Deutsch: Suborbitaler Start / Español: Lanzamiento suborbital / Português: Lançamento suborbital / Français: Lancement suborbital / Italiano: Lancio suborbitale
Suborbital launch in the space industry refers to the process of sending a vehicle into space on a trajectory that reaches outer space but does not complete a full orbit around the Earth. Instead, the vehicle follows a curved path, ascending above the boundary of space—commonly recognised as the Kármán line at 100 kilometres (62 miles) altitude—before descending back to Earth. Suborbital launches are typically used for scientific research, technology testing, military applications, and commercial space tourism.
Description
Suborbital launch systems play a significant role in space industry activities, offering relatively low-cost and flexible access to space for a variety of missions. Unlike orbital launches, which require a vehicle to reach a horizontal speed of approximately 28,000 kilometres per hour (17,500 miles per hour) to stay in orbit, suborbital launches only require enough energy to cross the threshold of space before gravity pulls the vehicle back down.
Suborbital flights generally last anywhere from a few minutes to an hour, depending on the trajectory and mission objectives. During the apogee—the highest point in the flight—the vehicle may experience several minutes of microgravity, making it ideal for scientific experiments or commercial passengers experiencing weightlessness.
Suborbital launch vehicles can take many forms:
- Sounding Rockets: Typically used for short-duration scientific missions, atmospheric studies, and microgravity research.
- Reusable Spaceplanes: Vehicles such as Virgin Galactic’s SpaceShipTwo that carry passengers and experiments on brief suborbital flights.
- Ballistic Missiles: Originally designed for military purposes, these vehicles follow suborbital paths and have influenced suborbital launch technologies.
The history of suborbital launches dates back to the early days of rocketry. Notable examples include the German V-2 rockets in the 1940s, which achieved suborbital spaceflight. In 1961, Alan Shepard’s Freedom 7 mission became the first American crewed suborbital spaceflight, paving the way for human space exploration.
Today, suborbital launches have expanded into commercial space tourism and scientific research platforms, offering relatively affordable and rapid access to space environments.
Regulatory frameworks for suborbital launches are established by organisations like the Federal Aviation Administration (FAA) in the United States, which issues licenses for commercial suborbital flights and ensures the safety of both participants and public airspace.
Special Aspects of Suborbital Trajectories and Vehicles
Special Considerations for Suborbital Flight Dynamics
Suborbital trajectories are typically parabolic, with the vehicle propelled vertically or at an angle and then following a natural descent due to gravity. Because the flight does not achieve orbit, the vehicle does not experience the same prolonged periods in microgravity or the need for orbital insertion burns.
The vehicle design can vary widely:
- Vertical Launch Vehicles: Rockets like Blue Origin’s New Shepard, which take off and land vertically.
- Air-Launched Vehicles: Virgin Galactic’s SpaceShipTwo, which is dropped from a mothership before igniting its rocket motor for ascent.
Safety systems for suborbital flights are tailored for the unique risks of short-duration spaceflight, including abort options, rapid descent mechanisms, and simplified life support systems for brief exposure to space.
Application Areas
- Space Tourism: Offering paying customers short trips to space with brief experiences of weightlessness and views of Earth from space.
- Microgravity Research: Providing researchers with access to short periods of weightlessness for testing scientific experiments and technology demonstrations.
- Atmospheric and Space Science: Collecting data from high-altitude and space environments, such as studying upper atmospheric phenomena and testing sensors.
- Military and Defence Testing: Simulating missile trajectories or testing defence systems in suborbital conditions.
- Technology Validation: Testing spacecraft components, reentry systems, and payload recovery techniques in near-space environments.
Well-Known Examples
- Blue Origin New Shepard: A reusable vertical launch vehicle that carries scientific payloads and space tourists on suborbital flights above the Kármán line.
- Virgin Galactic SpaceShipTwo: An air-launched spaceplane that carries passengers and research payloads on suborbital spaceflights, reaching altitudes of about 90–100 kilometres (56–62 miles).
- NASA Sounding Rocket Program: Provides suborbital launch capabilities for scientific experiments and atmospheric research.
- Rocket Lab HASTE (Hypersonic Accelerator Suborbital Test Electron): A suborbital version of Rocket Lab’s Electron rocket, used for hypersonic testing and research.
- Blue Origin’s Goddard Flight: The first developmental flight of the New Shepard system, laying the groundwork for suborbital commercial launches.
Risks and Challenges
- Safety Concerns: Suborbital flights, while generally shorter and simpler than orbital missions, still face risks related to launch, re-entry, and passenger safety.
- Limited Duration of Microgravity: Only a few minutes of weightlessness are available, which can limit the scope of scientific experiments.
- Regulatory Compliance: Operators must navigate complex licensing processes and adhere to safety and liability regulations.
- Cost versus Benefit: While less expensive than orbital flights, suborbital missions still require significant investment, and return on investment (ROI) can be uncertain, especially in the commercial tourism sector.
- Environmental Impact: Concerns over emissions and resource use for non-essential flights like space tourism are growing.
Similar Terms
- Orbital Launch: A flight that achieves sufficient velocity to stay in orbit around the Earth, offering prolonged space operations.
- Ballistic Flight: Any flight that follows a high-arcing trajectory, often applied to both military missiles and suborbital spaceflights.
- Sounding Rocket: A research rocket designed for suborbital missions to gather data from the upper atmosphere or near-space.
- Space Tourism: Commercial flights offering private individuals the experience of space travel, often using suborbital flight vehicles.
Summary
Suborbital launches are a key element of the space industry, enabling rapid, cost-effective access to space for scientific research, technology testing, and commercial tourism. Although they do not reach orbit, suborbital missions offer valuable opportunities to experience space conditions and develop technologies critical to future space exploration.
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