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