Abstract: A method for constructing a balloon assembly includes inserting balloon envelope material which will become an apex of a balloon envelope into a platen opening of a platen; flaring the balloon envelope material outward over the top surface of the platen; positioning a termination plate over the platen opening and within the apex opening; and folding at least some of the balloon envelope that overlies the platen onto the termination plate. The balloon envelope material further includes an apex opening.

Abstract: Aspects of the disclosure relate to systems and techniques for inspecting seals for high altitude balloons. In one example, a system may include a reflective surface, a translucent material on the reflective surface, and a movable light source configured to move along the reflective surface and provide light to the reflective surface. The light is provided such that it is reflected from the reflective surface and through the translucent material in order to backlight a balloon envelope seal for inspection. A method for inspecting a balloon envelope seal may include placing balloon envelope material on a table, forming a seal between portions of the material, moving a light over the seal, shining light onto a reflective portion of the table below the seal to backlight the seal, and inspecting the seal using the backlighting of the seal.

Abstract: Aspects of the disclosure relate to techniques for manufacturing a balloon envelope including a duct for high altitude balloons. In one example, a first sheet of material may be provided. A premade duct may be arranged at least partially on the first sheet of material. The duct may include a first substance on an internal surface. A second sheet of material may be arranged over at least a portion of the duct. A heat sealing device may be applied to the second sheet of material to heat seal the first sheet of material to the second sheet of material. The heat sealing device may be applied over at least a portion of the duct in order to seal external surfaces of the duct to each of the first and second sheets of material and form a balloon gore. The first substance may keep the duct from being sealed to itself.

Abstract: An assembly for use during manufacture of a balloon envelope that includes a table having first and second levels, an indicator disposed on the first level and a sealing component. The first level is arranged to receive a first sheet portion of material. The indicator is arranged along a lengthwise axis of the table to indicate a position for attaching a tendon to the first sheet portion. The second level is arranged to receive assembled gore portions of the envelope comprising the first sheet portion, the tendon and a second sheet portion of material. The sealing component is configured to move along the table and to apply a heat seal to bond together the first and second sheet portions disposed thereon in order to form at least part of a gore portion of the envelope, such that the tendon is arranged proximate to a centerline of the gore.

Abstract: An assembly for use during manufacture of a balloon envelope that includes a table having first and second levels, an indicator disposed on the first level and a sealing component. The first level is arranged to receive a first sheet portion of material. The indicator is arranged along a lengthwise axis of the table to indicate a position for attaching a tendon to the first sheet portion. The second level is arranged to receive assembled gore portions of the envelope comprising the first sheet portion, the tendon and a second sheet portion material. The sealing component is configured to move along the table and to apply a heat seal to bond together the first and second sheet portions disposed thereon in order to form at least part of a gore portion of the envelope, such that the tendon is arranged proximate to a centerline of the gore.

Abstract: A top cap assembly is provided for mounting tendon to a balloon that has a balloon envelope. The assembly includes a plate structure having a plurality of junction portions disposed at an apex of the balloon envelope and a plurality of tendon pairs. Each tendon pair includes first and second tendon members attached to the balloon envelope. The first tendon member is arranged to cross over the plate structure. The second tendon member is arranged to engage the first length tendon member at a given one of the junction portions of the doubler plate. A fastener member is attached to each tendon pair of the plurality of tendon pairs. The fastener member is used for securing the first and second tendon members of a given tendon pair together in order to support lift gas carried by the balloon envelope.

Abstract: An assembly for use during manufacture of a balloon envelope that includes a table having first and second levels, an indicator disposed on the first level and a sealing component. The first level is arranged to receive a first sheet portion of material. The indicator is arranged along a lengthwise axis of the table to indicate a position for attaching a tendon to the first sheet portion. The second level is arranged to receive assembled gore portions of the envelope comprising the first sheet portion, the tendon and a second sheet portion material. The sealing component is configured to move along the table and to apply a heat seal to bond together the first and second sheet portions disposed. thereon in order to form at least part of a gore portion of the envelope, such that the tendon is arranged proximate to a centerline of the gore.

Abstract: A top cap assembly is provided for mounting tendon to a balloon that has a balloon envelope. The assembly includes a plate structure having a plurality of junction portions disposed at an apex of the balloon envelope and a plurality of tendon pairs. Each tendon pair includes first and second tendon members attached to the balloon envelope. The first tendon member is arranged to cross over the plate structure. The second tendon member is arranged to engage the first length tendon member at a given one of the junction portions of the doubler plate. A fastener member is attached to each tendon pair of the plurality of tendon pairs. The fastener member is used for securing the first and second tendon members of a given tendon pair together in order to support lift gas carried by the balloon envelope.