The method 13, wherein {HEAD ~ the first system} is a first spacecraft and {TAIL ~ the second system} is a second spacecraft 
The method 13 , wherein { HEAD ~ the first system } is a first spacecraft and { TAIL ~ the second system } is a second spacecraft
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH