The mission, which launched in 2018, aims to study the sun and reveal some of its mysteries. Over the course of seven years, the probe will travel through the sun’s atmosphere and get closer to the surface of our star than any previous spacecraft.
Venus is critical to the success of the probe. The spacecraft uses the gravity of Venus as it rotates around the planet, called gravity assist, to help bend the probe’s orbit and bring it closer and closer to the sun.
The spacecraft’s WISPR instrument, or the wide-field imager for Parker Solar Probe, was actively imaging during the flyby and captured the night side, or the side opposite the sun, of Venus. The image was taken 7,693 miles from the planet.
The bright streaks seen in the image are the result of space dust and cosmic rays, or charged particles, reflecting sunlight. The stripes look a little different depending on how fast the probe is traveling.
There is also a noticeably dark feature in the center of the image. It is known as Aphrodite Terra, which is the largest mountainous region on Venus. The reason it looks so dark in the image is because it is actually at a temperature that is 85 degrees Fahrenheit lower than the surrounding areas.
The WISPR instrument was designed for the probe so that it can collect images of the solar corona, or outer atmosphere, in visible light. The imager can also capture the solar wind in action. The solar wind is a constant stream of energized particles that flow from the sun.
When he turned to look at Venus, WISPR surprised the scientists on the team. Instead of seeing clouds, the surface of Venus was revealed. Venus has an incredibly thick atmosphere that has proven difficult to see with instruments on other spacecraft in the past.
“WISPR effectively captured thermal emission from the surface of Venus,” Brian Wood, an astrophysicist and a member of the WISPR team at the US Naval Research Laboratory in Washington, DC, said in a statement.
What WISPR was able to do in visible light is similar to what Akatsuki captured from Venus in the near infrared, Wood said.
Angelos Vourlidas, the WISPR project scientist at the Johns Hopkins Applied Physics Laboratory in Maryland, coordinated an imaging campaign with the Akatsuki mission.
One of two things is happening. Either WISPR is really sensitive to infrared light and detects it as it passes Venus, which could open up possibilities to study the dust around the sun, or the imager is looking through Venus’s atmosphere and directly towards the surface.
Parker Solar Probe just made its fourth flyby of Venus on February 20, passing 1,482 miles from the planet’s surface, so the team planned another set of observations of the nightside of Venus. That information should be received by the end of April, according to NASA.
Each step of the sun leads the probe to break its own previous record, approaching more than a million miles closer than the previous step. These passes will bring the probe within 10.5 million kilometers of the sun’s surface.
“We are eager to see these new images,” said Javier Peralta, an astrophysicist on the Akatsuki team. Peralta was the first to suggest a Parker Solar Probe collaboration with the Japanese mission.
“If WISPR can sense the thermal emission from the surface of Venus and the nighttime glow, most likely from oxygen, at the extremity of the planet, it can make valuable contributions to studies of the surface of Venus.”