Before landing, the aircraft will do a flyover of Washington DC at approximately 1,500 feet near a variety of landmarks, including the National Mall, Reagan National Airport and the National Harbor.
Discovery retired in March after completing its 39th mission. It spent a total of 365 days in space, orbited the Earth 5,830 times, and travelled 148,221,675 miles.
More top news
Protestors angry about an immigration raid at Byron burger earlier this week reacted by launching hundreds of insects into the restaurant
Families and rebel fighters are believed to be among the people to have left besieged Aleppo on Saturday through safe corridors.
The balloon came down near Lockhart, Texas, around 8.30am local time.