STS-95 was a Space Shuttle mission launched from Kennedy Space Center, Florida on 29 October 1998, using the orbiter Discovery. It was the 25th flight of Discovery and the 92nd mission flown since the start of the Space Shuttle program in April 1981. It was a highly publicized mission due to former Project Mercury astronaut and United States Senator John H. Glenn Jr.'s return to space for his second space flight. At age 77, Glenn became the oldest person to go into space, a record that remained unbroken for 23 years until 82-year-old Wally Funk flew on a suborbital flight on Blue Origin NS-16, launching on July 20, 2021, which in turn was broken by William Shatner at age 90 on October 13, 2021. Glenn, however, remains the oldest person to reach Earth orbit. This mission is also noted for inaugurating ATSC HDTV broadcasting in the U.S., with live coast-to-coast coverage of the launch. In another first, Pedro Duque became the first Spaniard in space.

The mission's objectives involved investigating life-sciences experiments, using the SpaceHab module to perform these experiments on Senator Glenn. Scientific objectives on this mission were not limited to furthering an understanding of the human body, but also to increase astronomical understanding with regards to the Sun, and how it affects life on Earth. The Spartan 201 spacecraft was released by the crew, flying free from the Shuttle, studying the acceleration of the solar wind that originates in the Sun's solar corona. The mission lasted just under ten days, with Discovery completing its voyage by landing at the Kennedy Space Center's Shuttle Landing Facility.

The launch was rare in that the official launch weather forecast provided by the 45th Weather Squadron was 100 percent for favorable weather for launch as well as the Shuttle Landing Facility.Bill Clinton became the second sitting U.S. president to witness a crewed space launch, joined by his wife Hillary on the roof of the Launch Control Center, and the only one to witness a Space Shuttle launch (President Richard Nixon witnessed the launch of Apollo 12).

Space Shuttle Discovery (Orbiter Vehicle Designation: OV-103) is one of the orbiters from NASA's Space Shuttle program and the third of five fully operational orbiters to be built. Its first mission, STS-41-D, flew from August 30 to September 5, 1984. Over 27 years of service it launched and landed 39 times, aggregating more spaceflights than any other spacecraft to date. The Space Shuttle launch vehicle has three main components: the Space Shuttle orbiter, a single-use central fuel tank, and two reusable solid rocket boosters. Nearly 25,000 heat-resistant tiles cover the orbiter to protect it from high temperatures on re-entry.Discovery became the third operational orbiter to enter service, preceded by Columbia and Challenger. It embarked on its final mission, STS-133, on February 24, 2011, and touched down for the last time at Kennedy Space Center on March 9, having spent a cumulative total of nearly a full year in space. Discovery performed both research and International Space Station (ISS) assembly missions, and also carried the Hubble Space Telescope into orbit.

Discovery was the first operational shuttle to be retired, followed by Endeavour and then Atlantis. The shuttle is now on display at the Steven F. Udvar-Hazy Center of the Smithsonian National Air and Space Museum.