  30d
            preWaitText = Reach L5
            waitingText = Maintaining...
            completionText = Congrats!
        }
    }
}

Here you can see where the 30 and 150 come from