What does this mean?

"per aspera ad astra" is Latin for "through hardship to the stars"; I translate it as "to succeed despite adversity".

Why do I include it on my web site?

"per aspera ad astra" is (or perhaps was) used by my alma mater Stevens Institute of Technology. They have stopped using it (or perhaps they use it only occasionally) so I have added it to my 'branding'. For me, it is a nice way to tie back to my roots.