View source for Parker Solar Probe

{{Short description|NASA robotic space probe of the outer corona of the Sun}}
{{Use American English|date=June 2017}}
{{Use mdy dates|date=March 2020}}
{{Infobox spaceflight
| name               = Parker Solar Probe
| names_list         = Solar Probe (before 2002)<br />Solar Probe Plus (2010–2017)<br />Parker Solar Probe (since 2017)
| image              = Parker_Solar_Probe_spacecraft_model.png
| image_size         = 
| image_caption      = Model of the Parker Solar Probe
| image_alt          = Digital model of a spacecraft with a bus attached to a larger sun-shield. Two small solar panels are attached to the side of the bus, along with four rear-facing antennas.
| mission_type       = [[Heliophysics]]
| operator           = {{nowrap|[[NASA]] / [[Applied Physics Laboratory]]}}
| COSPAR_ID          = 2018-065A
| SATCAT             = 43592
| website            = {{url| http://parkersolarprobe.jhuapl.edu/|}}
| mission_duration   = 7 years (planned)<br />Elapsed: {{time interval|August 12, 2018, 07:31|show=ymd}}
| manufacturer       = [[Applied Physics Laboratory]]
| launch_mass        = {{cvt|685|kg|lb}}<ref name='extreme'>[http://parkersolarprobe.jhuapl.edu/index.php#spacecraft Parker Solar Probe – Extreme Engineering] {{Webarchive|url=https://web.archive.org/web/20180824070030/http://parkersolarprobe.jhuapl.edu/index.php#spacecraft |date=August 24, 2018 }}. NASA.</ref>
| dry_mass           = {{cvt|555|kg|lb}}
| payload_mass       = {{cvt|50|kg|lb}}
| dimensions         = {{cvt|1.0|x|3.0|x|2.3|m|ft}}
| power              = 343 [[Watt|W]] (at closest approach)
| launch_date        = 12 August 2018, 07:31 UTC {{r|NYT-20180812-kc}}<ref name="launch date">{{cite web|url=https://www.nasa.gov/image-feature/parker-solar-probe-ready-for-launch-on-mission-to-the-sun|title=Parker Solar Probe Ready for Launch on Mission to the Sun|publisher=[[NASA]]|date=10 August 2018|access-date=10 August 2018|archive-date=March 8, 2021|archive-url=https://web.archive.org/web/20210308160828/http://www.nasa.gov/image-feature/parker-solar-probe-ready-for-launch-on-mission-to-the-sun/|url-status=live}} {{PD-notice}}</ref>
| launch_rocket      = [[Delta IV Heavy]] / [[Star (rocket stage)|Star-48BV]]<ref name="Delta 4">{{cite news|url=http://spaceflightnow.com/2015/03/18/delta-4-heavy-selected-for-launch-of-solar-probe/|title=Delta 4-Heavy selected for launch of solar probe|work=Spaceflight Now|last=Clark|first=Stephen|date=March 18, 2015|access-date=March 18, 2015|archive-date=November 16, 2018|archive-url=https://web.archive.org/web/20181116033928/https://spaceflightnow.com/2015/03/18/delta-4-heavy-selected-for-launch-of-solar-probe/|url-status=live}}</ref>
| launch_site        = [[Cape Canaveral Air Force Station|Cape Canaveral]], [[Cape Canaveral Space Launch Complex 37|SLC-37]]
| launch_contractor  = [[United Launch Alliance]]
| orbit_reference    = [[Heliocentric orbit]]
| orbit_inclination  = 3.4°
| orbit_period       = 88 days
| orbit_semimajor    = {{convert|0.388|AU|AU+e6km+e6mi|abbr=unit|order=out}}
| orbit_apoapsis     = {{convert|0.73|AU|AU+e6km+e6mi|abbr=unit|order=out}}<ref name=feasible>{{cite report|author=Applied Physics Laboratory|title=Feasible Mission Designs for Solar Probe Plus to Launch in 2015, 2016, 2017, or 2018|publisher=[[Johns Hopkins University]]|url=https://www.physics.umd.edu/courses/Phys410/Anlage_Spring13/2015-2018missions.pdf|date=November 19, 2008 |archive-url=https://web.archive.org/web/20211221163952/https://www.physics.umd.edu/courses/Phys410/Anlage_Spring13/2015-2018missions.pdf |archive-date=December 21, 2021 |url-status=live }} {{PD-notice}}</ref>
| orbit_periapsis    = {{convert|9.86|solar radius|AU+e6km+e6mi+solar radius|abbr=unit|order=out|sigfig=2}}{{refn|group=note|Mission planning used a perihelion of {{cvt|9.5|solar radius|Gm+e6mi|lk=in}}, or {{cvt|8.5|solar radius|Gm+e6mi}} altitude above the surface,{{r|feasible}} but later documents all say {{solar radius|9.86}}. The exact value will not be finalized until the seventh Venus gravity assist in 2024. Mission planners might decide to alter it slightly before then.}}
| apsis              = helion
| trans_band         = [[Ka band|K<sub>a</sub>-band]]<br />[[X-band]]
| interplanetary     = [[Sun]]
| instruments_list   = {{Infobox spaceflight/Instruments
  |acronym1 = [[SWEAP]]     |name1 = Solar Wind Electrons Alphas and Protons Investigation
  |acronym2 = SPC       |name2 = Solar Probe Cup
  |acronym3 = SPAN      |name3 = Solar Probe Analyzers
  |acronym4 = [[WISPR]]    |name4 = Wide-field Imager for Solar Probe
  |acronym5 = [[FIELDS]]|name5 = Electromagnetic Fields Investigation
  |acronym6 = [[Integrated Science Investigation of the Sun|IS☉IS]] |name6 = Integrated Science Investigation of the Sun Energetic Particle Instruments
  }}
| insignia           = Parker Solar Probe insignia.png
| insignia_size      = 150x150px
| insignia_alt       = Artwork of the spacecraft next to the Sun, enclosed in a circle with a yellow border. The words "Parker Solar Probe" are placed around the interior of the border, while the words "a mission to touch the Sun" are written inline in a smaller font in the bottom right of the image.
| insignia_caption   = The official insignia for the mission.
| programme          = '''[[Large Strategic Science Missions]]'''<br><small>''Heliophysics Division''</small>
| previous_mission   = [[Magnetospheric Multiscale Mission]]
| next_mission       = 
| programme2         = '''''[[Living With a Star]]'' program'''
| previous_mission2  = [[Van Allen Probes]]
| next_mission2      = [[Solar Orbiter]]
}}
The '''Parker Solar Probe''' ('''PSP'''; previously '''Solar Probe''', '''Solar Probe Plus''' or '''Solar Probe+''')<ref name="bbc22jl18">{{cite news|url=https://www.theguardian.com/science/2018/jul/22/parker-solar-probe-set-the-controls-for-the-edge-of-the-sun|title=Parker Solar Probe: set the controls for the edge of the sun...|work=The Guardian|first=Stuart|last=Clark|date=July 22, 2018|access-date=July 22, 2018|archive-date=December 3, 2020|archive-url=https://web.archive.org/web/20201203015608/https://www.theguardian.com/science/2018/jul/22/parker-solar-probe-set-the-controls-for-the-edge-of-the-sun|url-status=live}}</ref> is a [[NASA]] [[space probe]] launched in 2018 with the mission of making observations of the [[Stellar corona|outer corona]] of the [[Sun]]. It will approach to within 9.86 [[solar radius|solar radii]] (6.9 million km or 4.3 million miles)<ref name="PressKit">{{cite web|url=https://www.nasa.gov/sites/default/files/atoms/files/parkersolarprobe_presskit_august2018_final.pdf|title=NASA Press Kit: Parker Solar Probe|date=August 2018|website=nasa.gov|publisher=NASA|access-date=15 August 2018|archive-date=September 1, 2020|archive-url=https://web.archive.org/web/20200901085825/https://www.nasa.gov/sites/default/files/atoms/files/parkersolarprobe_presskit_august2018_final.pdf|url-status=live}} {{PD-notice}}</ref><ref>{{cite web|url=https://directory.eoportal.org/web/eoportal/satellite-missions/p/psp|title=Parker Solar Probe—eoPortal Directory—Satellite Missions|website=directory.eoportal.org|access-date=October 6, 2018|archive-date=July 1, 2017|archive-url=https://web.archive.org/web/20170701232946/https://directory.eoportal.org/web/eoportal/satellite-missions/p/psp|url-status=live}}</ref> from the center of the Sun, and by 2025 will travel, at closest approach, as fast as {{convert|430000|mph|kph|abbr=on|order=flip}} or 191 km/s, which is 0.064% <!-- Do NOT "correct" this figure.  0.064% IS CORRECT.  Notice the percent sign; 0.00064 EQUALS 0.064%.  If this is not clear, please see the discussions on the Talk Page. --> the [[speed of light]].<ref name="PressKit"/><ref name="NASA-20180809">{{cite web|last=Garner|first=Rob|title=Parker Solar Probe: Humanity's First Visit to a Star|url=https://www.nasa.gov/content/goddard/parker-solar-probe-humanity-s-first-visit-to-a-star|date=August 9, 2018|publisher=[[NASA]]|access-date=August 9, 2018|archive-date=June 5, 2017|archive-url=https://web.archive.org/web/20170605051919/https://www.nasa.gov/content/goddard/parker-solar-probe-humanity-s-first-visit-to-a-star|url-status=live}} {{PD-notice}}</ref> It is the fastest object ever built.<ref>{{cite web|url=https://www.cnet.com/home/energy-and-utilities/nasa-solar-probe-becomes-fastest-object-ever-built-as-it-touches-the-sun/|title=NASA solar probe becomes fastest object ever built as it 'touches the sun'|date=May 2, 2021|publisher=CNET|access-date=June 17, 2022}}</ref>

The project was announced in the fiscal 2009 budget year. [[Johns Hopkins University]] [[Applied Physics Laboratory]] designed and built the spacecraft,<ref>{{cite news|url=http://www.baltimoresun.com/news/science/bs-md-apl-nasa-solar-probe-20180812-story.html|title=NASA probe operated from Johns Hopkins lab in Laurel rockets toward sun for closest look yet|last1=Bogel-Burroughs|first1=Nicholas|work=[[The Baltimore Sun]]|last2=Dunn|first2=Marcia|access-date=August 16, 2018|archive-date=October 16, 2018|archive-url=https://web.archive.org/web/20181016234749/http://www.baltimoresun.com/news/science/bs-md-apl-nasa-solar-probe-20180812-story.html|url-status=dead}}</ref> which was launched on 12 August 2018.<ref name="NYT-20180812-kc">{{cite news|last=Chang|first=Kenneth|title=Parker Solar Probe Launches on NASA Voyage to 'Touch the Sun'|url=https://www.nytimes.com/2018/08/11/science/parker-solar-probe-launch.html|date=August 12, 2018|work=[[The New York Times]]|access-date=August 12, 2018|archive-date=December 24, 2021|archive-url=https://web.archive.org/web/20211224041603/https://www.nytimes.com/2018/08/11/science/parker-solar-probe-launch.html|url-status=live}}</ref> It became the first NASA spacecraft named after a living person, honoring physicist [[Eugene Parker|Eugene Newman Parker]], [[professor emeritus]] at the [[University of Chicago]].<ref>{{cite web|url=https://www.nasa.gov/feature/goddard/2017/nasa-renames-solar-probe-mission-to-honor-pioneering-physicist-eugene-parker|title=NASA Renames Solar Probe Mission to Honor Pioneering Physicist Eugene Parker|publisher=NASA|date=May 31, 2017|access-date=May 31, 2017|archive-date=May 31, 2017|archive-url=https://web.archive.org/web/20170531213454/https://www.nasa.gov/feature/goddard/2017/nasa-renames-solar-probe-mission-to-honor-pioneering-physicist-eugene-parker|url-status=live}} {{PD-notice}}</ref>

A [[memory card]] containing names submitted by over 1.1 million people was mounted on a plaque and installed below the spacecraft's high-gain antenna.<ref name="million-names">{{cite news|title=More Than 1.1 Million Names Installed on NASA's Parker Solar Probe|url=https://www.nasa.gov/feature/goddard/2018/more-than-11-million-names-installed-on-nasa-s-parker-solar-probe|website=[[NASA]]|date=May 21, 2018|access-date=December 17, 2021|archive-date=December 16, 2021|archive-url=https://web.archive.org/web/20211216041859/https://www.nasa.gov/feature/goddard/2018/more-than-11-million-names-installed-on-nasa-s-parker-solar-probe/|url-status=live}}</ref> The card also contains photos of Parker and a copy of his 1958 scientific paper predicting important aspects of [[solar physics]].<ref>{{cite web|url=https://directory.eoportal.org/web/eoportal/satellite-missions/p/psp|title=NASA Press Kit: Parker Solar Probe|publisher=NASA|access-date=August 15, 2018|archive-date=July 1, 2017|archive-url=https://web.archive.org/web/20170701232946/https://directory.eoportal.org/web/eoportal/satellite-missions/p/psp|url-status=live}} {{PD-notice}}</ref>

On 29 October 2018, at about 18:04 UTC, the spacecraft became the closest ever artificial object to the Sun. The previous record, {{convert|26.55|e6mi|abbr=off|order=flip}} from the Sun's surface, was set by the ''[[Helios (spacecraft)|Helios 2]]'' spacecraft in April 1976.<ref>{{cite web|url=https://www.foxnews.com/science/nasas-parker-solar-probe-breaks-record-becomes-closest-spacecraft-to-the-sun|title=NASA's Parker Solar Probe breaks record, becomes closest spacecraft to the Sun|first=James|last=Rogers|date=October 29, 2018|website=Fox News|access-date=October 29, 2018|archive-date=March 25, 2021|archive-url=https://web.archive.org/web/20210325163510/https://www.foxnews.com/science/nasas-parker-solar-probe-breaks-record-becomes-closest-spacecraft-to-the-sun|url-status=live}}</ref> At its [[perihelion]] on 27 September 2023, the PSP's closest approach was {{convert|4.51|e6mi|abbr=off|order=flip}},<ref name=apo23/> reaching this distance again on 29 March 2024.<ref>{{cite web |title=Hey Nineteen! Parker Solar Probe Completes Record-Matching Sun Flyby |url=https://parkersolarprobe.jhuapl.edu/News-Center/Show-Article.php?articleID=196 |website=parkersolarprobe.jhuapl.edu |access-date=12 May 2024}}</ref> This will be surpassed after the remaining [[flyby (spaceflight)|flyby]] of [[Venus]].

