On Jan 31, 2018, at 6:02 AM, Thomas Jones-Low <xxxxxx@gmail.com> wrote:

How do you prevent the sphere or capsule from tumbling? 

In the real world for the people who do extreme height sky diving, their biggest fear is starting an uncontrollable tumble. In the thin atmosphere there is no way to stop it and by the time you hit thicker air, you have been rendered unconscious. 


Yes, this was a big issue with both recent recordbreaking jumps, http://www.iflscience.com/technology/57-year-old-man-skydives-stratosphere-breaking-baumgartner-s-record/ https://en.wikipedia.org/wiki/Red_Bull_Stratos and nearly killed Kittenger in his 1960 jump; only his automatic chute opener saved his life.

However, humans are very far from spherical (well most himans, anyway :-) a sphere would be less likely to tumble, I think. But if you’re not just wearing a suit, and are rising in some sort of encapsulating enclosure, at OTU tech levels cheap disposable attitude adjustment would certainly be readily available. Odds are you could do the control part today for a few dollars. The thruster part might cost a little more.

I can’t imagine that a hypersonic airflow makes this any easier to manage. 

On Wed, Jan 31, 2018 at 4:21 AM Tim <xxxxxx@little-possums.net> wrote:
On Wed, Jan 31, 2018 at 12:18:39AM -0500, Caleuche wrote:
> Could you explain that last part (" 50% margin for the harder to
> model variation of forces over the sphere") - do you mean with
> respect to the ability of the internal pressure of the sphere to
> keep the sphere rigid and spherical?

I mean that the drag comes from an average over the frontal surface,
and the pressure on the sphere near the stagnation point will
generally be greater than that further out.  The exact magnitude of
variation depends upon all sorts of surface detail factors that are
extremely annoying to model and may vary in reality anyway.  So I
allowed an extra 50% margin to cover these.


- Tim
-----
The Traveller Mailing List
Archives at http://archives.simplelists.com/tml
Report problems to xxxxxx@simplelists.com
To unsubscribe from this list please go to
http://archives.simplelists.com
--
Thomas Jones-Low
xxxxxx@gmail.com
-----
The Traveller Mailing List
Archives at http://archives.simplelists.com/tml
Report problems to xxxxxx@simplelists.com
To unsubscribe from this list please go to 
http://www.simplelists.com/confirm.php?u=SVsSnnCJk1ACiTghqxnWgr8yCl9WeXKi

-- 
Bruce Johnson
University of Arizona
College of Pharmacy
Information Technology Group

Institutions do not have opinions, merely customs