From 24f6a667e7932df903e7729b0f0a4fe387fc5fa0 Mon Sep 17 00:00:00 2001
From: "Giammarco, Kristin M" <kmgiamma@nps.edu>
Date: Wed, 16 Jun 2021 22:55:06 +0000
Subject: [PATCH] Upload New File

---
 Example54_Unmanned_Spacecraft_Comms.mp | 60 ++++++++++++++++++++++++++
 1 file changed, 60 insertions(+)
 create mode 100644 Example54_Unmanned_Spacecraft_Comms.mp

diff --git a/Example54_Unmanned_Spacecraft_Comms.mp b/Example54_Unmanned_Spacecraft_Comms.mp
new file mode 100644
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--- /dev/null
+++ b/Example54_Unmanned_Spacecraft_Comms.mp
@@ -0,0 +1,60 @@
+/* Heartbeat.mp
+October 4, 2015
+Created by: C. Nelson
+	
+The communication link between a spacecraft and the ISS is monitored
+through a frame counter called the "Heartbeat". This model represents
+the behavior of the Heartbeat while a Spacecraft is approaching 
+the ISS.
+
+Run for scope 1 and up. 
+ 
+*/
+
+/*—————————————————————————————
+ 	 		  Actors
+———————————————————————————————*/
+
+SCHEMA Heartbeat
+
+ROOT Spacecraft:	Receive_Heartbeat		
+					(+  Echo_Heartbeat
+						Receive_Incremented_Heartbeat	
+						Compare_Received_Heartbeat_Values
+						( SC_HB_Valid | SC_HB_Invalid )	+);
+
+	SC_HB_Valid:	( Continue_Approach | Switch_to_Redundant_Comm_System );
+
+	SC_HB_Invalid: 	Abort_Operations;
+			
+
+ROOT ISS: 	Generate_Heartbeat
+			Send_Heartbeat
+			(+	Receive_Echoed_Heartbeat	
+				Increment_Heartbeat Send_Incremented_Heartbeat
+            	Compare_Sent_and_Received_HB  
+				( HB_Valid | HB_Invalid ) +);
+
+	HB_Valid: 	( Continue_Approach | Abort_Operations );
+
+	HB_Invalid: ( Switch_to_Redundant_Comm_System | Abort_Operations );
+
+/*—————————————————————————————
+ 		        Interactions
+———————————————————————————————*/
+
+ISS, Spacecraft SHARE ALL 	Abort_Operations, 
+							Switch_to_Redundant_Comm_System,
+							Continue_Approach;
+
+COORDINATE 	$a: Send_Heartbeat		FROM ISS,
+			$b: Receive_Heartbeat	FROM Spacecraft
+	DO ADD 	$a PRECEDES $b; OD;
+
+COORDINATE 	$a: Echo_Heartbeat				FROM Spacecraft,
+			$b: Receive_Echoed_Heartbeat 	FROM ISS
+	DO ADD 	$a PRECEDES $b; OD;
+
+COORDINATE 	$a: Send_Incremented_Heartbeat 		FROM ISS,
+			$b: Receive_Incremented_Heartbeat 	FROM Spacecraft
+	DO ADD 	$a PRECEDES $b; OD;
-- 
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