None of the five teams involved in Google's 10-year competition to land a craft on the Moon will be successful by March's deadline, organisers say.
It had been hoped that the Google Lunar X Prize, where reward of $20m (£14m) was up for grabs, could be won by 2012 – but despite numerous extensions, insufficient progress has been made.
Organisers said they "did expect a winner by now" and were "disappointed" that the groups had failed to achieve something only accomplished by three superpowers to date.
Although the many millions of dollars in the prize pot will now go unclaimed, the contest's founders say they will continue to "launch competitions that are literal or figurative moonshots, pushing the boundaries of what's possible".
Moon Express, one of the five teams involved in the competition, told Space News: "The landscape for commercial lunar activity and opportunity couldn't be more positive."
They also praised Google for the launching the contest back in 2007, calling it a "bold move".
To earn the cash, the winner was required to land a craft on the Moon, move it at least 500m (1,640ft) and transmit specific images and data back to Earth.
Moon Express was the team from the US – with SpaceIL flying the flag for Israel, Team Hakuto representing Japan, Team Indus championing India and Synergy Moon including experts hailing from around the world.
A joint launch had seemed likely for the Japanese and Indian groups after they joined forces at the end of 2016, but the plan for a joint launch in India was called off earlier this month.
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Team Hakuto's leader, Takeshi Hakamada, complimented his team's resilience, saying: "(We can) come up with a solution if we don't give up. Regardless of today's news, we will continue our journey and reach for the Moon."
Team Indus posted that 2017 had been a "defining year" with the competition despite no launch and told fans to wait for news later this week.