Parker Solar Probe

Launch data: Designation  43592 / 18065A Launch date  12 Aug 2018 - 07:31 UT Launch site  CC, SLC-37B Launch vehicle  Delta-4H/Star48BV Mission  Solar Astronomy Heliocentric orbit: Perihelion / Aphelion  617 x -18602 Eccentricity   Inclination  33.0° Period   min

Spacecraft data: Prime manufacturer  NASA JHU/APL Platform  Hexagonal prism s/c bus configuration Operator  NASA JHU/APL Mass at launch  685 kg, including 80 kg of hydrazine propellant. Dry Mass   kg Basic shape   Dimension (m)  height: 3m, max dia.: 2.3m, bus dia.: 1m Equipment  FIELDS, WISPR, SWEAP, ISIS Solar array  2 deployable solar arrays (1.55 m2) Transmitting  0.6 m HGA, 34 W TWTA Ka-band science DL Science downlink rate  167 kb/s at 1AU Propulsion   DC power   Design lifetime  7 yrs

Anti-Ram Facing view. Credit: NASA/jhuapl.edu Ram Facing view. Credit: NASA/jhuapl.edu

Description:

• Parker Solar Probe will study the streams of charged particles the sun hurls into space from a vantage point within the sun′s corona – its outer atmosphere – where the processes that heat the corona and produce solar wind occur. At closest approach Solar Probe would zip past the sun at 201 km/s, protected by a carbon-composite heat shield that must withstand up to 1430 degrees Celsius and survive blasts of radiation and energized dust at levels not experienced by any previous spacecraft. Solar Probe is part of NASA′s Living with a Star Program, designed to learn more about the sun and its effects on planetary systems and human activities.
• Parker Solar Probe has a mass of 685 kg - including 80 kg of hydrazine propellant - and carries the WISPR wide field imager, the ISIS particle detector suite, the FIELDS experiment to measure electric and magnetic fields, and the SWEAP instrument for in situ measurements of the solar wind. It cowers behind a 73 kg, 2.4m wide carbon-carbon heatshield; at the end of its mission, when propellant has run out and the heatshield can′t be pointed at the Sun any longer, the rest of the probe will burn and melt, presumably leaving the heatshield to orbit the Sun on its own.
• Parker Solar Probe will use seven Venus flybys over nearly seven years to gradually shrink its orbit around the sun (V7GA), coming as close as 6.2 million km to the sun′s photosphere, well within the orbit of Mercury and about eight times closer than any spacecraft has come before.
• Solar Probe will employ a combination of in-place and remote measurements to achieve the mission′s primary 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; and explore dusty plasma near the sun and its influence on solar wind and energetic particle formation. Details will be spelled out in a Solar Probe Science and Technology Definition Team study that NASA will release later this year. NASA will also release a separate Announcement of Opportunity for the spacecraft′s science payload.
• Solar Probe will be fortified with heat-resistant technologies developed for APL′s MESSENGER spacecraft, which completed its first flyby of Mercury in January and will begin orbiting that planet in 2011. Solar Probe′s solar shield concept was partially influenced by designs of MESSENGER′s sunshade.
• Parker Solar Probe employs a host of autonomous systems to keep the spacecraft safe without guidance from Earth — including automatic retraction of the solar panels to regulate their temperature, attitude control using solar limb sensors that ensures all of the instruments remain in the heat shield′s shadow, and a sophisticated guidance and control system that keeps the spacecraft pointed correctly. This autonomy is key not only during no-contact phases around the 24 planned perihelia but also throughout the mission, when the round-trip light time — the time it takes for radio signals to go back and forth between Earth and Parker Solar Probe — can be up to 31 minutes.
• During the solar encounter phase, Parker Solar Probe′s four instrument suites measure the properties of material directly within the Sun′s outer atmosphere. These observations, gathered closer to the Sun than ever before, will help scientists begin to answer outstanding questions about the Sun′s fundamental physics — including how particles and solar material are accelerated out into space at such high speeds and why the Sun′s atmosphere, the corona, is so much hotter than the surface below.
• Because of the spacecraft′s distance from Earth and position relative to the Sun, it will be several weeks after the end of the solar encounter before Parker Solar Probe begins transmitting this science data back to Earth.

