WASHINGTON -- Two days after U.S. President George W. Bush unveiled a new NASA vision requiring a shift in the space agency’s spending priorities, NASA announced that it was curtailing any further space shuttle missions to the Hubble Space Telescope.

Launched aboard the space shuttle in 1990, Hubble has been serviced by astronauts four times since then. The last such mission was in 2002.

NASA had planned to visit Hubble one last time in 2006 to change out instruments and replace its gyroscopes with the intent of keeping the telescope in service until at least 2011, when its heir apparent, the James Webb Space Telescope, is expected to launch.

Scrapping the final servicing mission raises the likelihood that Hubble will fail before Webb is on orbit.