In article ,
says...

On 2018-04-22 19:37, Greg (Strider) Moore wrote:

Fair point. And I believe they already have helium tanks on board, just use
those as part of the supply.

In terms of mass, wouldn't the mass of the balloon(s) be far more
significant than that of the gas used to fill it/them?

Depends on the details. But in general I'd say the mass of the gas is
quite significant because every kg added to the upper stage for reuse
reduces payload capacity by the same amount.

How heavy would the fabric need to be to survive re-entry?

Depends on the details. Build a little, test a little, fly a little.

Or would they go with lighter "disposable" material where on balloon
does initial slowing down before re-entry interface (where it burns up)
and after it, another baloon is deployed do to the drag/lift in denser
atmosphere?

Depends on the details, but in general SpaceX has tried to reuse as much
as they can. They don't even use "pyros" to do stage separation. They
use pneumatic cylinders instead. Even the landing gear on Block 5 will
be retractable (earlier versions locked in place and had to be removed
from the stage so it could be transported). Designing everything for
reuse allows for higher flight rates.

Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.