First published in If. Reprinted by Orson Scott Card, Keith Olexa, Christian O'Toole, and James L. Sutter. This forms a part of Larry Niven's future history series, Known Space. Caveat: I will "ruin" some of these Larry Niven stories as it is impossible to discuss the science without revealing the key plot points.
The coldest place in the solar system is... the farside of Mercury--the side that faces away from the Sun. It may support an unusual form of life. Niven notes that some of the science may have dated.
A repeat character (see also "Becalmed in Hell"), Eric fused to his spaceship, possibly pays tribute to Anne McCaffrey's "The Ship Who Sang"--a story collected in Judith Merrill's Best SF. In the future, those with accidents can have an adventurous life as a ship.
These aspects make the tale worth reading--how ideas of science change, how we might envision working on a future Mercury, and the idea that the disabled are not "not abled", so to speak.