अन्तरिक्ष उड़ान के सन्दर्भ में, उपग्रह एक वस्तु है जिसे मानव } प्रयास के द्वारा कक्षा में रखा गया है। इस तरह की वस्तुओं को प्राकृतिक उपग्रहों जैसे चन्द्रमा(the moon) से अलग करने के लिए कभी कभी कृत्रिम उपग्रह{(artificial stellite)} भी कहा जाता है।

A satellite or artificial satellite is an object, typically a spacecraft, placed into orbit around a celestial body. Satellites have a variety of uses, including communication relay, weather forecasting, navigation (GPS), broadcasting, scientific research, and Earth observation. Additional military uses are reconnaissance, early warning, signals intelligence and, potentially, weapon delivery. Other satellites include the final rocket stages that place satellites in orbit and formerly useful satellites that later become defunct.