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