STS-95

The Spacehab module flown on STS-95 was provided by Spacehab, Inc., a private company. The Spacehab system provided additional pressurized workspace for experiments, cargo and crew activities. Spacehab modules supported various Shuttle science missions along with several of the joint Shuttle-Mir missions.

For STS-95, a single-module Spacehab flew in the forward portion of Discovery's payload bay, with the crew gaining access to the module through the airlock tunnel system. A variety of experiments sponsored by NASA, the Japanese Space Agency (NASDA) and the European Space Agency (ESA) focused on life sciences, microgravity sciences and advanced technology during the flight.

The Spartan 201-5 free-flyer was deployed and retrieved using the Shuttle's mechanical arm. It was designed to investigate physical conditions and processes of the hot outer layers of the Sun's atmosphere, or solar corona.[3] While deployed from the Shuttle, Spartan gathered measurements of the solar corona and solar wind. NASA expected that information collected during this mission would lead to a much better understanding of the solar winds that directly influence orbiting satellites and weather conditions on Earth which in turn impact television and phone communications.[3] This was the fifth flight for the Spartan payload; it originally flew on the STS-56 mission in April 1993.[6] On its previous mission, STS-87 in November 1997, Spartan developed problems shortly after being deployed from the Shuttle and had to be brought back into the Shuttle's payload bay by spacewalk.[6] These problems were due with the attitude control system for fine pointing toward solar targets, and Spartan was cleared for use again on STS-95. Its mission was to successfully perform the same experiments from the previous year.[6]

The Hubble Space Telescope Orbital Systems Test (HOST) platform carried experiments to validate components planned for installation during the third Hubble Space Telescope servicing mission and to evaluate new technologies in an earth orbiting environment. There were four experiments on the HOST platform. The NICMOS Cooling System allowed for zero-g verification of a reverse turbocharged Brayton cycle cooler, which allowed for longer life operation than the dewar system used on Hubble at the time. The HST 486 computer allowed for the identification of any radiation-susceptible parts in the DF-224 replacement computer to be carried on the third servicing mission, and demonstrate hardware and software responses to Single Event Upsets (SEUs). A solid state recorder compared on-orbit operation of the flight-spare solid state recorder with the unit installed in Hubble. A fiber optic line test used the same 4 kbit/s data stream that was sent to the orbiter's Payload Data Interrogator (PDI) and routed to a laptop computer for post-flight comparison.[7]

The International Extreme Ultraviolet Hitchhiker (IEH) payload involved a half dozen different experiments mounted on a support structure which was carried in Discovery's payload bay. The six experiments that made up the IEH payload were the Solar Extreme Ultraviolet Hitchhiker (SEH) payload, which obtained EUV and FUV fluxes that are required when studying the Earth's upper atmosphere; an Ultraviolet Spectrograph Telescope for Astronomical Research (UVSTAR) payload designed to measure EUV fluxes which could be used to form images of extended plasma sources (ex. Jupiter, hot stars, etc.); the STAR-LITE payload which made observations of extended and diffused astrophysical targets; the CONCAP-IV payload designed to grow thin films via physical vapor transport; the Petite Amateur Navy Satellite (PANSAT) payload which was managed by the Department of Defense Space Test Program, and involved a small deployable satellite that stored and transmitted digital communications to PANSAT ground stations; and a Getaway Special (GAS) payload.[7]

According to the New York Times, Glenn "won his seat on the shuttle flight by lobbying NASA for two years to fly as a human guinea pig for geriatric studies", which were named as the main reasons for his participation in the STS-95 mission.[8] This series of experiments conducted on Glenn during the mission was sponsored by NASA and the National Institute on Aging,[9] and based on the fact that the aging process and a space flight experience share a number of similar physiological responses.[3] The investigations were expected to gather information which may provide a model system to help scientists interested in understanding aging.[9] Some of these similarities include bone and muscle loss, balance disorders and sleep disturbances.[3] Shortly before the flight, researchers learned that Glenn had to be disqualified from another of the flight's two main priority human experiments (about the effects of melatonin) because he did not meet one of study's medical conditions; he still participated in two other experiments about sleep monitoring and protein use.[8] Data provided from Glenn during this mission was compared to data obtained from Glenn's Friendship 7 orbital mission in 1962.

Glenn was the oldest person, and the third sitting member of Congress, to fly into space. He was preceded by U.S. Senator from Utah Jake Garn (STS-51-D) and U.S. Representative (later Senator) from Florida Bill Nelson (STS-61-C). At the time, Glenn was Ohio's senior or ranking Senator. Other astronauts who later entered politics include Harrison Schmitt (Apollo 17), later U.S. Senator from New Mexico, Jack Swigert (Apollo 13), who was elected to Congress in the state of Colorado but died before being sworn in, and U.S. Senator from Arizona Mark Kelly (STS-108, STS-121, STS-124, and STS-134).

In a reprise of his first space flight, while in orbit, Glenn was greeted again by the citizens of Perth and Rockingham in Australia.[10] They left their private and municipal lights on while the Discovery passed overhead, just like they did during his Friendship 7 flight.[10]

This is the first mission with the NASA "meatball" insignia (above) displayed on a Space Shuttle orbiter, replacing the "worm" logotype (below).

This is the first mission wherein a Space Shuttle orbiter (Discovery in this mission) uses NASA's meatball insignia on its markings. It replaced the worm logotype that all orbiters had. Endeavour, Atlantis, and Columbia would follow in their respective missions of STS-88, STS-101, and STS-109. Space Shuttle orbiters Enterprise and Challenger didn't have this change, for Enterprise became the property of The Smithsonian in 1985 and Challenger was destroyed in 1986.