Mission details:

• The Solar Probe Plus mission, named in honour of solar wind discoverer Gene Parker, was launched on Aug 1, 2018 by a ULA Delta 4 Heavy with an additional Northrop Grumman-developed third stage using a Star 48BV solid motor. This was flight Delta 380.
  The Delta 4 Heavy′s second stage entered a 170 x 180 km x 28 deg parking orbit at 07:41 UTC and coasted to the equator where at 07:53 UTC the stage reignited. The slightly yawed burn changed orbit inclination to 33.0 degrees and accelerated the vehicle to 13.2 km/s (geocentric inertial). The third stage/payload stack then separated from the second stage.
• After venting excess propellant, the second stage continued on a hyperbolic trajectory of about 307 x -26350 km x 33.0 deg, with C3= 59.9 km**2/s**2, leaving the Earth′s gravitational sphere of influence on Aug 14 to enter a roughly 0.37 x 1.0 AU solar orbit. Meanwhile, one minute after separation, at 08:08 UTC Aug 12, the third stage ignited for an 89 second burn and accelerated to a blistering 16.0 km/s (geocentric). At 08:14 UTC the third stage separated from Parker Solar Probe, with both on a 615 x -18608 km x 33.0 deg hyperbola with C3=152.2 km**2/s**2. Both objects left the Earth′s Hill sphere at 1731 UTC Aug 13, entering a 0.21 x 1.01 AU x 5.6 deg solar orbit.
• The Parker Solar Probe entered Venus′ gravitational sphere at 20:35 UTC Oct 2, 2018. Parker flew 2428 km above the surface of Venus at 08:46 UTC Oct 03 and departed the Venus gravitational sphere at 20:56 UTC. Before encounter, Parker was in a 0.208 x 1.014 AU x 5.6 deg solar orbit (31 x 152 million km). Now, it is in a 0.166 x 0.938 AU x 3.4 deg (25 x 140 million km). First perihelion will be on Nov 6 at 0329 UTC.
• As of Oct 23, 2018 Parker Solar Probe became closer to the Sun than Mercury and had picked up speed to 50.3 km/s (heliocentric; 181,000 km/hr).
  On Oct 30, 2018 it broke the speed record of 68.6 km/s set by Helios 2 in 1976 and at perihelion Nov 6 at 0330 TDB (03:28 UTC) it set a new speed record of 95.33 km/s and closeness-to-Sun record of 0.165 AU (24.8 million km).
  Relative to Earth (which you should not care abou) Parker broke the Helios 2 record of 98.9 km/s early on Nov 5 and set a new record of 109.9 km/s on Nov 7 around 1900 UTC.
  
  

  Concept of operations

  Parker Solar Probe trajectory

  
  
• On Oct. 31, 2018, Parker Solar Probe began its first of 24 solar encounters. This period — which lasts until Nov. 11 — is the time during which the spacecraft is within 0.25 astronomical units, or 23.2 million miles, of the Sun′s center. Parker Solar Probe′s four suites of science instruments are on and collecting data throughout this phase, giving scientists their closest-yet look at this dynamic region of the Sun′s outer atmosphere.
• For several days around the Nov. 5, 2018 perihelion, Parker Solar Probe will be completely out of contact with Earth because of interference from the Sun′s overwhelming radio emissions.
• After completing three perihelia (2018 Nov 6 0329UTC, 2019 Apr 4 2240UTC, 2019 Sep 1 1740UTC) at 0.166AU, Parker is in a 0.166 x 0.938 AU x 3.4 deg solar orbit approaching its second Venus flyby. It will be in the Venusian sphere of influence from 0605 Dec 26, 2019 to 0626 Dec 27, with a flyby on Dec 26 1815 UTC in a 3008 x -16349 km x 3.6 deg hyperbola.
• The Parker Solar Probe passed 3008 km from Venus on Dec 26, 2019 at 1815 UTC, its second Venus flyby. Parker was within Venus′ Hill sphere from Dec 26 0605 to Dec 27 0626 UTC. Once back in solar orbit its perhelion will be only 0.130 AU, compared to 0.166 AU before the flyby.
• This will lower its solar orbit perihelion to 0.130 AU. Perhelion 4 will be at 0938 UTC (0939 TDB) Jan 29, 2020 at a distance of 0.1296 AU from the center of the Sun and a heliocentric inertial velocity of 109.18 km/s (393,000 km/hr or 0.36 millilight). The corresponding kinematic Lorentz factor is 1.0 + 6.5E-8. The gravitational redshift z is slightly larger, 1.0 + 7.6E-8.
• Parker passed through its 5th perihelion, 0.1296 AU from the Sun, at 0823 UTC Jun 7, 2020.
• Parker passed through Perhelion 6 at 0916 TDB on 2020 Sep 27, at a record close distance of 0.095 AU to the Sun and a record heliocentric velocity of 129.6 km/s. Parker′s orbit is 0.095 x 0.817 AU x 3.4 deg.

External links:

• NASA: Track Parker Solar Probe′s speed and position online.
• AmericaSpace: Parker Solar Probe Reveals Sun in New, Surprising Ways
• Satellite tracking (n2ya.com): Real time satellite tracking

Astrophilately covers:

Testing antenna′s, cancel KSC. Credit both: #411

Launch cancel KSC

Closest approch of the Sun, cancel Goddard Space Flight Sep 27, 2020. Credit: #411