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.
Once helium is released into the atmosphere in the form of party balloons or boiling helium it is lost to the Earth forever, lost to the Earth forever, he emphasised. What helium is used for. *Airships. As helium is lighter than air it can be used to inflate airships, blimps and balloons, providing lift.