TERMINOLOGY AND DEFINITIONS

For Clarity of Spaceplanes and Rocket-Powered Aircraft:

Last updated 1 January 2026

"Is it a plane or a rocket?" – We get this a lot, so let us help clarify this emerging space as best we can. More scope and disclaimer information here.

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Purpose:

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Terminology in the spaceplane and advanced aerospace domain is used inconsistently across regulators, jurisdictions, academic institutions, and industry. Terms such as spaceplane, rocket-powered aircraft, and suborbital vehicle may carry different meanings depending on technical, regulatory, or operational context. 

This page provides a shared reference for how Dawn Aerospace uses these terms when describing its own vehicles, missions, and technology in general communications. 

These definitions are intended to support clarity and understanding, not to serve as formal legal, regulatory, or contractual classifications. Further detail on scope, limitations, and authoritative sources is provided in the Scope and Disclaimer section below. 

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Vehicle​

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A vehicle is a machine designed to transport people or payloads from one place to another. 

Aircraft, rockets, spacecraft, and spaceplanes are all types of vehicles. 

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Aircraft

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An aircraft is an engine-driven, fixed-wing aircraft heavier than air that is supported in flight by the dynamic reaction of air against its wings (ref: FAA Glossary) 

Spaceplane

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A spaceplane is a vehicle designed to operate both within Earth’s atmosphere and at the boundary of space. 

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Spaceplanes may share characteristics with aircraft, spacecraft, or both, depending on their design and method of operation. 

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Spaceplanes are defined by mission profile rather than propulsion method. As a result, spaceplanes are not a single regulatory or technical category, and may include vehicles that are aircraft-like, rocket-launched, or hybrid in nature. 

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In this vein, not all spaceplanes are aircraft. Some historical spaceplanes relied primarily on rocket launch systems and did not take off or land as conventional aircraft. 

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Suborbital Spaceplane

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A suborbital spaceplane is a spaceplane that reaches space (or near-space) without entering Earth orbit. 

It follows a suborbital trajectory ascending to high altitude before returning to Earth, rather than remaining in continuous orbit around the planet.  

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Rocket-Powered Aircraft

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A rocket-powered aircraft is a rare class of aircraft that:​

-  uses rocket propulsion to achieve extreme altitude, speed, or space-adjacent flight

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Rocket-powered aircraft often sit at the intersection of aircraft and spaceplane definitions. Because they retain runway operations and aerodynamic control throughout flight, they are considered aircraft, while also potentially qualifying as a type of spaceplane depending on their mission envelope.  

The X-15 is the leading vehicle in this rare category. It is worth noting it does not universally get referred to as a spaceplane as it was air-launched from a B-52.