NASA has unveiled a stunning photo of Venus taken by its Parker Solar Probe from 7,693 miles away.
The image, taken on July 11 last year, is an almost eerie black and white photograph of the planet’s night side – the side facing away from the sun.
A bright rim around the edge of the planet is the nightglow – light emitted by oxygen atoms high in the atmosphere that rejoin into molecules.
NASA’s $ 1.5 billion Parker Solar Probe – which aims to study the sun and represents humanity’s first visit to a star – was launched in August 2018.
Venus, however, plays a big role in Parker’s seven-year mission, as it uses the planet’s gravity during multiple fly-bys.
This new photo, taken in July, was taken during the third of seven Venus fly-bys planned during Parker’s mission.
NASA’s Parker Solar Probe had a close-up of Venus when it flew past the planet in July 2020. Some features seen by scientists are labeled in this annotated image. The dark spot that appears on the lower part of Venus is an artifact of the WISPR instrument
Parker successfully completed his fourth fly-by of Venus last Saturday (Feb. 20).
This new July image was taken by the spacecraft’s WISPR instrument – Wide-field Imager for Parker Solar Probe.
WISPR is designed to capture images of the solar corona and inner heliosphere in visible light, as well as images of the solar wind and its structures as they approach and pass by the spacecraft.
The prominent dark feature in the center of the image is Aphrodite Terra, the largest highland region on the Earth’s surface.
The feature appears dark because of its cooler temperature, about 85 ° F (30 ° C) cooler than its surroundings.
That aspect of the image surprised the team, according to Angelos Vourlidas, WISPR project scientist at Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland.
“WISPR has been tailor-made and tested for visible light observations – we expected to see clouds, but the camera peered straight to the surface,” said Vourlidas.
Although the focus of Parker Solar Probe is the sun, Venus plays a vital role in the mission. The spacecraft will float past Venus a total of seven times during its seven-year mission. Pictured, artist’s impression of Parker and the Sun
This surprising observation sent the WISPR team back to the lab to measure the instrument’s sensitivity to infrared light.
If WISPR can indeed capture near-infrared wavelengths of light, it would open up new possibilities to study dust around the sun and in the inner solar system.
If it can’t pick up extra infrared wavelengths, these images – showing signatures of features on Venus’ surface – may have revealed a previously unknown ‘window’ through the Venusian atmosphere.
“Regardless, we have some exciting scientific opportunities ahead of us,” said Vourlidas.
Parker’s main scientific goals are to track energy flow and understand the warming of the solar corona – the sun’s outermost layer – and to investigate what accelerates the solar wind.
Although Parker’s focus is on the sun, Venus plays a critical role in its seven-year mission, which will run until 2025.
The spacecraft will whip past Venus a total of seven times, using the planet’s gravity to bend the spacecraft’s orbit and reduce its orbital energy.
These gravitational assistants from Venus allow Parker to fly ever closer to the sun on his mission to study the dynamics of the solar wind close to its source.
In the seven-year period, Parker makes 24 close approximations to the Sun (also known as a perihelion), each one closer than the last.
At the closest approach, Parker will race around the sun at about 430,000 miles per hour – fast enough to get from Philadelphia to Washington, DC in one second.
Parker launched on August 12, 2018 and uses Venus’s gravity to bend its orbit. These gravity assistants allow Parker to fly closer to the sun. Any new close approximation is called a perihelion. The first Venus flyby was on October 3, 2018, and the first perihelion came on November 6, 2018 (03:27 UTC), about Rs 35.7 from the sun. Rs stands for sunburst. 1 Rs is the distance from the center of the sun to the surface (approximately 432,000 miles or 696,000 kilometers)
It will fly as close as 3.83 million miles to the sun’s surface, facing heat and radiation “ like no spacecraft before it, ” NASA says.
This is well within Mercury’s orbit and about seven times closer than any spacecraft has ever come before.
Parker uses a heat shield known as the Thermal Protection System, which is 8 feet in diameter and 4.5 inches thick.
When closest to the sun, while the front of the Parker Solar Probe sunshade faces temperatures approaching 2,600 ° F (1,400 ° C), the spacecraft’s payload will be near room temperature, about 85 ° F.
The WISPR team captured more observations of the night side of Venus during Parker’s latest Venus flyby five days ago.
Just after 8:05 PM GMT on Saturday, Parker passed 1,482 miles (2385 km) above the surface as it orbited the planet, at a speed of about 15 miles (nearly 25 km) per second.
Scientists from the mission team expect to receive that data and process it for analysis by the end of April.
“We are very much looking forward to these new images,” said planet scientist Javier Peralta, who is working on Akatsuki, the Japanese space probe that studies the atmosphere of Venus.
“If WISPR can observe the thermal emission from the surface of Venus and nightglow – most likely from oxygen – at the edge of the planet, it could make valuable contributions to studies of the Venusian surface.”
Venus’s fourth gravitational assistant over the weekend sets Parker for his eighth and ninth perihelion, scheduled for April 29 and August 9.
During each of those passages, Parker will break its own record when it gets about 10.5 million miles from the solar surface, about 3 million miles closer than the previous 8.4 million mile perihelion on January 17.
Parker was launched on August 12, 2018 from Cape Canaveral, Florida, and just 78 days later became the most artificial object ever for the sun, breaking the record set in April 1976 by the Helios 2 spacecraft (a joint venture of West Germany and NASA).
The mission is named after Eugene Parker, an American solar astrophysicist at the University of Chicago – the first NASA mission named after a living individual.
In the 1950s, Parker proposed a number of concepts about how stars – including our sun – give off energy.
He called this cascade of energy the solar wind, and he described a very complex system of plasmas, magnetic fields and energetic particles that make up this phenomenon.
HOW DOES THE PARKER SOLAR PROBE GET SO CLOSE TO THE SUN?
The Parker Solar Probe mission requires 55 times more energy than it would need to reach Mars, according to NASA.
It launched on top of a United Launch Alliance Delta IV Heavy, one of the most powerful missiles in the world, with a third stage attached.
But trajectory and speed are critical to getting on the right track.
Because the Earth, and everything on it, is traveling sideways to the sun at about 108,000 miles per hour, the craft must be launched backwards to cancel sideways motion, NASA explains.
The Parker probe is going past the sun, so it will need to move about 85,000 miles per hour, according to the space agency.
The Parker Solar Probe will swing around Venus a total of seven times, with each movement slowing it down and pushing it closer to the sun. These jobs are shown in the animation above
This requires a boost from the powerful Delta IV rocket and several Venus’ gravity assistants to slow it down.
The probe will rely on a series of Venus’ gravity assistants to slow its lateral motion, allowing it to be just 6.1 million miles from the sun’s surface.
“In this case, instead of accelerating the spacecraft like a typical gravity assistant, Venus slows its lateral motion so that the spacecraft can get close to the sun,” NASA explains.
When it finally gets close, the Parker Solar Probe has lost much of its lateral speed, but the sun’s gravity has made it much faster overall.
“Parker Solar Probe will sweep past the sun at 430,000 miles per hour.”
At its closest approach, it will be just 6.1 million miles from the surface of the Sun, making it the only spacecraft to ever get that close.