The International Energy Agency projected in 2014 that under its ‘high renewables’ scenario, solar would be the world’s largest source of electricity by 2050. We are all aware of the benefits of using a renewable source of energy such as solar. It is non-polluting, non-exhaustible, sustainable, abundant, and a free source of power. Yet how much do we know about the source itself? As a commoner, just that it is a huge ball of gases and is the largest object in the solar system with a mass of 1,988,920,000,000,000,000,000,000,000,000 kilograms only! (1.98892 x 1030 kilograms), which is actually slowly decreasing over time. The warmth we feel from the Sun is the Sun’s lost mass.
Thus, understanding the Sun is, and has always been, a top priority for astronomers and astrophysicists. Studying how the Sun affects space and the environment of planets is not only crucial to understanding earth’s life-sustaining star, but also in supporting exploration in the solar system and beyond.
Launched on August 12, 2018, Parker Solar Probe is on a seven-year mission, targeting to unlock the mysteries of solar wind (constant stream of highly charged plasma leaving the sun) and the corona (star’s outer atmosphere). It is named after Eugene Parker, an American solar astrophysicist, who in the 1950s proposed a number of concepts about how stars give off energy. Parker also theorised an explanation for the corona, which is – contrary to what was expected by the laws of physics – hotter than the surface of the sun itself!
The primary objectives for the mission are:
- Trace the flow of energy that heats and accelerates the corona and solar wind.
- Determine the structure and dynamics of the plasma and magnetic fields at the sources of the solar wind.
- Examine mechanisms that accelerate and transport energetic particles.
In short, the probe’s mission is to provide insights into what drives the solar winds and study the space weather throughout the solar system (shaped by the solar winds).
It is carrying out four experiments in space:
- Fields Experiment, which studies electric and magnetic fields.
- Integrated Science Investigation of the Sun, which measures high-energy charged particles in the solar wind and corona.
- Wide-Field Imager for Solar Probe, which images the solar wind and other structures.
- Solar Wind Electrons Alphas and Protons Investigation, which measures different types of particles in the solar wind, how fast they go, how hot they get and how many of them there are.
Nearly 18 months into its mission, the Parker Solar Probe has returned more than 22 gigabytes of data on the Sun and its atmosphere. The data will be useful in improving forecasts of major eruptions on the Sun like solar storms that can disrupt technology and endanger astronauts. The craft is intended to orbit the Sun 24 times, soon after which it will run out of fuel, disintegrate and become part of the dust cloud. It has already made its third flyby of the Sun and the probe’s next closest approach is on January 29, 2020.
If you’re wondering why the probe hasn’t burst into flames till now, you’re not alone. The biggest challenge faced by the engineers was protecting the spacecraft and its instruments from the Sun’s heat. The entire structure is covered by a four and a half-inch thick heat shield made from a single layer of carbon foam and is layered between two panels to withstand 2,500°F (or 1371°C) temperatures. Materials like niobium were used that have a high melting point. Besides this, they also need to keep the probe perfectly aligned, as if the probe tilts more than just 1° off course, part of the heat-sensitive payload would be exposed to the searing heat causing it to melt (which is what’s going to happen once the fuel runs out at the end of the mission).
Scientists had been dreaming about putting a spacecraft near the Sun since 1958. “We’ve had to wait so long for our technology to catch up with our dreams”, said Nicola Fox, a scientist at John Hopkins University. NASA finally had the courage and the backing to bet $1.5 billion on their dreams, and the returns can be seen with the gamut of data that the probe is transmitting, aiding in solving long-standing mysteries.