Parker Solar Probe | A New Milestone In Space World

NASA’s ‘Parker Solar Probe’ has become the first-ever mission to “touch” the Sun. The spacecraft, about the size of a small car, will travel directly into the Sun’s atmosphere about 4 million miles from the surface. Parker Solar Probe launched aboard a Delta IV-Heavy rocket from Cape Canaveral, the USA. 

In order to unlock the mysteries of the Sun’s atmosphere, Parker Solar Probe will use Venus’ gravity during seven flybys over nearly seven years to gradually bring its orbit closer to the Sun. The spacecraft will fly through the Sun’s atmosphere as close as 3.8 million miles to our star’s surface, well within the orbit of Mercury and more than seven times closer than any spacecraft has come before. (Earth’s average distance to the Sun is 93 million miles.) 

Inside that part of the solar atmosphere, a region known as the corona, Parker Solar Probe will provide unprecedented observations of what drives the wide range of particles, energy and heat that course through the region — flinging particles outward into the solar system and far past Neptune. 

Parker Solar Probe has been designed to withstand the extreme conditions and temperature fluctuations for the mission. The key lies in its custom heat shield and an autonomous system that helps protect the mission from the Sun’s intense light emission but does allow the coronal material to “touch” the spacecraft.

One key to understanding what keeps the spacecraft and its instruments safe, is understanding the concept of heat versus temperature. Counterintuitively, high temperatures do not always translate to actually heating another object. 

In space, the temperature can be thousands of degrees without providing significant heat to a given object or feeling hot. Why? Temperature measures how fast particles are moving, whereas heat measures the total amount of energy that they transfer. Particles may be moving fast (high temperature), but if there are very few of them, they won’t transfer much energy (low heat). Since space is mostly empty, there are very few particles that can transfer energy to the spacecraft.

The corona through which Parker Solar Probe flies, for example, has an extremely high temperature but very low density. Think of the difference between putting your hand in a hot oven versus putting it in a pot of boiling water (don’t try this at home!) — in the oven, your hand can withstand significantly hotter temperatures for longer than in the water where it has to interact with many more particles. Similarly, compared to the visible surface of the Sun, the corona is less dense, so the spacecraft interacts with fewer hot particles and doesn’t receive as much heat.

That means that while Parker Solar Probe will be travelling through space with temperatures of several million degrees, the surface of the heat shield that faces the Sun will only get heated to about 2,500 degrees Fahrenheit (about 1,400 degrees Celsius). 

Of course, thousands of degrees Fahrenheit is still fantastically hot. (For comparison, lava from volcano eruptions can be anywhere between 1,300 and 2,200 F (700 and 1,200 C)  And to withstand that heat, Parker Solar Probe makes use of a heat shield known as the Thermal Protection System, or TPS, which is 8 feet (2.4 meters) in diameter and 4.5 inches (about 115 mm) thick. Those few inches of protection mean that just on the other side of the shield, the spacecraft body will sit at a comfortable 85 F (30 C). 

In the mid-1950s, a young physicist named Eugene Parker proposed a number of concepts about how stars — including our sun — give off energy. He called this cascade of energy the solar wind, and he described an entire complex system of plasmas, magnetic fields and energetic particles that make up this phenomenon. 

• The National Aeronautics and Space Administration (NASA) is an independent agency of the executive branch of the Federal government of the United States responsible for the civilian space program, as well as aeronautics and aerospace research. 
• It was founded on 1958. 
• Jim Bridenstine is the present Administrator of NASA.