SERA 230 N criterion and direct payload-to-balloon-neck attachment

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Horst Reiterer

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May 16, 2022, 6:52:01 AMMay 16
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Hi,

I'm glad a community like yours exists! I'm new to high-altitude ballooning. After extensive research, I'm trying to get my head around the following SERA heavy balloon classification criterion that I'd like to avoid to be classified as "light":


1. CLASSIFICATION OF UNMANNED FREE BALLOONS
1.1. Unmanned free balloons shall be classified as (see Figure AP2-1):
(c) heavy: an unmanned free balloon which carries a payload which:
(4) uses a rope or other device for suspension of the payload that requires an impact force of 230 N or more to separate the suspended payload from the balloon.

With a classic payload train - particularly a long one - that classification criterion is clear and makes sense to me. However, what happens in case of a payload that is directly attached to the ballon neck like Stanford's ValBal (https://stanfordssi.org/blog/ssi-63-shatters-world-record-again)? The paragraph does not state that the payload itself must exhibit a separation force of less than 230 N. But a payload attached that way leaves only two entities - the payload and the balloon. Subtracting the balloon, there's only the payload and no rope of concern.

If the parachute is directly attached to the payload as well (thinking ValBal again), a similar question arises. The sum of all shroud lines definitely exceeds 230 N, so my assumption is that it only applies to the connection between the balloon, the parachute and individual payloads. If the connection effectively has a length of zero, is the criterion fulfilled without a predetermined braking point?

Do both scenarios call for a predetermined braking point to comply?

I know that you cannot make official statements concerning SERA but I'm very interested in your interpretation based on your collective experience, which exceeds mine by years and years.

Cheers,

Horst Reiterer
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