satellites and types of orbits. space science

satellite

1. Satellites

2. Do you know what is a satellite?

3. Objectives What is a satellite? Classify satellites based on their payloads, orbit, and size

4. Satellites A satellite is any object that revolves around another object. Satellite can be natural and artificial (man-made). Examples of natural satellite can be moon, planets, asteroids etc. Satellite can be used in many application like broadcasting television signal, weather forecasting, and navigation. The first satellite was launched by the Soviet Union and was called Sputnit-1.

5. Classification of sateliites Size Nano satellite Cube satellite Small satellite Large satellite Payload Payload of Communication satellite. Payload of Remote sensing satellite. Payload of Global positioning satellite. Orbit Geostationary orbit (GEO) b. Low Earth orbit (LEO) c. Medium Earth orbit (MEO) d. Polar orbit and Sun-synchronous orbit (SSO)

6. Nano Satellite: Definition : Nano satellites, often referred to as nanosats , are a category of small artificial satellites characterized by their compact size and low weight. They typically weigh less than 10 kilograms (22 pounds). Purpose: Nano satellites are used for a variety of purposes, including Earth observation, technology demonstration, scientific research, and educational projects. They offer a cost-effective way to conduct experiments and gather data in space.

7. Cube Satellite ( CubeSat ): Definition : CubeSats are a specific category of nanosatellites characterized by their standardized cube-shaped design. They come in different sizes, with 1U CubeSats being a cube with dimensions of 10 x 10 x 10 centimeters and larger versions available as 2U, 3U, 6U, and even 12U, with each U representing one 10 x 10 x 10 cm cube. Purpose: CubeSats are designed for various missions and experiments, such as Earth observation, technology testing, scientific research, and education. They are often used by universities and small organizations due to their compact size and affordability.

8. Small Satellite: Definition : Small satellites encompass a broad category of satellites that are generally smaller and lighter than traditional large satellites. They can include small, medium, and large smallsats , with weights ranging from hundreds to a few thousand kilograms. Purpose: Small satellites are versatile and can serve various purposes, such as Earth observation, communication, scientific research, and technology demonstration. They offer cost advantages compared to larger satellites and can be launched as part of rideshare missions.

9. Large Satellite: Definition : Large satellites are the traditional, heavier, and more massive satellites that typically weigh several tons. They are significantly larger than small satellites and often require dedicated launch vehicles to reach orbit. Purpose: Large satellites are used for critical missions such as communication, broadcasting, weather observation, scientific exploration, and national defense. They are equipped with advanced payloads and systems to accomplish their missions.

10. Based on Orbits

11. Low earth orbit Low Earth Orbit satellites are moving at an  altitude of roughly 160–1,500 kilometers  above the Earth’s surface. They have a short orbital period, between 90 and 120 minutes, meaning they can travel around the planet up to 16 times a day. This makes them particularly well-suited to all types of  remote sensing, high-resolution earth observation, and scientific research , as data can be acquired and transmitted rapidly .

12. Medium earth orbit satellites A Medium Earth type of orbit is located between low Earth and geostationary orbits, typically at an  altitude of about 5,000 to 20,000 kilometers . Positioning and  navigation services, like GPS , extensively use MEO type of satellites.

13. Geostationary Orbit (GEO) Satellites Spacecraft in geostationary Earth orbit are positioned  35,786 kilometers above Earth’s surface , precisely over the equator. Three evenly spaced machines in GEO can give nearly worldwide coverage thanks to the huge area they cover on Earth . satellite orbits the Earth at the same rotational speed as the Earth's rotation. This means that a geostationary satellite remains fixed relative to a specific point on the Earth's surface, appearing stationary in the sky when observed from the ground.

14. Sun-Synchronous Orbit (SSO) Satellites The Sun-synchronous orbit type of satellites goes from north to south across the polar regions at an  altitude of 600 to 800 km  above the Earth. The orbital inclination and altitude of SSO spacecraft are calibrated so that they always cross any given location at precisely the same local solar time. Thus, the lighting conditions are consistent for imaging, making this type of satellite ideal for  earth observation and environmental monitoring .

15. Advantage of geostationary orbit Fixed Position Relative to Earth: Use: Ideal for continuous and uninterrupted communication services like satellite TV broadcasting. Constant Coverage: Use: Suitable for real-time applications such as live television broadcasting, internet services, and weather forecasting. Simplified Ground Equipment: Use: Simplifies the design and operation of ground stations, making them suitable for fixed ground antennas in applications like satellite communication .. Wide Area Coverage: Use: Efficiently covers large areas, making it valuable for global broadcasting and regional communication networks. Predictable Orbits: Use: Simplifies satellite tracking and maintenance, ensuring reliable performance. Reduced Relocation Needs: Use: Saves fuel and extends satellite operational lifetimes by minimizing the need for frequent orbital adjustments. Continuous Observation: Use: Crucial for tracking weather patterns, climate monitoring, and environmental surveillance using Earth observation and meteorological satellites.

16. Payloads a. Payload of Communication satellite. b. Payload of Remote sensing satellite. c. Payload of Global positioning satellite.

17. Payloads Communication Satellites: Communication satellites are designed to facilitate the transmission of data, voice, and video signals over long distances. They are equipped with transponders that receive signals from Earth and relay them to other locations on Earth or to other satellites.

18. Earth Observation Satellites: Earth observation satellites are equipped with sensors and cameras to capture images and data about Earth's surface, atmosphere, and oceans. They are used for weather forecasting, environmental monitoring, and disaster management.

19. Navigation Satellites: Navigation satellites, such as those in the Global Positioning System (GPS), provide precise positioning and timing information to users on or near Earth's surface. They are essential for navigation and location-based services.