
It has been many years since I read it but I shall sum up what I can remember about the story:
There were two space travelers who came upon a planet that was quite dry and dead. Upon landing they discovered a large, rusty parabolic reflector of immense size. One of the men discovered large conduits that led down under ground, and assumed that there must have been power supplied to the machine through them. They were hooked up to the ship's power supply and suddenly the huge machine creaked into action and turned toward the planet's sun.
As soon as the machine found the sun they looked around to find that water was pouring out of the surrounding hills and very soon plants began to grow. The space men were taken by surprise at this occurance, but before long buildings and streets formed from the barren landscape.
Soon there were some kind of aliens peeking out of the buildings, and they came out onto the streets dressed as if there was a celebration. Soon there was music and food and the men found that the alien women were extremely attractive.
They lost themselves in the festivities and ate the most delicious food, listened to the most sublime music and danced with the most beautiful creatures they had ever laid eyes on. It was as if they had gone to heaven.
This went on for what seemed like days. One of the space men found the other and told him that it must have been a long time at this festival and that he was feeling very, very tired. The two men agreed that they were both extremely tired. This party was more than they were used to.
Just about then the planet's sun began to set. The darkness was about to fall. The festival seemed to end, with all the aliens retreating to their buildings. Then the buildings shriveled back into the dirt and the plants dried up and turned to dust. All the water stopped flowing and the land returned to arid, barren dust.
And in the fading light the two spacemen discovered themselves at the bottom of a deep crater -- a hole that they had been digging with their worn out, bloody gloves.
They barely made it back to their space ship to recover and escape the planet. The machine -- the Lotus Engine -- was simply a mind warping device that a dying race must have built in order to keep the remnants of their people digging for the last drying dregs of water.