This challenge coin was issued by the Explorers Club, an international organization that promotes science and exploration, as well as friendship and fellowship. Challenge coins such as this one are issued by military units, organizations, agencies, and companies and given to members, employees, supporters, and VIP guests.
Founded in 1904, the club did not open its doors to women until 1981. This challenge coin belonged to NASA astronaut Kathryn D. Sullivan, who was among the first class of women admitted to the club that year.
Sullivan gifted this challenge coin to the Museum in 2019.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.