Highlights from the Fifteenth Episode of Season 5 of The Big Bang Theory

­Sheldon’s selfish demands force Leonard to reconsider their friendship. Meanwhile, Wolowitz tries to pick his astronaut nickname.

Follow the Light

1. Follow the Light

Sheldon's (Jim Parsons, right) selfish demands force Leonard (Johnny Galecki, left) to reconsider their friendship. Meanwhile, Wolowitz tries to pick his astronaut nickname, on THE BIG BANG THEORY. NASA astronaut Mike Massimino guest stars as himself. Photo: Michael Yarish/Warner Bros. ©2012 Warner Bros. Television. All Rights Reserved.
Night Light

2. Night Light

Sheldon's selfish demands force Leonard (Johnny Galecki, left) to reconsider their friendship. Meanwhile, Wolowitz tries to pick his astronaut nickname, on THE BIG BANG THEORY. Also pictured: Kaley Cuoco, right. Photo: Michael Yarish/Warner Bros. ©2012 Warner Bros. Television. All Rights Reserved.
Lunch Time

3. Lunch Time

Sheldon's selfish demands force Leonard to reconsider their friendship. Meanwhile, Wolowitz tries to pick his astronaut nickname, on THE BIG BANG THEORY. Pictured (clockwise from left): Johnny Galecki, Kunal Nayyar, Simon Helberg, Jim Parsons. Photo: Michael Yarish/Warner Bros. ©2012 Warner Bros. Television. All Rights Reserved.
Group Therapy

4. Group Therapy

Sheldon's selfish demands force Leonard to reconsider their friendship. Meanwhile, Wolowitz tries to pick his astronaut nickname, on THE BIG BANG THEORY. Pictured (clockwise from left): Kunal Nayyar, Simon Helberg, Melissa Rauch, Mayim Bialik, Johnny Galecki, Kaley Cuoco. Photo: Michael Yarish/Warner Bros. ©2012 Warner Bros. Television. All Rights Reserved.
Selfish Demands

5. Selfish Demands

Sheldon's (Jim Parsons, right) selfish demands force Leonard (Johnny Galecki, center) to reconsider their friendship. Meanwhile, Wolowitz tries to pick his astronaut nickname, on THE BIG BANG THEORY. Also pictured: Kaley Cuoco, left. Photo: Michael Yarish/Warner Bros. ©2012 Warner Bros. Television. All Rights Reserved.
Smores

6. Smores

Sheldon's (Jim Parsons) selfish demands force Leonard to reconsider their friendship. Meanwhile, Wolowitz tries to pick his astronaut nickname, on THE BIG BANG THEORY. Photo: Michael Yarish/Warner Bros. ©2012 Warner Bros. Television. All Rights Reserved.
Couch Consult

7. Couch Consult

Sheldon's (Jim Parsons, right) selfish demands force Leonard (Johnny Galecki, left) to reconsider their friendship. Meanwhile, Wolowitz tries to pick his astronaut nickname, on THE BIG BANG THEORY. Photo: Michael Yarish/Warner Bros. ©2012 Warner Bros. Television. All Rights Reserved.
Emergency Preparedness

8. Emergency Preparedness

Sheldon's (Jim Parsons, left) selfish demands force Leonard (Johnny Galecki, right) to reconsider their friendship. Meanwhile, Wolowitz tries to pick his astronaut nickname, on THE BIG BANG THEORY. Photo: Michael Yarish/Warner Bros. ©2012 Warner Bros. Television. All Rights Reserved.
Astronaut Nickname

9. Astronaut Nickname

Sheldon's selfish demands force Leonard to reconsider their friendship. Meanwhile, Koothrappali (Kunal Nayyar, left) helps Wolowitz (Simon Helberg, right) pick his astronaut nickname, on THE BIG BANG THEORY. Photo: Michael Yarish/Warner Bros. ©2012 Warner Bros. Television. All Rights Reserved.
Comic Book Confrontation

10. Comic Book Confrontation

Sheldon's (Jim Parsons, right) selfish demands force Leonard to reconsider their friendship. Meanwhile, Wolowitz tries to pick his astronaut nickname, on THE BIG BANG THEORY. Photo: Michael Yarish/Warner Bros. ©2012 Warner Bros. Television. All Rights Reserved.
Sheldon's Curiosity

11. Sheldon's Curiosity

Sheldon's (Jim Parsons) selfish demands force Leonard to reconsider their friendship. Meanwhile, Wolowitz tries to pick his astronaut nickname, on THE BIG BANG THEORY. Photo: Michael Yarish/Warner Bros. ©2012 Warner Bros. Television. All Rights Reserved.

12. "The Friendship Contraction"

Sheldon's (Jim Parsons, left) selfish demands force Leonard (Johnny Galecki, right) to reconsider their friendship. Meanwhile, Wolowitz tries to pick his astronaut nickname, on THE BIG BANG THEORY. Photo: Michael Yarish/Warner Bros. ©2012 Warner Bros. Television. All Rights Reserved.