The calculated distance (air line) between Staraya Kupavna and Vostochnyy is approximately 12 miles respectively 20 kilometers.
By car or train, the actual journey to Vostochnyy is certainly longer, as only the direct route (as the crow flies) between Staraya Kupavna and Vostochnyy has been calculated here.
Air line (approximately)
20 kilometers
11 nautical miles