The Hammer of God

By Arthur C. Clarke

Set in the 2100s, the book finds humanity facing doom in the form of a big wayward space rock on a collision course with the planet, with catastrophic consequences.
Captain Singh has the responsibility of hauling a powerful engine out to the location of the rock and placing the engine on the rock and firing it up, in the hopes that it will nudge the rock into a different orbit, one that will not send it crashing into Earth or the moon or Mars, all of which now have human populations. It doesn't have to move it much, just a little nudge would be enough to send it into a safer orbit.
But, not unexpectedly, there are religious zealots who are eager for the end, for God's judgment of wicked humanity. The zealots have managed to throw a monkey wrench into the proceedings: the engine spills its fuel instead of doing what was intended. And the space rock remains on its killer trajectory. Now it is up to Captain Singh and the bright minds of the 22nd Century to try and save Earth and its people, including the nutters who want to see it all go up in smoke.

A pretty interesting tale, but filled with a lot of technical jabber that I just skipped over.

A Fall of Moondust

By Arthur C. Clarke

People are living on the moon and a tourism industry has been established. One of the things the visitors to the moon like to do is take a sightseeing cruise on the Sea of Thirst in a boat specially designed to travel across the surface of this sea of dust. Captain Pat Harris has made this trip many times before without incident. But this time something entirely unexpected occurs: a sinkhole opens in the dust beneath the boat and it is pulled down some fifty feet into the dusty depths.
The boat is a bubble air trapped beneath the cold, airless moon dust and the 22 people on board can do nothing to save themselves. They just have to sit and wait and pray that help arrives before they run out of air.

Written about 1960 and somewhat dated, this was still an OK story. I found myself skipping parts of it, mainly the technical descriptions of the rescue effort which provided a lot more detail than I was interested in reading. Other than the sometimes boring tech stuff, it was pretty interesting, despite the fact that the moon does not have seas of dust deep enough to sink a boat.