CAPE CANAVERAL, Fla. — Spacewalking astronauts prepped the Hubble Space Telescope on Tuesday for its riskiest surgery yet: a power-unit replacement that has been likened to a heart transplant.
If the operation fails, the $2-billion-plus telescope could be crippled or rendered useless.
"Any major surgery entails a certain degree of risk," cautioned Hubble's project scientist Dave Leckrone.
Surgery was scheduled for this morning during the third spacewalk in as many days for shuttle Columbia's astronauts.
Assigned to the task: John Grunsfeld, an astrophysicist who has operated on Hubble before, and Richard Linnehan, a veterinarian who has cut into animals but not a 43-foot telescope.
NASA said it had little choice but to replace Hubble's original power control unit, a long, narrow box with 36 connectors jammed together.