== History ==
The Parker Solar Probe concept originates in the 1958 report by the Fields and Particles Group, Committee 8 of the [[National Academy of Sciences]]' Space Science Board,<ref>{{cite book|title=First Among Equals: The Selection of NASA Space Science Experiments|chapter=3.2.2: Physics of Fields and Particles in Space|first=John E.|last=Naugle|series=The NASA History Series|year=1991|page=34|url=https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19910018746.pdf#page=49|chapter-url=https://history.nasa.gov/SP-4215/ch3-2.html#3.2.2|lccn=91-13286|id=NASA SP-4215|access-date=February 11, 2020|archive-date=July 29, 2020|archive-url=https://web.archive.org/web/20200729104156/https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19910018746.pdf#page=49|url-status=live}} {{PD-notice}}</ref><ref>{{cite press release|title=National Academy of Sciences Establishes Space Science Board|date=August 3, 1958|first=Detlev W.|last=Bronk|author-link=Detlev Bronk|publisher=National Academy of Sciences; National Research Council|url=https://sites.nationalacademies.org/cs/groups/ssbsite/documents/webpage/ssb_052237.pdf|access-date=February 11, 2020|archive-date=March 3, 2019|archive-url=https://web.archive.org/web/20190303100301/http://sites.nationalacademies.org/cs/groups/ssbsite/documents/webpage/ssb_052237.pdf|url-status=live}} {{PD-notice}}</ref><ref name="Guo2021">{{cite journal |last1=Guo |first1=Yanping |last2=Thompson |first2=Paul |last3=Wirzburger |first3=John |last4=Pinkine |first4=Nick |last5=Bushman |first5=Stewart |last6=Goodson |first6=Troy |last7=Haw |first7=Rob |last8=Hudson |first8=James |last9=Jones |first9=Drew |last10=Kijewski |first10=Seth |last11=Lathrop |first11=Brian |last12=Lau |first12=Eunice |last13=Mottinger |first13=Neil |last14=Ryne |first14=Mark |last15=Shyong |first15=Wen-Jong |last16=Valerino |first16=Powtawche |last17=Whittenburg |first17=Karl |title=Execution of Parker Solar Probe's unprecedented flight to the Sun and early results |journal=Acta Astronautica |date=February 2021 |volume=179 |pages=425–438 |doi=10.1016/j.actaastro.2020.11.007|doi-access=free }}</ref> which proposed several space missions including "a solar probe to pass inside the orbit of Mercury to study the particles and fields in the vicinity of the Sun".<ref name=McNutt>{{cite conference|title=Solar Probe Plus: A Scientific Investigation Sixty Years in the Making|first=Ralph L. Jr.|last=McNutt|date=December 15, 2015|conference=American Geophysical Union Fall Meeting|bibcode=2015AGUFMSH24A..01M|url=https://agu.confex.com/agu/fm15/webprogram/Paper61485.html|access-date=February 11, 2020|archive-date=September 25, 2021|archive-url=https://web.archive.org/web/20210925002929/https://agu.confex.com/agu/fm15/webprogram/Paper61485.html|url-status=live}}</ref><ref>{{cite news|title=A 60-year race to touch the Sun|first=Ian|last=Graber-Stiehl|date=August 13, 2018|journal=[[Astronomy (magazine)|Astronomy]]|url=http://astronomy.com/news/2018/08/60-year-race-to-the-sun|access-date=February 11, 2020|archive-date=January 24, 2020|archive-url=https://web.archive.org/web/20200124144616/http://www.astronomy.com/news/2018/08/60-year-race-to-the-sun|url-status=live}}</ref> 

Studies in the 1970s and 1980s reaffirmed its importance,{{r|McNutt}} but it was always postponed due to cost.<!-- Ref: https://www.youtube.com/watch?v=pG44eEjYmFg&t=1280 Justin Casper - First Discoveries by Parker Solar Probe and the SWEAP Investigation (CfA Colloquium, January 20, 2020)--> A cost-reduced Solar Orbiter mission was studied in the 1990s, and a more capable Solar Probe mission served as one of the centerpieces of the Outer Planet/Solar Probe (OPSP) program formulated by [[NASA]] in the late 1990s. The first three missions of the program were planned to be: the ''Solar Orbiter'', the [[Pluto]] and [[Kuiper belt]] reconnaissance [[Pluto Kuiper Express]] mission, and the [[Europa Orbiter]] astrobiology mission focused on [[Europa (moon)|Europa]].<ref>{{cite press release |title=McNamee Chosen to Head NASA's Outer Planets/Solar Probe Projects|url=http://www.jpl.nasa.gov/news/news.php?feature=5174|publisher=Jet Propulsion Laboratory|access-date=January 2, 2017|archive-url=https://web.archive.org/web/20170102204522/http://www.jpl.nasa.gov/news/news.php?feature=5174|archive-date=January 2, 2017|date=April 15, 1998|url-status=live}}</ref><ref name=opsp>{{cite conference|last1=Maddock|first1=Robert W.|last2=Clark|first2=Karla B.|last3=Henry|first3=Curt A.|last4=Hoffman|first4=Pamela J.|title=The Outer Planets/Solar Probe Project: "Between an ocean, a rock, and a hot place"|url=https://trs.jpl.nasa.gov/bitstream/handle/2014/20792/98-1875.pdf|conference=1999 IEEE Aerospace Conference|date=March 7, 1999|bibcode=1999aero....1..383M|access-date=August 12, 2018|archive-date=May 11, 2019|archive-url=https://web.archive.org/web/20190511123116/https://trs.jpl.nasa.gov/bitstream/handle/2014/20792/98-1875.pdf|url-status=live}}</ref>

[[File:Evolution of PSP design.jpg|thumb|left|Evolution of PSP design]]

The original Solar Probe design used a [[gravity assist]] from [[Jupiter]] to enter a [[polar orbit]] which dropped almost directly toward the Sun. While this explored the important solar poles and came even closer to the surface (3 {{solar radius}}, a perihelion of 4 {{solar radius}}),{{r|opsp}} the extreme variation in solar irradiance made for an expensive mission and required a [[radioisotope thermal generator]] for power. The trip to Jupiter also made for a long mission, {{frac|3|1|2}} years to first solar perihelion, 8 years to second.

Following the appointment of [[Sean O'Keefe]] as [[List of administrators and deputy administrators of NASA|Administrator of NASA]], the entirety of the OPSP program was canceled as part of President [[George W. Bush]]'s request for the [[2003 United States federal budget]].<ref name="space.com-1">{{cite web|last1=Berger|first1=Brian|title=NASA Kills Europa Orbiter; Revamps Planetary Exploration |url=http://www.space.com/news/nasa_budget_020204.html|website=space.com|publisher=[[Purch Group]]|access-date=January 2, 2017|archive-url=https://web.archive.org/web/20020210015816/http://www.space.com/news/nasa_budget_020204.html|archive-date=February 10, 2002|date=February 4, 2002|url-status=dead}}</ref> Administrator O'Keefe cited a need for a restructuring of NASA and its projects, falling in line with the Bush Administration's wish for NASA to refocus on "research and development, and addressing management shortcomings".<ref name="space.com-1"/>

In the early 2010s, plans for the Solar Probe mission were incorporated into a lower-cost ''Solar Probe Plus''.<ref>{{cite web|last1=Fazekas|first1=Andrew|title=New NASA Probe to Dive-bomb the Sun |url=https://news.nationalgeographic.com/news/2010/09/100909-science-space-sun-new-nasa-solar-probe-plus-dive-bomb/|website=National Geographic|publisher=21st Century Fox/National Geographic Society|access-date=January 2, 2017|archive-url=https://web.archive.org/web/20170102202026/http://news.nationalgeographic.com/news/2010/09/100909-science-space-sun-new-nasa-solar-probe-plus-dive-bomb/|archive-date=January 2, 2017|url-status=dead|date=September 10, 2010}}</ref> The redesigned mission uses multiple Venus gravity assists for a more direct flight path, which can be powered by [[Solar panels on spacecraft|solar panels]]. It has a higher perihelion, reducing the demands on the thermal protection system.

In May 2017, the spacecraft was renamed the Parker Solar Probe in honor of astrophysicist [[Eugene Parker|Eugene Newman Parker]],<ref name="NYT-20180810kc">{{cite news|last=Chang|first=Kenneth|title=NASA's Parker Solar Probe Is Named for Him. 60 Years Ago, No One Believed His Ideas About the Sun|url=https://www.nytimes.com/2018/08/10/science/eugene-parker-solar-wind-nasa-probe.html|date=August 10, 2018|work=[[The New York Times]]|access-date=January 16, 2024|archive-date=August 11, 2018|archive-url=https://web.archive.org/web/20180811211441/https://www.nytimes.com/2018/08/10/science/eugene-parker-solar-wind-nasa-probe.html|url-status=live|quote=It is the Parker Solar Probe, named after Dr. Parker, now 91 years old. It is the first time that NASA has named a mission for a living person.}}</ref><ref>{{cite news|url=https://www.wired.co.uk/article/nasa-sun-mission-parker-solar-probe|title=Nasa's mission to Sun renamed after astrophysicist behind solar wind theory|last=Burgess|first=Matt|magazine=Wired|date=May 31, 2017|access-date=January 1, 2018|archive-date=November 25, 2020|archive-url=https://web.archive.org/web/20201125060335/https://www.wired.co.uk/article/nasa-sun-mission-parker-solar-probe|url-status=live}}</ref> who had proposed the existence of [[Nanoflare|nanoflares]] as an explanation of [[coronal heating]]<ref>{{Cite web |last=Chhabra |first=Sherry |date=2022-04-30 |title=Obituary: Eugene N. Parker (1927 - 2022) |url=https://solarnews.nso.edu/obituary-eugene-n-parker-1927-2022/ |access-date=2024-01-07 |website=SolarNews |language=en-US}}</ref> as well as having developed a mathematical theory that predicted the existence of [[solar wind]].<ref>{{Cite web |date=2022-03-16 |title=Eugene Parker, 'legendary figure' in solar science and namesake of Parker Solar Probe, 1927-2022 {{!}} University of Chicago News |url=https://news.uchicago.edu/story/eugene-parker-legendary-figure-solar-science-and-namesake-parker-solar-probe-1927-2022 |access-date=2024-01-07 |website=news.uchicago.edu |language=en}}</ref> The solar probe cost NASA US$1.5 billion.<ref>[https://www.space.com/41424-parker-solar-probe-sun-science.html How NASA's New Solar Probe Will 'Touch' the Sun on Historic Mission] {{Webarchive|url=https://web.archive.org/web/20210127035614/https://www.space.com/41424-parker-solar-probe-sun-science.html |date=January 27, 2021 }}. Meghan Bartels, Space.com. August 9, 2018.</ref><ref>[http://www.satnews.com/story.php?number=258258659&menu=2 Successful Launch of NASA's Parker Solar Probe.] {{Webarchive|url=https://web.archive.org/web/20190219093915/http://satnews.com/story.php?number=258258659&menu=2 |date=February 19, 2019 }} ''SatNews Daily''. August 12, 2018.</ref> The launch rocket bore a dedication in memory of [[Applied Physics Laboratory|APL]] engineer Andrew A. Dantzler who had worked on the project.<ref>{{cite news|title=Parker Solar Probe Begins Mission on Rocket Dedicated to APL's Andy Dantzler|url=http://parkersolarprobe.jhuapl.edu/News-Center/Show-Article.php?articleID=102|publisher=The Johns Hopkins University Applied Physics Laboratory|date=September 26, 2018|access-date=December 3, 2018|archive-date=November 26, 2020|archive-url=https://web.archive.org/web/20201126174556/http://parkersolarprobe.jhuapl.edu/News-Center/Show-Article.php?articleID=102|url-status=live}}</ref>

== Spacecraft ==
The Parker Solar Probe is the first spacecraft to fly into the low solar corona. It will assess the structure and dynamics of the Sun's coronal plasma and magnetic field, the energy flow that heats the solar corona and impels the solar wind, and the mechanisms that accelerate energetic particles.

