Future spacecraft to carry 'black boxes'

 作者:宰父彡     |      日期:2019-03-03 06:07:04
By Maggie McKee (Image: Eric Hamburg/The Aerospace Corporation) Small, heat-resistant “black boxes” will transmit data back to Earth when future space probes break up during re-entry to the Earth’s atmosphere, according to a development plan signed recently by NASA. The boxes will be used to improve spacecraft design for both human and robotic missions. Aeroplane speed and altitude data, as well as pilot conversations, are recorded in briefcase-sized black boxes that can be retrieved and studied in the wake of a crash. But such technologies are not usually used on spacecraft such as the shuttle, which experiences extreme heating when roaring back into Earth’s atmosphere. “People had not figured how to put black boxes on spacecraft before because the boxes would tend to burn up during re-entry,” says Dan Rasky, a materials scientist at NASA’s Ames Research Center in Moffett Field, California, US. Instead, flight data is continuously beamed to Earth using satellites – a stream that stops abruptly during a catastrophe like the break-up of the shuttle Columbia in February 2003. But that shuttle happened to contain an experimental data recorder that stored information about the temperature, pressure, and vibrations felt by 721 different onboard sensors. “It wasn’t really designed to survive [a disaster upon] re-entry, but it did, and it was very helpful in reconstructing what happened to the orbiter,” says William Ailor, director of the Center for Orbital and Reentry Debris Studies at the Aerospace Corporation, a non-profit analytical company in El Segundo, California, US. Now, the Aerospace Corporation and NASA are working together to develop black boxes called Reentry Breakup Recorders (REBRs). These could be used in the space shuttle’s successor, called the Crew Exploration Vehicle (CEV), planned for launch in 2014, and in any other object that re-enters Earth’s atmosphere from space. “They’d be like little parasites,” says James Arnold, a researcher at NASA’s Ames Center for Nanotechnology. A number of small, dome-shaped black boxes – weighing just 1 kilogram and spanning less than 30 centimetres – would stick to surfaces inside the CEV’s crew cabin and wings. They would quietly take data during the flight, but would only “activate” in the event of a major disaster. The heat from the craft’s explosion would trigger the boxes to detach – perhaps by melting the adhesive that fixes them to the CEV. Then, as they fall to Earth, the boxes would transmit their data, obviating any need to retrieve them later. “If you understand how it breaks apart, you can then design a spacecraft that breaks apart the way you want it to,” Ailor told New Scientist. For example, he says engineers could use materials that rupture into smaller pieces – or melt completely – during re-entry to prevent large debris falling to the ground, potentially injuring someone. Ailor hopes to learn these lessons by monitoring uncrewed spacecraft. About 100 large objects, such as spent rocket stages and satellites, fall to Earth each year, but not much of the resulting debris is recovered. “We have basically no data on the break-up of satellites,” he laments. He plans to launch the first REBR prototypes in 2006 on a rocket that spends no more than a month or so in space. He expects a commercial company could later manufacture the black boxes, selling them for about $50,000 each. He says new technologies, such as the development of solid-state storage devices and smaller transmitters, will make the boxes small and light enough to be commercially viable – every extra ounce of mass requires more fuel to launch. “These things are so light and easy to attach, we would like to have several on everything that flies,