How to disable Self Control application?
Have you tried opening Terminal (Applications -> Utilities -> Terminal) and using the commands:

killall SelfControl


or

sudo killall SelfControl


As it is not working try the hosts file:

sudo nano /etc/hosts


And look for something like this

# BEGIN SELFCONTROL BLOCK
127.0.0.1   www.nasa.gov
127.0.0.1   nasa.gov
# END SELFCONTROL BLOCK


delete the entire block and hit CTRL + O to save the file and CTRL + X to exit.
Everything you put at hosts file like:

127.0.0.1 facebook.com
127.0.0.1 nasa.gov
127.0.0.1 stackoverflow.com


Those addresses will be blocked, you will not be able to access them while they are inside the hosts file

To stop and delete SelfControl running as a background process:

sudo su -
cd /Library/PrivilegedHelperTools/
rm org.eyebeam.SelfControl


To delete the firewall rules that have been introduced by SelfControl, read this blog article by Joshua Kehn:

http://joshuakehn.com/2010/10/25/Defeating-SelfControl.html