http://abcnews.go.com/US/wireStory?id=713418
NASA to Delay Space Shuttle Launch
Reuters
Apr. 29, 2005 - NASA plans to delay the launch of space shuttle
Discovery, the first shuttle set to fly since the 2003 Columbia
accident, from May until July, an official familiar with NASA's
timetable said on Thursday.
The official, speaking on condition of anonymity, said the decision
was made by NASA's new administrator, Michael Griffin, and would be
formally announced on Friday.
The U.S. space agency on Thursday temporarily halted preparations for
Discovery's launch while managers debated nagging concerns that debris
could damage the spacecraft during liftoff.
Shuttle program managers met at the Kennedy Space Center in Florida to
talk about the likelihood of ice formations on the shuttle's fuel tank
and the possible effects if they broke off during the ship's climb and
hit the orbiter.
A piece of insulating foam from the tank hit the shuttle Columbia
during its launch in January 2003, damaging the orbiter's wing, which
broke apart as the shuttle attempted to return through the atmosphere
for landing. Seven astronauts died.
NASA grounded its remaining three shuttles for extensive
refurbishments, particularly to the massive external fuel tank, which
holds the fuel consumed during the shuttle's 8-1/2-minute climb into
orbit.
In addition to revamping how the tank's insulating foam is applied, as
well as replacing some areas of suspect foam, NASA engineers have been
analyzing the threat of ice formations and the possibility that they
could break off, as the foam on Columbia's tank did, and damage the
ship.
NASA has targeted May 22 as a launch date for the first shuttle's
return to flight. The next possible launch window is from July 13 to
31.
Because of new safety rules implemented after the Columbia accident,
NASA has only limited opportunities to launch Discovery.
The new rules, for example, restrict the U.S. space agency from
launching at night. In addition, the release of the external fuel tank
as the shuttle reaches orbit must take place when there is enough
light for clear photography.
John Doe - 29 Apr 2005 03:51 GMT
> Shuttle program managers met at the Kennedy Space Center in Florida to
> talk about the likelihood of ice formations on the shuttle's fuel tank
> and the possible effects if they broke off during the ship's climb and
> hit the orbiter.
pardon my total ignorance, but if it is that O2 pipe that causes
problems, is this something totally new to the ET, or has this pipe
existed since the inception of the shuttle programme , and if so, why
the hell was this never addressed ??????
ed kyle - 29 Apr 2005 04:04 GMT
> > Shuttle program managers met at the Kennedy Space Center in Florida to
> > talk about the likelihood of ice formations on the shuttle's fuel tank
[quoted text clipped - 5 lines]
> existed since the inception of the shuttle programme , and if so, why
> the hell was this never addressed ??????
The LOX feedline has always been there, but in the
wake of the Columbia failure, NASA decided to
re-shape the foam insulation around the LOX feedline
bellows in an effort to reduce ice formation. The
feedline itself is pretty much unchanged from its
previous design, so there must be some issues with
the foam redesign that may have cropped up during
the on-pad tanking test.
- Ed Kyle
Brian Gaff - 29 Apr 2005 09:45 GMT
Hmm, well, I get the distinct impression here that nobody is quite sure if
what they have done has actually made things better or not. Judging from
previous launches, I think you may be justified in saying that the tiles,
though not that strong, have not failed to do their job, despite being hit
many times at launch . Now how you view this is up to you, but the real
killer was the brittle rcc panels on the leading edge. So, is the ice issue
now being looked at, likely to have any problems here?
Maybe some aerodynamic solution is needed, ie, the creation of local
airflow patterns by some design changes that make free debris migrate away
from orbiter.
Brian

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Craig Fink - 29 Apr 2005 12:13 GMT
> Maybe some aerodynamic solution is needed, ie, the creation of local
> airflow patterns by some design changes that make free debris migrate
> away from orbiter.
Sure, they could do this on the Day of Launch.
It's a really simple change (essentially changing one number) to fly a
different angle of attack late in first stage. Instead of flying a
positive angle of attack, they could fly a negative angle of attack. With
a negative angle of attack, the wind is blowing away from the Orbiter and
towards the ET, instead of from the ET towards the Orbiter. But it's not
free, it'll cost some payload performance, because it will loft the
vehicle late in first stage.
In the article, they talk about this a little bit, the "tweaking" bit.
http://www.orlandosentinel.com/news/custom/space/orl-bk-nasa042805,0,3809195.sto
ry?coll=orl-home-headlines
<begin quote>
One proposal would have covered the joints with a gel-filled wrap. Another
would have tweaked the orbiter's orientation during launch as it flew
through the most critical time for possible ice-debris shedding.
<end quote>

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