NASA has selected Northrop Grumman Space Technology to help design a nuclear-powered spacecraft to orbit and explore three moons of Jupiter that may have oceans beneath their icy surfaces. The $400 million contract covers work through mid-2008.
The Prometheus Jupiter Icy Moons Orbiter spacecraft will be designed to explore Callisto, Ganymede, and Europa sometime in the next decade, after launching in 2012 or later.
Scientists want to know what the big moons are made of, what their history is, and whether the oceans that possibly exist under the ice could sustain life.
It would be the first NASA mission to use nuclear-electric propulsion, in which a reactor provides power to generate electricity for engines that expel electrically charged particles called ions to provide thrust.
The number of children and teenagers taking antidepressants has fallen more than 20 percent this year after US warnings the medicines may increase suicidal tendencies among youths, according to pharmacy-benefits manager Medco Health Solutions Inc.
Medco said its research indicates an 18 percent decrease in the number of patients under age 18 who took an antidepressant in the first quarter of 2004. An additional 5 percent decrease was seen in the second quarter, it said.
The data suggest a turnaround from prescription trends between 2000 and 2003, when there was a combined 25 percent surge in sales of such drugs to children, Medco said.
The findings conflict with estimates of a Food and Drug Administration official, who earlier this month said antidepressant prescriptions for children rose this year despite widespread publicity about risks of the drugs to youths.
The FDA official said his conclusion was based on pharmacy sales figures collected by IMS Health, a consulting company that tracks drug sales.
Medco, which authorizes filling of prescriptions for 60 million Americans in insurance plans, came up with the findings after analyzing prescription patterns among its clients.