#NASA's #ParkerSolarProbe Mission to Touch the Sun Documentary in Telugu || Aditya 2018 || #PrashanthFacts
For the first time, a NASA spacecraft will swoop in and touch the sun. The Parker Solar Probe will make 24 orbits of the star before swooping into the outermost part of the solar atmosphere, known as the corona, to study the sun up close and personal. At its closest approach, Parker Solar probe will fly within 3.7 million miles (6 million kilometers) of the sun's surface — more than eight times closer than any other spacecraft and more than eight times closer than Mercury.
The probe launched on Aug. 11, 2018, from Cape Canaveral, Florida. It will study how heat and energy move through the corona and explore what accelerates the solar winds that affect Earth and other planets. The probe is named after Eugene Parker, who first hypothesized that high-speed matter and magnetism constantly escaped the sun, and that it affected the planets and space throughout our solar system. This phenomenon is now known as the solar wind.
The Parker Solar Probe will arrive at the sun in November, spending seven years studying the star from 3.7 million miles (6 million km) away. Mercury, the closest planet to the sun, only gets as close as 29 million miles (47 million km) in its highly eccentric orbit. The spacecraft will make 24 orbits around the sun, using Venus to make seven gravity assists.
Flying through the corona for the first time, the probe will take a combination of measurements and imaging to help revolutionize our understanding of the corona and expand our knowledge and evolution of the solar wind. At its closest approach, the front of the solar shield faces temperatures approaching 2,500 degrees Fahrenheit (1,377 degrees Celsius). It will be protected by a heat shield that will keep most of the instruments near room temperature.
"Our solar arrays are going to operate in an extreme environment that other missions have never operated in before," Johns Hopkins Applied Physics Lab's Mary Kae Lockwood, spacecraft system engineer for Parker Solar Probe, said in a statement.
These temperatures would prove dangerous to conventional arrays that have flown on other missions, so new technology was required. The mission relies on a first-of-its-kind actively cooled solar array system.
But before the spacecraft reaches the sun, it will have to travel through the freezing temperatures of space.
"One of the biggest challenges in testing this is those transitions from very cold to very hot in a short period of time," Lockwood said.
It turns out that pressurized water makes the best coolant for the instruments when the spacecraft reaches the sun. Because the probe will first have to travel through the freezing temperatures of space before reaching the broiling solar environment, any coolant would need to operate between 50 F (10 C) and 257 F (125 C), and few liquids can handle that range like water. Pressurizing the water raises its boiling point.
"For the temperature range we required, and for the mass constraints, water was the solution," Lockwood said.
After launch, temperature swings will impact the water. First, the temperatures of the solar arrays and cooling system radiators will drop down as low as minus 220 F (minus 140 C) before they can be warmed by the sun. Less than an hour later, the spacecraft will separate from the launch vehicle and begin a complex post-separation sequence in which the probe rotates several times and water flows from the heated accumulator tank into the two of the radiators and power charges the batteries.
When the spacecraft reaches the sun, it will need to make further adjustments, without the help of engineers on the ground. It takes light — and radio signals — about eight minutes to travel from the sun to Earth. That means that the complex adjustments the spacecraft needs to undergo to protect itself will be done autonomously. New software will help the spacecraft to instantly alter its pointing to maximize protection from the sun.
"During solar encounters, very small changes in the wing angle of the solar array can vastly change cooling capacity needed." Lockwood said that a one-degree change in the array angle of one wing would require 35 percent more cooling capacity.