This site presents audio interviews mostly of science fiction authors:

Mike Hodel's Hour 25.
http://www.hour25online.com/index.html

But sometimes it also has interviews of space scientists:

Dr. Frank Drake
"On Thursday - August 26rd, 2004 - our guest was Dr. Frank Drake of the SETI Institute chatting with us about the Search for Extra-Terrestrial Intelligence. {SETI}"
http://www.hour25online.com/Hour25_Previous_Shows_2004-08.html#frank-drake_2004-08-26

Tim Ziemba
"On Sunday - February 24th, 2002 - we brought you an interview with Plasma Physicist Tim Ziemba talking about a very exciting new development in space technology. Tim is a graduate student at the University of Washington working with Dr. Robert Winglee to see if small artificially created magnetospheres can be used for spacecraft propulsion. If this technology proves practical, it will offer unprecedented capabilities for solar system exploration."
http://www.hour25online.com/Hour25_Previous_Shows_2002-02.html#tim-ziemba_2002-02-24

Bob Clark