They discovered that they were in a more elliptical orbit than they wanted, so they did a burn to correct it and fired up their laser range sensor for powered descent to see how far away they were. That sensor didn't work. They forgot to take off the safety switch which protects the worker's eyes on earth.
So they swapped their range finding sensor within a few hours while orbiting the moon with a completely different sensor that was on the vehicle as a technology test.
They discovered that they were in a more elliptical orbit than they wanted, so they did a burn to correct it and fired up their laser range sensor for powered descent to see how far away they were. That sensor didn't work. They forgot to take off the safety switch which protects the worker's eyes on earth.
So they swapped their range finding sensor within a few hours while orbiting the moon with a completely different sensor that was on the vehicle as a technology test.