Editing Space weather (section)

===Satellite-based===
A host of research spacecraft have explored space weather.<ref name="PfaffBorovsky1998">{{cite book|first1=Robert F. |last1=Pfaff|first2=Joseph E. |last2=Borovsky|first3=David T. |last3=Young|title=Measurement Techniques in Space Plasmas: Particles|url={{google books |plainurl=y |id=3pBNNEykLIIC}}|date=4 February 1998|publisher=American Geophysical Union|isbn=978-0-87590-085-8}}</ref><ref>{{Cite journal|title = The Large Angle Spectroscopic Coronagraph (LASCO)|journal = Solar Physics|date = 1995-12-01|issn = 0038-0938|pages = 357–402|volume = 162|issue = 1–2|doi = 10.1007/BF00733434|first1 = G. E.|last1 = Brueckner|first2 = R. A.|last2 = Howard|first3 = M. J.|last3 = Koomen|first4 = C. M.|last4 = Korendyke|first5 = D. J.|last5 = Michels|first6 = J. D.|last6 = Moses|first7 = D. G.|last7 = Socker|first8 = K. P.|last8 = Dere|first9 = P. L.|last9 = Lamy|bibcode = 1995SoPh..162..357B|s2cid = 121739815}}</ref><ref>{{Cite journal|title = The NOAA Goes-12 Solar X-Ray Imager (SXI) 1. Instrument, Operations, and Data|journal = Solar Physics|date = 2005-02-01|issn = 0038-0938|pages = 255–281|volume = 226|issue = 2|doi = 10.1007/s11207-005-7416-x|first1 = S. M.|last1 = Hill|first2 = V. J.|last2 = Pizzo|first3 = C. C.|last3 = Balch|first4 = D. A.|last4 = Biesecker|first5 = P.|last5 = Bornmann|first6 = E.|last6 = Hildner|first7 = L. D.|last7 = Lewis|first8 = R. N.|last8 = Grubb|first9 = M. P.|last9 = Husler|bibcode = 2005SoPh..226..255H|s2cid = 119351649|url = https://zenodo.org/record/1232846}}</ref><ref>{{Cite book|publisher = Springer Berlin Heidelberg|date = 2010-01-01|isbn = 978-3-540-70606-9|pages = 226–241|series = Landolt-Börnstein - Group VI Astronomy and Astrophysics|first = Klaus|last = Wilhelm|editor-first = J. E.|editor-last = Trümper|doi = 10.1007/978-3-540-70607-6_11|title = Instruments and Methods|volume = 4A|chapter = 2.3 Solar short-wavelength telescopes and spectrometers on space missions}}</ref> The [[Orbiting Geophysical Observatory]] series were among the first spacecraft with the mission of analyzing the space environment. Recent spacecraft include the NASA-ESA Solar-Terrestrial Relations Observatory (STEREO) pair of spacecraft launched in 2006 into solar orbit and the [[Van Allen Probes]], launched in 2012 into a highly [[Elliptic orbit|elliptical]] Earth orbit. The two STEREO spacecraft drift away from the Earth by about 22° per year, one leading and the other trailing the Earth in its orbit. Together they compile information about the solar surface and atmosphere in three dimensions. The Van Allen probes record detailed information about the radiation belts, geomagnetic storms, and the relationship between the two.

Some spacecraft with other primary missions have carried auxiliary instruments for solar observation. Among the earliest such spacecraft were the [[Applications Technology Satellite]]<ref>{{Cite web|title = NASA - ATS|url = http://www.nasa.gov/centers/goddard/missions/ats.html|website = www.nasa.gov|access-date = 2015-07-24}}</ref> (ATS) series at GEO that were precursors to the modern [[Geostationary Operational Environmental Satellite]] (GOES) weather satellite and many communication satellites. The ATS spacecraft carried environmental particle sensors as auxiliary payloads and had their navigational magnetic field sensor used for sensing the environment.

