Guest:  Dr. Umair Siddiqui;  Topics:  The Phase Four radio frequency plasma thruster, plasma science, Hall thrusters, LEO, comsats, mega satellite constellations and more.

Guests: Josh Neubert, Dr. Larry Cooper. Topics: NASA Centennial Challenges and the Night Rover Challenge. You are invited to comment, ask questions, and discuss the Space Show program/guest(s) on the Space Show blog, http://thespaceshow.wordpress.com. Comments, questions, and any discussion must be relevant and applicable to Space Show programming. Transcripts of Space Show programs are not permitted without prior written consent from The Space Show (even if for personal use) & are a violation of the Space Show copyright.