"JF Mezei" wrote in message news

On 2018-04-17 20:05, Jeff Findley wrote:
In article ,
says...

https://www.space.com/40313-spacex-r...y-balloon.html

By "party balloon" are we talking helium or Hydrogen filled balloons
that will "lift" the stage to slow its descent? (and I assume provide
drag initially).


I'm guessing nitrogen myself. I don't think lift is nearly as important at
this point is as drag over as large a surface area as you can manage.



Is this a case of planning bouyancy such that it is massively positive
initially to slow down descent, but as it drops into denser atmpsphere,
bouyancy dimonishes and they plan it such that it gets to just a tad
below neutral bouyancy for a gentle touch down with the engine firing to
stop vertical speed just bfore touching ground?

Are we talking langing legs and fins?

Or is this going to be dead weight falling back help by a balloon and
truly fall on some mattress factury like when Batman and Robin had
engine problems in a helicopter?


Did you read any of the article?


How would de-orbit work? From the point stage-2 is no longer needed for
payload, isn't it firmly in orbit and coudl stay there for very long
time? I assume it would require de-orbit burn?


They already deorbit the 2nd stages to reduce the orbital debris problem




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