limit NICMOS science so plans for purging and refilling the circulation system with clean neon gas were developed by NASA. The circulation loop is equipped with an extra neon tank and remotely operated solenoid valves for on-orbit purge-fill operations. As of 2013, these purge-fill operations have not yet been performed. WFC3, installed 2009, was designed to partly replace NICMOS. On June 18, 2010, it was announced NICMOS would not be available for science during the latest proposal Cycle 18. As of 2013, a decision as to whether the purge-fill operations will be performed and whether NICMOS will be available for science in the future has not been made. NICMOS is also the name of the device's 256×256-pixel imaging sensor built by Rockwell International Electro-Optical Center (now DRS Technologies). Scientific results NICMOS was noted for its performance in Near-infrared space astronomy, in particular its ability to see objects through dust. It was used for about 23 months after it was installed, its life limited by set amount of cryo-coolant, and then later it was used for several years when a new cryo-cooler was installed in 2002. NICMOS combined near infrared performance with a large mirror. NICMOS allowed investigation of high redshift galaxies and quasars with high spatial resolution, which was especially useful when analyzed in conjunction with other instruments such as the STIS, and it also allowed deeper investigation of stellar populations. In planetary science, NICMOS was used to discover an impact basin on the south pole of the asteroid 4 Vesta. (4 Vesta was later visited by Dawn (spacecraft) in the 2010s which investigated it more closely by orbiting it.) In 2009, an old NICMOS image was processed to show a predicted exoplanet around the star HR 8799. The system is thought to be about 130 light-years from Earth. In 2011, around that same star, four exoplanets were rendered viewable in a NICMOS image taken in 1998, using advanced data processing. The exoplanets were originally discovered with the Keck telescopes and the Gemini North telescope between 2007 and 2010. The image allows the orbits of the exoplanets to be analyzed more closely, since they take many decades, even hundreds of Earth years, to orbit their host star. NICMOS observed the exoplanet XO-2b at star XO-2, and a spectroscopy result was obtained for this exoplanet in 2012. This uses the spectroscopic abilities of the instrument, and in astronomy spectroscopy during a