diff --git a/sc2/src/uqm/planets/generate-base.cpp b/sc2/src/uqm/planets/generate-base.cpp
index 0a9263cc1..c1e02c111 100644
--- a/sc2/src/uqm/planets/generate-base.cpp
+++ b/sc2/src/uqm/planets/generate-base.cpp
@@ -23,6 +23,7 @@
 
 #include <exception>
 #include <stdexcept>
+#include <algorithm>
 
 #include <iostream>
 
@@ -232,6 +233,21 @@ namespace Planets  ::detail::  Generate_m
 		void
 		validateAllStars()
 		{
+			const auto where= std::is_sorted_until( GetAllStars(),
+				GetAllStars() + GetStarCount(),
+				[]( const auto &lhs_, const auto &rhs_ )
+				{
+					const auto &lhs= lhs_.star_pt;
+					const auto &rhs= rhs_.star_pt;
+
+					if( lhs.y == rhs.y ) return lhs.x < rhs.x;
+					return lhs.y < rhs.y;
+				} );
+			if( where != GetAllStars() + GetStarCount() )
+			{
+				throw std::runtime_error( "Found star out of order" );
+			}
+
 			for( int i= 0; i < GetStarCount(); ++i )
 			{
 				const auto &star= GetAllStars()[ i ];