The spacecraft's systems are protected from the extreme heat and radiation near the [[Sun]] by a solar shield. Incident solar radiation at perihelion is approximately {{val|{{#expr:475*1.361 round -1}}|u=kW |up=m2}}, or 475 times the [[solar constant|intensity at Earth orbit]].{{r|extreme|Fox 2016|p2=31}} The solar shield is hexagonal, mounted on the Sun-facing side of the spacecraft, {{cvt|2.3|m}} in diameter,{{r|jhuapl}} {{cvt|11.4|cm}} thick, and is made of two panels of [[reinforced carbon–carbon]] composite with a lightweight {{convert|4.5|in|cm|disp=flip|sp=us|adj=mid|-thick}} carbon foam core,<ref name="svs">{{cite web |title=GMS: Cutting-Edge Heat Shield Installed on NASA's Parker Solar Probe |url=https://svs.gsfc.nasa.gov/12992 |website=svs.gsfc.nasa.gov |access-date=4 November 2022 |language=en |date=5 July 2018}} {{PD-notice}}</ref> which is designed to withstand temperatures outside the spacecraft of about {{cvt|2500|F|C|order=flip}}.<ref name=extreme/> The shield weighs only {{convert|160|lbs|kg|order=flip}} and keeps the spacecraft's instruments at {{cvt|85|F|C|order=flip}}.<ref name="svs"/>

A white reflective [[Aluminium oxide|alumina]] surface layer minimizes absorption. The spacecraft systems and [[scientific instrument]]s are located in the central portion of the shield's shadow, where direct radiation from the Sun is fully blocked. If the shield were not between the spacecraft and the Sun, the probe would be damaged and become inoperative within tens of seconds. As radio communication with Earth will take about eight minutes in each direction, the Parker Solar Probe has to act autonomously and rapidly to protect itself. This will be done using four light sensors to detect the first traces of direct [[sunlight]] coming from the shield limits and engaging movements from [[reaction wheel]]s to reposition the spacecraft within the shadow again. According to project scientist Nicky Fox, the team describe it as "the most autonomous spacecraft that has ever flown".{{r|bbc22jl18}}

The primary power for the mission is a dual system of [[Solar panels on spacecraft|solar panels]] ([[Photovoltaic system|photovoltaic arrays]]). A primary photovoltaic array, used for the portion of the mission outside {{Val|0.25|u=au}}, is retracted behind the shadow shield during the close approach to the Sun, and a much smaller secondary array powers the spacecraft through closest approach. This secondary array uses pumped-fluid cooling to maintain [[operating temperature]] of the solar panels and instrumentation.<ref>{{cite conference|url=https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20090004577.pdf|title=Solar Power System Design for the Solar Probe+ Mission|conference=6th International Energy Conversion Engineering Conference|location=Cleveland, Ohio.|first1=Geoffrey A.|last1=Landis|first2=Paul C. |last2=Schmitz|first3=James|last3=Kinnison|first4=Martin|last4=Fraeman|first5=Lew|last5=Roufberg|first6=Steve|last6=Vernon|first7=Melissa|last7=Wirzburger|display-authors=1|date=July 28–30, 2008|id=AIAA 2008-5712|access-date=July 25, 2018|archive-date=November 11, 2020|archive-url=https://web.archive.org/web/20201111220403/https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20090004577.pdf|url-status=live}} {{PD-notice}}</ref><ref>{{cite web|url=https://www.techexplorist.com/traveling-sun-parker-solar-probe-melt/15586/|title=Traveling to the Sun: Why won't Parker Solar Probe melt?|first=Pranjal|last=Mehar|website=Tech Explorist|date=July 20, 2018|access-date=August 15, 2018|archive-date=December 29, 2019|archive-url=https://web.archive.org/web/20191229084547/https://www.techexplorist.com/traveling-sun-parker-solar-probe-melt/15586/|url-status=live}}</ref>

<gallery mode="packed" heights="180">
File:KSC-20180605-PH GEB01 0116 (41073463690).jpg|A light bar testing in the [[Astrotech Corporation|Astrotech]] processing facility.
File:Parker Solar Probe mated.jpg|Parker Solar Probe mated to its third stage rocket motor
File:Parker Solar Probe.webm|PSP during extensive environmental testing.
File:Parker fairing.jpg|PSP encapsulated in fairing.
File:NASA's Parker Solar Probe Mission Launches to Touch the Sun.webm|The launch of the probe.
</gallery>

== Trajectory ==
[[File:Animation of Parker Solar Probe trajectory.gif|thumb|right|An animation of the Parker Solar Probe{{'s}} trajectory from August 7, 2018, to August 29, 2025:<br />{{legend2|magenta|Parker Solar Probe}}{{·}}{{legend2|Yellow|[[Sun]]}}{{·}}{{legend2|Lime|[[Mercury (planet)|Mercury]]}}{{·}}{{legend2|Cyan|[[Venus]]}}{{·}}{{legend2|RoyalBlue|[[Earth]]}}<br />For more detailed animation, see [[:File:Animation of Parker Solar Probe trajectory.webm|this video.]]]]

The Parker Solar Probe mission design uses repeated [[gravity assist]]s at [[Venus]] to incrementally decrease its orbital [[Apsis|perihelion]] to achieve a final altitude (above the surface) of approximately 8.5 solar radii, or about {{cvt|6|e6km|e6mi+au|abbr=off}}.<ref name=jhuapl>{{cite web|title=Solar Probe Plus: A NASA Mission to Touch the Sun|url=http://solarprobe.jhuapl.edu/|publisher=Johns Hopkins University Applied Physics Laboratory|date=September 4, 2010|access-date=September 30, 2010|archive-date=March 1, 2021|archive-url=https://web.archive.org/web/20210301043541/http://solarprobe.jhuapl.edu///|url-status=live}}</ref> The spacecraft trajectory will include seven Venus flybys over nearly seven years to gradually shrink its elliptical orbit around the Sun, for a total of 24 orbits.{{r|extreme}} The near Sun radiation environment is predicted to cause spacecraft charging effects, radiation damage in materials and electronics, and communication interruptions, so the orbit will be highly elliptical with short times spent near the Sun.{{r|Fox 2016}}

The trajectory requires high launch energy, so the probe was launched on a [[Delta IV Heavy]] [[launch vehicle]] and an upper stage based on the [[Star (rocket stage)|Star 48BV]] solid rocket motor.{{r|Fox 2016}} Interplanetary [[gravity assist]]s will provide further deceleration relative to its [[heliocentric orbit]], which will result in a heliocentric speed record at [[perihelion]].{{r|Delta 4}}<ref>{{cite web|last1=Scharf|first1=Caleb A.|title=The Fastest Spacecraft Ever?|url=https://blogs.scientificamerican.com/life-unbounded/the-fastest-spacecraft-ever/|website=Scientific American Blog Network|access-date=July 21, 2017|archive-date=December 27, 2021|archive-url=https://web.archive.org/web/20211227074426/https://blogs.scientificamerican.com/life-unbounded/the-fastest-spacecraft-ever/|url-status=live}}</ref> As the probe passes around the [[Sun]], it will achieve a velocity of up to {{cvt|200|km/s}}, which will temporarily make it the fastest human-made object, almost three times as fast as the previous record holder, [[Helios (spacecraft)#Helios-B|Helios-2]].<ref>{{cite web|url=http://www.aerospaceweb.org/question/performance/q0023.shtml|title=Aircraft Speed Records|date=November 13, 2014|publisher=Aerospaceweb.org|access-date=March 7, 2017|archive-date=December 23, 2018|archive-url=https://web.archive.org/web/20181223182053/http://www.aerospaceweb.org/question/performance/q0023.shtml|url-status=live}}</ref><ref>{{cite web|url=http://www.guinnessworldrecords.com/world-records/66135-fastest-spacecraft-speed|title=Fastest spacecraft speed|date=July 26, 2015|website=guinnessworldrecords.com |archive-url=https://web.archive.org/web/20161219024804/http://www.guinnessworldrecords.com/world-records/66135-fastest-spacecraft-speed|archive-date=December 19, 2016|url-status=dead}}</ref><ref>{{Citation|title=Parker Solar Probe – Check123, Video Encyclopedia|url=https://www.check123.com/videos/13450-parker-solar-probe|access-date=June 1, 2017|archive-url=https://web.archive.org/web/20170810211059/https://www.check123.com/videos/13450-parker-solar-probe|archive-date=August 10, 2017|url-status=dead}}</ref> 

Launch injection was very close to the modelled one, but nevertheless required path correction. Trajectory was re-optimized after the launch to save the fuel. The first Venus flyby was only 52 days after the launch; three trajectory correction maneuvers were performed in this window.<ref name="Guo2021"/>

On September 27, 2023, the spacecraft traveled at 394,736 miles per hour (176.5 km/s), fast enough to fly from New York to Tokyo in just over a minute.<ref name=apo23>{{cite web |last1=Apodaca|first1=Desiree |title=For the Record: Parker Solar Probe Sets Distance, Speed Marks on 17th Swing by the Sun |url=https://blogs.nasa.gov/parkersolarprobe/2023/09/28/for-the-record-parker-solar-probe-sets-distance-speed-marks-on-17th-swing-by-the-sun/ |website=blogs.nasa.gov |access-date=2023-10-12 |date=2023-09-28}}</ref> [[Kepler's laws of planetary motion|Like every object in an orbit]], due to gravity the spacecraft will accelerate as it nears perihelion, then slow down again afterward until it reaches its [[Apsis|aphelion]].

== Science goals ==
[[File:Sun's Apparent Size as Seen From Earth vs From Solar Probe Plus's orbit.png|thumb|An apparent size of the Sun as seen from the Parker Solar Probe at perihelion compared to its apparent size seen from Earth]]

The goals of the mission are:<ref name="Fox 2016"/>

* Trace the flow of energy that heats the [[Stellar corona|solar corona]] and accelerates the [[solar wind]].
*# How is energy from the lower solar atmosphere transferred to, and dissipated in, the corona and solar wind?
*# What processes shape the non-equilibrium velocity distributions observed throughout the heliosphere?
*# How do the processes in the corona affect the properties of the solar wind in the heliosphere?
* Determine the structure and dynamics of the plasma and [[Sun#Magnetic field|magnetic fields]] at the sources of the solar wind.
*# How does the magnetic field in the solar wind source regions connect to the photosphere and the heliosphere?
*# Are the sources of the solar wind steady or intermittent?
*# How do the observed structures in the corona evolve into the solar wind?
* Explore mechanisms that accelerate and transport energetic particles.
*# What are the roles of shocks, reconnection, waves, and turbulence in the acceleration of energetic particles?
*# What are the source populations and physical conditions necessary for energetic particle acceleration?
*# How are energetic particles transported in the corona and heliosphere?<ref name="Fox 2016"/>

== Instruments ==
[[File:Parker-Solar-Probe-Ram-Facing-View.png|thumb|upright=1.2|Schematic view of all PSP's instruments]]
[[File:Parker Solar Probe 3D model.stl|thumb|upright=1.2|Parker Solar Probe 3D model]]

Parker Solar Probe has four main instruments:<ref name="nasa-instruments">{{cite web |last1=Garner |first1=Rob |title=Parker Solar Probe Instruments |url=https://www.nasa.gov/content/goddard/parker-solar-probe-instruments |website=NASA |access-date=3 August 2022 |date=12 July 2018 |archive-date=August 11, 2018 |archive-url=https://web.archive.org/web/20180811133110/https://www.nasa.gov/content/goddard/parker-solar-probe-instruments/ |url-status=dead }}{{PD-notice}}</ref><ref name="jhuapl-instruments">{{cite web |title=Parker Solar Probe: Spacecraft |url=http://parkersolarprobe.jhuapl.edu/Spacecraft/index.php#Instruments |website=parkersolarprobe.jhuapl.edu |access-date=3 August 2022}}</ref>

