Michael Sheetz, reporting for CNBC: More than ten years after it was announced -- and extended over and over -- the Google-sponsored race to win $20 million by landing on the moon will end with no winners. The four teams racing to win the Google Lunar Xprize, which requires a company to land a spacecraft on the moon by March 31, are either short of money or unable to launch this year, three people familiar with the matter told CNBC. Meanwhile, Google -- which extended the deadline from 2012 to 2014 and then eventually to 2018 -- is not willing to push out the date further. "Google does not have plans at this time to extend the deadline again, however we are so thrilled with the progress made by these teams over the last ten years," a Google spokesperson said in a statement to CNBC. The commercial space industry has written off the Lunar Xprize as improbable, and not worth pursuing, according to sources.