## Synthetic Aperture Radar (SAR) Synthetic aperture radar (SAR) is a type of active data collection where an instrument sends out a pulse of energy and then records the amount of that energy reflected back after it interacts with Earth. Unlike optical imagery, which is a passive data collection technique based on emitted energy, SAR imagery is created from the reaction of an emitted pulse of energy with physical structures (like mountains, forests, and sea ice) and conditions like soil moisture. SAR has been used in a wide range of applications, including studying Antarctic icebergs, tracking the paths of oil spills into sensitive marshes, and mapping the wetlands of Alaska. [More Info on SAR](https://www.earthdata.nasa.gov/learn/earth-observation-data-basics/sar) <iframe width="564" height="322" src="https://www.youtube.com/embed/u2bUKEi9It4" title="Satellites Use &#39;This Weird Trick&#39; To See More Than They Should - Synthetic Aperture Radar Explained." frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" referrerpolicy="strict-origin-when-cross-origin" allowfullscreen></iframe> ### Example use cases: - detecting anomalies in road, rail, energy and other infrastructure, resulting in lower maintenance costs and accident risk, - monitoring crop growth conditions and analyzing soil and vegetation health to help reduce costs and increase efficiency for farmers, - detecting illegal logging and fishing in the most remote parts of the world, - providing rapid damage assessment after flooding, landslides and volcanic eruptions, as well as risk assessment for land subsidence, - enabling the persistent monitoring of maritime traffic, border activities and other potential security threats, and advances maritime domain awareness, - analyzing tree cover to calculate CO2 absorption and carbon credits. ![[Pasted image 20250206201150.png]] ## Internet of Things (IoT) IoT Satellites (Internet of Things satellites) are specialized small satellites designed to facilitate global connectivity for IoT devices. These satellites provide low-cost, low-power, and widespread data connectivity, making them suitable for remote and inaccessible areas where terrestrial networks like cellular or Wi-Fi are unavailable or impractical. [More info on IoT Sats](https://news.viasat.com/blog/corporate/satellite-iot-the-future-of-networking#:~:text=Satellite%20IoT%20refers%20to%20the,seamless%20connectivity%20and%20data%20exchange.&text=Firstly%2C%20IIoT%2Denabled%20devices%20such,communication%20%7Bmodules%2Fterminals%7D.) <iframe width="564" height="322" src="https://www.youtube.com/embed/f3WZ2bc2LnQ" title="IoT-over-Satellite / Massive LEO Constellations, challenges and opportunities" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" referrerpolicy="strict-origin-when-cross-origin" allowfullscreen></iframe> ## Earth Observation Earth observation satellites are spacecraft equipped with sensors and instruments designed to collect data about Earth's surface, atmosphere, and oceans. These satellites use technologies such as optical cameras, radar, and infrared sensors to monitor a wide range of phenomena, including climate change, natural disasters, urban development, and agricultural productivity. Operating in various orbits—most commonly [[🌍 Orbits#Polar|polar orbits]] for global coverage or geostationary orbits for constant monitoring of specific regions—they provide critical data for scientific research, environmental monitoring, and resource management. Applications include mapping deforestation, tracking weather patterns, monitoring sea level rise, and supporting emergency response efforts. Earth observation satellites play a vital role in understanding and addressing environmental challenges and are increasingly used in commercial sectors for insights into industries like agriculture, insurance, and energy. [More info on Earth Observation Sats](https://en.wikipedia.org/wiki/Earth_observation_satellite)