The time limit for. shipping a POV is the same as for travel and HHG transportation limits (JTR Para 5366, POV. Transportation Time Limitation), 1 year from the date of retirement/separation with severance. pay or 180 days from the date of separation.
The envelope is the large bag that holds the helium gas. The envelope is generally cigar-shaped, for aerodynamic purposes, and made of a durable, airtight, lightweight fabric (polyester composites) that is much like the fabric of a space suit.
Helium is a chemical element and a colorless, odorless, tasteless, inert gas. It has the smallest atomic radius of any element and the second lowest atomic weight.hese properties of helium gas make it the atmosphere of choice for many metallurgical processes, growing perfect crystals in chemical vapors, manufacturing optical fibers and other uses. Helium has a very low viscosity, a high diffusion coefficient and the smallest atom of any element.