How many {crew member} are to/by {Chris Hadfield} ?
Which is the number of crew members that there are in Chris Hadfield?
How many cre members are there in the  {Chris Hadfield} ?
SELECT ( COUNT ( ?z ) AS ?v ) { ?z property:crew_member(s) resource:Chris_Hadfield }
SELECT (COUNT(?sub) AS ?subs ) {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> ?sub .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P1029> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> http://wikidata.dbpedia.org/resource/Q1076962 .
} 

SELECT (COUNT(?sub) AS ?value ) { ?sub wdt:P1029 wd:Q1076962 }
5