diff --git a/planetstack/observer/event_loop.py b/planetstack/observer/event_loop.py
index 482c5a8..f67e2eb 100644
--- a/planetstack/observer/event_loop.py
+++ b/planetstack/observer/event_loop.py
@@ -176,7 +176,7 @@
 		self.last_run_times[step.__name__]=time.time()
 
 	def check_schedule(self, step):
-		time_since_last_run = time.time() - self.last_run_times[step.__name__]
+		time_since_last_run = time.time() - self.last_run_times.get(step.__name__, 0)
 		try:
 			if (time_since_last_run < step.requested_interval):
 				raise StepNotReady