Luca Parmitano is younger than Ulrich Walter.
Prof. Dr. Ulrich Hans Walter (born February 9, 1954) is a German physicist/engineer and a former DFVLR astronaut. 
Luca Parmitano (born 27 September 1976 in Patern, Sicily) is an Italian engineer and astronaut in the European Astronaut Corps for the European Space Agency (ESA). 
