Exploratory engineering is a process for understanding a subset of the potential capabilities of future levels of technology. This process resembles the first phase of standard design engineering (termed conceptual engineering, or conceptual design), but it serves a different purpose:
In standard engineering, design leads to the manufacturing of a product.
In exploratory engineering, design leads to understanding of what a future manufacturing process could produce.
Exploratory engineering allows to show how some capabilities that intuitively seem absurd may actually be achieved in the future.
Exploratory Engineering: Applying the predictive power of science to future technologies by Eric Drexler