Many of the early instruments were research spacecraft that were re-purposed for space weather applications. One of the first of these was the IMP-8 (Interplanetary Monitoring Platform).<ref>{{Cite web|title = IMP-8 Project Information|url = http://spdf.gsfc.nasa.gov/imp8/project.html|website = spdf.gsfc.nasa.gov|access-date = 2015-07-24}}</ref> It orbited the Earth at 35 Earth radii and observed the solar wind for two-thirds of its 12-day orbits from 1973 to 2006. Since the solar wind carries disturbances that affect the magnetosphere and ionosphere, IMP-8 demonstrated the utility of continuous solar wind monitoring. IMP-8 was followed by [[International Cometary Explorer|ISEE-3]], which was placed near the {{L1}} Sun-Earth [[Lagrangian point]], 235 Earth radii above the surface (about 1.5&nbsp;million km, or 924,000 miles) and continuously monitored the solar wind from 1978 to 1982. The next spacecraft to monitor the solar wind at the {{L1}} point was [[WIND (spacecraft)|WIND]] from 1994 to 1998. After April 1998, the WIND spacecraft orbit was changed to circle the Earth and occasionally pass the {{L1}} point. The NASA [[Advanced Composition Explorer]] <!-- (ACE) --> has monitored the solar wind at the {{L1}} point from 1997 to present.

In addition to monitoring the solar wind, monitoring the Sun is important to space weather. Because the solar EUV cannot be monitored from the ground, the joint [[NASA]]-[[ESA]] [[Solar and Heliospheric Observatory]] (SOHO) spacecraft was launched and has provided solar EUV images beginning in 1995. SOHO is a main source of near-real time solar data for both research and space weather prediction and inspired the [[STEREO]] mission. The [[Yohkoh]] spacecraft at LEO observed the Sun from 1991 to 2001 in the X-ray portion of the solar spectrum and was useful for both research and space weather prediction. Data from Yohkoh inspired the [[Solar X-ray Imager]] on GOES.

[[File:ExtremeEvent 19891018-00h 19891031-24h.jpg|thumb|right|320px|GOES-7 monitors space weather conditions during the October 1989 solar activity resulted in a Forbush Decrease, [[ground level enhancement]]s, and many satellite anomalies.<ref name="Extreme Space Weather Events"/>]]

Spacecraft with instruments whose primary purpose is to provide data for space weather predictions and applications include the [[Geostationary Operational Environmental Satellite]] (GOES) series of spacecraft, the [[Polar Operational Environmental Satellites|POES]] series, the [[Defense Meteorological Satellite Program|DMSP]] series, and the [[Meteosat]] series. The GOES spacecraft have carried an X-ray sensor (XRS) which measures the flux from the whole solar disk in two bands – 0.05 to 0.4&nbsp;nm and 0.1 to 0.8&nbsp;nm – since 1974, an X-ray imager (SXI) since 2004, a magnetometer which measures the distortions of the Earth's magnetic field due to space weather, a whole disk [[extreme ultraviolet|EUV]] sensor since 2004, and particle sensors (EPS/HEPAD) which measure ions and electrons in the energy range of 50 keV to 500 MeV. Starting sometime after 2015, the GOES-R generation of GOES spacecraft will replace the SXI with a solar EUV image (SUVI) similar to the one on [[Solar and Heliospheric Observatory|SOHO]] and [[STEREO]] and the particle sensor will be augmented with a component to extend the energy range down to 30&nbsp;eV.

The [[Deep Space Climate Observatory]] (DSCOVR) satellite is a [[NOAA]] Earth observation and space weather satellite that launched in February 2015. Among its features is advance warning of coronal mass ejections.<ref>{{cite news | url = http://www.accuweather.com/en/weather-news/nasa-set-to-launch-satellite-t/40450948 | title = NOAA's DSCOVR Satellite Launch Attempt Delayed by Technical Issues | first = Mark | last = Leberfinger | work = AccuWeather.com | publisher = AccuWeather, Inc. | date = February 9, 2015}}</ref>