NASA Administrator Michael Griffin tomorrow will announce his decision on whether a space shuttle will be dispatched on a mission to service the Hubble Space Telescope and keep it functioning.

The announcement is scheduled for 10 a.m. ET during an agency-wide employee meeting from NASA’s Goddard Space Flight Center, Greenbelt, Md. The event will be live on NASA TV and http://www.nasa.gov.

A news conference will follow at Goddard, also broadcast live on NASA TV at 12:45 p.m.

The decision follows a final evaluation meeting at NASA headquarters Friday, where senior agency officials presented their recommendations to Griffin on the feasibility of a servicing mission.

On the one hand, the Hubble telescope has provided a cornucopia of scientific discoveries and astronomical treasures, such as helping to understand the origins of the universe. It requires a maintenance mission to continue functioning properly.

On the other hand, NASA faces the pressure of having to perform roughly four shuttle missions yearly to finish construction of the International Space Station (ISS). Some of the segments to complete the artificial moon are so huge that only the shuttle can carry them, and the shuttle fleet is set for retirement in 2010. That means each shuttle mission must go well so as to finish the ISS construction job on time.

The Hubble servicing task would add yet another shuttle mission to the crowded launch schedule.

But the last two shuttle missions, involving Space Shuttles Atlantis and Discovery, have gone well, with no major damage caused by foam insulation ripping loose from the external fuel tank and hitting the orbiter vehicle. That was how the Space Shuttle Columbia was damaged in 2003, an incident that later resulted in loss of the orbiter and crew.