Envelope film suspenders for high-altitude balloons
A high altitude or stratospheric balloon system may include a balloon envelope including envelope film, at least one tendon, and a suspender. The suspender may have a first end attached to the envelope film. The suspender is arranged to stretch such that the first end moves towards an equator of the balloon envelope as the balloon envelope pressurizes in order to control movement of the envelope film relative to the tendon and towards the equator as the balloon pressurizes.
1. A method comprising:
inflating a balloon envelope of a balloon with lift gas, the balloon envelope including at least one suspender arranged in order to gather a portion of envelope film adjacent to a plate system of the balloon envelope;
allowing the balloon envelope to rise towards the stratosphere and pressurize; and
during the pressurization, pulling the gathered portion of envelope film towards an equator of the balloon envelope and allowing the suspender to stretch against the balloon envelope.
2. The method of claim 1 , wherein when the balloon is fully pressurized, the suspender is arranged flat against the balloon envelope.
3. The method of claim 1 , wherein the plate system is arranged at an apex of the balloon.
4. The method of claim 1 , wherein the plate system is arranged at a base of the balloon.
5. The method of claim 1 , wherein the suspender includes a first end attached to a mounting point of the plate system and a second end attached to the balloon envelope.
6. The method of claim 5 , wherein the suspender shares the mounting point with at least one other suspender arranged in order to gather a second portion of envelope film adjacent to the plate system, and wherein the method further comprises, during the pressurization, pulling the second gathered portion of envelope film towards an equator of the balloon envelope and allowing the at least one other suspender to stretch against the balloon envelope.
7. The method of claim 5 , further comprising, attaching the first end to the mounting point.
8. The method of claim 5 , wherein the mounting point is a stud used to attach a tendon to the plate system, and wherein the method further comprises attaching the first end to the stud.
9. The method of claim 5 , wherein the balloon envelope includes tubing for a support tendon of the balloon, and the method further comprises attaching the second end to the tubing.
10. The method of claim 9 , wherein attaching the second end to the tubing includes heat sealing the second end to the tubing.
11. The method of claim 5 , wherein the balloon envelope includes a plurality of gores, and the method further comprises attaching the second end to one of the plurality of gores.
12. The method of claim 11 , wherein attaching the second end to the one of the plurality of gores includes heat sealing the second end to the one of the plurality of gores.
13. The method of claim 1 , wherein the suspender includes a loop at a first end, and the method further comprises attaching the loop to the plate system.
14. The method of claim 13 , further comprising, forming the loop by heat sealing a portion of the suspender to itself.
15. The method of claim 13 , wherein the suspender includes an eye at a first end, and the method further comprises attaching the loop to the plate system.
16. The method of claim 15 , further comprising, forming the eye by cutting or punching the suspender.
17. The method of claim 1 , wherein the stretching does not cause the suspender to break.
18. The method of claim 1 , wherein the suspender includes first and second ends, and during the pressurization, as the suspender stretches, the second end of the suspender is pulled towards the equator.
19. The method of claim 18 , wherein during the pressurization, as the suspender stretches, the first end remains attached to the plate system.
20. The method of claim 1 , wherein the suspender includes a first end, the balloon includes a piece of film arranged near an apex or a base of the balloon envelope, the piece of film being attached to the plate system, and the suspender further includes a second end attached to the balloon envelope, and wherein the method further comprises, attaching the first end to the piece of film.