* [[FIELDS]] (Electromagnetic Fields Investigation). The instrument suite captures the scale and shape of electric and magnetic fields in the Sun's atmosphere. FIELDS measures waves and turbulence in the inner heliosphere with high time resolution to understand the fields associated with waves, shocks and magnetic reconnection, a process by which magnetic field lines explosively realign. FIELDS measures the electric field around the spacecraft with five antennas, four of which stick out beyond the spacecraft's heat shield and into the sunlight, where they experience temperatures of {{convert|2500|F|C}}. The {{convert|2|m||adj=mid|-long|sp=us}} antennas are made of a [[niobium]] alloy, which can withstand extreme temperatures. FIELDS measures electric fields across a broad frequency range both directly and remotely. Operating in two modes, the four sunlit antennas measure the properties of the fast and slow solar wind — the flow of solar particles constantly streaming out from the Sun. The fifth antenna, which sticks out perpendicular to the others in the shade of the heat shield, helps make a three-dimensional picture of the electric field at higher frequencies. The suite also has three magnetometers to assess the magnetic field. A search coil magnetometer, or SCM, measures how the magnetic field changes over time. Two identical fluxgate magnetometers, MAGi and MAGo, measure the large-scale coronal magnetic field. The fluxgate magnetometers are specialized for measuring the magnetic field further from the Sun where it varies at a slower rate, while the search coil magnetometer is necessary closer to the Sun where the field changes quickly, as it can sample the magnetic field at a rate of two million times per second. The Principal Investigator is Stuart Bale at the [[University of California, Berkeley]].<ref name="nasa-instruments"/>
* [[Integrated Science Investigation of the Sun|IS☉IS]] (Integrated Science Investigation of the Sun). The instrument uses two complementary instruments to measure particles across a wide range of energies. By measuring electrons, protons and ions, IS☉IS will understand the particles' lifecycles — where they came from, how they became accelerated and how they move out from the Sun through interplanetary space. The two energetic particle instruments on IS☉IS are called EPI-Lo and EPI-Hi (EPI stands for Energetic Particle Instrument). EPI-Lo measures the spectra of electrons and ions and identifies carbon, oxygen, neon, magnesium, silicon, iron and two isotopes of helium, He-3 and He-4. Distinguishing between helium isotopes will help determine which of several theorized mechanisms caused the particles' acceleration. The instrument has a design with an octagonal dome body supporting 80 viewfinders. Multiple viewfinders provide a wide field of view to observe low-energy particles. An ion that enters EPI-Lo through one of the viewfinders first passes through two carbon-polyimide-aluminum foils and then encounters a solid-state detector. Upon impact, the foils produce electrons, which are measured by a microchannel plate. Using the amount of energy left by the ion's impact on the detector and the time it takes the ions to pass through the sensor identifies the species of the particles. EPI-Hi uses three particle sensors composed of stacked layers of detectors to measure particles with energies higher than those measured by EPI-Lo. The front few layers are composed of ultra-thin silicon detectors made up of geometric segments, which allows for the determination of the particle's direction and helps reduce background noise. Charged particles are identified by measuring how deep they travel into the stack of detectors and how many electrons they pull off atoms in each detector, a process called ionization. At closest approach to the Sun, EPI-Hi will be able to detect up to 100,000 particles per second. The Principal Investigator is David McComas at [[Princeton University]].<ref name="nasa-instruments"/><ref>{{cite journal|last1=McComas|first1=D.J. |last2=Alexander|first2=N.|last3=Angold|first3=N.|last4=Bale|first4=S.|last5=Beebe|first5=C.|last6=Birdwell|first6=B.|last7=Boyle|first7=M.|last8=Burgum|first8=J. M.|last9=Burnham|first9=J. A.|last10=Christian |first10=E. R.|last11=Cook|first11=W. R. |last12=Cooper|first12=S. A.|last13=Cummings|first13=A. C.|last14=Davis|first14=A. J.|last15=Desai|first15=S. I.|last16=Dickinson |first16=J.|last17=Dirks|first17=G |last18=Do|first18=D. H.|last19=Fox|first19=N.|last20=Giacalone|first20=J.|last21=Gold|first21=R. E.|last22=Gurnee|first22=R. S.|last23=Hayes|first23=J. R.|last24=Hill|first24=M. E.|last25=Kasper|first25=J. C. |last26=Kecman|first26=B.|last27=Klemic |first27=J.|last28=Krimigis|first28=S. M.|last29=Labrador|first29=A. W.|last30=Layman|first30=R. S.|last31=Leske|first31=R. A.|last32=Livi|first32=S.|last33=Mathaeus |first33=W. H.|last34=McNutt Jr.|first34=R. L.|last35=Mewaldt|first35=R. A.|last36=Mitchell|first36=D. G.|last37=Nelson|first37=K.S.|last38=Parker|first38=C.|last39=Rankin|first39=J. S.|last40=Roelof|first40=E. C.|last41=Schwadron|first41=N. A.|last42=Seifert|first42=H.|last43=Shuman|first43=S.|last44=Stokes|first44=M. R.|last45=Stone|first45=E. C.|last46=Vandergriff|first46=J. D.|last47=Velli|first47=M.|last48=von Rosenvinge|first48=T. T.|last49=Weidner|first49=S. E.|last50=Wiedenbeck|first50=M. E.|last51=Wilson IV|first51=P.|date=December 2016|title=Integrated Science Investigation of the Sun (ISIS): Design of the Energetic Particle Investigation|journal=Space Science Reviews|volume=204|issue=1–4|pages=187–156|display-authors=1|doi=10.1007/s11214-014-0059-1|bibcode=2016SSRv..204..187M|doi-access=free}}</ref>
* [[WISPR]] (Wide-field Imager for Solar Probe). These optical telescopes acquire images of the [[solar corona|corona]] and inner [[heliosphere]]. WISPR uses two cameras with radiation-hardened Active Pixel Sensor CMOS detectors. The camera's lenses are made of a radiation hard BK7, a common type of glass used for space telescopes, which is also sufficiently hardened against the impacts of dust. The Principal Investigator is Russell Howard at the [[Naval Research Laboratory]].<ref name="nasa-instruments"/>
* [[SWEAP]] (Solar Wind Electrons Alphas and Protons). This investigation will count the electrons, protons and helium ions, and measure their properties such as velocity, density, and temperature. Its main instruments are the Solar Probe Analyzers (SPAN, two [[electrostatic analyzer]]s) and the Solar Probe Cup (SPC). SPC is a [[Faraday cup]], a metal device that can catch charged particles in a vacuum. Peeking over the heat shield to measure how electrons and ions are moving, the cup is exposed to the full light, heat and energy of the Sun. The cup is composed of a series of highly transparent grids — one of which uses variable high voltages to sort the particles — above several collector plates, which measure the particles' properties. The variable voltage grid also helps sort out background noise, such as cosmic rays and photoionized electrons, which could otherwise bias the measurements. The grids, located near the front of the instrument, can reach temperatures of {{convert|3000|F|C}}, glowing red while the instrument makes measurements. The instrument uses pieces of sapphire to electrically isolate different components within the cup. As it passes close to the Sun, SPC takes up to 146 measurements per second to accurately determine the velocity, density and temperature of the Sun's plasma. SPAN is composed of two instruments, SPAN-A and SPAN-B, which have wide fields of view to allow them to see the parts of space not observed by SPC. Particles encountering the detectors enter a maze that sends the particles through a series of deflectors and voltages to sort the particles based on their mass and charge. While SPAN-A has two components to measure both electrons and ions, SPAN-B looks only at electrons. The Principal Investigator is Justin Kasper at the [[University of Michigan]] and the [[Smithsonian Astrophysical Observatory]].<ref name="nasa-instruments"/>

An additional theoretical investigation named Heliospheric origins with Solar Probe Plus (HeliOSPP) starting from 2010 and ending in 2024 has the role of providing theoretical input and independent assessment of scientific performance to the Science Working Group (SWG) and the SPP Project to maximize the scientific return from the mission. The Principal Investigator is Marco Velli at the [[University of California, Los Angeles]] and the [[Jet Propulsion Laboratory]]; he also serves as the Observatory Scientist for the mission.<ref name="Fox 2016">{{cite journal| last1=Fox|first1=N.J.| last2=Velli|first2=M.C.| last3=Bale|first3=S.D.| last4=Decker|first4=R.|last5=Driesman|first5=A.|last6=Howard|first6=R.A. |last7=Kasper|first7=J.C.| last8=Kinnison|first8=J.| last9=Kusterer|first9=M.| first10=D.|last10=Lario| first11=M.K.|last11=Lockwood| first12=D.J.|last12=McComas| first13=N.E.| last13=Raouafi| first14=A.| last14=Szabo | date = November 11, 2015|title=The Solar Probe Plus Mission: Humanity's First Visit to Our Star|journal=Space Science Reviews| volume=204| issue=1–4| pages=7–48| doi=10.1007/s11214-015-0211-6| issn=0038-6308 | bibcode=2016SSRv..204....7F | doi-access=free}} [[File:CC-BY icon.svg|50px]] Text was copied from this source, which is available under a [https://creativecommons.org/licenses/by/4.0/  Creative Commons Attribution 4.0 International License].</ref>

== Mission ==
[[File:Parker Solar Probe Launch (NHQ201808120013).jpg|thumb|upright|Launch of the Parker Solar Probe in 2018]]
[[File:Parker Solar Probe.jpg|thumb|Artist's rendition of the Parker Solar Probe approaching the Sun]]
The Parker Solar Probe was launched on 12 August 2018, at 07:31 UTC. The spacecraft operated nominally after launching. During its first week in space it deployed its high-gain antenna, magnetometer boom, and electric field antennas.<ref>{{cite web|url=https://spaceflightnow.com/2018/08/19/first-mission-milestones-accomplished-on-nasas-newly-launched-parker-solar-probe/|title=First milestones accomplished on NASA's newly-launched Parker Solar Probe – Spaceflight Now|website=spaceflightnow.com|access-date=August 22, 2018|archive-date=August 22, 2018|archive-url=https://web.archive.org/web/20180822181409/https://spaceflightnow.com/2018/08/19/first-mission-milestones-accomplished-on-nasas-newly-launched-parker-solar-probe/|url-status=live}}</ref> The spacecraft performed its first scheduled trajectory correction on 20 August 2018, while it was 8.8 million kilometers (5.5 million mi) from Earth, and travelling at {{convert|63569|km/h}}<ref>[http://parkersolarprobe.jhuapl.edu/News-Center/Show-Article.php?articleID=96 After Near-Perfect Trajectory Maneuver, Parker Solar Probe On Course To Touch The Sun] {{Webarchive|url=https://web.archive.org/web/20180826005039/http://parkersolarprobe.jhuapl.edu/News-Center/Show-Article.php?articleID=96 |date=August 26, 2018 }}. NASA. August 21, 2018 {{PD-notice}}</ref>

Instrument activation and testing began in early September 2018. On 9 September 2018, the two [[WISPR]] telescopic cameras performed a successful [[first light (astronomy)|first-light]] test, transmitting wide-angle images of the background sky towards the [[Galactic Center|galactic center]].<ref>{{cite web|url=https://blogs.nasa.gov/parkersolarprobe/2018/09/19/illuminating-first-light-data-from-parker-solar-probe/|website=blogs.nasa.gov/parkersolarprobe|title=Illuminating First Light Data from Parker Solar Probe|date=September 19, 2018|access-date=September 22, 2018|archive-date=September 22, 2018|archive-url=https://web.archive.org/web/20180922072822/https://blogs.nasa.gov/parkersolarprobe/2018/09/19/illuminating-first-light-data-from-parker-solar-probe/|url-status=live}} {{PD-notice}}</ref>

The probe successfully performed the first of the seven planned Venus flybys on 3 October 2018, where it came within about {{convert|2400|km}} of Venus in order to reduce the probe's speed and orbit closer to the Sun.<ref name="blogvenus"/>

[[File:Parker Solar Probe Flyby of Venus.svg|thumb|right|The second flyby of Venus on December 26, 2019. The velocity decreases by 2.9 km/s to 26 km/s (red circle), shifting the spacecraft to a new orbit closer to the Sun.]]

