In News:

Recently, the NASA’s Parker Solar Probe made another close approach to the Sun, reaching within 6 million km of its surface. It continues to break records as the closest any human-made object has come to the Sun, aiming to improve our understanding of solar activity and space weather.

Key Highlights:

• Background:Launched on August 12, 2018, by NASA from Cape Canaveral, Florida, the Parker Solar Probe is designed for in-situ study of the Sun's outer atmosphere (corona), solar wind, and magnetic field. It was named after physicist Eugene Parker, who first theorized the existence of the solar wind in the late 1950s.
• Mission Objectives:
  • Investigate the structure and dynamics of the solar corona
  • Understand the origin and evolution of solar wind
  • Study energetic particles responsible for solar storms
  • Examine the mechanisms that heat the corona to over a million degrees Celsius while the Sun’s surface remains relatively cooler at ~6,000°C
• Orbital Details & Speed:The Parker Probe moves in a highly elliptical orbit using Venus' gravity for repeated assists to get closer to the Sun. It is the fastest human-made object, reaching speeds of up to 692,000 km/hr. Its closest planned approach is 6.16 million km (3.83 million miles) from the Sun—about seven times closer than any previous spacecraft.
• Heat Protection Technology:To withstand extreme solar radiation, the probe uses an 8-foot-wide, 4.5-inch-thick carbon-carbon composite heat shield capable of resisting temperatures up to 1,377°C. The shield’s sun-facing side is coated with white ceramic paint to reflect sunlight, and its design ensures that just behind the shield, temperatures drop to a manageable 29°C, protecting the onboard instruments.
• Scientific Instruments Onboard:
  • FIELDS – Measures electric and magnetic fields in the corona.
  • ISoIS (Integrated Science Investigation of the Sun) – Studies high-energy solar particles.
  • SWEAP (Solar Wind Electrons, Alphas, and Protons) – Captures data on solar wind particles.
  • WISPR (Wide-Field Imager) – Takes images of the solar corona and heliosphere.
  • Faraday Cup – An external device made of molybdenum alloy (melting point: 2,349°C), measures ion and electron densities in solar wind.
• Key Discoveries:
  • First ‘Touch’ of the Sun (April 2021): The probe crossed the Sun’s Alfvén surface — the boundary where solar wind escapes the Sun’s influence — thus officially entering the solar corona.
  • Magnetic Switchbacks: Detected sudden reversals in the Sun’s magnetic field direction, providing clues about how solar wind accelerates.
  • Dust-Free Zones: Found regions near the Sun unexpectedly devoid of dust, challenging earlier theories about uniform dust distribution in the solar system.
  • Corona Heating Mystery: Parker’s data, especially on Alfvén waves and magnetic switchbacks, may help solve why the corona is vastly hotter than the Sun’s surface
• Challenges Overcome:Contrary to expectations, the Sun’s gravity, not heat, posed a significant challenge. High speeds needed careful navigation to avoid crashing into the Sun. The mission used Earth and Venus flybys to gradually spiral inward for closer approaches rather than the initial, longer route via Jupiter.
• Mission Timeline:The Parker Solar Probe is scheduled to make 24 close passes of the Sun, continuing into the 2030s. Each pass provides new insights into solar activity and its potential impacts on Earth.
• Comparison with India’s Aditya-L1 Mission:While the Parker Solar Probe performs in-situ analysis by flying into the corona, ISRO’s Aditya-L1, launched in 2023, is stationed at the Lagrange Point 1 (L1), 1.5 million km from Earth. Aditya-L1 remotely observes solar flares, coronal mass ejections (CMEs), and magnetic storms using seven payloads, including a coronagraph.

In News:

NASA scientists announced that the Parker Solar Probe survived the closest-ever approach to the Sun. The craft was operating normally after it passed just 6.1 million km from the solar surface.

About the Parker Solar Probe:

• Launched: August 12, 2018, as part of NASA’s Living With a Star program.
• Named After: Eugene Newman Parker, a solar astrophysicist, marking the first NASA mission named after a living researcher.
• Mission Objectives:
  • To study the Sun’s corona and the solar wind, investigating why the corona is hotter than the Sun’s surface.
  • To explore the origins of solar winds and high-energy particles that impact space weather.
  • To understand the structure and dynamics of plasma and magnetic fields around the Sun.
  • To examine the mechanisms behind the acceleration and transportation of energetic particles.

Technological Feats:

• Heat Shield: Equipped with a 4.5-inch carbon-composite shield that withstands temperatures up to 1,377°C (2,500°F) while keeping the instruments cool at about 29.4°C (85°F).
• Speed: Travels at a speed of 692,000 km/h (430,000 mph), making it the fastest human-made object.
• Venus Flybys: Uses gravitational assists from Venus to gradually reduce its orbit and get closer to the Sun.

Historic Milestone:

• Closest Approach: On December 24, 2024, Parker Solar Probe reached a historic distance of 6.1 million km from the Sun's surface, the closest any human-made object has ever been.
  • Comparison: If the Earth and Sun were 1 meter apart, Parker Solar Probe would be just 4 cm from the Sun.
  • Temperature: At its closest, it endured temperatures up to 1,377°C.

Significance of the Mission:

• Scientific Contributions:
  • Solar Wind: Helps scientists understand the origins of solar winds, which affect space weather and Earth’s technological systems.
  • Corona Heating: Investigates why the Sun's corona is much hotter than its surface (a long-standing astrophysical mystery).
  • Space Weather: Provides critical data for predicting space weather events that can impact satellites, communication systems, and power grids on Earth.
• Practical Implications:
  • Improves understanding of space weather, potentially aiding in the protection of Earth’s infrastructure from solar storms.
• Technological and Engineering Marvel:
  • Demonstrates advanced spacecraft technology that can withstand extreme conditions close to the Sun.

Recent Developments:

• Data Collection: As the probe passed through the Sun’s outer atmosphere (the corona), it collected valuable data expected to answer fundamental questions about solar behavior.
• Communication: Despite the extreme proximity to the Sun, the probe sent back a signal on December 26, confirming its status.

Key Dates:

• Launch: August 12, 2018.
• Closest Approach: December 24, 2024.
• Data Expected: Detailed telemetry data on January 1, 2025.