A Walk in the Sun
Geoffrey A. Landis
 The story follows Trish, the only survivor of a terrible crash landing on the moon. After regaining her senses, she contacts Earth and learns that it will be thirty days before she can be rescued. In the meantime, she depends on a wing-like solar panel to provide power to her suit's recycling facilities. While she waits for the rescue party, she has to continually walk westward in order to stay in the sunlight.