Interp1 returning NaN

I recently completed this code for a Prelab in one of my courses, the first time I ran the code, it worked perfectly and returned the three rpm values I was looking for, when I went back to check the numbers later that day, the code would return NaN and I can't seem to figure out why. The Target_J variable is returning as NaN and therefore causing my n value to be NaN as well.

J=0.01:0.01:1.1; size_J=size(J); loop_J=size_J(2);

size_V_a=size(V); loop_V=size_V_a(2); V_a=zeros(size_V_a(2),1);

size_n=size(V); n=zeros(size_n(2),1);

size_T=size®; loop_T=size_T(2); T=zeros(size_T(2),1);

size_target=size(V_a); loop_target=size_target(1);

for k=1:loop_target for r=1:loop_T

        T(r,1)=R(1,r)/(1-t);

    end
    for v=1:loop_V

        V_a(v,1)=(1-w)*V(v);

    end

    target_Thrust (k,1) = T(k,1)/(rho*(D^2)*(V_a(k,1)^2));

end

K_T = zeros(size_C_T(1),1); K_T_2 = zeros(size_J(2), size_V_a(2)); KT_J = zeros(size_J(2), size_V_a(2));

for i=1:loop_V for j=1:loop_J for m=1:loop_C_T

            K_T(m,1) = C_T(m,1)*((J(1,j))^(C_T(m,2)))*...
                (P_D^C_T(m,3))*(BAR^C_T(m,4)*Z^C_T(m,5));

            K_T_2(j,i)=K_T_2(j,i)+K_T(m,1);

        end

        KT_J(j,i)=K_T_2(j,i)/(J(1,j)^2);

    end
end

Target_J = zeros(1,3);

Target_J(1,1)=interp1(KT_J(:,1), J(1,:), target_Thrust(1,1)); Target_J(1,2)=interp1(KT_J(:,2), J(1,:), target_Thrust(2,1)); Target_J(1,3)=interp1(KT_J(:,3), J(1,:), target_Thrust(3,1));

n(1,1)=V_a(1,1)/(Target_J(1,1)*D) n(2,1)=V_a(2,1)/(Target_J(1,2)*D) n(3,1)=V_a(3,1)/(Target_J(1,3)*D)