Within each orbit of the Parker Solar Probe around the Sun, the portion within 0.25 AU is the Science Phase, in which the probe is actively and autonomously making observations. Communication with the probe is largely cut off in that phase.<ref name="mission design">{{cite conference|url=https://www.researchgate.net/publication/301998540|title=Solar Probe Plus Mission Design Overview and Mission Profile|last1=Guo|first1=Yanping|last2=Ozimek|first2=Martin|last3=Mcadams|first3=James|last4=Shyong|first4=Wen-Jong|date=May 2014|conference=International Symposium on Space Flight Dynamics, at Laurel, MD|website=ResearchGate|access-date=November 6, 2018|archive-date=May 2, 2022|archive-url=https://web.archive.org/web/20220502174648/https://www.researchgate.net/publication/301998540_SOLAR_PROBE_PLUS_MISSION_DESIGN_OVERVIEW_AND_MISSION_PROFILE|url-status=live}}</ref>{{rp|4}} Science phases run for a few days both before and after each perihelion. They lasted 11.6 days for the earliest perihelion, and will drop to 9.6 days for the final, closest perihelion.<ref name="mission design"/>{{rp|8}}

Much of the rest of each orbit is devoted to transmitting data from the science phase. But during this part of each orbit, there are still periods when communication is not possible. First, the requirement that the heat shield of the probe be pointed towards the Sun sometimes puts the heat shield between the antenna and Earth. Second, even when the probe is not particularly near the Sun, when the angle between the probe and the Sun, as seen from Earth, is too small, the Sun's radiation can overwhelm the communication link.<ref name="mission design"/>{{rp|11–14}}

After the first [[Venus]] [[List of planetary flybys|flyby]], the probe was in an [[Elliptic orbit|elliptical orbit]] with a period of 150 days (two-thirds the period of Venus), making three orbits while Venus makes two. After the second flyby, the period shortened to 130 days. After less than two orbits, only 198 days later, it encountered Venus a third time at a point earlier in the orbit of Venus. This encounter shortened its period to half of that of Venus, or about 112.5 days. After two orbits it met Venus a fourth time at about the same place, shortening its period to about 102 days.<ref name=the_mission/>

After 237 days, it met Venus for the fifth time and its period was shortened to about 96 days, three-sevenths that of Venus. It then made seven orbits while Venus made three. The sixth encounter, almost two years after the fifth, shortened its period down to 92 days, two-fifths that of Venus. After five more orbits (two orbits of Venus), it will meet Venus for the seventh and last time, decreasing its period to 88 or 89 days and allowing it to approach closer to the [[Sun]].<ref name=the_mission>See data and figure at {{cite web|url=http://parkersolarprobe.jhuapl.edu/The-Mission/index.php#Journey-to-the-Sun|title=Solar Probe Plus: The Mission|date=2017|publisher=Johns Hopkins University Applied Physics Laboratory|access-date=June 17, 2017|archive-date=August 22, 2017|archive-url=https://web.archive.org/web/20170822222954/http://parkersolarprobe.jhuapl.edu/The-Mission/index.php#Journey-to-the-Sun|url-status=live}} {{PD-notice}}</ref>

== Timeline ==
{{wide image|Velocity of Parker Solar Probe wide.svg|900px|The speed of the probe and distance from the Sun, from launch until 2026|center|alt=}}

{| class="wikitable" style="border: none;"
|+ List of events{{r|the_mission}}{{r|Fox 2016|p=31}}<ref>{{cite web|title=HORIZONS System|publisher=Jet Propulsion Laboratory, NASA|url=https://ssd.jpl.nasa.gov/?horizons|access-date=August 16, 2018|archive-date=May 25, 2019|archive-url=https://web.archive.org/web/20190525123930/https://ssd.jpl.nasa.gov/?horizons|url-status=live}} [https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND='-96'&MAKE_EPHEM='YES'&TABLE_TYPE='VECTORS'&START_TIME='2018-Aug-12%2008:17'&STOP_TIME='2025-Aug-31%2009:18'&STEP_SIZE='1%20h'&CSV_FORMAT='YES'&CENTER='500@10'&REF_PLANE='ECLIPTIC'&REF_SYSTEM='J2000'&OUT_UNITS='AU-D'&VEC_TABLE='2'&OBJ_DATA='YES' Data file] {{PD-notice}}</ref>

! rowspan=2 | Year !! rowspan=2 | Date !! rowspan=2 | Event !! [[Apsis#Perihelion and aphelion|Perihelion]]<br />distance ({{abbr|Gm|gigameters}}){{Efn|For altitude above the surface, subtract one solar radius ≈0.7 Gm.  (A Gm (gigametre) is a million km or about 621371 mi.)}} !! Speed <br />(km/s) !! Orbital period<br />(days) !! rowspan=2 | Notes
|-
! ''Flyby altitude<br />over Venus''&thinsp;{{Efn|Details on Venus flybys from Guo et al.<ref name="mission design"/>{{rp|6}} This was published in 2014, four years before the mission began. For a variety of reasons, including the fact that the launch had to be delayed at the last minute, actual details could differ from the ones presented in the work.}} !! ''Leg of<br />Parker's orbit''&thinsp;{{Efn|'''Inbound''' indicates that the Venus flyby will take place after ''Parker''{{'}}s aphelion (in the case of the first flyby, after its launch), on its way to perihelion. '''Outbound''' indicates that the Venus flyby will take place after ''Parker''{{'}}s perihelion, on its way to aphelion.}} !! ''Inside/Outside<br />orbit of Venus''&thinsp;{{Efn|'''Inside''' indicates that the probe will pass in between Venus and the Sun. '''Outside''' indicates that the probe will pass beyond Venus from the Sun; the probe will briefly pass through Venus's shadow in those instances.}}
|-
| rowspan=3 | 2018
| 12 August<br />07:31 UTC || bgcolor=PaleGreen | Launch || 151.6 || – || 174{{Efn|The first orbital period of 174 days was the orbit established by the launch and course adjustments, and was the orbit the probe would have taken had nothing further happened to change it. That orbit was, per mission plan, never completed. On the probe's first inbound course towards the Sun, it made its first planned encounter with Venus, which shortened its orbit considerably.}} ||
|-
| ''3 October<br />08:44 UTC'' || bgcolor=PowderBlue | ''Venus flyby #1'' || ''2548 km''{{Efn|The altitude is from the source cited,<ref name="mission design"/>{{rp|6}} dated 2014. 2548 km comes to 1583 mi. NASA's <ref>{{cite news|url=https://www.nasa.gov/feature/goddard/2018/parker-solar-probe-changed-the-game-before-it-even-launched|title=Parker Solar Probe Changed the Game Before it Even Launched|website=Parker Solar Probe News Center|publisher=Johns Hopkins University Applied Physics Laboratory|date=October 4, 2018|access-date=December 26, 2018|archive-date=October 6, 2018|archive-url=https://web.archive.org/web/20181006113133/https://www.nasa.gov/feature/goddard/2018/parker-solar-probe-changed-the-game-before-it-even-launched/|url-status=live}} {{PD-notice}}</ref> and Johns Hopkins's <ref>{{cite news|url=http://parkersolarprobe.jhuapl.edu/News-Center/Show-Article.php?articleID=104|title=How A Change in Mission Design Unlocked the Journey to the Sun|website=Parker Solar Probe Mission News|publisher=NASA|date=October 4, 2018|access-date=December 26, 2018|archive-date=December 8, 2018|archive-url=https://web.archive.org/web/20181208063415/http://parkersolarprobe.jhuapl.edu/News-Center/Show-Article.php?articleID=104|url-status=live}} {{PD-notice}}</ref> press releases (identical), say "...came within about 1500 miles of Venus' surface..." A NASA blog,<ref name="blogvenus">{{cite news|url=https://blogs.nasa.gov/parkersolarprobe/2018/10/03/parker-solar-probe-successfully-completes-first-venus-flyby/|title=Parker Solar Probe Successfully Completes First Venus Flyby|website=blogs.nasa.gov/parkersolarprobe|publisher=NASA|date=October 3, 2018|access-date=December 26, 2018|archive-date=November 30, 2018|archive-url=https://web.archive.org/web/20181130041029/https://blogs.nasa.gov/parkersolarprobe/2018/10/03/parker-solar-probe-successfully-completes-first-venus-flyby/|url-status=live}} {{PD-notice}}</ref> says, "...completed its flyby of Venus at a distance of about 1500 miles..." Other news reports, presumably taking that information, also provide a figure of 2414 km. But neither the NASA/Hopkins press release nor the blog gives a figure in kilometers.<br />Both the NASA and Hopkins press releases say that the flyby reduced the speed of the ''Parker Solar Probe'' (relative to the Sun) by about 10%, or 7000 mph. This altered the orbit, bringing perihelion about 4 million miles closer to the Sun than it would have been without the gravity assist.}} || ''Inbound'' || ''Inside'' || ''Flybys 1 and 2 occur at the<br />same point in Venus's orbit''.
|-
| 6 November<br />03:27 UTC || bgcolor=Ivory | Perihelion  #1 || rowspan="3" | {{cvt|35.66|solar radius|Gm|1|disp=number}}{{Efn|By way of comparison, the planet [[Mercury (planet)|Mercury]] orbits the Sun at a distance varying from about 46.0 Gm (46,001,200 km) at its closest to about 69.8 Gm (69,816,900 km) at its farthest.}} || rowspan="3" | 95 || rowspan="3" | 150 || Solar encounter phase<br />31 October – 11 November<ref>{{cite web|url=http://parkersolarprobe.jhuapl.edu/News-Center/Show-Article.php?articleID=113|title=Parker Solar Probe Reports First Telemetry, Acquisition of Science Data Since Perihelion|date=November 20, 2018|website=parkersolarprobe.jhuapl.edu|publisher=Johns Hopkins University Applied Physics Laboratory|access-date=December 18, 2018|archive-date=November 23, 2018|archive-url=https://web.archive.org/web/20181123220510/http://parkersolarprobe.jhuapl.edu/News-Center/Show-Article.php?articleID=113|url-status=live}}</ref>
|-
| rowspan=3 | 2019
| 4 April<br />22:40 UTC || bgcolor=Ivory | Perihelion  #2 || Solar encounter phase<br />30 March – 10 April<ref>{{cite web|url=http://www.sci-news.com/space/parker-solar-probe-second-perihelion-07067.html|title=NASA's Parker Solar Probe Makes Second Close Approach to Sun|website=sci-news.com|date=April 18, 2019|access-date=May 11, 2019|archive-date=April 10, 2019|archive-url=https://web.archive.org/web/20190410220259/http://www.sci-news.com/space/parker-solar-probe-second-perihelion-07067.html|url-status=live}}</ref>
|-
| 1 September<br />17:50 UTC<ref>{{cite web|url=https://www.space.com/parker-solar-probe-third-sun-flyby.html|title=NASA's Daring Solar Probe Is Skimming Past the Sun Today!|author=Meghan Bartels|date=September 1, 2019|website=Space.com|access-date=September 2, 2019|archive-date=September 1, 2019|archive-url=https://web.archive.org/web/20190901212922/https://www.space.com/parker-solar-probe-third-sun-flyby.html|url-status=live}}</ref> || bgcolor=Ivory | Perihelion  #3 || Solar encounter phase<br />16 August – 20 September {{Efn| After the second solar encounter phase, ''Parker Solar Probe'' was able to download much more data than NASA had expected. So NASA announced a substantial extension of the third solar encounter phase from 11 days to about 35 days. The observational instruments were turned on when ''Parker Solar Probe'' came within 0.45 [[Astronomical unit|au]] on the inbound trip, and are planned to run until the probe reaches about 0.50 au outbound.<ref>{{cite web|url=http://parkersolarprobe.jhuapl.edu/News-Center/Show-Article.php?articleID=126|title=Parker Solar Probe Gets Extra Observation Time|date=August 16, 2018|website=parkersolarprobe.jhuapl.edu|publisher=Johns Hopkins University Applied Physics Laboratory|access-date=September 2, 2018|archive-date=October 4, 2019|archive-url=https://web.archive.org/web/20191004055610/http://parkersolarprobe.jhuapl.edu/News-Center/Show-Article.php?articleID=126|url-status=live}} {{PD-notice}}</ref>}}
|-
| ''26 December''<br>''18:14 UTC''<ref>{{cite web|url=http://parkersolarprobe.jhuapl.edu/News-Center/Show-Article.php?articleID=113|title=Parker Solar Probe Heads Toward Second Venus Flyby|date=November 20, 2018|website=Parker Solar Probe News Center|publisher=Johns Hopkins University Applied Physics Laboratory|access-date=December 23, 2019|archive-date=December 26, 2019|archive-url=https://web.archive.org/web/20191226013618/http://parkersolarprobe.jhuapl.edu/News-Center/Show-Article.php?articleID=113|url-status=live}} Gives the time as "1:14 p.m. EST" and the distance of the flyby as "within 1870 miles". {{PD-notice}}</ref> || bgcolor=PowderBlue | ''Venus flyby'' #2 || ''3023 km'' || ''Inbound'' || ''Inside'' || ''Flybys 1 and 2 occur at the<br />same point in Venus's orbit''.
|-
| rowspan=4 | 2020
| 29 January<br>09:37 UTC<ref>{{cite web|url=http://parkersolarprobe.jhuapl.edu/News-Center/Show-Article.php?articleID=141|title=Parker Solar Probe Completes Fourth Closest Approach, Breaks New Speed and Distance Records|date=January 29, 2020|website=Parker Solar Probe News Center|publisher=Johns Hopkins University Applied Physics Laboratory|access-date=February 21, 2020|archive-date=February 3, 2020|archive-url=https://web.archive.org/web/20200203223700/http://parkersolarprobe.jhuapl.edu/News-Center/Show-Article.php?articleID=141|url-status=live}} {{PD-notice}}</ref> || bgcolor=LightYellow | Perihelion  #4 || rowspan="2" | {{cvt|27.85|solar radius|Gm|1|disp=number}} || rowspan="2" | 109 || rowspan="2" | 130 || Solar encounter phase<br />23 January – 29 February<ref>{{cite web|url=http://parkersolarprobe.jhuapl.edu/News-Center/Show-Article.php?articleID=143|title=Parker Solar Probe Reports Successful Record-Setting Fourth Close Encounter of the Sun|date=February 1, 2020|website=Parker Solar Probe News Center|publisher=Johns Hopkins University Applied Physics Laboratory|access-date=February 21, 2020|archive-date=February 3, 2020|archive-url=https://web.archive.org/web/20200203223539/http://parkersolarprobe.jhuapl.edu/News-Center/Show-Article.php?articleID=143|url-status=live}} {{PD-notice}}</ref>
|-
| 7 June<br />08:23 UTC<ref>{{cite web|url=https://www.space.com/parker-solar-probe-fifth-close-approach-flyby.html|title=NASA's Parker Solar Probe flies by the sun in 5th close encounter|last=Bartels|first=Meghan|date=June 7, 2020|website=space.com|publisher=Future US Inc|access-date=June 11, 2020|archive-date=June 9, 2020|archive-url=https://web.archive.org/web/20200609191022/https://www.space.com/parker-solar-probe-fifth-close-approach-flyby.html|url-status=live}}</ref> || bgcolor=LightYellow | Perihelion  #5 || Solar encounter phase<br />9 May – 28 June<ref>{{cite web|url=http://parkersolarprobe.jhuapl.edu/News-Center/Show-Article.php?articleID=146|title=Parker Solar Probe Begins Longest Science Observation Campaign|last=Surowiec|first=Justyna|date=May 12, 2020|website=parkersolarprobe.jhuapl.edu|publisher=Johns Hopkins University Applied Physics Laboratory|access-date=June 11, 2020|archive-date=June 12, 2020|archive-url=https://web.archive.org/web/20200612013603/http://parkersolarprobe.jhuapl.edu/News-Center/Show-Article.php?articleID=146|url-status=live}} {{PD-notice}}</ref>
|-
| ''11 July''<br />''03:22 UTC''<ref name=Venus3>{{cite web|url=https://www.space.com/parker-solar-probe-venus-tail-flyby.html|title=NASA's Parker Solar Probe swings through Venus 'tail' in flyby today|last=Bartels|first=Meghan|date=July 10, 2020|website=space.com|publisher=Future US Inc|access-date=July 18, 2020|archive-date=July 18, 2020|archive-url=https://web.archive.org/web/20200718000230/https://www.space.com/parker-solar-probe-venus-tail-flyby.html|url-status=live}}</ref> || bgcolor=PowderBlue | ''Venus flyby #3'' || ''834 km'' || ''Outbound'' || ''Outside''&thinsp;{{Efn| The third flyby of Venus was the first to pass behind Venus from the point of view of the Sun. The probe was in Venus's shadow, obscured from the Sun, for about 11 minutes, and passed through a so-called "tail" of Venus – a trail of charged particles from the atmosphere of Venus. The probe's instruments were to be turned on to make observations.{{r|Venus3}}}} || ''Flybys 3 and 4 occur at the<br /> same point in Venus's orbit''.
|-
| 27 September || bgcolor=LemonChiffon | Perihelion  #6 || rowspan="2" | {{cvt|20.35|solar radius|Gm|1|disp=number}} || rowspan="2" | 129 || rowspan="2" | 112.5 ||
|-
| rowspan=6 | 2021
| 17 January || bgcolor=LemonChiffon | Perihelion  #7 ||
|-
| ''20 February'' || bgcolor=PowderBlue | ''Venus flyby #4'' || ''2392 km'' || ''Outbound'' || ''Outside'' || ''Flybys 3 and 4 occur at the<br /> same point in Venus's orbit''.
|-
| 28 April || bgcolor="Cornsilk" | Perihelion  #8 || rowspan="2" | {{cvt|15.98|solar radius|Gm|1|disp=number}} || rowspan="2" | 147 || rowspan="2" | 102 ||First perihelion to enter the<br />solar corona
|-
| 9 August || bgcolor=Cornsilk | Perihelion  #9 ||
|-
| ''16 October'' || bgcolor=PowderBlue | ''Venus flyby #5'' || ''3786 km'' || ''Inbound'' || ''Inside'' || ''Flybys 5 and 6 occur at the<br />same point in Venus's orbit''.
|-
| 21 November || bgcolor=PapayaWhip | Perihelion #10 || rowspan="7" | {{cvt|13.28|solar radius|Gm|1|disp=number}} || rowspan="7" | 163 || rowspan="7" | 96 ||
|-
| rowspan=4 | 2022
| 25 February || bgcolor=PapayaWhip | Perihelion #11 ||
|-
| 1 June || bgcolor=PapayaWhip | Perihelion #12 ||
|-
| 6 September || bgcolor=PapayaWhip | Perihelion #13 ||
|-
| 11 December || bgcolor=PapayaWhip | Perihelion #14 ||
|-
| rowspan=5 | 2023
| 17 March || bgcolor=PapayaWhip | Perihelion #15 ||
|-
| 22 June || bgcolor=PapayaWhip | Perihelion #16 ||
|-
| ''21 August'' || bgcolor=PowderBlue | ''Venus flyby  #6'' || ''3939 km'' || ''Inbound'' || ''Inside'' || ''Flybys 5 and 6 occur at the<br /> same point in Venus's orbit''.
|-
| 27 September || bgcolor=Moccasin | Perihelion #17 || rowspan="5" | {{cvt|11.42|solar radius|Gm|1|disp=number}} || rowspan="5" | 176 || rowspan="5" | 92 ||
|-
| 29 December || bgcolor=Moccasin | Perihelion #18 ||
|-
| rowspan=5 | 2024
| 30 March || bgcolor=Moccasin | Perihelion #19 ||
|-
| 30 June || bgcolor=Moccasin | Perihelion #20 ||
|-
| 30 September || bgcolor=Moccasin | Perihelion #21 ||
|-
| ''6 November'' || bgcolor=PowderBlue | ''Venus flyby #7'' || ''317 km'' || ''Outbound'' || ''Outside'' ||
|-
| 24 December || bgcolor=Gold | Perihelion #22 || rowspan="5" |  {{cvt|9.86|solar radius|Gm|1|disp=number}} || rowspan="5" | 192 || rowspan="5" | 88 ||
|-
| rowspan=4 | 2025
| 22 March || bgcolor=Gold | Perihelion #23 ||
|-
| 19 June || bgcolor=Gold | Perihelion #24 ||
|-
| 15 September || bgcolor=Gold | Perihelion #25 ||
|-
| 12 December || bgcolor=Gold | Perihelion #26 ||
|}

