Enrty #3 Omega, by Jack McDevitt

(Ace, Nov 2003) Priscilla "Hutch" Hutchens, has had a full career as a space pilot and is now administrator of the government agency in charge of space research. Like most people, she's only mildly concerned with the long-range threat of the omega clouds ,,,,
McDevitt has not won the Nebula nor the Hugo before.