In response to a schedule described as "unsettled and changing daily", NASA postponed the launch date of the telescope until April 1985.. 
SM1 Flew aboard ẹrúsìnour in December 1993, and involved installation of several instruments and other Equipment over 10 days.Most importantly, the high speed photometer was replaced with the costar àtọkànwáctive Optics paladoge, and WFPc was replaced with the wide field and Planetary camera 2 (WFPc2) with its internal thought fífọ̀ction system.. 