NASA's Ambitious Mission: Journeying to 'Touch the Sun

 NASA's Historic Solar Encounter: Parker Solar Probe to Achieve Unprecedented Speeds and Proximity to the Sun

In a groundbreaking moment for space exploration, NASA's Parker Solar Probe is set to mark a milestone on December 24 next year. Racing past the Sun at an astounding speed of 195 km/s (435,000 mph), this mission will bring a human-made object closer to our star than ever before—merely 6.1 million km (3.8 million miles) from the Sun's "surface."

Describing the significance of this daring endeavor, Dr. Nour Raouafi, the project scientist for Parker, exclaimed, "We are basically almost landing on a star." Drawing parallels to the historic Moon landing of 1969, he emphasized that this achievement will be monumental for all of humanity.

Parker's unprecedented speed is attributed to the immense gravitational pull it experiences as it hurtles towards the Sun—a journey likened to flying from New York to London in under 30 seconds. Launched in 2018, NASA's Parker Solar Probe is hailed as one of the most audacious missions ever conceived, with the goal of making repeated and progressively closer passes of the Sun.

In late 2024, Parker's trajectory will bring it within just 4% of the Sun-Earth distance, covering a mere 149 million km (93 million miles). The challenges are immense, with temperatures on the front of the spacecraft likely reaching 1,400°C at perihelion, the closest point to the star in its orbit.

Parker's strategy involves swift maneuvers, entering and exiting quickly while deploying a suite of instruments from behind a robust heat shield to make crucial measurements of the solar environment. Researchers anticipate that the reward for this audacious mission will be breakthrough knowledge on key solar processes, particularly providing a clearer understanding of the workings of the corona—the Sun's outer atmosphere.

                                 Photo: High-resolution views of the solar surface

In a perplexing revelation, the Parker Solar Probe has encountered a phenomenon of counter-intuitive superheating within the Sun's corona. While the surface temperature at the photosphere is around 6,000°C, the corona defies expectations by reaching temperatures exceeding a million degrees.

Contrary to the anticipated decrease in temperature with distance from the Sun's nuclear core, scientists are grappling with the enigma of the corona's extreme heat. Additionally, the corona becomes the epicenter of accelerated outward flows of charged particles—electrons, protons, and heavy ions—transforming into a supersonic wind hurtling at 400 km/s or 1,000,000 mph. This acceleration remains a puzzle for scientists, yet its comprehension holds critical implications for enhancing solar behavior forecasts and understanding "space weather."

The term "space weather" encompasses potent eruptions of particles and magnetic fields from the Sun, capable of disrupting communications on Earth and even destabilizing power grids. These solar events also pose health risks to astronauts, especially as plans for lunar missions and establishing a permanent presence on the Moon gain momentum.

                                               Photo:  The Solar Corona

Dr. Nour Raouafi, the project scientist for Parker, emphasized the heightened significance of this mission, particularly in the context of lunar exploration. Parker recently completed one of its close approaches to the Sun, with three more planned in 2024. On 6 November, it will swing around Venus to adjust its orbit, setting the stage for a historic flyby on 24 December. Dr. Nicky Fox, NASA's head of science and former lead scientist on Parker, highlighted the unique aspect of the upcoming flyby—the extended time the probe will spend within the corona, surpassing any previous passes. The mission aims to explore waves in the solar wind associated with the heating, offering potential insights into long-debated processes.

As the apex of Parker's mission approaches in the coming year, the probe won't be able to draw any closer to the Sun beyond December. This limitation is not only due to orbital constraints but also the risk of exposing the spacecraft's rear to intolerable temperatures by shortening the protective shadow cast by its heat shield. The culmination of Parker's mission promises to unlock unprecedented knowledge about the Sun's mysteries, paving the way for advancements in solar science and space exploration.