I've not been on game since server main this morning, but aside from possible issues with servers after todsy's maintenance, other sggestions wouls be ensure graphics and sound drivers are up to date, and verify game files. Can you plot elsewhere for instance. If you are out in the black and need to find the nearest DSSA or other service carrier, Megaship, Or deep space outpost, the Interactive Galaxy map at edastro.com might be able to help.
I sometimes see a freeze EXITING galaxy map after plotting. But that is leaving galmap, not launching it or plotting.