27 February 2017 Current Affairs: The National Aeronautics and Space Administration (NASA) plans to send its first robotic spacecraft to the Sun in 2018.
The Solar Probe Plus mission, which is going to be NASA’s first to the Sun, is expected to get within six million kilometres of the Sun to probe its atmosphere.The Sun is about 149 million kilometres from the Earth.
According to Eric Christian, a NASA research scientist at the Goddard Space Flight Centre, though the spacecraft would not be able to get to the surface of the Sun it would definitely get close enough to answer three very important questions.
Why is the Sun’s surface, which is called photosphere, not as hot as its atmosphere?
What accelerates the speed of the solar wind?
Why does the Sun occasionally emit high-energy particles that pose a danger to unprotected astronauts and spacecraft?
Christian explained the queries by saying that according to the data collected by NASA, the surface temperature of the Sun is only 5500 degrees Celsius but the temperature of its atmosphere is about two million degrees Celsius and generally the farther away you go from the heat source, the colder it gets but with the Sun, it’s the opposite.
Further, he added that the Sun blows a stream of charged particles in all directions at a million miles an hour however, it is not clear from where it gets that much speed.
Features of the spacecraft : It will have a 11.4 centimetres carbon-composite shield that has been designed by NASA to withstand temperatures outside the spacecraft of 1370 degrees Celsius.
The spacecraft will also have special heat tubes called thermal radiators, which will radiate the heat that permeates the heat shield to open space so that it does not reach the instruments that are sensitive to heat.