{{Notelist}}

== Findings ==
[[File:Switchbacks on the Sun.gif|thumb|PSP observed switchbacks — traveling disturbances in the solar wind that caused the magnetic field to bend back on itself.]]
[[File:Parker Solar Probe touches the Sun.webm|thumb|NASA animation of the Probe passing through the Sun's [[stellar corona]]. Inside the boundary at the corona's edge, its [[Alfvén surface|Alfvén critical surface]], plasma connects to the Sun by waves traveling back and forth to the surface.]]

On November 6, 2018, Parker Solar Probe observed its first [[magnetic switchback]]s – sudden reversals in the [[magnetic field]] of the [[solar wind]].<ref name="New Insight">{{cite web |last1=Hatfield |first1=Miles |title=New Insight Into Parker Solar Probe's Early Observations |url=https://www.nasa.gov/feature/goddard/2020/new-insight-into-parker-solar-probes-early-observations |website=NASA |date=29 April 2020}}{{PD-notice}}</ref> They were first observed by the NASA-ESA  mission ''[[Ulysses (spacecraft)|Ulysses]]'', the first spacecraft to fly over the [[Sun]]'s poles.<ref name="nasa-Switchbacks">{{cite web |last1=Hatfield |first1=Miles |title=Switchbacks Science: Explaining Parker Solar Probe's Magnetic Puzzle |url=https://www.nasa.gov/feature/goddard/2021/switchbacks-science-explaining-parker-solar-probe-s-magnetic-puzzle |website=NASA |access-date=31 July 2022 |date=8 March 2021}}{{PD-notice}}</ref><ref name=fisk-casper>{{cite journal |last1=Fisk |first1=L. A. |last2=Kasper |first2=J. C. |title=Global Circulation of the Open Magnetic Flux of the Sun |journal=The Astrophysical Journal Letters |date=1 May 2020 |volume=894 |issue=1 |pages=L4 |doi=10.3847/2041-8213/ab8acd|bibcode=2020ApJ...894L...4F |doi-access=free }}[[File:CC BY icon.svg|50px]] Material was copied from this source, which is available under a [https://creativecommons.org/licenses/by/3.0/ Creative Commons Attribution 3.0]</ref> The switchbacks generate heat that warms solar corona.<ref>{{cite web |last1=Zurbuchen |first1=Thomas |title=How a NASA Probe Solved a Scorching Solar Mystery |url=https://www.quantamagazine.org/how-a-nasa-probe-solved-a-scorching-solar-mystery-20240429/ |publisher=Quanta Magazine |access-date=11 May 2024}}</ref>

On 4 December 2019, the first four research papers were published describing findings during the spacecraft's first two dives near the Sun.<ref>{{cite journal|last=Verscharen|first=Daniel|date=December 4, 2019 |title=A step closer to the Sun's secrets|journal=Nature|volume=576|issue=7786|pages=219–220|doi=10.1038/d41586-019-03665-3|pmid=31822830|bibcode=2019Natur.576..219V|doi-access=free}}</ref><ref name=":0">{{cite news|url=https://www.nytimes.com/2019/12/04/science/nasa-parker-solar-probe-pictures.html|title=NASA's Parker Solar Probe Is Unlocking the Sun's Mysteries|last=Chang|first=Kenneth|date=December 4, 2019|work=The New York Times|access-date=January 16, 2024|issn=0362-4331|archive-date=December 5, 2019|archive-url=https://web.archive.org/web/20191205001130/https://www.nytimes.com/2019/12/04/science/nasa-parker-solar-probe-pictures.html|url-status=live}}</ref><ref name=":1"/><ref>{{Cite journal|last1=McComas|first1=D. J.|last2=Christian|first2=E. R.|last3=Cohen|first3=C. M. S.|last4=Cummings|first4=A. C. |last5=Davis|first5=A. J.|last6=Desai|first6=M. I.|last7=Giacalone|first7=J.|last8=Hill|first8=M. E.|last9=Joyce|first9=C. J.|last10=Krimigis|first10=S. M.|last11=Labrador|first11=A. W.|date=December 4, 2019 |title=Probing the energetic particle environment near the Sun|journal=Nature|volume=576|issue=7786|pages=223–227|doi=10.1038/s41586-019-1811-1|pmid=31802005|issn=1476-4687|pmc=6908744|bibcode=2019Natur.576..223M}}</ref><ref>{{cite journal|last1=Howard|first1=R. A.|last2=Vourlidas|first2=A.|last3=Bothmer|first3=V.|last4=Colaninno|first4=R. C.|last5=DeForest|first5=C. E.|last6=Gallagher|first6=B.|last7=Hall|first7=J. R.|last8=Hess|first8=P.|last9=Higginson|first9=A. K.|last10=Korendyke|first10=C. M.|last11=Kouloumvakos|first11=A.|date=December 4, 2019|title=Near-Sun observations of an F-corona decrease and K-corona fine structure|journal=Nature|volume=576|issue=7786|pages=232–236|doi=10.1038/s41586-019-1807-x|pmid=31802002|bibcode=2019Natur.576..232H|hdl=2268/242497|s2cid=208620616|issn=1476-4687|url=https://orbi.uliege.be/handle/2268/242497|access-date=August 31, 2020|archive-date=June 25, 2020|archive-url=https://web.archive.org/web/20200625174408/https://orbi.uliege.be/handle/2268/242497|url-status=live}}</ref> They reported the direction and strength of the Sun's magnetic field, and described the unusually frequent and short-lived changes in the direction of the Sun's magnetic field. These measurements confirm the hypothesis that [[Alfvén wave]]s are the leading candidates for understanding the mechanisms that underlie the [[coronal heating problem]].<ref name=":0"/><ref>{{cite journal|last1=Bale|first1=S. D.|last2=Badman|first2=S. T. |last3=Bonnell|first3=J. W.|last4=Bowen|first4=T. A.|last5=Burgess|first5=D.|last6=Case|first6=A. W.|author-link6=Anthony W. Case|last7=Cattell|first7=C. A.|author-link7=Cynthia Cattell|last8=Chandran|first8=B. D. G.|last9=Chaston|first9=C. C.|last10=Chen|first10=C. H. K.|last11=Drake|first11=J. F.|date=December 4, 2019|title=Highly structured slow solar wind emerging from an equatorial coronal hole|journal=Nature|volume=576|issue=7786|pages=237–242|doi=10.1038/s41586-019-1818-7|pmid=31802007|bibcode=2019Natur.576..237B|issn=1476-4687|hdl=11603/17219|s2cid=208623434|url=https://qmro.qmul.ac.uk/xmlui/handle/123456789/62038 |hdl-access=free}}</ref> The probe observed approximately a thousand "rogue" magnetic waves in the solar atmosphere that instantly increase [[solar winds]] by as much as {{convert|300000|mph|kph}} and in some cases completely reverse the local [[magnetic field]].<ref name=:0/><ref name=:1/><ref>{{cite journal|last=Witze|first=Alexandra |date=December 4, 2019|title=Sun-bombing spacecraft uncovers secrets of the solar wind|journal=[[Nature (journal)|Nature]]|volume=576|issue=7785|pages=15–16|doi=10.1038/d41586-019-03684-0|pmid=31802020|bibcode=2019Natur.576...15W |doi-access=free}}</ref><ref>{{cite news|last=Drake|first=Nadia|author-link=Nadia Drake|url=https://www.nationalgeographic.com/science/2019/12/sun-keeps-getting-stranger-parker-solar-probe-shows/|title=The sun keeps getting stranger, dive-bombing solar probe shows|date=December 4, 2019|work=[[National Geographic]]|access-date=December 6, 2019|archive-date=December 6, 2019|archive-url=https://web.archive.org/web/20191206002311/https://www.nationalgeographic.com/science/2019/12/sun-keeps-getting-stranger-parker-solar-probe-shows/|url-status=dead}}</ref> 

