Satellite Launch Vehicle in Satellite Communication

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Satellite Launch Vehicle are of two kinds:


1. Elongated launch vehicles

2. Reusable Launch Vehicles
 

  • Elongated launch Vehicles are Atlas, Delta (US), Soyuz (Russia), and Ariane (EU)
    Reusable Launch Vehicles are Up until 2011, Space Shuttle (STS)
  • Falcon 9, Dragon (Space X) Buran? Orion?
    Typically, launches are carried out in phases.
    A launch vehicle propels the satellite into one of the transfer low-Earth orbits.
    The satellite is moved into the final orbit from a transfer orbit.
  • The launch is simplest from the equator because of Earth’s rotation.
  • Earth rotational velocity enhancement of about 0.47 km/sec
  • LEO orbits demand speeds of about 7.5 km/sec. Start at the equator and save about 6% on fuel.
  • Satellites in inclined orbits are launched from locations not on the equator. The orbit inclination must be corrected if the satellite is to be placed in a GEO stationary orbit.
  • A satellite achieves a stable orbit only when its orbital height and velocity vector are precisely aligned. 
  • GEO Ex: An orbiting geostationary satellite must be at a height of 35,786.03 km above the earth’s surface (42,164.17 km radius from the earth’s center) with an elliptically zero inclination and a tangential velocity of 3074.7 m/s in the orbit’s plane, which is the equatorial plane of the planet. 
  • The more energy a launch vehicle needs to reach an orbit, the farther it is from Earth’s orbit.
  • The majority of the rocket energy utilized in any Earth satellite launch goes into accelerating the vehicle from rest to a height of roughly 20 miles (32 km) above the planet.
  • During launch, staging occurs, where unnecessary mass is jettisoned from the launcher to optimize fuel consumption.

Launch Vehicles:

Satellite Launch Vehicle

Ref: isro

  • Most launch vehicles consist of several stages, and when a stage is finished, a portion of the launcher is used to propel the satellite into the desired trajectory in the final stage. Thus, ELV stands for expendable launch vehicle.
  • The Space Shuttle is partially reusable; NASA refers to it as the Space Transportation System (STS).
  • The shuttle ship is flown back to Earth for restoration and reuse, while the solid rocket boosters are collected and repaired for use on the next flights. Thus, the acronym RLV stands for Reusable Launch Vehicle.
  • A new generation of sophisticated launch vehicles is being designed with the flexibility to perform RLV and SSTO operations.

How Satellite Launch Vehicle Works?

Satellite Launch Vehicles (SLVs) are meticulously engineered rockets built to transport objects such as satellites and spacecraft into outer space. Their operation is based on fundamental principles and components:

1. Rocket Propulsion and Newton’s Third Law:

SLVs utilize a scientific principle known as Newton’s Third Law. By expelling a substantial amount of fuel downwards at high velocity, an equal and opposing force (termed thrust) propels the rocket upwards.

2. Multistage Rockets:

SLVs are typically constructed with multiple stages, resembling distinct sections stacked vertically. Each stage is equipped with its propulsion system and fuel supply. As each stage exhausts its fuel, it is discarded, reducing the overall mass and enhancing efficiency.

3. Guidance and Control Systems:

SLVs utilize sophisticated guidance and control mechanisms to achieve accurate navigation and execute necessary trajectory adjustments during flight, ensuring successful mission completion.

4. Payload Fairings:

The satellite or spacecraft being launched is shielded by a protective covering known as a payload fairing. Once the rocket ascends beyond the densest regions of the atmosphere, the fairing is no longer required and is discarded further reducing the rocket’s weight.

The Launch Sequence:

  1. Lift-off: Ignition of the rocket’s engines initiates its ascent.
  2. Vertical Ascent: Initially, the rocket maintains a vertical trajectory and swiftly traverses the densest part of the atmosphere.
  3. Trajectory Adjustment: As the rocket gains altitude, it gradually tilts to align with its intended orbital path.
  4. Stage Separation: The various stages of the rocket are sequentially detached as their fuel is depleted.
  5. Payload Deployment: Upon reaching the desired orbit, the final stage releases the payload fairing, deploying the satellite into space.
  6. Orbital Insertion: The satellite’s velocity and position are meticulously adjusted to maintain a stable orbit.

Types of SLVs:

SLVs vary in size based on their payload capacity:

  • Small-lift: These rockets can launch smaller satellites into low Earth orbits.
  • Medium-lift: Medium-lift SLVs can propel larger satellites into Earth’s orbit or a specialized geosynchronous transfer orbit (GTO).
  • Heavy-lift: Designed to carry substantial payloads, heavy-lift SLVs can launch objects into GTO and even farther into space.

Examples of SLVs:

SLVs originate from various countries around the globe, including:

  • India: PSLV, GSLV, LVM3
  • USA: Falcon 9, Atlas V, Delta IV Heavy
  • Europe: Ariane 5, Vega
  • Russia: Soyuz, Proton
  • China: Long March series

The future of SLVs promises exciting advancements and innovations:

  • Reusable Launch Vehicles: The development of reusable rockets is actively being pursued, promising to substantially decrease the cost of accessing space.
  • Small Satellite Launchers: The proliferation of small satellites has created a demand for rockets tailored specifically for their deployment.

Applications of SLVs

  1. Deployment of Communication Satellites: SLVs are essential for placing communication satellites into orbit, enabling global telecommunication, broadcasting, and internet connectivity. These satellites facilitate voice, video, and data transmission across vast distances.
  2. Launching Earth Observation Satellites: SLVs carry Earth observation satellites into orbit, which gather valuable data about our planet’s weather patterns, climate change, natural resources, and environmental conditions. This information is crucial for scientific research, disaster management, and resource planning.
  3. Placement of Navigation Satellites: SLVs are used to deploy navigation satellites, such as those in the Global Positioning System (GPS) network. These satellites enable precise positioning, navigation, and timing services for various applications, including aviation, maritime, and personal navigation.
  4. Deployment of Scientific Research Satellites: SLVs transport scientific research satellites into space to study the universe, explore other planets, and conduct experiments in microgravity. These missions contribute to our understanding of astrophysics, cosmology, and planetary science.
  5. Launching Commercial and Military Satellites: SLVs are used to launch various commercial and military satellites for diverse purposes. Among these are reconnaissance satellites, military communication satellites, and commercial satellites catering to diverse sectors such as telecommunication, broadcasting, and remote sensing.

1. What is a satellite launch vehicle (SLV) and how does it work?

  • A satellite launch vehicle, or rocket, propels satellites into their designated orbits. It uses multiple stages with powerful engines to overcome Earth’s gravity and achieve the necessary velocity for orbital insertion.

2. What are the different types of satellite launch vehicles?

  • SLVs can be classified based on size, payload capacity, number of stages, and reusability. Common types include expendable launch vehicles (ELVs) and reusable launch vehicles (RLVs), like SpaceX’s Falcon 9.

3. Which countries have the most advanced satellite launch capabilities?

  • The United States, Russia, China, Europe (through the European Space Agency), and India are among the countries with significant satellite launch capabilities. Private companies like SpaceX and Blue Origin are also emerging as major players.

4. What are the challenges and risks associated with satellite launches?

  • Satellite launches are complex and involve various risks, including technical failures, weather conditions, and potential collisions with space debris. Launch providers take extensive measures to mitigate these risks and ensure mission success.

5. What is the future of satellite launch vehicles?

  • The future of SLVs is focused on developing more cost-effective, reliable, and sustainable launch options. Reusable launch vehicles, like SpaceX’s Starship, are poised to revolutionize the industry by significantly reducing launch costs and increasing access to space.
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