The original laser-powered range finders had been rendered non-functional because company engineers at NASA's Kennedy Space Center in Florida had inadvertently failed to unlock a safety switch before the lander's launch to space last Thursday, Altemus said.
"That was an oversight on our part," he said, likening the overlooked switch to a safety mechanism on a firearm.
The problem was only detected by happenstance a week later during lunar orbit, with just hours to go before landing, when flight controllers were troubleshooting a different issue.