SpaceShipOne and reentry heat

[copied to .shuttle, followups set]
On 2004-07-17, Jorge R. Frank wrote:

If your conclusion above is correct, then it seems to me that previous
flights have been lucky in that, for instance, those paint flecks made
their pits in the windows and not some piece of RCC.

Indeed.

A related query:

In a study of orbital debris I have at home, it shows a graph of the
statistically expected number of window replacements - due to impact
pitting, I believe - against the orbital attitude of the Orbiter.
(tail-first getting less damage than nose-first, for example). It
comments that flight rules require that, all other factors (mission
requirements, say) considered, the attitude should be planned to
minimise window damage.

Is there plans to develop a similar rule regarding RCC "exposure", or is
the expected flux low enough that attitude isn't a significant factor?

(I suppose this is a lot less relevant now that most on-orbit time will
be docked to ISS, where attitude is pretty much mandated by the station,
but...)

--
-Andrew Gray

Am 21 Jul 2004 19:23:57 GMT schrieb "Andrew Gray":

In a study of orbital debris I have at home, it shows a graph of the
statistically expected number of window replacements - due to impact
pitting, I believe - against the orbital attitude of the Orbiter.
(tail-first getting less damage than nose-first, for example). It
comments that flight rules require that, all other factors (mission
requirements, say) considered, the attitude should be planned to
minimise window damage.

Is there plans to develop a similar rule regarding RCC "exposure", or is
the expected flux low enough that attitude isn't a significant factor?

Even if "they" wanted to make such a rule - it wouldn't be necessary
to be invented, simply because the RCC panels point to the same
general direction as the orbiter's windows. So all flight rules caused
by window impact pitting possibility are also valid for RCC pitting
prevention. So no further action is necessary for that...

cu, ZiLi aka HKZL (Heinrich Zinndorf-Linker)
--
"Abusus non tollit usum" - Latin: Abuse is no argument against proper use.

mailto: http://zili.de

"Heinrich Zinndorf-Linker (zili@home)" wrote in
:

Am 21 Jul 2004 19:23:57 GMT schrieb "Andrew Gray":

In a study of orbital debris I have at home, it shows a graph of the
statistically expected number of window replacements - due to impact
pitting, I believe - against the orbital attitude of the Orbiter.
(tail-first getting less damage than nose-first, for example). It
comments that flight rules require that, all other factors (mission
requirements, say) considered, the attitude should be planned to
minimise window damage.

Is there plans to develop a similar rule regarding RCC "exposure", or is
the expected flux low enough that attitude isn't a significant factor?

Even if "they" wanted to make such a rule - it wouldn't be necessary
to be invented, simply because the RCC panels point to the same
general direction as the orbiter's windows. So all flight rules caused
by window impact pitting possibility are also valid for RCC pitting
prevention. So no further action is necessary for that...

That's kinda sorta true, but not completely true. It does happen to be true
that the best orbiter standalone attitude for protecting the windows (bay
to Earth, tail forward) is also good for protecting the RCC. However, when
the orbiter is docked to ISS, its attitude (roughly tail to Earth, belly
forward) is good for the windows but not so good for the RCC.

Unfortunately, there don't seem to be any easy answers to this. Flipping
the stack around protects the TPS better, but exposes the windows and
radiators more. There is one proposal to reconfigure ISS to have PMA3 on
Node 2 nadir, and have the orbiter dock from below, tail forward (similar
to what was done on assembly flights 4A and 5A). However, this
configuration is really bad for docking mechanism capture performance and
RCS plume impingement during final approach.


--
JRF

Reply-to address spam-proofed - to reply by E-mail,
check "Organization" (I am not assimilated) and
think one step ahead of IBM.