Re: Grocery Store pricing

On Tue, 23 Sep 2008 07:09:30 -0700 (PDT), cryptoguy
<treifamily@xxxxxxxxx> wrote:

On Sep 23, 1:22 am, mike weber <fairport...@xxxxxxxxx> wrote:
On 22 Sep 2008 23:50:44 -0400, "Keith F. Lynch" <k...@xxxxxxxxxxxxxx>
wrote:

Space is very nearly empty.  Micrometeoroids are few and far between.
Nothing ever launched is known to have been damaged by space junk,
other than man-made space junk.  Not even the several probes that have
been flown through the Asteroid Belt, nor a couple that were flown
through Saturn's rings.

Which explains why NASA is having a second shuttle standing by as a
rescue ship for the upcoming mission to the Hubble.

Uh, no. The danger to the Shuttle is not from random space junk. It's
from insulation falling off the External Tank during the hypersonic
phase of the
ascent through the atmosphere, striking and damaging the Shuttle.


May i direct your attention to the following articles, located in
about five minutes of Googling. Particularly the first, which is what
i read that led me to make the statement that i did:

[quote]

HOUSTON ? NASA's shuttle Atlantis will be at a higher risk of
suffering serious damage from tiny space rocks and orbital trash than
past missions when it launches to the Hubble Space Telescope next
month, a top program official said Monday.

NASA shuttle program manager John Shannon said Atlantis and its
seven-astronaut crew are facing the extra risk solely because of their
destination.

"It's worse for Hubble because we fly higher," he told reporters
during a briefing here at NASA's Johnson Space Center.

[snip]

That puts the estimated odds of Atlantis suffering a critical strike
from a micrometeorite or orbital debris (MMOD) during its Hubble
mission at about a 1-in-185 chance, up from the typical 1-in-300
chance for flights to the space station, he added.

"It's not theoretical," Shannon said. "Every time we fly the vehicle
back, we have MMOD damage on the space shuttle."

[end quote]

NB: "every time".

8 September 2008

http://www.space.com/missionlaunches/080908-sts125-toprisk.html


[quote]

Just to remind us all that the astronauts are really quite exposed up
there in orbit, a micrometeorite took a small chunk out of Endeavour's
front windshield at some point during the mission - the astronauts
just noticed it. NASA officials said that the space debris impacted
the shuttle's window #2. With the impact discovered, NASA engineers
are planning to study it, but they don't think it's a risk to
astronaut safety.

Space shuttles have been beaten up by orbital debris in the past. In
most cases, the impact is very small, and the impactor is absorbed by
the shuttle's external skin. In this situation, the shuttle is very
well equipped with the analysis gear to really study this windshield
ding if they wanted to.

[end quote]

August 16th, 2007

http://www.universetoday.com/2007/08/16/sts-118-micrometeorite-dings-shuttle-windshield/


[quote]

Sensors inside the wing indicated that a micrometeorite might have
struck that area of the wing while the shuttle crew was sleeping early
Monday. Mission managers wanted the astronauts to take a precautionary
look to avoid ordering up a time-consuming focused inspection on the
fifth day of a busy flight.

[end quote]

December 12, 2006

http://www.local6.com/technology/10516570/detail.html


[quote]

Hypervelocity Micrometeorite Damage in Fused Silica Space Shuttle
Windows

Chapter Authors: J. Lankford, K. Edelstein, Lyndon B. Johnson

Series: Ceramic Engineering and Science Proceedings
Summary

Thermal protection windows of fused silica on the space shuttle are
subject to hypervelocity impacts by microscopic meteorites. Because of
the extreme nature of these events, where velocities may reach 14
km/s, the resulting damage is qualitatively different from that
produced under quasistatic or even normal high velocity (several
hundred m/s) conditions. In particular, unusual petaloid cracking
patterns are observed, whereby half penny-shaped cracks appear to
nucleate on the base of the impact crater. These expand
circumferentially (like Hertzian cracks), and then grow into the
glass, curving outward continuously until they form one or more large
lateral cracks attached to, but floating below, the crater. Also
observed are smaller circumferentially-tangent half penny surface
cracks located outside of the crater area. These several flaw types
are characterized qualitatively and quantitatively, and correlated
with crater dimensions (impact energy). Implications for window
residual strength.

[end quote]

http://www3.interscience.wiley.com/cgi-bin/summary/117942382/SUMMARY?CRETRY=1&SRETRY=0

(Note, NASA apparently includes all externally-originating debris
strikes {i.e, not insulating foam} as "MMOD", but they are definitely
claiming at least some of them for actual mcro-meteors.)
.

Relevant Pages

  • Re: Time to remove the mask
    ... quite a bit of detail in the CAIB. ... Why did witnesses see debris coming off the shuttle so early during reentry? ... If the shuttle had sensors to detect structural damage why wasn't the crew ...
    (sci.space.shuttle)
  • Re: More one NASA management
    ... Here is more info on the Dumb failure of NASA managers to seek ... QUOTE START ... shuttle when John Glenn went into orbit in 1998. ... shuttle to give the Maui telescope a better view. ...
    (sci.crypt)
  • Re: More one NASA management
    ... beat the hubble. ... another fine example of NASA management screwing up. ... added to the shuttle to not completely fix the porblem it still ... QUOTE ON ...
    (sci.crypt)
  • Re: So is the shuttle ok or what?
    ... I think they won't say anything, especially if there was damage. ... Every mission since the Columbia disaster, they do a spacewalk and visual inspection of the shuttle to check for heat shield damage. ... I think NASA will only report major damage if it results in a disaster. ...
    (sci.space.shuttle)
  • Re: YET ANOTHER SHUTTLE ACCIDENT:(
    ... incidents which maybe never caught the eyes of the media in the past. ... A halogen lamp falls onto the nose of a shuttle external ... causing minor damage to foam insulation. ... Shuttle orbiter power controller damaged during testing. ...
    (sci.space.shuttle)