Aerospace vehicle system and method of operation
An aerospace vehicle system, preferably including one or more capsules, and optionally including one or more propulsion modules and/or safety modules. A capsule, preferably including a pressure vessel including a structural frame and one or more windows, and optionally including a cabin. In alternate embodiments, the system can additionally or alternatively function as a terrestrial vehicle, a watercraft, and/or any other suitable vehicle. A method of operation, preferably including operating the aerospace vehicle system in flight, while maintaining a pressure differential between the pressure vessel interior and an environment surrounding the system.
1. An aerospace vehicle comprising a pressure vessel, the pressure vessel defining a pressure vessel interior, the pressure vessel comprising:
a structural frame comprising a frame interior surface that bounds the pressure vessel interior, wherein:
the structural frame substantially defines a reference surface that encloses the frame interior surface;
the reference surface is a convex closed surface of revolution about a central axis;
the reference surface defines a surface diameter equal to twice a maximum distance from the central axis to the reference surface;
a meridian of the reference surface intersects the central axis at a first point and a second point;
the reference surface defines a surface height along the central axis between the first and second points, wherein the surface height is substantially less than the surface diameter;
the reference surface defines a meridian length along a meridian of the reference surface between the first and second points;
the structural frame further comprises a set of meridional members, the set comprising a first meridional member and a second meridional member; and
the structural frame defines a first aperture, wherein the first and second meridional members cooperatively define a first aperture boundary; and
a set of windows, comprising a first window arranged at the first aperture and attached to the structural frame at the first aperture boundary, the first window comprising a first window interior surface that bounds the pressure vessel interior;
wherein:
the first window interior surface extends outside the reference surface; and
the first window defines a meridional window length along the first window interior surface, wherein the meridional window length is greater than 20% of the meridian length; and
the pressure vessel fluidly isolates the pressure vessel interior from an environment surrounding the pressure vessel.
2. The aerospace vehicle of claim 1 , wherein the reference surface is symmetric about a midplane normal to the central axis.
3. The aerospace vehicle of claim 2 , wherein the surface height is substantially equal to 0.6 times the surface diameter.
4. The aerospace vehicle of claim 3 , wherein the reference surface is an Euler's elastica surface.
5. The aerospace vehicle of claim 2 , wherein the reference surface is an isotensoid symmetric about a midplane normal to the central axis.
6. The aerospace vehicle of claim 1 , wherein a circumferential window curvature of the first window is greater than a circumferential surface curvature of the reference surface.
7. The aerospace vehicle of claim 6 , wherein:
the maximum distance from the central axis to the reference surface is defined on a reference plane normal to the central axis; and
an intersection of the reference plane with the first window interior surface defines a window radius of curvature substantially less than half the surface diameter.
8. The aerospace vehicle of claim 1 , wherein:
the set of meridional members further comprises a third meridional member, wherein the second meridional member is arranged between the first and third meridional members;
the structural frame further defines a second aperture, wherein the second and third meridional members cooperatively define a second aperture boundary;
the set of windows further comprises a second window arranged at the second aperture and attached to the structural frame at the second aperture boundary, the second window comprising a second window interior surface that bounds the pressure vessel interior;
the second window interior surface extends outside the reference surface; and
the second window defines a second meridional window length along the window interior surface, wherein the second meridional window length is greater than 20% of the meridian length.
9. The aerospace vehicle of claim 8 , wherein:
an interior air pressure of the pressure vessel interior is substantially greater than an exterior air pressure of the environment, thereby generating stresses in the pressure vessel;
the first and second windows each intersect a first plane and a second plane, wherein the first and second planes are normal to the central axis;
the first window defines a first midplane normal to the first and second planes;
the second window defines a second midplane normal to the first and second planes;
within a first region bounded by the first and second planes and the first midplane, a first set of hoop stresses are generated in the first window;
within a second region bounded by the first and second planes and the second midplane, a second set of hoop stresses are generated in the second window;
the first set of hoop stresses generate a first load within the second meridional member; and
the second set of hoop stresses generate a second load within the second meridional member, wherein the first and second loads substantially counterbalance each other.
10. The aerospace vehicle of claim 1 , wherein:
an interior air pressure of the pressure vessel interior is substantially greater than an exterior air pressure of the environment, thereby generating mechanical stresses in the pressure vessel; and
a maximum window hoop stress in the set of windows is substantially less than an average frame hoop stress of the structural frame.
11. The aerospace vehicle of claim 10 , wherein the interior air pressure is greater than the exterior air pressure by at least 0.1 atmospheres.
12. An aerospace vehicle comprising a pressure vessel, the pressure vessel defining a pressure vessel interior, the pressure vessel comprising:
a structural frame comprising a frame interior surface that bounds the pressure vessel interior, wherein:
the structural frame substantially defines a reference surface that encloses the frame interior surface;
the reference surface is a convex closed surface defining a central axis;
the reference surface defines a maximum surface width on a reference plane normal to the central axis;
the central axis intersects the reference surface at a first point and a second point, wherein the reference surface defines a surface height along the central axis between the first and second points, wherein the surface height is substantially less than the maximum surface width;
the structural frame further comprises a first structural member and a second structural member, wherein the first and second structural members extend through the reference surface; and
the structural frame defines a first aperture that intersects the reference surface, wherein the first and second structural members cooperatively define a first aperture boundary; and
a set of windows, comprising a first window arranged at the first aperture and attached to the structural frame at the first aperture boundary, the first window comprising a first window interior surface that bounds the pressure vessel interior;
wherein:
the first window interior surface extends outside the reference surface; and
the first window interior surface defines a window height parallel to the central axis, wherein the window height is greater than 20% of the surface height; and
the pressure vessel fluidly isolates the pressure vessel interior from an environment surrounding the pressure vessel.
13. The aerospace vehicle of claim 12 , further comprising a balloon tethered to the pressure vessel at the first structural member, the balloon containing a low-density gas, wherein a density of the low-density gas is less than a density of the environment.
14. The aerospace vehicle of claim 12 , wherein the pressure vessel is configured to carry a live human occupant within the pressure vessel interior.
15. The aerospace vehicle of claim 12 , further comprising a human support mechanism arranged within the pressure vessel interior, the human support mechanism configured to orient eyes of a human occupant toward the first window.
16. The aerospace vehicle of claim 15 , wherein the human support mechanism comprises a seat arranged between the central axis and the first window.
17. The aerospace vehicle of claim 12 , wherein the first window defines a window width on the reference plane, wherein the window width is less than half the window height.
18. The aerospace vehicle of claim 12 , wherein the reference surface is a surface of revolution about the central axis.
19. The aerospace vehicle of claim 18 , wherein the reference surface is an Euler's elastica surface.
20. The aerospace vehicle of claim 18 , wherein a circumferential window curvature of the first window is greater than a circumferential surface curvature of the reference surface.