The Solar Mesosphere Explorer (also known as Explorer 64) was a

NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the US federal government responsible for the civil List of government space agencies, space program ...

spacecraft to investigate the processes that create and destroy

ozone Ozone (), or trioxygen, is an inorganic molecule with the chemical formula . It is a pale blue gas with a distinctively pungent smell. It is an allotrope of oxygen that is much less stable than the diatomic allotrope , breaking down in the lo ...

in Earth's upper of the

atmosphere of Earth The atmosphere of Earth is the layer of gases, known collectively as air, retained by Earth's gravity that surrounds the planet and forms its planetary atmosphere. The atmosphere of Earth protects life on Earth by creating pressure allowing fo ...

. The mesosphere is a layer of the atmosphere extending from the top of the stratosphere to an altitude of about . The spacecraft carried five instruments to measure ozone,

water vapor (99.9839 °C) , - , Boiling point , , - , specific gas constant , 461.5 J/( kg·K) , - , Heat of vaporization , 2.27 MJ/kg , - , Heat capacity , 1.864 kJ/(kg·K) Water vapor, water vapour or aqueous vapor is the gaseous p ...

, and incoming solar radiation.

Mission

Explorer 64 studied the processes that create and destroy ozone in the Earth's mesosphere. Over its 7.5 years mission, SME measured ultraviolet solar flux, ozone density, and the density of other molecules important to the understanding of ozone chemistry. During the mission over one hundred undergraduate and graduate students were involved in nearly every aspect of SME operations, including planning and scheduling spacecraft and science activities, controlling the spacecraft and its ground support system, and analyzing spacecraft subsystem performance.

Spacecraft

Managed for NASA by the

Jet Propulsion Laboratory The Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center in the City of La Cañada Flintridge, California, United States. Founded in the 1930s by Caltech researchers, JPL is owned by NASA an ...

, the Solar Mesosphere Explorer was built by Ball Space Systems and operated by the

Laboratory for Atmospheric and Space Physics The Laboratory for Atmospheric and Space Physics (LASP) is a research organization at the University of Colorado Boulder. LASP is a research institute with over one hundred research scientists ranging in fields from solar influences, to Earth' ...

of the

University of Colorado Boulder The University of Colorado Boulder (CU Boulder, CU, or Colorado) is a public research university in Boulder, Colorado. Founded in 1876, five months before Colorado became a state, it is the flagship university of the University of Colorado sy ...

. Characteristics: * Mass: 437 kilograms * Power: Solar panels and nickel-cadmium batteries * Configuration: Cylinder 1.25 meter diameter by 1.7 meter high * Science instruments: Ultraviolet ozone spectrometer, Micrometre spectrometer, Nitrogen dioxide spectrometer, Four-channel infrared radiometer, Solar ultraviolet monitor, Solar proton alarm detector

Launch

Launched on 6 October 1981, on a Thor-Delta 2310 from

Vandenberg Air Force Base Vandenberg may refer to: * Vandenberg (surname), including a list of people with the name * USNS ''General Hoyt S. Vandenberg'' (T-AGM-10), transport ship in the United States Navy, sank as an artificial reef in Key West, Florida * Vandenberg Sp ...

, in

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 ...

, the satellite returned data until 4 April 1989.

Atmospheric entry

The spacecraft reentered Earth's atmosphere on 5 March 1991.

References

External links