Work on an improved Westwind began in the late 1970s, with the first prototype flight on March 19, 1984. The first production Astra flew on March 20, 1985, with FAA certification granted on August 29, 1985 and customer deliveries starting in 1986.
The original 1125 Astra was replaced by the Astra SP, announced in 1989, of which 37 were built. The third variant, Astra SPX, flew in August 1994. This variant was renamed G100 from September 2002 following Gulfstream's acquisition of Galaxy Aerospace, which held the Astra certifications, in May 2001. IAI built G100s in Israel and then flew the completed airframes to the United States for interior outfitting. Production of the G100 was discontinued in 2005 with the introduction of the G150.