His Name In Lights

A novella originally published in the Universe Annex of the Grantville Gazette.
On the strongly volcanic and radiation-soaked surface of the moon Io, the smallest mishap means mortal peril, even for artificial humans like Daniel and Oscar. Clones are expendable and easy to re-create. Why then does company boss Eilin Gunnarsson care so much about these young men that she sends them warnings written on the clouds of Jupiter?