NASA's Parker Solar Probe nailed its fourth swing past Venus on Feb. 20, and mission scientists celebrated the release of a stunning image captured during a similar maneuver in July.
Parker Solar Probe launched a daring mission in August 2018: to fly closer to the sun than any previous spacecraft. But along the way, the probe must have passed Venus a total of seven times, with each passage pulling the spacecraft closer to the sun. And while Parker Solar Probe is tailored to the study of the sun, if a spacecraft has to loop past our "bad twin" planet anyway, it might as well turn the instruments on, the team figured.
NASA's Parker Solar Probe nailed its fourth swing past Venus on Feb. 20, an
On July 11, 2020, the spacecraft was flying its third Venus, zooming 7,693 miles (12,380 kilometers) away from the planet, according to the NASA statement. During the maneuver, the crew switched to the Wide-field Imager for the Parker Solar Probe (WISPR) spacecraft to take a look at Venus—with stunning results.
WISPR is designed to capture distant, visible-light images of phenomena surrounding the sun, such as the solar wind that continuously emits charged particles from the sun through the solar system, or coronal mass ejections that vomit blobs of matter into space, according to NASA.
So this isn't your typical planetary glamour shot: there's no color, no intricate clouds, no cosmic crispness.
But it's a fascinating view of the Earth's neighbor and one that scientists are still looking at, according to the NASA release. The bright rim around the edge of Venus may be light from the individual oxygen atoms in the upper atmosphere of the planet, creating what is known as the nightglow since it occurs on it. The bright rim around Venus' edge may be light from individual oxygen atoms in the planet's upper atmosphere pairing up, creating what's known as nightglow since it occurs on the shadowed side of the planet.
Strikes that can be seen passing through the image also offer a puzzle. Some may be traces of cosmic rays, while some may be dust reflecting sunlight in the camera, and some may be tiny particles from the spacecraft itself, flung away by impacting dust.
But the real highlight is Venus itself, which looks nothing like what scientists expected to see with WISPR. "WISPR is tailored and tested for visible-light observations," Angelos Vourlidas, the WISPR project scientist from the Johns Hopkins Applied Physics Laboratory (APL) in Maryland said in the statement. "We expected to see clouds, but the camera peered right through to the surface."
Specifically, the instrument captured differences in the surface temperature of Venus. The dark blob at the center of the image of the planet is a massive highland region that scientists call Aphrodite Terra. Here, scientists know that the rock is cooler, about 85 degrees Fahrenheit (30 degrees Celsius) compared to nearby regions, according to NASA.
WISPR The WISPR Seeing this temperature difference could mean that something strange is happening in the thick atmosphere of Venus, which allows the instrument to see through the clouds. Or, it could mean that WISPR could actually pick up some near-infrared light it wasn't technically designed to see, which could create new opportunities for space observation.
To determine which scenario is at play, WISPR took similar photographs during the fourth Venus flyby of Parker Solar Probe, which took place on Feb. 20. At the time of the closest approach, at 3:05 p.m. EST (2005 GMT), the spacecraft arrived within 1,500 miles (2,400 km) of the Venusian surface, according to the NASA statement.
However, these images will not make it to Earth until the end of April. The next milestone of the spacecraft will be a close approach to the sun on April 29; its next Venus flyby is scheduled for October 16.