Abstract: Aspects of the technology relate to lighter-than-air (LTA) high altitude platforms configured to operate in the stratosphere. Such platforms can generate operate for weeks, months or longer. Shaped envelope LTA platforms may support a payload that provides telecommunications and/or other services to remote regions around the world. The payload may be arranged with other components on a modular bus-type chassis. One or more components may be moveable along the chassis to change the pitch of the vehicle for more effective flight operation. The modular chassis may include a truss configuration assembled from one or more subunits. The subunits may be preassembled with different equipment packages. Trusses formed using sets of struts may have two or more struts terminating at one interconnection node. Node connection elements, such as compound dovetail interconnects, facilitate a reliable, repeatable and quick mounting method for structural interconnections, which can lead to faster assembly and disassembly times.

Abstract: A method of managing leakage of liquid inside a battery system comprises: containing leaking liquid in a non-liquid sensitive region of the battery system so as to protect internal electrical components of the battery system from coming in contact with the leaking liquid; and in direct response to the leakage, expunging the leaking liquid from the battery system. A drain device includes: a body with a port therethrough, the body configured to be positioned in a wall of a container; means for opening the port in response to a first liquid contacting the drain device on an inside of the container; and means for resisting ingress into the container by a second liquid that contacts the drain device on an outside of the container.

Abstract: A method of managing leakage of liquid inside a battery system comprises: containing leaking liquid in a non-liquid sensitive region of the battery system so as to protect internal electrical components of the battery system from coming in contact with the leaking liquid; and in direct response to the leakage, expunging the leaking liquid from the battery system. A drain device includes: a body with a port therethrough, the body configured to be positioned in a wall of a container; means for opening the port in response to a first liquid contacting the drain device on an inside of the container; and means for resisting ingress into the container by a second liquid that contacts the drain device on an outside of the container.