Parker Solar Probe

Parker Solar Probe

Artist's impression of Parker Solar Probe
Names	Solar Probe (–2002) Solar Probe Plus (2010–17)
Mission type	Solar heliophysics orbiter
Operator	NASA · Applied Physics Laboratory
Website	solarprobe.jhuapl.edu
Mission duration	6 years, 321 days (planned)
Spacecraft properties
Manufacturer	Applied Physics Laboratory
Launch mass	610 kg (1,340 lb)
Dry mass	555 kg (1,224 lb)
Payload mass	50 kg (110 lb)
Dimensions	1.0 m × 3.0 m × 2.3 m (3.3 ft × 9.8 ft × 7.5 ft)
Power	343 W (at closest approach)
Start of mission
Launch date	July 31–August 19, 2018 (planned)[1]
Rocket	Delta IV Heavy / Star-48BV[2]
Launch site	Cape Canaveral SLC-37
Orbital parameters
Reference system	Heliocentric
Perihelion	6.0 million km; 0.040 AU (3.7 million mi)
Apohelion	109.3 million km; 0.730 AU (67.9 million mi)
Inclination	3.4°
Period	88 days
Transponders
Band	Ka band X band
Instruments SWEAP Solar Wind Electrons Alphas and Protons Investigation SPC Solar Probe Cup SPAN Solar Probe Analyzers WISPR Wide-field Imager for Solar Probe FIELDS Electromagnetic Fields Investigation ISIS‒EPI Integrated Science Investigation of the Sun Energetic Particle Instruments
Official insignia for the Parker Solar Probe mission

Parker Solar Probe (previously Solar Probe, Solar Probe Plus, or Solar Probe+) is a planned NASA robotic spacecraft to probe the outer corona of the Sun.^[3][4] It will approach to within 8.5 solar radii (5.9 million kilometers or 3.67 million miles) to the 'surface' (photosphere) of the Sun.^[5] The project was announced as a new mission start in the fiscal 2009 budget year. On May 1, 2008 Johns Hopkins University Applied Physics Laboratory announced it will design and build the spacecraft, on a schedule to launch it in 2015.^[6] The launch date has since been pushed back to 2018.^[7] The Delta IV Heavy as launch vehicle is planned to enable the mission to be the fastest spacecraft to date.^[2][8][9] On May 31, 2017 the probe was renamed after solar astrophysicist Eugene Parker.^[3][10] This was the first time a NASA spacecraft was named after a living person.^[11]

History

The Parker Solar Probe originates from a predecessor Solar Orbiter project conceived in the 1990s. Similar in design and objectives, the Solar Probe mission served as one of the centerpieces of the eponymous Outer Planet/Solar Probe (OPSP) program formulated by NASA. The first three missions of the program were planned to be the Solar Orbiter, the Pluto and Kuiper Belt reconnaissance mission Pluto Kuiper Express, and the Europa Orbiter astrobiology mission focused on Europa.^[12][13] Following the appointment of Sean O'Keefe as Administrator of NASA, the entirety of the OPSP program was cancelled as part of President George W. Bush's request for the 2003 United States federal budget.^[14] 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."^[14]

The cancellation of the program also resulted in the initial cancellation of New Horizons, the mission that won the competition to replace Pluto Kuiper Express in the former OPSP program.^[15] That mission, which would eventually be launched as the first mission of the New Frontiers program, a spiritual successor to the OPSP program, would undergo a lengthy political battle to secure funding for its launch, which occurred in 2006.^[16] Plans for the Solar Probe mission would later manifest as the Solar Probe Plus in the early 2010s.^[17]

Mission and trajectory

Apparent size of the Sun as seen from the orbit of Solar Probe Plus compared to its apparent size seen from Earth.

The Parker Solar Probe mission design uses repeated gravity assists at Venus to incrementally decrease the orbital perihelion to achieve multiple passes of the Sun at approximately 8.5 solar radii, or about 6 million km (3.7 million mi; 0.040 AU).^[18]

The mission is designed to survive the harsh environment near the Sun, where the incident solar intensity is approximately 520 times the intensity at Earth orbit, by the use of a solar shadow-shield. The solar shield, at the front of the spacecraft, is made of reinforced carbon-carbon composite. The spacecraft systems and scientific instruments are located in the central portion of the shield's shadow (the umbra) , where direct radiation from the sun is fully blocked. The primary power for the mission will be by use of a dual system of photovoltaic arrays. A primary photovoltaic array, used for the portion of the mission outside 0.25 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.^[19]

As the probe passes around the Sun, it will achieve a velocity of up to 200 km/s (120 mi/s) making it by any measure, the fastest manmade object ever, almost three times faster than the current record holder, Helios-B.^[20][21][22]

Scientific goals

• Determine the structure and dynamics of the magnetic fields at the sources of solar wind.
• Trace the flow of energy that heats the corona and accelerates the solar wind.
• Determine what mechanisms accelerate and transport energetic particles.
• Explore dusty plasma near the Sun and its influence on solar wind and energetic particle formation.

Timeline

After the first Venus fly-by, the probe will be in an elliptical orbit with a period of 150 days (two-thirds the period of Venus), making three orbits while Venus makes two. On the second fly-by, the period shortens to 130 days. After less than two orbits (only 198 days later) it encounters Venus a third time at a point earlier in the orbit of Venus. This encounter shortens its period to half of that of Venus, or about 112.5 days. After two orbits it meets Venus a fourth time at about the same place, shortening its period to about 102 days. After 237 days it meets Venus for the fifth time and its period is shortened to about 96 days, three-sevenths that of Venus. It then makes seven orbits while Venus makes three. The sixth encounter, almost two years after the fifth, brings its period down to 92 days, two-fifths that of Venus. After five more orbits (two orbits of Venus) it meets Venus for the seventh and last time, decreasing its period to 88 or 89 days and allowing it to approach close to the sun.^[23]

See also

• Advanced Composition Explorer (ACE), launched 1997, still operational.
• List of vehicle speed records
• MESSENGER
• Solar Orbiter, 45 R_s
• STEREO (Solar TErrestrial RElations Observatory), launched 2006, still operational.
• WIND (spacecraft) launched 1994, still operational.

References

External links

Wikimedia Commons has media related to Parker Solar Probe.

• Solar Probe Plus at the Johns Hopkins Applied Physics Laboratory
• Solar Probe Plus Mission Engineering Study Report
• NASA – Heliophysics Research
• Explorers and Heliophysics Projects Division (EHPD)

Solar space missions
Current	ACE DSCOVR GGS WIND Hinode (Solar-B) IRIS MinXSS PICARD RHESSI SOHO SDO SOLAR STEREO
Past	Apollo Telescope Mount ESRO 2B Genesis GOES 13 Helios Hinotori (Astro-A) IMP-8 Intercosmos 26 ISEE 1–3 Koronas-Foton Orbiting Solar Observatory OSO 1 OSO 2 OSO 3 OSO 4 OSO 5 OSO 6 OSO 7 OSO 8 Solwind Pioneer 5 Pioneer 6, 7, and 8 Prognoz 6 SolarMax Spartan 201 Taiyo (SRATS) TRACE Ulysses Yohkoh (Solar-A)
Planned	ADAHELI Aditya-1 Parker Solar Probe Proba-3 Solar-C Solar Orbiter Solar Sentinels
Cancelled	Pioneer H OSO J
Sun-Earth	SORCE SXI ACRIMSAT