using System;

public static class Constants
{
    // Constants (these should be defined with appropriate values)
    private const double kAirDensity = 1.204; // Sea level air density in kg/m^3
    private const double kAirDensityScaleHeight = 10.4; // Scale height in km
    private const double kGravity = 9.80665; // Standard gravity in m/s^2
    private const double kEarthMeanRadius = 6378137; // Earth's mean radius in meters

    public static double CalculateAirDensityAtAltitude(double altitude)
    {
        return kAirDensity * Math.Exp(-altitude / (kAirDensityScaleHeight * 1000));
    }

    public static double CalculateGravityAtAltitude(double altitude)
    {
        return kGravity * Math.Pow(kEarthMeanRadius / (kEarthMeanRadius + altitude), 2);
    }
}