Redondo Beach, Calif.-based Northrop Grumman Aerospace Systems said April 13 that the James Webb Space Telescope’s (JWST) first fully manufactured and tested primary mirror segment has been delivered to NASA’s Goddard Space Flight Center in Greenbelt, Md.

The hexagonal mirror segment, which has gone through polishing, coating and cryotesting, will not actually fly in space. It is a flight spare designed to verify manufacturing processes and pave the way for fabrication of the mirror segments that will fly aboard JWST.

JWST’s primary mirror is designed to deploy on orbit, unfolding to approximately 6.5 meters in diameter. The mirror will consist of 18 segments, all individually controlled and aligned.

Northrop Grumman said in a press release that there are three different “optical prescriptions” for the 18 mirror segments, with the Northrop-led industry team required to deliver six flight and one spare for each prescription. The delivered segment is the first of the so-called A prescription segments.

JWST is slated to launch in mid-2014 aboard an Ariane 5 rocket, but an independent review completed last fall concluded the program is at least $1.5 billion and 15 months behind schedule. NASA Administrator Charles Bolden told a Senate panel April 11 that JWST’s launch could slip into 2018. He said NASA expects to complete by the end of April a fresh assessment of how much time and money are needed to finish and launch JWST.



Bolden: JWST Making ‘Exceptional Technical Progress’ Despite Schedule, Budget Issues