Deutsch: Orbitaler Start / Español: Lanzamiento orbital / Português: Lançamento orbital / Français: Lancement orbital / Italiano: Lancio orbitale
Orbital launch refers to the process of sending a spacecraft or satellite from the Earth's surface into a stable orbit around the planet. In the space industry, this operation requires a launch vehicle (rocket) capable of accelerating a payload to a velocity sufficient to counteract the pull of Earth's gravity, typically around 28,000 kilometres per hour (17,500 miles per hour) for low Earth orbit (LEO). Orbital launches are fundamental for deploying satellites, space stations, and interplanetary missions.
Description
Orbital launch is a critical activity within the space industry, enabling the deployment of various types of spacecraft and satellites into Earth's orbit and beyond. The primary objective of an orbital launch is to achieve a velocity and trajectory that allows the payload to continuously fall around the Earth, effectively entering orbit rather than falling back to the surface.
Achieving orbit requires overcoming two main challenges: reaching sufficient altitude and attaining the necessary horizontal speed. Most orbital launches are conducted using multi-stage rockets, which sequentially shed weight as fuel is consumed and stages are jettisoned. This design maximises efficiency, allowing the payload to reach orbital velocity.
There are several categories of orbital launches based on the target orbit:
- Low Earth Orbit (LEO): Typically up to 2,000 kilometres (1,200 miles) altitude, commonly used for Earth observation satellites, the International Space Station (ISS), and many commercial communication satellites.
- Medium Earth Orbit (MEO): From 2,000 to 35,786 kilometres (1,200 to 22,236 miles), often used for navigation systems like GPS.
- Geostationary Orbit (GEO): At 35,786 kilometres (22,236 miles), where satellites appear stationary relative to Earth's rotation, widely used for communications and weather satellites.
- Highly Elliptical Orbits (HEO): Used for special missions, including communications over polar regions and certain scientific applications.
The history of orbital launches began with the Soviet Union's Sputnik 1 in 1957, marking humanity's first artificial satellite in orbit. This milestone sparked the space race and laid the foundation for the modern space industry.
Today, orbital launch providers include government agencies like NASA, Roscosmos, and ESA, as well as private companies such as SpaceX, Rocket Lab, and Blue Origin. The increasing involvement of commercial entities has led to more frequent and affordable access to space.
Legal frameworks govern orbital launches to ensure safe and responsible space operations. The Outer Space Treaty (1967) and national laws regulate launches, liability, and space debris mitigation.
Special Aspects of Launch Sites and Windows
Special Considerations for Launch Locations and Timing
The selection of a launch site is strategic, often chosen based on proximity to the equator (for added rotational speed), safety considerations, and mission requirements. Locations such as Cape Canaveral (USA), Kourou (French Guiana), and Baikonur (Kazakhstan) are prominent orbital launch sites.
Launch windows—the specific times when conditions are optimal—are crucial for missions targeting specific orbits or interplanetary trajectories. Missing a launch window can delay missions by days, weeks, or even months.
Application Areas
- Communications Satellites Deployment: Enabling global telecommunications, broadcasting, and internet services.
- Earth Observation and Remote Sensing: Providing imagery and data for environmental monitoring, disaster response, and resource management.
- Navigation Systems: Supporting global positioning services like GPS, GLONASS, and Galileo.
- Space Science Missions: Launching telescopes, scientific instruments, and interplanetary probes.
- Human Spaceflight: Transporting astronauts and cargo to space stations and beyond.
- Military and Defence Applications: Deploying reconnaissance, surveillance, and strategic communication satellites.
Well-Known Examples
- SpaceX Falcon 9 Launches: Frequently used for deploying satellites and missions to the ISS, known for reusability.
- Arianespace Ariane 5: A workhorse for launching heavy payloads into geostationary orbit, often carrying telecommunications satellites.
- Soyuz Launches: Long-standing Russian launch vehicle family used for crewed and uncrewed missions, including ISS resupply.
- Rocket Lab Electron: Specialises in launching small satellites into LEO from New Zealand and Virginia.
- NASA’s Saturn V: Historic rocket used for Apollo lunar missions, demonstrating the power required for orbital and trans-lunar injection.
Risks and Challenges
- Launch Failures: Technical malfunctions can result in mission loss, with significant financial and strategic consequences.
- Space Debris Generation: Orbital launches contribute to the growing problem of space debris, raising concerns for future missions.
- Cost and Accessibility: Despite falling prices, orbital launches remain expensive and technologically demanding.
- Environmental Impact: Rocket launches can release pollutants and contribute to atmospheric disturbance.
- Regulatory Compliance: Launches must adhere to international and national laws, requiring extensive coordination and approval processes.
Similar Terms
- Suborbital Launch: A flight that reaches space but does not complete an orbit, typically for research or tourism purposes.
- Interplanetary Launch: Missions that leave Earth orbit to travel to other planets or celestial bodies.
- Payload Deployment: The process of releasing satellites or cargo into their designated orbits following an orbital launch.
- Launch Vehicle: The rocket system used to perform the orbital launch, often comprising multiple stages.
Summary
Orbital launch is the essential mechanism for placing satellites and spacecraft into orbit, forming the backbone of modern space operations. It enables global communication, navigation, scientific discovery, and exploration missions. While technological advances and commercial participation have revolutionised access to space, orbital launches remain complex and challenging endeavours.
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