<http://schema.org/alternativeHeadline>
"Endeavour and its six-astronaut crew completed the 16-day STS-134 mission to the International Space Station, its 25th and final flight."^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.mnn.com/earth-matters/space/stories/space-shuttle-endeavour-returns-to-earth>