Reentry Buffeting

Just how rough is a shuttle reentry? I've read a lot of reports in the
press over the years about "buffeting" during reentry, but I've never heard
any crews mention it. I've also never noticed any buffeting on onboard
videos shot during reentry. It always looks smooth as silk until the
shuttle gets under 30,000ft or so, where it sometimes encounters normal
clear air turbulence.

In the old capsule days I know buffeting was sometimes a problem, but is
this still true for the shuttle? I believe it was an early design concern,
but in reality is it less of a factor than originally expected?

"Mike Dennis" wrote in message
news
Just how rough is a shuttle reentry? I've read a lot of reports in the
press over the years about "buffeting" during reentry, but I've never
heard any crews mention it. I've also never noticed any buffeting on
onboard videos shot during reentry. It always looks smooth as silk until
the shuttle gets under 30,000ft or so, where it sometimes encounters
normal clear air turbulence.

In the old capsule days I know buffeting was sometimes a problem, but is
this still true for the shuttle? I believe it was an early design
concern, but in reality is it less of a factor than originally expected?

Nobody know, huh? On this group I've heard of a lot of design points argued
that "it has to be designed this way due to reentry buffeting and loads".
But it doesn't really seem like any of us know, do we?

Mike Dennis wrote:
"Mike Dennis" wrote in message
news
Just how rough is a shuttle reentry? I've read a lot of reports in the
press over the years about "buffeting" during reentry, but I've never

Nobody know, huh? On this group I've heard of a lot of design points argued
that "it has to be designed this way due to reentry buffeting and loads".
But it doesn't really seem like any of us know, do we?

Well, I'd start by looking for records of accellerometer data from shuttle
entries.

Have you spent a little while with the NASA search engine?

"Ian Stirling" wrote in message
...
Mike Dennis wrote:
"Mike Dennis" wrote in message
news
Just how rough is a shuttle reentry? I've read a lot of reports in the
press over the years about "buffeting" during reentry, but I've never

Nobody know, huh? On this group I've heard of a lot of design points
argued
that "it has to be designed this way due to reentry buffeting and loads".
But it doesn't really seem like any of us know, do we?

Well, I'd start by looking for records of accellerometer data from shuttle
entries.

Have you spent a little while with the NASA search engine?

Yes, but what I've found doesn't seem to back up assertions of buffeting on
reentry. It looks to be quite the opposite: very smooth. I really can't
figure out why it appears so much different than, say, an Apollo command
module. Is it the flight profile, the shape, or something I'm overlooking.
I found a lot of stuff on why they designed the shuttle's TPS to handle
heavy vibrations, but the actual results appear quite benign. I know the
CFD tools available back then were primitive by today's standards, but was
NASA that far off?

I'm wondering how the shuttle's results might affect design of the TPS on
the CEV.

(Of course, I concede it's possible there is significant buffeting, but I'm
just not finding the evidence online.)

Mike Dennis wrote:
[...]
Nobody know, huh? On this group I've heard of a lot of design points argued
that "it has to be designed this way due to reentry buffeting and loads".
But it doesn't really seem like any of us know, do we?

Well, Ken Iliff and Mary Shafer probably know. I'd take a look at
either Ken's book, or papers by either/both on the NASA servers. The
certainly know about "early trip" of the airflow (laminar detachment?).

Story Musgrave appearently knows, since he did his cowboy trick of
standing during early entry phases.

/dps

"snidely" wrote in message
ups.com...

Mike Dennis wrote:
[...]
Nobody know, huh? On this group I've heard of a lot of design points
argued
that "it has to be designed this way due to reentry buffeting and loads".
But it doesn't really seem like any of us know, do we?

Well, Ken Iliff and Mary Shafer probably know. I'd take a look at
either Ken's book, or papers by either/both on the NASA servers. The
certainly know about "early trip" of the airflow (laminar detachment?).

Story Musgrave appearently knows, since he did his cowboy trick of
standing during early entry phases.

I hadn't heard anything about that--sounds very interesting. I wonder if
his trick is special because of the pitching and yawing (which does seem
slow, but noticeable, looking at the data), or if it's due to any buffeting.