Two Chinese satellites have rendezvoused with one another more than 20,000 miles above the Earth in what analysts believe is the first high-altitude attempt at orbital refueling. China’s Shijian-21 ...

One of the most crucial elements of a forecast is sky conditions. Whether it's sunny, partly cloudy, or storming. Typically, we use radar to detect rain, but when it is not raining, how do we observe ...