After the depletion of cryogen in the dewar NICMOS was unavailable for science from January 1999 to March 2002. (stsci.edu)
The frozen nitrogen ice cryogen in NICMOS was exhausted in early 1999, rendering the Instrument inoperable at that time. (stsci.edu)
The carbon - fiber part is tricky when dealing with deep cryogens, and trying to achieve both liquid and gas impermeability, and not have gaps occur due to cracking or pressurization that would make the carbon fiber leaky. (businessinsider.com)