java　初期化したのにされてないというエラーが出る

記載したプログラムで、それぞれ71,80,84,101行目のx_fuel,x_power,x_power,x_fuelが初期化されていない可能性があるというエラーが出てしまいます。どうすればよいか教えてください。よろしくお願いします。
import java.util.Scanner;
class LaunchAndLandWithLog4{
public static void main(String args[]){
Scanner stdIn=new Scanner(System.in);
double x, y, x_speed, y_speed, x_initial_speed, x_wind_speed1;
double y_power,y_fuel,y_braking_point;
double y_brakepower,y_brakefuel;
double x_lounchpower, y_lounchpower, y_lounchfuel, y_releasepoint;
double r;
double g;
double x_target;
double x_power;
double x_fuel;
int c;

    g = -9.80665;
    
    x = 0;
    y = 0;
    x_initial_speed = 0;
    x_wind_speed1 = 200;
    y_brakepower = 50;
    y_lounchpower = 25;
    x_lounchpower = 4;
    
    y_brakefuel = 200;
    y_lounchfuel = 300;
    y_releasepoint =  40000;
    y_power = 50;
    y_fuel = 200;

    System.out.print("x方向の目標を指定してください。：");
     x_target=stdIn.nextDouble();
    
    y_braking_point = 20000;
    
    x_speed = x_initial_speed;
    y_speed = 0;
    
    r = 100000;
    
    c = 0;


    while( y >= 0 ) {
        y_speed += g/r;
        if( y_lounchfuel > 0 ) {
            /* use booster to lounch */
            x_speed += x_lounchpower/r;
            y_speed += y_lounchpower/r;
            y_lounchfuel -= 1.0/r;
            if( y > y_releasepoint ) {
                y_lounchfuel = 0; /* released */
            }
        }else if( y_brakefuel > 0 ) {
            /* use brake thruster */
            if( y < y_braking_point && y_speed < -2.0 ) {
                y_speed += y_brakepower/r;
                y_brakefuel -= 1.0/r;
            }
        }
        if( y > 8000 ) {
            if( x_speed < x_initial_speed + x_wind_speed1 ) {
                x_speed += 1.4/r;
            } else if ( x_speed > x_initial_speed + x_wind_speed1 ) {
                x_speed -= 1.4/r;
            }
        } else {
            x_speed = x_initial_speed;
        }
        
        if( x_fuel > 0 ) {
            /* estimate where it is going to fall */
            double est_x;
            est_x = x + (y /(-1* y_speed))*x_speed;
            
            /* use thruster */
            if( est_x > x_target + 10 ) {
                
                x_speed -= x_power/r;
             
                x_fuel -= 0.000001;
            } else if ( est_x < x_target - 10 ) {
                x_speed += x_power/100000;
                x_fuel -= 0.000001;
            }
        }
        x += x_speed/r;
        y += y_speed/r;
        c++;
        if( c >= r ) {
            System.out.print("" + x + "\t" + y + "\n");
            c = 0;
        }
    }
    System.out.print("" + x + "\t" + y + "\n");
    
    System.out.print("estimated distance = "+x+"\n");
    System.out.print("landing y speed = "+ y_speed + "\n");
    System.out.print("rest brakefuel = "+ y_brakefuel + "\n");
     System.out.print("rest fuel = "+ x_fuel + "\n");
    return;
}