NASA’s Parker Solar Probe reached 6.1 million km from the Sun’s surface on December 24, 2024—the closest a spacecraft has ever been.
Took seven years to reach this point.
Further close approaches on March 22 and June 19, 2025.
Importance of Observing the Sun
Sunlight is Earth’s primary energy source, generated by nuclear fusion in the core.
The Sun has strong magnetic fields, whose sudden changes cause solar flares.
The solar corona ejects electrons, protons, and heavy nuclei at 900 km/s.
Coronal mass ejections (CMEs) can lead to solar storms, affecting:
Electric grids
Telecommunication systems
Ozone layer
Satellite instruments
India’s Aditya-L1 mission is also studying the Sun from 150 million km away.
Heat Shield and Design
Named after Eugene Parker, who predicted solar wind.
Launched in August 2018 aboard a Delta IV rocket from Cape Canaveral.
Maximum speed: 692,000 km/hr.
Heat shield:
8-foot-wide, 4.5-inch thick carbon-carbon composite material.
Can withstand 1,370º C, but weighs only 73 kg.
Built by Johns Hopkins Applied Physics Laboratory.
Sun-facing side: coated with white ceramic paint to reflect heat.
Behind the shield, the temperature drops to 29º C, protecting instruments.
Two sets of solar panels:
One in the shield’s shadow (powers instruments).
One sun-facing (uses a fluid pump for cooling).
Challenges in Reaching the Sun
First challenge: Not the heat, but gravity.
The probe had to slow down significantly to avoid crashing into the Sun.
Initially considered using Jupiter’s gravity but abandoned due to long travel time.
Instead, used Earth and Venus’s gravity to gradually spiral closer.
Scientific Instruments
FIELDS – Measures electric and magnetic fields in the solar atmosphere.
ISoIS – Analyzes energetic particles causing solar storms.
WISPR – Captures images of the solar corona.
SWEAP – Records properties of solar wind particles.
Faraday Cup – Measures ion & electron density in solar wind, made of molybdenum alloy (melting point: 2,349º C).
Discoveries So Far
Found dust-free pockets near the Sun, challenging previous beliefs.
Detected magnetic switchbacks, where the solar wind’s magnetic field bends backward.
Helped investigate why the solar corona (1 million ºC) is much hotter than the Sun’s surface (6,000º C).
Scientists believe Alfvén waves (plasma oscillations driven by magnetic fields) play a role in this mystery.
Latest Updates
On March 22, 2025, the probe attempted another close approach (~6 million km).
Scientists are analyzing new findings from this mission.
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