In April 2022, news headlines declared that a NASA spacecraft had “touched the sun” for the first time in history. This was in reference to the Parker Solar Probe, a spacecraft launched in 2018 to study the sun up close. But did the Parker Solar Probe really make direct contact with the blazing hot surface of the sun? Let’s take a closer look at what this milestone achievement actually entailed.
What is the Parker Solar Probe?
The Parker Solar Probe is a NASA spacecraft launched in 2018 with the goal of studying the sun from closer than any spacecraft before it. It is named after astrophysicist Eugene Parker, who first theorized the concept of solar wind in 1958.
Some key facts about the Parker Solar Probe:
- It was launched on August 12, 2018 from Cape Canaveral, Florida.
- Its goal is to study the outer atmosphere of the sun, known as the corona.
- It will provide new data on solar wind, coronal mass ejections, and other solar phenomena.
- It is equipped with cutting-edge heat shields and cooling systems to withstand the extreme environment near the sun.
- Over 7 years, it will make 24 orbits around the sun, coming as close as 3.8 million miles to the surface.
The data collected by the Parker Solar Probe will help scientists better understand the inner workings of the sun and its dynamic effects on the solar system. This could lead to improved space weather prediction capabilities.
The Milestone Achievement
In April 2022, the Parker Solar Probe completed the tenth close approach of its mission. During this approach, it set a new record for the closest any spacecraft has come to the surface of the sun.
Specifically, the Parker Solar Probe reached a distance of only 8.4 million miles from the visible surface of the sun. To put that in perspective:
- The average distance between the Earth and sun is about 93 million miles.
- The previous record for closest solar approach was set by the Helios 2 spacecraft in 1976 at 27 million miles.
- At its peak velocity during this approach, the Parker probe was moving at 363,660 miles per hour relative to the sun.
For the first time, a spacecraft was close enough to pass through the outermost part of the sun’s atmosphere, known as the corona. This required withstanding extraordinary levels of radiation and heat.
Did It Really “Touch” the Sun?
Given the news headlines, you might think the Parker Solar Probe actually made direct contact with the surface of the sun. But in reality, the spacecraft still remained millions of miles away from the sun’s photosphere – the visible “surface” that we see glowing bright.
At its record distance of 8.4 million miles, the Parker probe was still more than 9 times farther away from the sun’s surface than the Earth is. The corona region it reached extends far beyond the photosphere.
So while it did not actually “touch” the sun, the Parker probe did have a remarkable encounter with the outer atmosphere of the star. Its instruments were able to sample solar particles and radiation at closer range than ever before.
Why Remaining Miles Away is Necessary
You might wonder, if the goal is to study the sun up close, why does the spacecraft need to stay millions of miles away from the surface?
The answer is that the environment becomes incredibly hostile as you near the sun’s visible surface. Let’s look at some of the conditions the Parker probe actually experienced at 8.4 million miles out:
- A solar irradiation level of 514 times greater than that experienced in Earth orbit.
- A peak temperature on its heat shield of 1,377 degrees Fahrenheit.
- An extreme radiation dose equivalent to 5,000 dental X-rays per hour.
And keep in mind, the visible surface of the sun reaches temperatures of nearly 10,000 degrees Fahrenheit! Any spacecraft exposed to that heat would melt in an instant. The pressure from solar material and radiation is also exponentially greater closer to the surface.
So in order to collect meaningful data while surviving long enough to beam it back, the Parker probe has to maintain a safe distance of millions of miles. Its cutting-edge thermal protection system allows it to get tantalizingly close while making record-breaking solar science observations.
Key Discoveries
Although the Parker Solar Probe mission still has several more years to go, some significant discoveries about the sun have already been made in its first few orbits. Here are a few examples:
- Switchbacks: These are sudden reversals in the direction of solar magnetic field lines, and the Parker probe detected many more than expected in the corona.
- Slow solar wind: The origins of the slow solar wind were traced to holes in the corona at the equator.
- Nanoflares: Tiny bursts of energy likely contribute to coronal heating and the acceleration of the solar wind.
- Coronal streamers: Enormous structures were observed reaching out from the sun into interplanetary space.
There are still many mysteries to solve, as a majority of the solar material that escapes the sun comes from regions that remain unobserved. The next flybys will bring the Parker probe even closer, and more groundbreaking revelations are anticipated.
Conclusion
While it makes for flashy headlines to say a spacecraft “touched the sun,” the reality is more complex. The Parker Solar Probe did not actually make contact with the sun’s visible surface. However, in flying through the outer corona for the first time, it provided humanity’s first up-close glimpse of our star. The unprecedented data gathered by the mission will advance our understanding of the sun and its impacts for decades to come.