They also reported that, using the "beam of electrons that stream along the magnetic field", they were able to observe that "the reversals in the Sun's magnetic field are often associated with localized enhancements in the radial component of the plasma velocity (the velocity in the direction away from the Sun's center)". The researchers found a "surprisingly large [[azimuth]]al component of the plasma velocity (the velocity perpendicular to the radial direction). This component results from the force with which the Sun's rotation slingshots plasma out of the corona when the plasma is released from the coronal magnetic field".<ref name=":0"/><ref name=":1">{{cite journal |last1=Kasper |first1=J. C. |last2=Bale |first2=S. D.|last3=Belcher|first3=J. W.|last4=Berthomier|first4=M.|last5=Case|first5=A. W.|author-link5=Anthony W. Case|last6=Chandran|first6=B. D. G.|last7=Curtis|first7=D. W.|last8=Gallagher|first8=D.|last9=Gary|first9=S. P. |last10=Golub |first10=L. |last11=Halekas |first11=J. S. |date=December 4, 2019|title=Alfvénic velocity spikes and rotational flows in the near-Sun solar wind|journal=Nature|volume=576|issue=7786|pages=228–231 |doi=10.1038/s41586-019-1813-z |pmid=31802006 |bibcode=2019Natur.576..228K |issn=1476-4687 |hdl=10150/636481 |hdl-access=free |s2cid=208625853}}</ref>

PSP discovered evidence of a [[cosmic dust]]-free zone of 3.5 million miles (5.6 million kilometres) radius from the Sun, due to vaporisation of cosmic dust particles by the Sun's radiation.<ref>{{cite web|url=https://www.sciencealert.com/the-sun-s-magnetic-field-appears-to-unexpectedly-flip-and-scientists-don-t-know-what-s-going-on|title=Scientists 'Blown Away' by Unexpected Results From NASA's Sun-Kissing Solar Probe|last=Tangermann|first=Victor|date=December 4, 2019 |publisher=ScienceAlert|agency=Futurism|access-date=December 16, 2019|archive-date=December 16, 2019|archive-url=https://web.archive.org/web/20191216012915/https://www.sciencealert.com/the-sun-s-magnetic-field-appears-to-unexpectedly-flip-and-scientists-don-t-know-what-s-going-on|url-status=live}}</ref>

On April 28, 2021, during its eighth flyby of the Sun, Parker Solar Probe encountered the specific magnetic and particle conditions at 18.8 solar radii that indicated that it penetrated the [[Alfvén surface]];<ref name="touching">{{cite web |last1=Hatfield |first1=Miles |title=NASA Enters the Solar Atmosphere for the First Time |url=https://www.nasa.gov/feature/goddard/2021/nasa-enters-the-solar-atmosphere-for-the-first-time-bringing-new-discoveries |website=NASA |date=13 December 2021}}{{PD-notice}}</ref><ref name=animation>{{cite web |title=GMS: Animation: NASA's Parker Solar Probe Enters Solar Atmosphere |url=https://svs.gsfc.nasa.gov/14036 |website=svs.gsfc.nasa.gov |access-date=30 July 2022 |language=en |date=14 December 2021}}</ref> the probe measured the solar wind plasma environment with its FIELDS and SWEAP instruments.<ref>{{cite web |title=SVS: Parker Solar Probe: Crossing the Alfven Surface |url=https://svs.gsfc.nasa.gov/4958 |website=svs.gsfc.nasa.gov |access-date=30 July 2022 |language=en |date=14 December 2021}}{{PD-notice}}</ref> This event was described by NASA as "touching the Sun".<ref name="touching"/>

On 25 September 2022, the first discovery of a comet was made in images from the Parker Solar Probe. The comet is named PSP-001. It was found by Peter Berrett, who participates in the NASA funded Sungrazer project.<ref>{{cite web |title=Welcome to Sungrazer |url=https://sungrazer.nrl.navy.mil |website=sungrazer.nrl.navy.mil |access-date=18 July 2023 |language=en }}{{PD-notice}}</ref> PSP-001 was discovered in images from 29 May 2022, part of the spacecraft's 12th approach to the Sun.

Since this discovery, a further 19 sungrazer comets have been discovered in the images taken by the Parker Solar Probe, including two non-group comets.

{| class="wikitable"
|-
! Designation !!Comet classification !!Image date!! Discovery date<ref name="psp-confs-jul2023">{{cite web |title=Parker Solar Probe (WISPR) Comets |url=https://sungrazer.nrl.navy.mil/psp-confs-jul2023 |website=sungrazer.nrl.navy.mil |access-date=18 July 2023 |language=en }}{{PD-notice}}</ref>!!Discoverer<ref name="psp-confs-jul2023"/><ref>{{cite web |title=September 2023 and PSP confirmations |url=https://sungrazer.nrl.navy.mil/confs-Sep2023 |website=sungrazer.nrl.navy.mil |access-date=16 November 2023 |language=en }}{{PD-notice}}</ref>
|-
|PSP-001|| [[Kreutz Sungrazers|Kreutz]] 
 ||29 May 2022||25 Sep 2022|| Peter Berrett
|-
|PSP-002|| Kreutz ||1 Sep 2022||N/A|| Karl Battams
|-
|PSP-003|| Kreutz ||2 Sep 2022||N/A|| Karl Battams
|-
|PSP-004|| Kreutz ||1 Sep 2022||N/A|| Karl Battams
|-
|PSP-005|| Kreutz ||18 Nov 2021||11 Feb 2023|| Peter Berrett
|-
|PSP-006|| Non Group ||11 Dec 2022||13 May 2023|| Peter Berrett
|-
|PSP-007|| Kreutz ||12 Mar 2023||12 Jul 2023|| Karl Battams
|-
|PSP-008|| Non Group ||6 Dec 2022||16 Jul 2023|| Rafał Biros 
|-
|PSP-009|| Kreutz ||25 Apr 2021||28 Jul 2023|| Rafał Biros 
|-
|PSP-010|| Kreutz ||25 Apr 2021||28 Jul 2023|| Rafał Biros 
|-
|PSP-011|| Kreutz ||17 Nov 2021||24 Jul 2023|| Rafał Biros 
|-
|PSP-012|| Kreutz ||21 Feb 2022||30 Jul 2023|| Rafał Biros 
|-
|PSP-013|| Kreutz ||15 Feb 2022||27 Jul 2022|| Peter Berrett 
|-
|PSP-014|| Kreutz ||4 Aug 2021||3 Aug 2023|| Rafał Biros 
|-
|PSP-015|| Kreutz ||5–6 Aug 2021||3 Aug 2023|| Rafał Biros 
|-
|PSP-016|| Kreutz ||29 May 2022||4 Aug 2023|| Rafał Biros 
|-
|PSP-017|| Kreutz ||12 Jan 2021||16 Aug 2023|| Robert Pickard 
|-
|PSP-018|| Kreutz ||19 Jun 2023||13 Oct 2023|| Peter Berrett 
|-
|PSP-019|| Non Group ||27 Sep 2023||2 Nov 2023|| Guillermo Stenborg 
|-
|PSP-020|| Kreutz ||13 Jan 2021||8 Aug 2023|| Peter Berrett 
|-

|}

In 2024, it was reported that the probe detected a [[Kelvin-Helmholtz instabilities|Kelvin-Helmholtz instability]] (KHI) during an observed [[coronal mass ejection]]. It is the first spacecraft that detected this long theorized event.<ref>{{Cite journal|title=First Direct Imaging of a Kelvin-Helmholtz Instability by PSP/WISPR|author1=Paouris, Evangelos|author2=Stenborg, Guillermo|author3=Linton, Mark G.|author4=Vourlidas, Angelos|author5=Howard, Russell A.|author6=Raouafi, Nour E.|year=2024|journal=The Astrophysical Journal|volume=964|issue=2|pages=139|doi=10.3847/1538-4357/ad2208|doi-access=free |bibcode=2024ApJ...964..139P }}</ref>

== PSP and Solar Orbiter collaboration ==
PSP and ESA-NASA's [[Solar Orbiter]] (SolO) missions cooperated to trace solar wind and transients from their sources on the Sun to the inner interplanetary space.<ref>{{cite journal |last1=Biondo |first1=Ruggero |last2=Bemporad |first2=Alessandro |last3=Pagano |first3=Paolo |last4=Telloni |first4=Daniele |last5=Reale |first5=Fabio |last6=Romoli |first6=Marco |last7=Andretta |first7=Vincenzo |last8=Antonucci |first8=Ester |last9=Da Deppo |first9=Vania |last10=De Leo |first10=Yara |last11=Fineschi |first11=Silvano |last12=Heinzel |first12=Petr |last13=Moses |first13=Daniel |last14=Naletto |first14=Giampiero |last15=Nicolini |first15=Gianalfredo |last16=Spadaro |first16=Daniele |last17=Stangalini |first17=Marco |last18=Teriaca |first18=Luca |last19=Landini |first19=Federico |last20=Sasso |first20=Clementina |last21=Susino |first21=Roberto |last22=Jerse |first22=Giovanna |last23=Uslenghi |first23=Michela |last24=Pancrazzi |first24=Maurizio |title=Connecting Solar Orbiter remote-sensing observations and Parker Solar Probe in situ measurements with a numerical MHD reconstruction of the Parker spiral |journal=Astronomy & Astrophysics |date=December 2022 |volume=668 |pages=A144 |doi=10.1051/0004-6361/202244535 |display-authors=1|arxiv=2211.12994 |bibcode=2022A&A...668A.144B }} {{Creative Commons text attribution notice|cc=by4|from this source=yes}}</ref>

