The sheer amount of data produced by modern science research has created a need for the construction and understanding of "data-intensive systems", large-scale, distributed systems which integrate information. The formal nature of constructing such software systems; however, is relatively unstudied, and has been a large focus of the super-computing and distributed computing communities, rather than the software engineering communities. These data-intensive systems exhibit characteristics which appear fruitful for research from a software engineering, and software architectural focus. From our experience, the methodologies and notations for design and implementation of data-intensive systems look to be a good starting point for this important research area. This paper presents our experience with OODT, a software architectural style, and middleware-based implementation for data-intensive systems developed and maintained at the Jet Propulsion Laboratory. To date, OODT has been successfully evaluated in several different science domains including Planetary Science with NASA's Planetary Data System (PDS) and Cancer Research with the National Cancer Institute (NCI).