Parker Solar Probe / WISPR
Given that this year’s prediction model captures both the corona and inner heliosphere in near-real-time, it is possible to generate synthetic white-light data for NASA’s Parker Solar Probe (PSP) mission. Launched in 2018 and now in its extended mission, PSP successfully completed its closest approach to the Sun (at 9.86 solar radii) on December 24, 2024. The spacecraft carries four instrument suites: three in-situ suites (FIELDS, SWEAP, and IS☉IS) and one remote-sensing suite, the Wide-field Imager for Parker Solar Probe (WISPR). Designed, developed, and led by the U.S. Naval Research Laboratory, WISPR records visible-light images of the solar corona and heliosphere using two partially overlapping cameras (WISPR-Inner and WISPR-Outer), which together provide an angular field of view exceeding 100°.
In the animation on the left, we present synthetic WISPR observables (specifically the K-coronal total brightness, tB) both at the time of totality on August 12 and throughout the simulated evolution of the spacecraft’s viewpoint. The blue contour outlines the approximate field of view of WISPR-Inner, while the green contours indicate that of WISPR-Outer. These outlines are only approximate because the orientation of the instrument changes slightly with the spacecraft’s roll angle along its orbit, causing the projected fields of view to vary by a few degrees.
To aid with the interpretation of these images, the animations on the right show a top-down view of the heliosphere along with the evolution of the mass density scaled by the radius squared in the equatorial plane (the Sun-centered plane perpendicular to the rotation axis of the Sun). As described in more detail on the Heliospheric Imagers page, we can also color the WISPR field of view by its relative expected sensitivity along each line of sight. This helps connect the evolution that we see in the central region of the WISPR images with the large-scale context and evolution in the heliosphere.
PSP follows a highly elliptical orbit with a period of (currently) about 88 days, reaching perihelion at 9.86 solar radii and aphelion at approximately 157 solar radii (or 0.73 au). During the interval simulated for the 2026 total solar eclipse, however, the spacecraft is near aphelion, whereas WISPR normally operates only around perihelion. Consequently, the instrument would not actually be acquiring observations during this period. We nevertheless generate these synthetic data to illustrate what WISPR might have observed from a much greater heliocentric distance than during its nominal observing intervals.
