Question: Which satellite was operational for longer, International Ultraviolet Explorer or EXOSAT?

Passages:
GOES 7, known as GOES-H before becoming operational, is an American satellite.  It was originally built as a weather satellite, and formed part of the US National Oceanic and Atmospheric Administration's Geostationary Operational Environmental Satellite system.  Originally built as a ground spare, GOES-H was launched in 1987 due to delays with the next series of satellites.  It was operated by NOAA until 1999, before being leased to Peacesat, who use it as a communications satellite.  As of 2009, it was operational over the Pacific Ocean, providing communications for the Pacific Islands.  On April 12, 2012, the spacecraft was finally decommissioned and moved to a graveyard orbit. The Extreme Ultraviolet Explorer (EUVE) was a space telescope for ultraviolet astronomy, launched on June 7, 1992.  With instruments for ultraviolet (UV) radiation between wavelengths of 7 and 76 nm, the EUVE was the first satellite mission especially for the short-wave ultraviolet range.  The satellite compiled an all-sky survey of 801 astronomical targets before being decommissioned on January 31, 2001.  It re-entered the atmosphere on January 30, 2002. The European X-ray Observatory Satellite (EXOSAT), originally named HELOS, was an X-ray telescope operational from May 1983 until April 1986 and in that time made 1780 observations in the X-ray band of most classes of astronomical object including active galactic nuclei, stellar coronae, cataclysmic variables, white dwarfs, X-ray binaries, clusters of galaxies, and supernova remnants. The Tel Aviv University Ultraviolet Explorer, or TAUVEX, is a space telescope array conceived by Noah Brosch of Tel Aviv University and designed and constructed in Israel for Tel Aviv University by El-Op, Electro-Optical Industries, Ltd. (a division of Elbit systems) acting as Prime Contractor, for the exploration of the ultraviolet (UV) sky.  TAUVEX was selected in 1988 by the Israel Space Agency (ISA) as its first priority scientific payload.  Although originally slated to fly on a national Israeli satellite of the Ofeq series, TAUVEX was shifted in 1991 to fly as part of a Spektr-RG international observatory, a collaboration of a large number of countries with the Soviet Union (Space Research Institute) leading. UVS, known as the Ultraviolet Spectrograph or Ultraviolet Imaging Spectrometer is the name of an instrument on the "Juno" orbiter for Jupiter.  The instrument is an imaging spectrometer that observes the ultraviolet range of light wavelengths, which is shorter wavelengths than visible light but longer than X-rays.  Specifically, it is focused on making remote observations of the aurora, detecting the emissions of gases such as hydrogen in the far-ultraviolet.  UVS will observes light from as short a wavelength as 70 nm up to 200 nm, which is in the extreme and far ultraviolet range of light.  The source of aurora emissions of Jupiter is one of the goals of the instrument.  UVS is one of many instruments on "Juno", but it is in particular designed to operate in conjunction with JADE, which observes high-energy particles.  With both instruments operating together, both the UV emissions and high-energy particles at the same place and time can be synthesized.  This supports the Goal of determining the source of the Jovian magnetic field.  There has been a problem understanding the Jovian aurora, ever since Chandra determined X-rays were coming not from, as it was thought Io's orbit but from the polar regions.  Every 45 minutes an X-ray hot-spot pulsates, corroborated by a similar previous detection in radio emissions by Galileo and Cassini spacecraft.  One theory is that its related to the solar wind.  The mystery is not that there are X-rays coming Jupiter, which has been known for decades, as detected by previous X-ray observatories, but rather why with the Chandra observation, that pulse was coming from the north polar region. Ultraviolet (UV) is an electromagnetic radiation with a wavelength from 10 nm to 400 nm, shorter than that of visible light but longer than X-rays. UV radiation constitutes about 10% of the total light output of the Sun, and is thus present in sunlight.  It is also produced by electric arcs and specialized lights, such as mercury-vapor lamps, tanning lamps, and black lights. Although it is not considered an ionizing radiation because its photons lack the energy to ionize atoms, long-wavelength ultraviolet radiation can cause chemical reactions and causes many substances to glow or fluoresce.  Consequently, the biological effects of UV are greater than simple heating effects, and many practical applications of UV radiation derive from its interactions with organic molecules. The International Ultraviolet Explorer (IUE) was an astronomical observatory satellite primarily designed to take ultraviolet spectra.  The satellite was a collaborative project between NASA, the UK Science Research Council and the European Space Agency (ESA).  The mission was first proposed in early 1964, by a group of scientists in the United Kingdom, and was launched on January 26, 1978 aboard a NASA Delta rocket.  The mission lifetime was initially set for 3 years, but in the end it lasted almost 18 years, with the satellite being shut down in 1996.  The switch-off occurred for financial reasons, while the telescope was still functioning at near original efficiency. ULTRASAT (Ultraviolet Transient Astronomy Satellite) is a proposed astronomical satellite mission whose wide-angle UV telescope will detect and monitor transient astrophysical phenomena in the near-ultraviolet spectral region.  ULTRASAT will observe a large patch of sky, more than 200 square degrees, alternating every six months between the southern and northern hemisphere.  The satellite will orbit the Earth from an altitude of about 300 km above the geosynchronous orbit, getting a ‘ride’ as a secondary payload in the fairing of the rocket carrying a communications satellite.  Upon detection of a transient event, ULTRASAT will provide alerts to other ground-based and space telescopes to be directed to the source for further observation of the event in other wavelength bands.  A joint American-Israeli proposal for this project was submitted to NASA by a team from Caltech/JPL (Jet Propulsion Laboratory), the Weizmann Institute of Science and Israel Aerospace Industries (IAI).  The Israeli contribution will be funded by the Israel Space Agency and launch is expected before 2021. Lewis was an American satellite which was to have been operated by NASA as part of the Small Satellite Technology Initiative.  It carried two experimental Earth imaging instruments, and an ultraviolet astronomy payload.  Due to a design flaw it failed within three days of reaching orbit, before it became operational. The Far Ultraviolet Spectroscopic Explorer (FUSE) is a space-based telescope operated by the Johns Hopkins University Applied Physics Laboratory.  "FUSE" was launched on a Delta II rocket on 24 June 1999, as a part of NASA's Origins program.  "FUSE" detected light in the far ultraviolet portion of the electromagnetic spectrum, between 90.5-119.5 nanometres, which is mostly unobservable by other telescopes.  Its primary mission was to characterize universal deuterium in an effort to learn about the stellar processing times of deuterium left over from the Big Bang.

Supporting sentences:
The International Ultraviolet Explorer (IUE) was an astronomical observatory satellite primarily designed to take ultraviolet spectra.  The mission lifetime was initially set for 3 years, but in the end it lasted almost 18 years, with the satellite being shut down in 1996. The European X-ray Observatory Satellite (EXOSAT), originally named HELOS, was an X-ray telescope operational from May 1983 until April 1986 and in that time made 1780 observations in the X-ray band of most classes of astronomical object including active galactic nuclei, stellar coronae, cataclysmic variables, white dwarfs, X-ray binaries, clusters of galaxies, and supernova remnants.