STS-48 was a

Space Shuttle The Space Shuttle is a retired, partially reusable low Earth orbital spacecraft system operated from 1981 to 2011 by the U.S. National Aeronautics and Space Administration (NASA) as part of the Space Shuttle program. Its official program n ...

mission that launched on September 12, 1991, from

Kennedy Space Center The John F. Kennedy Space Center (KSC, originally known as the NASA Launch Operations Center), located on Merritt Island, Florida, is one of the National Aeronautics and Space Administration's (NASA) ten field centers. Since December 196 ...

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and ...

. The orbiter was . The primary payload was the Upper Atmosphere Research Satellite (UARS). The mission landed on September 18 at 12:38 a.m. EDT at

Edwards Air Force Base Edwards Air Force Base (AFB) is a United States Air Force installation in California. Most of the base sits in Kern County, but its eastern end is in San Bernardino County and a southern arm is in Los Angeles County. The hub of the base is ...

on runway 22. The mission was completed in 81 revolutions of the

Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's sur ...

and traveled . The 5 astronauts carried out a number of experiments and deployed several satellites. The total launch mass was and the landing mass was .

Crew

Crew seating arrangements

Mission highlights

Space Shuttle ''Discovery'' was launched into a 57.00°

inclination Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a reference plane and the orbital plane or axis of direction of the orbiting object. For a satellite orbiting the Ea ...

orbit from the Kennedy Space Center (KSC) Launch Complex 39A at 7:11 p.m. EDT on September 12, 1991. Launch was delayed for 14 minutes at the T-5 minute mark due to a noise problem in the air-to-ground link. The noise cleared itself, and the countdown proceeded normally to launch. On the third day of the mission, the Upper Atmosphere Research Satellite (UARS) was deployed from Discovery's payload bay above Earth to study human effects on the planet's atmosphere and its shielding

ozone layer The ozone layer or ozone shield is a region of Earth's stratosphere that absorbs most of the Sun's ultraviolet radiation. It contains a high concentration of ozone (O3) in relation to other parts of the atmosphere, although still small in rel ...

. The UARS mission objectives were to provide an increased understanding of the energy input into the

upper atmosphere Upper atmosphere is a collective term that refers to various layers of the atmosphere of the Earth above the troposphere and corresponding regions of the atmospheres of other planets, and includes: * The mesosphere, which on Earth lies between th ...

, global photochemistry of the upper atmosphere, dynamics of the upper atmosphere, the coupling among these processes, and the coupling between the upper and lower atmosphere. This provided data for a coordinated study of the structure, chemistry, energy balance, and physical action of the Earth's middle atmosphere – that slice of air between and above the Earth. The UARS was the first major flight element of NASA's Mission to Planet Earth, a multi-year global research program that would use ground-based, airborne, and space-based instruments to study the Earth as a complete environmental system. UARS had ten sensing and measuring devices: Cryogenic Limb Array Etalon Spectrometer (CLAES); Improved Stratospheric and Mesospheric Sounder (ISAMS); Microwave Limb Sounder (MLS); Halogen Occultation Experiment (HALOE); High Resolution Doppler Imager (HRDI); Wind Imaging Interferometer (WlNDII); Solar Ultraviolet Spectral Irradiance Monitor (SUSIM); Solar/Stellar Irradiance Comparison Experiment (SOLSTICE); Particle Environment Monitor (PEM) and Active Cavity Radiometer Irradiance Monitor (ACRIM II). UARS's initial 18-month mission was extended several times – it was finally retired after 14 years of service. Secondary payloads were: Ascent Particle Monitor (APM); Middeck 0-Gravity Dynamics Experiment (MODE); Shuttle Activation Monitor (SAM); Cosmic Ray Effects and Activation Monitor (CREAM); Physiological and Anatomical Rodent Experiment (PARE); Protein Crystal Growth (PCG II-2); Investigations into Polymer Membrane Processing (IPMP); and the Air Force Maui Optical Site (AMOS) experiment. The flight was the first to test an electronic still camera in space, a modified

Nikon NASA F4 The Nikon NASA F4 Electronic Still Camera was one of the first and rarest fully digital cameras with development started in 1987. While Nikon delivered a modified Nikon F4 body, most of the electronics for the digital camera and housings were d ...

. Images obtained during the flight were

monochrome A monochrome or monochromatic image, object or palette is composed of one color (or values of one color). Images using only shades of grey are called grayscale (typically digital) or black-and-white (typically analog). In physics, monochr ...

with 8 bits of digital information per pixel (256 gray levels) and stored on a removable hard disk. The images could be viewed and enhanced on board using a modified lap-top computer before being transmitted to the ground via the orbiter digital downlinks. STS-48 was the second post-''Challenger'' mission to have Kennedy Space Center as the planned End-Of-Mission landing site, and the first mission to have a planned night landing at KSC. However, due to weather conditions at KSC in Florida, Discovery flew one extra orbit and landed at Edwards Air Force Base,

California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...

, at 3:38 a.m. EDT on September 18, 1991. The orbiter returned to KSC on September 26, 1991.

Ice particles

Video while in orbit on September 15, 1991, shows a flash of light and several objects that appear to be flying in an artificial or controlled fashion. NASA explained the objects as ice particles reacting to engine jets. Philip C. Plait discussed the issue in his book ''

Bad Astronomy ''Bad Astronomy: Misconceptions and Misuses Revealed, from Astrology to the Moon Landing "Hoax"'' is a non-fiction book by the American astronomer Phil Plait, also known as "the Bad Astronomer". The book was published in 2002 and deals with vario ...

'', agreeing with NASA. This topic was also discussed in an episode of '' UFO Hunters''.

Wake-up calls

NASA began a tradition of playing music to astronauts during the

Project Gemini Project Gemini () was NASA's second human spaceflight program. Conducted between projects Mercury and Apollo, Gemini started in 1961 and concluded in 1966. The Gemini spacecraft carried a two-astronaut crew. Ten Gemini crews and 16 individual ...

, and first used music to wake up a flight crew during

Apollo 15 Apollo 15 (July 26August 7, 1971) was the ninth crewed mission in the United States' Apollo program and the fourth to land on the Moon. It was the first J mission, with a longer stay on the Moon and a greater focus on science than ear ...

. Each track is specially chosen, often by the astronauts' families, and usually has a special meaning to an individual member of the crew, or is applicable to their daily activities.

References

External links

NASA mission summary

{{Orbital launches in 1991 Space Shuttle missions Edwards Air Force Base Spacecraft launched in 1991