In 2022, PSP and SolO collaborated to study why the Sun's atmosphere is "150 times hotter" than its surface. SolO observed the Sun from 140 million kilometers, while PSP simultaneously observed the Sun's corona during flyby at a distance of nearly 9 million kilometers.<ref>{{cite magazine |last1=Skibba |first1=Ramin |title=A Pair of Sun Probes Just Got Closer to Solving a Solar Enigma |url=https://www.wired.com/story/a-pair-of-sun-probes-just-got-closer-to-solving-a-solar-enigma/ |magazine=Wired |access-date=30 March 2024 |archive-url=https://archive.today/20230920125049/https://www.wired.com/story/a-pair-of-sun-probes-just-got-closer-to-solving-a-solar-enigma/ |archive-date=20 September 2023}}</ref><ref>{{cite journal |last1=Telloni |first1=Daniele |last2=Romoli |first2=Marco |last3=Velli |first3=Marco |last4=Zank |first4=Gary P. |last5=Adhikari |first5=Laxman |last6=Downs |first6=Cooper |last7=Burtovoi |first7=Aleksandr |last8=Susino |first8=Roberto |last9=Spadaro |first9=Daniele |last10=Zhao |first10=Lingling |last11=Liberatore |first11=Alessandro |last12=Shi |first12=Chen |last13=De Leo |first13=Yara |last14=Abbo |first14=Lucia |last15=Frassati |first15=Federica |last16=Jerse |first16=Giovanna |last17=Landini |first17=Federico |last18=Nicolini |first18=Gianalfredo |last19=Pancrazzi |first19=Maurizio |last20=Russano |first20=Giuliana |last21=Sasso |first21=Clementina |last22=Andretta |first22=Vincenzo |last23=Da Deppo |first23=Vania |last24=Fineschi |first24=Silvano |last25=Grimani |first25=Catia |last26=Heinzel |first26=Petr |last27=Moses |first27=John D. |last28=Naletto |first28=Giampiero |last29=Stangalini |first29=Marco |last30=Teriaca |first30=Luca |last31=Uslenghi |first31=Michela |last32=Berlicki |first32=Arkadiusz |last33=Bruno |first33=Roberto |last34=Capobianco |first34=Gerardo |last35=Capuano |first35=Giuseppe E. |last36=Casini |first36=Chiara |last37=Casti |first37=Marta |last38=Chioetto |first38=Paolo |last39=Corso |first39=Alain J. |last40=D’Amicis |first40=Raffaella |last41=Fabi |first41=Michele |last42=Frassetto |first42=Fabio |last43=Giarrusso |first43=Marina |last44=Giordano |first44=Silvio |last45=Guglielmino |first45=Salvo L. |last46=Magli |first46=Enrico |last47=Massone |first47=Giuseppe |last48=Messerotti |first48=Mauro |last49=Nisticò |first49=Giuseppe |last50=Pelizzo |first50=Maria G. |last51=Reale |first51=Fabio |last52=Romano |first52=Paolo |last53=Schühle |first53=Udo |last54=Solanki |first54=Sami K. |last55=Straus |first55=Thomas |last56=Ventura |first56=Rita |last57=Volpicelli |first57=Cosimo A. |last58=Zangrilli |first58=Luca |last59=Zimbardo |first59=Gaetano |last60=Zuppella |first60=Paola |last61=Bale |first61=Stuart D. |last62=Kasper |first62=Justin C. |title=Coronal Heating Rate in the Slow Solar Wind |journal=The Astrophysical Journal Letters |date=1 September 2023 |volume=955 |issue=1 |pages=L4 |doi=10.3847/2041-8213/ace112 |doi-access=free |arxiv=2306.10819 |bibcode=2023ApJ...955L...4T |display-authors=1}}</ref>

In March 2024, both space probes were at their closest approach to the Sun, PSP at 7.3 million km, and SolO at 45 million km. SolO observed the Sun, while PSP sampled the plasma of solar wind, that allowed scientists to compare data from both probes.<ref>{{cite web |title=ESA and NASA team up to study solar wind |url=https://www.esa.int/Science_Exploration/Space_Science/Solar_Orbiter/ESA_and_NASA_team_up_to_study_solar_wind |website=www.esa.int |access-date=30 March 2024 |language=en}}</ref>

== Gallery ==
<gallery mode="packed" heights="200px">
File:WISPR first light image.png|WISPR first light image. The right portion of the image is from WISPR's inner telescope, which is a 40-degree field of view and begins 58.5 degrees from the Sun's center. The left portion is from the outer telescope, which is a 58-degree field of view and ends about 160 degrees from the Sun.<ref>{{Cite web |url=http://parkersolarprobe.jhuapl.edu/News-Center/Show-Article.php?articleID=101 |title=Illuminating First Light Data from Parker Solar Probe |publisher=Johns Hopkins University Applied Physics Laboratory |first1=Sarah |last1=Frazier |first2=Justyna |last2=Surowiec |date=19 September 2018 |access-date=22 September 2018 |archive-date=December 30, 2021 |archive-url=https://web.archive.org/web/20211230155521/http://parkersolarprobe.jhuapl.edu/News-Center/Show-Article.php?articleID=101 |url-status=live }}</ref>
File:Parker-view-of-earth.jpg|The view from the probe's WISPR instrument on Sept. 25, 2018, shows Earth, the bright sphere near the middle of the right-hand panel. The elongated mark toward the bottom of the panel is a lens reflection from the WISPR instrument<ref>{{cite web |last1=Garner |first1=Rob |title=Parker Solar Probe Looks Back at Home |url=https://www.nasa.gov/feature/goddard/2018/parker-solar-probe-looks-back-at-home |website=NASA |access-date=29 April 2022 |date=22 October 2018 |archive-date=April 29, 2022 |archive-url=https://web.archive.org/web/20220429112442/https://www.nasa.gov/feature/goddard/2018/parker-solar-probe-looks-back-at-home/ |url-status=live }}</ref>
File:Parker Solar Probe coronal stream wispr-big 1-st flyby.jpg|Photo from the WISPR shows a coronal streamer, seen over the east limb of the Sun on Nov. 8, 2018, at 1:12&nbsp;a.m. EST. The fine structure of the streamer is very clear, with at least two rays visible. Parker Solar Probe was about 16.9 million miles (21.2 million km) from the Sun's surface when this image was taken. The bright object near the center of the image is Mercury, and the dark spots are a result of background correction.<ref>{{Cite web|url=http://parkersolarprobe.jhuapl.edu/News-Center/Show-Article.php?articleID=115|title=Preparing for Discovery With NASA's Parker Solar Probe|publisher=Johns Hopkins University Applied Physics Laboratory|website=Parker Solar Probe|language=en|access-date=2018-12-23|archive-date=February 14, 2022|archive-url=https://web.archive.org/web/20220214234620/http://parkersolarprobe.jhuapl.edu/News-Center/Show-Article.php?articleID=115|url-status=live}}</ref>
File:Wispr merged six planets.jpg|When Parker Solar Probe was making its closest approach to the Sun on June 7, 2020, WISPR captured the planets Mercury, Venus, Earth, Mars, Jupiter and Saturn in its field of view<ref>{{cite web |last1=Buckley |first1=Mike |title=Parker Solar Probe Captures a Planetary Portrait |url=http://parkersolarprobe.jhuapl.edu/News-Center/Show-Article.php?articleID=158 |website=Parker Solar Probe |publisher=Johns Hopkins APL |access-date=29 April 2022 |language=en |archive-date=April 29, 2022 |archive-url=https://web.archive.org/web/20220429112813/http://parkersolarprobe.jhuapl.edu/News-Center/Show-Article.php?articleID=158 |url-status=live }}</ref>
File:Venus-ParkerSolarProbe-July2020.jpg|Photo taken by the probe during its second [[Venus]] flyby, July 2020
File:Parker Solar Probe flew by Venus on its fourth flyby.gif|As Parker Solar Probe flew by Venus on its fourth flyby, its WISPR instrument captured these images, showing the nightside surface of the planet<ref>{{cite web |last1=Hatfield |first1=Miles |title=Parker Solar Probe Captures Visible Light Images of Venus' Surface |url=https://www.nasa.gov/feature/goddard/2022/sun/parker-solar-probe-captures-its-first-images-of-venus-surface-in-visible-light-confirmed |website=NASA |access-date=29 April 2022 |date=9 February 2022 |archive-date=April 14, 2022 |archive-url=https://web.archive.org/web/20220414155959/https://www.nasa.gov/feature/goddard/2022/sun/parker-solar-probe-captures-its-first-images-of-venus-surface-in-visible-light-confirmed/ |url-status=live }}</ref><ref name="Geophysical Research Letters 2022">{{cite journal | journal=Geophysical Research Letters | last1=Wood | first1=B. E. | last2=Hess | first2=P. | last3=Lustig-Yaeger | first3=J. | last4=Gallagher | first4=B. | last5=Korwan | first5=D. | last6=Rich | first6=N. | last7=Stenborg | first7=G. | last8=Thernisien | first8=A. | last9=Qadri | first9=S. N. | last10=Santiago | first10=F. | last11=Peralta | first11=J. | last12=Arney | first12=G. N. | last13=Izenberg | first13=N. R. | last14=Vourlidas | first14=A. | last15=Linton | first15=M. G. | last16=Howard | first16=R. A. | last17= Raouafi | first17=N. E. | doi=10.1029/2021GL096302 | date=February 9, 2022 | title=Parker Solar Probe Imaging of the Night Side of Venus | volume=49 | issue=3| pages=e2021GL096302 | pmid=35864851 | pmc=9286398 | bibcode=2022GeoRL..4996302W }}</ref>
File:Parker Solar Probe Encounters Streamers on the Way to the Sun.webm|As the probe passed through the Sun's corona in early 2021, it flew by structures called [[Helmet streamer|coronal streamers]]
</gallery>

== See also ==
* {{annotated link|Living With a Star}}
* {{annotated link|Advanced Composition Explorer}}, launched 1997
* [[List of vehicle speed records]]
* {{annotated link|Solar and Heliospheric Observatory}}, launched 1995
* {{annotated link|Solar Dynamics Observatory}}, ''SDO'', launched 2010
* {{annotated link|STEREO}}, launched 2006
* {{annotated link|TRACE}}, launched 1998
* {{annotated link|Wind (spacecraft)|''WIND''}}, launched 1994
* {{annotated link|Ulysses (spacecraft)|''Ulysses''}}
* {{annotated link|Spacecraft thermal control}}
* ''[[MESSENGER]]'', Mercury orbiter (2011–2015) with sun shield
* ''[[Solar Orbiter]]'',  Sun-observing space probe developed by the European Space Agency (ESA) launched on 10 February 2020

== Notes ==
{{Reflist|group=note}}

== References ==
{{Reflist}}

== Further reading ==
* {{cite journal |last1=Raouafi |first1=N. E. |last2=Matteini |first2=L. |last3=Squire |first3=J. |last4=Badman |first4=S. T. |last5=Velli |first5=M. |last6=Klein |first6=K. G. |last7=Chen |first7=C. H. K. |last8=Matthaeus |first8=W. H. |last9=Szabo |first9=A. |last10=Linton |first10=M. |last11=Allen |first11=R. C. |last12=Szalay |first12=J. R. |last13=Bruno |first13=R. |last14=Decker |first14=R. B. |last15=Akhavan-Tafti |first15=M. |last16=Agapitov |first16=O. V. |last17=Bale |first17=S. D. |last18=Bandyopadhyay |first18=R. |last19=Battams |first19=K. |last20=Berčič |first20=L. |last21=Bourouaine |first21=S. |last22=Bowen |first22=T. A. |last23=Cattell |first23=C. |last24=Chandran |first24=B. D. G. |last25=Chhiber |first25=R. |last26=Cohen |first26=C. M. S. |last27=D’Amicis |first27=R. |last28=Giacalone |first28=J. |last29=Hess |first29=P. |last30=Howard |first30=R. A. |last31=Horbury |first31=T. S. |last32=Jagarlamudi |first32=V. K. |last33=Joyce |first33=C. J. |last34=Kasper |first34=J. C. |last35=Kinnison |first35=J. |last36=Laker |first36=R. |last37=Liewer |first37=P. |last38=Malaspina |first38=D. M. |last39=Mann |first39=I. |last40=McComas |first40=D. J. |last41=Niembro-Hernandez |first41=T. |last42=Nieves-Chinchilla |first42=T. |last43=Panasenco |first43=O. |last44=Pokorný |first44=P. |last45=Pusack |first45=A. |last46=Pulupa |first46=M. |last47=Perez |first47=J. C. |last48=Riley |first48=P. |last49=Rouillard |first49=A. P. |last50=Shi |first50=C. |last51=Stenborg |first51=G. |last52=Tenerani |first52=A. |last53=Verniero |first53=J. L. |last54=Viall |first54=N. |last55=Vourlidas |first55=A. |last56=Wood |first56=B. E. |last57=Woodham |first57=L. D. |last58=Woolley |first58=T. |title=Parker Solar Probe: Four Years of Discoveries at Solar Cycle Minimum |journal=Space Science Reviews |date=February 2023 |volume=219 |issue=1 |pages=8 |doi=10.1007/s11214-023-00952-4 |arxiv=2301.02727 |bibcode=2023SSRv..219....8R |s2cid=255546506 |display-authors=3}}

== External links ==
{{Commons category}}
* [http://parkersolarprobe.jhuapl.edu/ ''Parker Probe Plus''] at [[Johns Hopkins University Applied Physics Laboratory]] (JHUAPL)
* [https://web.archive.org/web/20110719221441/http://solarprobe.jhuapl.edu/mission/docs/SolarProbeME.pdf ''Solar Probe Plus''] (Mission Engineering Report; JHUAPL)
* [https://web.archive.org/web/20160828040133/http://science.nasa.gov/about-us/smd-programs/heliophysics-research/ Heliophysics Research] (NASA)
* [http://ehpd.gsfc.nasa.gov/ Explorers and Heliophysics Projects Division] (EHPD; NASA)
* [https://www.nasa.gov/content/goddard/parker-solar-probe ''Parker Solar Probe''] (data and news; NASA)
* [https://www.nytimes.com/video/science/100000006012333/nasa-parker-solar-probe.html ''Parker Solar Probe''] (Video/3:45; [[NYT]]; August 12, 2018)
* [https://www.youtube.com/watch?v=BUClxcUbuNM ''Parker Solar Probe''] (Video—360°/3:27; [[NASA]]; September 6, 2018)
* [https://directory.eoportal.org/web/eoportal/satellite-missions/p/psp#mission-status ''eoPortal: Mission Status'']
* [https://wispr.nrl.navy.mil/encounter-summaries PSP/WISPR Encounter Summaries]

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