United Launch Alliance plans to begin 2026 with a national security mission as its Vulcan Centaur rocket prepares to launch ...

A small asteroid came within a cosmic hairbreadth of the ring of communications satellites circling the Earth in geosynchronous orbit this week. Passing by our planet at an altitude of about 35,000 km ...

A Long March 3B lifts off from Xichang, sending Shijian-25 on its way to orbit, Jan. 6, 2025. Credit: Ourspace HELSINKI — China’s experimental Shijian-21 and Shijian-25 satellites have separated in ...

Geosynchronous Synthetic Aperture Radar (GEO SAR) systems represent a promising frontier in Earth observation technology, offering continuous monitoring of specified regions with exceptionally short ...

A geosynchronous orbit is a geocentric orbit that has the same orbital period as the sidereal rotation period of the Earth. It has a semi-major axis of 42,164 km (26,200 miles). In the special case of ...

Amateur radio operators like to say that working a contact in space can be done with a simple handheld transceiver and a homemade antenna. And while that’s true, it’s true only for low Earth orbit ...