Earth is clearly discernible. The air is so thin–only 1.4 percent of the density at sea level–it is incapable of supporting life. It is also incapable of supporting sustained horizontal flight of an ...

A giant, solar-powered flying wing soared past record heights Monday but failed to reach its 100,000 goal. NASA spokesman Alan Brown said the Helios Prototype reached a height of about 96,500 feet ...

When you purchase through links on our site, we may earn an affiliate commission. Here’s how it works. In this historical photo from the U.S. space agency, the Helios Prototype is an enlarged version ...