Lisa Chu-ThielbarScience Communications, SETI Institute SPACE.com , wrote an interesting article about Probing Planets: Can You Get There From Here? In this article she mentions a number of difficulties in dealing with the many places where the scientific community would like to probe in order to understand the origin of the universe and how our solar system works.
The top difficulty is expense because items are specialized. What we've learned about manufacturing is that a process that is able to produce an object many times will be less expensive. Most probes are manufactured specifically for an environment that is different from all the others visited before.
A secondary difficulty is using new untested technologies and getting them approved for launch.
She explained that there's an annual conference where issues about probes are discussed.
My thoughts--still gelling in my mind. More later.