NASA’s Parker Solar Probe (PSP) has set a new record. It approached the Sun at a distance of only 6.1 million kilometers.
A six-year journey to the Sun
PSP was launched in 2018. It is designed to study the upper, thinnest and hottest layer of the solar atmosphere, called the corona, and the processes occurring in it. The solar corona consists of plasma with a temperature of about a million degrees Celsius.
Powerful solar radiation and high temperatures are not the only factors hindering the study of the corona. For a spacecraft to get closer to the Sun, its orbital velocity must be reduced. And that requires more fuel than it can take with it.
So, the mission developers took advantage of gravity. They planned the trajectory of the PSP flight in such a way that it periodically approached Venus. During each pass of the planet, its gravity slowed down the probe, reducing the perihelion of its orbit. The last, seventh maneuver near Venus took place on November 6, 2024. It allowed to transfer of the probe to a record close orbit. By this point, the distance traveled by PSP during its journey through the solar system exceeded 6 billion kilometers. This is more than the distance from Earth to Pluto.
The fastest and closest vehicle to the Sun in history
On December 24 at 11:53 AM UTC (6:53 AM UTC -5), PSP passed the perihelion of its new orbit. At that moment, it was moving at a heliocentric speed of 692 thousand km/h (192.2 km/s), being at a distance of only 6.1 million kilometers from the solar surface. It thus became the fastest and closest spacecraft to the Sun in history. By comparison, Mercury never comes closer to the Sun than 46 million km.
It is estimated that the composite heat shield of the PSP heated up to a temperature of 1400°C as it passed perihelion. This is only slightly below the melting point of nickel.
According to engineers on 27 December the probe will have to send a signal to Earth confirming that it has successfully passed perihelion. Retransmission of the collected information to Earth will begin next year when the vehicle moves away from the Sun.
It is worth noting that this is the final orbit of the PSP. The vehicle will no longer perform gravitational maneuvers near Venus and reduce the perihelion of its orbit. The current flight plan suggests that PSP should perform two more passes around the Sun, after which its mission will be completed. However, it cannot be ruled out that if the apparatus is in good technical condition, NASA will decide to extend its service life.
Earlier we told you about Europe’s Proba-3 mission, which will study the solar corona by creating artificial eclipses in space.
