diff --git a/data/SSC-01/SSC-01-01/SSC-01-01.al.owl.ttl b/data/SSC-01/SSC-01-01/SSC-01-01.al.owl.ttl
index a46edc80843f43543b9f0cb1686439bb9fc8f97d..b3e2012e5e83c88d2f2003436b9ae28bb9b36ae2 100644
--- a/data/SSC-01/SSC-01-01/SSC-01-01.al.owl.ttl
+++ b/data/SSC-01/SSC-01-01/SSC-01-01.al.owl.ttl
@@ -9,6 +9,7 @@
 
 
 # ::predefined-property :has-part :part-of :manner
+
 :part-of a owl:ObjectProperty .
 
 :has-part
@@ -95,19 +96,17 @@
 		owl:hasValue :sun
 	] .
 
-:direct-orbit a rdf:Property ;
+:direct-orbit a owl:ObjectProperty ;
 	rdfs:subPropertyOf :orbit ;
 	:manner :direct .
 
-:indirect-orbit a rdf:Property ;
+:indirect-orbit a owl:ObjectProperty ;
 	rdfs:subPropertyOf :orbit ;
 	:manner :indirect .
 
-:direct a rdfs:Class .
+:direct a owl:ObjectProperty .
 
-:indirect a rdfs:Class ;
-	owl:equivalentClass [
-		a owl:Class ;
-		owl:complementOf :direct
-	] .
+:indirect
+	a owl:ObjectProperty ;
+	owl:inverseOf :part-of .