In 2006 a pulse of this type of beam sent a message a record 15 million miles to the MESSENGER spacecraft
.... As the 1.2-mile (2 km) asteroid zipped by, NASA aimed two of its 
largest... [DOC] [TLE] Physics Buzz: October 2008 [PAR] Oct 31, 2008 ... You could even figure out a way to circulate "proton beams".