Dafydd Williams, media personality with a Welsh connection!
Dafydd WilliamsCanadian born, Dr. Dafydd R. Williams has worked with Canadian Space Agency and NASA.
Connection: Welsh father, William Williams.
In his native Canada he calls himself David, in Wales he uses given name Dafydd.
link by: meltedgoldfish
Dafydd Williams Bio
His biography on the NASA website. I believe the head of NASA has Welsh connections too.