Question: Which is the sub-orbital spaceflight for Astronaut Alan Shepard?
Paraphrase: Which is the sub-orbital spaceflight for Space explorer Alan Shepard?
SPARQL (Wikidata):  select distinct ?obj where { wd:Q174979 wdt:P450 ?obj . ?obj wdt:P31 wd:Q832435 } 
Answer: Mercury-Redstone 3