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. It will approach to within 8.86 solar radii (6.2 million kilometers or 3.85 million miles) from the 'surface' (photosphere) of the Sun.
The project was announced in the fiscal 2009 budget year. Johns Hopkins University Applied Physics Laboratory designed and built the spacecraft, which was originally scheduled to launch in 2015. The launch date has since been rescheduled to the summer of 2018. This was the first time a NASA spacecraft was named after a living person, honoring physicist Eugene Parker.
Video Parker Solar Probe
History
The Parker Solar Probe concept 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. 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. 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."
The cancellation of the program also resulted in the initial cancellation of New Horizons, the mission that eventually won the competition to replace Pluto Kuiper Express in the former OPSP program. That mission, which would eventually be launched as the first mission of the New Frontiers program, a conceptual successor to the OPSP program, would undergo a lengthy political battle to secure funding for its launch, which occurred in 2006. Plans for the Solar Probe mission would later manifest as the Solar Probe Plus in the early 2010s.
In May 2017, the spacecraft was renamed Parker Solar Probe in honor of astrophysicist Eugene Parker.
Maps Parker Solar Probe
Overview
The Parker Solar Probe will be the first spacecraft to fly into the low solar corona. It will determine the structure and dynamics of the Sun's coronal magnetic field, understand how the solar corona and wind are heated and accelerated, and determine what processes accelerate energetic particles. The Parker Solar Probe mission design uses repeated gravity assists at Venus to incrementally decrease its 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).
The spacecraft's systems are designed to endure the extreme radiation and heat 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 is 11.4 cm (4.5 in) thick and is made of reinforced carbon-carbon composite, which is designed to withstand temperatures outside the spacecraft of about 1,377 °C (2,511 °F). The shield is hexagonal and is mounted at the Sun-facing side of the spacecraft. The spacecraft systems and scientific instruments are located in the central portion of the shield's shadow, where direct radiation from the Sun is fully blocked. The primary power for the mission will be a dual system of solar panels (photovoltaic array). 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.
Trajectory
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. The science phase will take place during those 7 years, focusing on the periods when the spacecraft is closest to the Sun. The near Sun radiation environment is predicted to cause both 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.
The trajectory requires high launch energy, so the probe will be launched on a Delta IV Heavy class launch vehicle and an upper stage based on the STAR-48B solid rocket motor. Interplanetary gravity assists will provide further deceleration relative to its heliocentric orbit, which may result in a heliocentric speed record at perihelion. As the probe passes around the Sun, it will achieve a velocity of up to 200 km/s (120 mi/s), which will temporarily make it the fastest manmade object, almost three times as fast as the current record holder, Helios-B. Like every object in an orbit, due to gravity the spacecraft will accelerate as it nears perihelion, then slow down again afterwards until it reaches its aphelion.
Scientific goals
The goals of the mission are:
- 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 solar energetic particles formation.
Investigations
In order to achieve these goals, the mission will perform five major experiments or investigations:
- Electromagnetic Fields Investigation (FIELDS) -- This investigation will make direct measurements of electric and magnetic fields, radio waves, Poynting flux, absolute plasma density, and electron temperature. Its main instrument is a flux-gate magnetometer. The Principal investigator is Stuart Bale, at the University of California, Berkeley.
- Integrated Science Investigation of the Sun (IS?IS)-- This investigation will measure energetic electrons, protons and heavy ions. The instrument suite is composed of two independent instruments, EPI-Hi and EPI-Lo. The Principal investigator is David McComas, at the Princeton University.
- Wide-field Imager for Solar PRobe (WISPR)-- These optical telescopes will acquire images of the solar corona and inner heliosphere. The Principal Investigator is Russell Howard, at the Naval Research Laboratory.
- Solar Wind Electrons Alphas and Protons (SWEAP)-- This investigation will count the electrons, protons and helium ions, and measure their properties such as velocity, density, and temperature. Its main instruments are two electrostatic analyzers and a Faraday cup. The Principal Investigator is Justin Kasper at the University of Michigan and the Smithsonian Astrophysical Observatory.
- Heliospheric origins with Solar Probe Plus (HeliOSPP) is a theory and modeling investigation to maximize the scientific return from the mission. The Principal Investigator is Marco Velli.
Planned timeline
Perihelion means the point in the PSP's orbit closest to the Sun
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.
See also
- Advanced Composition Explorer (ACE), launched 1997, still operational as of December 2017.
- List of vehicle speed records
- MESSENGER, Mercury flybys and orbited from 2011-2015. Mercury ranges from about 50 to 70 solar radii from the Sun
- Solar Orbiter, 45 R?
- Prior or current Sun observation spacecraft
- STEREO (Solar TErrestrial RElations Observatory), launched 2006, partially operational as of December 2017. (solar orbit)
- WIND (spacecraft) launched 1994, still operational as of December 2017 (studies solar wind)
- Ulysses (spacecraft) Unique solar polar orbiter (1990-2009)
References
External links
- Parker 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)
Source of article : Wikipedia
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