Engineering news
It will reach an orbit of 6 million km, or just eight-and-a-half solar radii, as it “tastes, touches and smells” the Sun’s atmosphere.
The unmanned NASA craft will launch in 2018 to study the Sun’s magnetic fields and ejections of particles. Scientists hope the machine, renamed yesterday after scientist and first theoriser of solar wind Eugene Parker, will answer questions which have stood for 60 years.
John Hopkins University in Maryland has designed and built the craft to withstand temperatures of up to 1,377°C. The university said it has made “significant progress on several enabling technologies” for the mission, including a 11.43cm-thick carbon-composite shield and a liquid cooling system for the craft’s solar arrays.
“The challenges are not just the peak in temperature, there is also the difference in temperature that the space craft will experience,” said Matteo Ceriotti, a rocket scientist at the University of Glasgow. He told Professional Engineering the craft will have to be able to withstand temperatures from close to absolute zero (-273°C) to the hottest point, where the Sun’s intensity will be about 475 times that on Earth.
The multi-layered shield will insulate and protect the craft’s 10 scientific instruments, which scientists hope will answer why the Sun’s outer atmosphere, or corona, is hotter than its surface and what force is accelerating the solar wind hitting Earth. The craft’s solar panels will also be retractable to cope with the extreme temperatures.
“Solar panels heat up and effectively the efficiency drops,” said Ceriotti. “The amount of energy that can be dissipated on a space craft is very limited, so if there is an excess of electricity generated by the solar panels there is no way to dissipate it, the space craft will simply increase in temperature even further.” The craft’s retractable panels are an “unusual” feature, he added.
Scientists hope the craft’s findings will help improve forecasts of solar storms, which bombard Earth’s atmosphere with particles and radiation. The craft is a “functioning reality ready to do battle with the solar elements as it divulges the secrets of the expanding corona,” said Eugene Parker of his namesake at the University of Chicago yesterday.