Chandra has a nominal design life of 5 years, but there are no expendables or life-limiting items which would limit the mission to 5 years (or to 10 years either). NASA and CXC staff are working carefully with the Instrument teams to ``protect" the science instruments from large solar flares and the damaging cosmic ray (proton) environment as the satellite passes through the earth's radiation zones. Special procedures are used to operate the spacecraft during eclipse seasons (twice per year) when the solar arrays are unable to see the Sun directly for several separate periods up to about 2 hours duration, with the spacecraft then operated strictly on battery power. Special procedures are also used to minimize risk and damage during events such as the Leonid showers. For ``normal" operations, every load uplinked to the Observatory is checked and double-checked by the Operations Control Center, the Instrument Teams, and the Science Operations Team in order to reduce risk of errors to a minimum.
We are all very appreciative of how well the NASA-industry-science team designed and built this ``Great Observatory". Perhaps with continued hard and careful work, and with continued good luck, another extension will be in the offing 5 or so years from now.
- Harvey Tananbaum, CXC Director