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NASA Shuttle Specific Sections => Atlantis (Post STS-135, T&R) => Topic started by: Chris Bergin on 08/24/2006 11:26 pm

Title: NASA seeks Shuttle exhaust waiver
Post by: Chris Bergin on 08/24/2006 11:26 pm
http://www.nasaspaceflight.com/content/?cid=4731 - debut article by Joe for this site.

Associated images.

Document and four associated videos with the document on L2.
Title: RE: NASA seeks Shuttle exhaust waiver
Post by: Chris Bergin on 08/24/2006 11:26 pm
Title: RE: NASA seeks Shuttle exhaust waiver
Post by: Chris Bergin on 08/24/2006 11:29 pm
Title: RE: NASA seeks Shuttle exhaust waiver
Post by: Chris Bergin on 08/24/2006 11:30 pm
Title: Re: NASA seeks Shuttle exhaust waiver
Post by: astrobrian on 08/24/2006 11:56 pm
Is this waiver just a covering thier bases move or something else? After 1200 test fires I think if there was a defiante problem it would have been in process to be fixed during the 2 years down time they had. Kinda puzzles me. Granted for the flight that the video comes from, yes, there was something needing to be done about that
Title: Re: NASA seeks Shuttle exhaust waiver
Post by: psloss on 08/25/2006 12:06 am
A cutoff just before "launch commit" would be the most extreme scenario -- although this situation without the HBOI capability during shutdown was the case for all the FRFs, given their run time.
Title: Re: NASA seeks Shuttle exhaust waiver
Post by: psloss on 08/25/2006 12:17 am
Quote
astrobrian - 24/8/2006  7:43 PM

After 1200 test fires I think if there was a defiante problem it would have been in process to be fixed during the 2 years down time they had. Kinda puzzles me. Granted for the flight that the video comes from, yes, there was something needing to be done about that
Don't know, although the test firings at Stennis have rarely involved three engine clusters.

The videos on L2 are from different countdowns; the IR video is from the FRF prior to STS-26 (10 August 1988), although the effect that is obvious in the STS-68 abort video sure looks to be present (to differing degrees) in the FRFs I've seen shutdown video from.
Title: Re: NASA seeks Shuttle exhaust waiver
Post by: Shuttle Man on 08/25/2006 12:27 am
A good opening article from Joe.
Title: Re: NASA seeks Shuttle exhaust waiver
Post by: SimonShuttle on 08/25/2006 04:25 pm
Thank goodness this site is still reporting space flight news, when the others all seem to be obsessed with that crappy former planet.
Title: Re: NASA seeks Shuttle exhaust waiver
Post by: Avron on 08/25/2006 05:26 pm
Quote
SimonShuttle - 25/8/2006  12:12 PM

Thank goodness this site is still reporting space flight news, when the others all seem to be obsessed with that crappy former planet.


What planet?.. :)
Title: Re: NASA seeks Shuttle exhaust waiver
Post by: psloss on 08/25/2006 05:32 pm
Quote
Avron - 25/8/2006  1:13 PM

Quote
SimonShuttle - 25/8/2006  12:12 PM

Thank goodness this site is still reporting space flight news, when the others all seem to be obsessed with that crappy former planet.


What planet?.. :)
Why Earth (http://www.nasawatch.com/archives/2006/08/earth_and_jupit.html), of course.  (And Jupiter.)

(I say we take up a collection and form our own solar system.  Maybe we can get Chris to do the web site.)
Title: Re: NASA seeks Shuttle exhaust waiver
Post by: Chris Bergin on 08/25/2006 07:15 pm
Quote
astrobrian - 25/8/2006  12:43 AM

Is this waiver just a covering thier bases move or something else?

Covering the bases, I'd say.
Title: RE: NASA seeks Shuttle exhaust waiver
Post by: spaceshuttle on 08/26/2006 06:47 pm
i was reading a (frozen) article about the aborts and the burnoff ignitor issues...they already have six ignitors: two in the back across from each other, two in the front across from each other, and two more in the back that point towards the middle(see attachments). they're gonna need more?

Title: Re: NASA seeks Shuttle exhaust waiver
Post by: MKremer on 08/26/2006 06:54 pm
Not so much 'more', maybe, as much as tweaking the timings and maybe duration (longer-lasting) of the existing ignitor locations.
Title: Re: NASA seeks Shuttle exhaust waiver
Post by: spaceshuttle on 08/26/2006 07:00 pm
Quote
MKremer - 26/8/2006  1:41 PM

Not so much 'more', maybe, as much as tweaking the timings and maybe duration (longer-lasting) of the existing ignitor locations.

cool! well, they should have them start up at t-12 or -15 to ENSURE enough time. besides, the used to start at t-8...
Title: Re: NASA seeks Shuttle exhaust waiver
Post by: MKremer on 08/26/2006 07:18 pm
Don't need them earlier, but either staggered or to last longer through a possible shut down process.
Title: Re: NASA seeks Shuttle exhaust waiver
Post by: spaceshuttle on 08/26/2006 07:39 pm
Quote
MKremer - 26/8/2006  2:05 PM

Don't need them earlier, but either staggered or to last longer through a possible shut down process.

well, true...i just noticed that they do slow down and stop AT t-0
Title: Re: NASA seeks Shuttle exhaust waiver
Post by: Chris Bergin on 08/26/2006 11:13 pm
Quote
MKremer - 26/8/2006  7:41 PM

Not so much 'more', maybe, as much as tweaking the timings and maybe duration (longer-lasting) of the existing ignitor locations.

Yep, that's exactly it.
Title: Re: NASA seeks Shuttle exhaust waiver
Post by: Mark Max Q on 08/30/2006 12:28 am
This may be a stupid question, but are huge mechanical areas of the orbiter, such as the MPS, affected by the vibrations of a rollout, then rollback, brakes on, rollback out? Whole lotta shaking going on?
Title: Re: NASA seeks Shuttle exhaust waiver
Post by: Jim on 08/30/2006 01:49 am
Less than a launch
Title: Re: NASA seeks Shuttle exhaust waiver
Post by: Bruhn on 08/30/2006 08:32 pm
Quote
Mark Max Q - 29/8/2006  7:15 PM

This may be a stupid question, but are huge mechanical areas of the orbiter, such as the MPS, affected by the vibrations of a rollout, then rollback, brakes on, rollback out? Whole lotta shaking going on?

Yes, there are areas of the Orbiter and SSMEs that are effected by rollout induced vibrations.  It does subtract from the fatigue life of the systems.  Vibes aren't as much as launch like Jim stated, but fatigue damage is cumulative.  I've got a video of the SSMEs and other parts of the orbiter during rollout that really shows the parts shaking.  More than you would think.  I've been trying to get the video to Chris but its too big.

Each track of the crawler, I don't know how much they weigh but its alot, slaps down on the ground in a steady rythm.  This excites the structure just as if it were a modal survey test.  You can tune the vibrations by changing the speed of the crawler, but not by much.