The only thing the general public remember about the wreck of the Silver Queen is that Dr. Horace Quentin, a great scientist, was killed.

The three men learn via Moore's Multivac terminal that Quentin had a prototype of a revolutionary new invention with him on the ship, and that it is still missing.

An apparently useless tube a few inches long, it seems to employ force-fields instead of conventional optics and can be used as a powerful microscope or telescope.

In the first story, the irony was that the men were in orbit around Vesta with no source of motive power and limited food and air but a year's supply of water.

Asimov notes in his comments on the story that Moore picking up the device had been a throwaway line he included in the original "Marooned Off Vesta".