Powdered bones keep Solar Orbiter cool thanks to Irish startup ENBIO
Apr 1, 2021
Joint mission with NASA, the Solar Orbiter was launched in February 2020 and recently emerged from its first pass behind the sun. It must be able to withstand temperatures hot enough to melt lead, as well as 13 times the radiation that reaches the Earth’s surface. At first, the agency looked for conventional, metal-based and carbon-fiber solutions, but they weren’t good enough, Cesar Garcia Marirrodriga, ESA project manager for Solar Orbiter, told CNN Business. . Instead, the agency found the answer in material that dates back to the Stone Age. After ESA issued an invitation to come up with solutions, it was approached by the Irish biotech company ENBIO. He had developed a technique for applying synthetic bone coatings to orthopedic and dental implants, in order to make them more easily accepted by a patient’s body. Because the technique reduced weight and prevented issues like chipping, ENBIO thought it might be useful for the titanium surfaces of Solar Orbiter. But the synthetic bone was light in color, and tests showed it would darken after prolonged exposure to sunlight, altering the amount of heat absorbed and reflected. A black coating meant that its properties would be stable throughout the mission, absorbing energy from the sun in the form of heat and then releasing it back into space. “I tried coloring the bone powder to make it black, but it didn’t work very well,” recalls John O’Donoghue, founder of ENBIO. Instead, he started looking for a naturally black bone powder. “I remembered reading when I was a child that in rock art people used charcoal and in some cases [burnt] animal bones because the end would be like a pencil and they could draw on the walls, ”he said. After O’Donoghue obtained some burnt animal bone powder, ESA found it to be ideal for the solar mission. Besides being black, there is nothing combustible in the material – so when heated, it does not release any gas that could damage the spacecraft, Garcia Marirrodriga explained. The resulting coating, called SolarBlack, covers about a fifth of Solar Orbiter’s surface and keeps its most delicate parts at room temperature while absorbing heat up to 1,000 degrees Fahrenheit. ENBIO, in collaboration with Airbus (EADSF), has also developed SolarWhite, a white coating that covers other parts of the satellite where sunlight needs to be reflected rather than absorbed. Aim for space
O’Donoghue’s interest in coatings technology began while studying biomedical engineering at Trinity College Dublin. He founded ENBIO in 2006 and in 2015 the company opened a 1.5 million euro ($ 1.8 million) industrial coating facility in Clonmel, approximately 100 miles southwest of Dublin. Solar Orbiter has brought the company several million euros, according to O’Donoghue, and ESA has deployed SolarBlack on other missions. O’Donoghue said the coatings and the coating process can find applications in the automotive, metal, heating and power industries, among others, but the current focus is beyond this planet. “We are targeting the space sector because we felt that if we went to the top of the pyramid and [do well there], the rest of the industry will accept it more, ”he said. Although its main mission does not begin until November, Solar Orbiter returned last July the closest images of the sun ever taken. Over the next several years, the 1.5 billion euro ($ 1.8 billion) mission will use the gravity of Earth and Venus to launch itself closer and closer to the sun, ultimately achieving one of the most close to the star in the orbit of Mercury. “The goal is to really understand the physics of how the sun creates and controls the heliosphere (the area around the sun), and why solar activity changes over time,” Garcia Marirrodriga said. .