NASA's Parker Solar Probe will change what we know about our Sun

On August 12, 2018, NASA launched a small, car-sized spacecraft to venture where no other spacecraft has gone before, as close as 4 million miles from the burning hot Sun.

The Parker Solar Probe is designed to withstand the scorching heat of our host star, where surface temperature reach 10,000 degrees Fahrenheit, in order to give us an unprecedented view of the Sun and help scientists better understand solar wind.

Earlier this month, the spacecraft embarked on its longest observational campaign to date during its fifth solar flyby, and it is scheduled to get as close as 11.6 million miles from the Sun’s surface on June 7. On this day, the Parker Solar Probe will essentially break its own record for closest man-made object to the Sun.

The spacecraft has already completed four orbits around the Sun. However, for its fifth encounter with the star, the Parker Solar Probe turned on its science instruments at a distance of 62.5 million miles from the Sun’s surface, which is around 39 million miles farther from the Sun than a typical solar encounter.

That means that the spacecraft will be collecting data for a far longer period of time than during its other orbits around the Sun. In fact, NASA's Parker Solar Probe started collecting data on May 9, and will continue to do so until June 28. That's a significantly longer time than the usual 11-day period of previous solar encounters.

What is the goal of the Parker Solar Probe mission?

The mission is designed to touch the Sun, or at least get as close to doing that as possible.

Parker Solar Probe will help scientists get a better understanding of solar activity, and space weather. Space weather refers to solar wind and ejections of matter from the Sun’s corona, both of which can have a direct effect on orbiting satellites, and, more importantly, on human spaceflight.

Previous efforts to study solar wind have been done at a distance of one AU, or about 93 million miles. But the Parker Solar Probe will inch closer and closer to the Sun with each orbit, eventually reaching a distance of 4 million miles of the Sun’s surface — offering unprecedented new details about this mysterious process.

The tiny probe carries a host of instruments onboard to measure solar wind, particles, magnetic fields, solar radio emissions, and the structure of the Sun's corona.

By getting a better look at the Sun’s corona, scientists hope to solve another of the biggest solar mysteries. For years, they have been baffled by the extreme temperatures in the corona, which can rise to one million degrees Celsius. This is hotter than the Sun’s surface — at a relatively cool 5,700 degrees C.

What is the timeline of the mission?

The Parker Solar Probe launched in August, 2018, and entered into its first orbit of the Sun on November 5, 2018.

It is scheduled for 24 orbits around the Sun. The spacecraft will reach its closest encounter with the Sun during its fifth orbit on June 7, and will continue to draw closer and closer to the star with each orbit.

The final close encounter will take place on June 19, 2025, where it will be just 4 million miles away from the burning surface of the Sun.

How is the solar probe different from other missions?

The coming years are set to be transformative in the area of heliophysics, or the science of the Sun.

With NASA's Parker Solar Probe already in orbit, NASA and the European Space Agency (ESA) launched another mission to the Sun. Solar Orbiter will travel toward the Sun to measure its magnetic fields — the streams of particles and plasma ejected from the star. It will also give scientists their first good look at the Sun’s poles.

The two will work side by side to answer some of the burning questions scientists have about our host star.

However, even on its closest encounter with the Sun, the Solar Orbiter will be at a distance of 26 million miles away from the star. Instead, the spacecraft will be focused on capturing the Sun's magnetic poles with an unprecedented view, essentially staring down at them.

What have we learned so far from the solar probe?

Although the Parker Solar Probe still has a long way to go in its six year duration mission, initial data from its first encounters with the Sun have already proven to be quite lucrative.

In December, 2019, scientists released a series of four studies based on the probe's first two solar encounters. The data was collected in late 2018 and in March and April of 2019, when the spacecraft was around 23,250,000 miles away from the Sun.

In one study, researchers focused on the probe’s observations of solar plasma and discovered that as the Sun’s magnetic field reverses, it increases the speed of the solar wind leaving the core of the Sun.

A second study looked at high-energy ions and electrons being ejected by the Sun. These are more abundant near the the outermost part of the Sun’s atmosphere. The findings show that these particles are accelerated by sudden eruptions of radiation, or plasma, from the corona itself.

And that's not all.

Data from the Parker Solar Probe's fifth observation campaign will be downlinked to Earth between late June and mid-August, 2020, and will be released to the public in November 2020.

The fifth observation campaign will also help scientists learn a little more about a nearby planet. The solar probe uses the planet Venus as a gravity assist, using the gravitational force of the planet to propel itself into orbit around the Sun.

The Parker Solar Probe is scheduled for its third Venus flyby on July 11, 2020, where it will be at an altitude of approximately 516 miles above Venus’ surface. During this brief encounter with the planet, the probe will witness an 11-minute solar eclipse which will allow it to gather data on Venus' atmosphere and the planet's nightside.