seeking for help: too few initial conditions for differential equations in mathcad

Hi,

I want to solve trwo consecutive differential equations in Mathcad 15, which is like following picture,

Actually, I want to get the plot of S(r) with r. In addition, "r" ranges from 0 to 0.001. I don't know how to deal with my error, hope to get your help.

Please, kindly find the attachment about this task. Thank you very much.

Jason