Conference 7.286::space

    Michael Braukus                                  July 12, 1996
    Headquarters, Washington, DC
    (Phone:  202/358-1979)
    
    RELEASE:  96-138
    
    NASA DELAYS LAUNCH OF SPACE SHUTTLE
    
            NASA managers today decided to replace the reusable 
    solid rocket motors on the Space Shuttle Atlantis, delaying 
    its July 31, 1996, launch to rendezvous with the Russian 
    space station Mir until mid-September.
    
            Atlantis' motors are being replaced because 
    technicians disassembling the motors of the previous Space 
    Shuttle mission, STS-78, observed that hot gas had seeped 
    into J-joints in the field joints of the motors.  In some areas, 
    the hot gas had penetrated through the J-joint to, but not 
    past, the capture feature O-ring. 
    
            An investigation of this field joint found that the 
    most probable cause of this seepage was related to the use of 
    a new adhesive and cleaning fluid.  The change to the new 
    adhesive and cleaning fluid was required to comply with new 
    Environmental Protection Agency regulations which reduce 
    ozone depleting substances.
    
            The investigation also concluded that the risk of a 
    field joint failure was improbable and that the STS-79 
    boosters, assembled with the new field joint cleaning process 
    and adhesive, were safe to fly.
    
            The decision to replace the STS-79 solid rocket motors, 
    which also utilized the new adhesive, was made to provide an 
    opportunity to better understand the J-joint failure and to 
    improve the safety margin of the joint.
    
     

Oh-oh.  Shannon will not be happy.  Being on orbit must get old after a while!

Burns

>Oh-oh.  Shannon will not be happy.  Being on orbit must get old after a while!

I had read that she will potentially be the woman in space longest.  And
that she was happier than a previous American on MIR who had really limited
contact with home & family; NASA has apparently given regular communications
to help astronaut sanity.  ;-)

Charlie

Just another 8 weeks to go, hopefully.


   NOTE: Today KSC launch managers recommended a launch date of Sept. 12
   for Space Shuttle Atlantis.  NASA program managers will review this
   recommendation and announce a target launch date later this week.

I pulled this off the shuttle news group (sci.space.shuttle) over
the weekend. It offered some detailed information not mentioned before.
The comments are not mine but of the person who posted this in
the newsgroup.
BTW, I also do think that there is a tendency to go overboard when being
concerned about the amount of impact that a few gallons (amount of TCA
used on each shuttle flight), would have on the environment. I say
this quite readily while also wearing my environmental hat. In other words
I'd be more concerned with the total lack of regulation on such vehicles
as buses, trucks and other such vehicles that spew out tons of particulates,
while logging many miles daily on our roads.
An adhesives and materials chemist I know with 37+ years of experience
(my father), has said that it is not easy coming up with an adhesive
that will stay tacky, and set up, over a generous enough temperature range,
and still retain its other physical properties like elasticity, curing
rate, etc. The cleaning agent also has to be picked to be molecularly
compatible with the adhesive that is to be applied after the surface
is cleaned, as there is always going to be some cleaner left behind,
and this should be taken advantage of so as to provide a better bonding
between the dissimilar surfaces such as the metal of the SRB surfaces
 and the foam insulation material used in the SRB's.

-Bob
----------------------------------------------------------------------------
From: p3voices <[email protected]>
Subject: Good details on SRB joint problem - only 100+ gallons left!
Date: Fri, 26 Jul 1996 23:30:01 -0400

{MY COMMENT: I always favored a clean environment....but have we gone 
overboard???  read on, and please don't cringe!}

I recently read this story and thought some of you would find it as 
interesting.  From ChemicaL and Engineering News (always a good reliable 
source on chemistry-related shuttle subjects), 7/22/96, P. 11:
<EDIT EARLY STUFF FROM ARTICLE>
"when technicians dissasembled the rockets from the most recent shuttle 
Colombia mission they discovered hot gas had seeped into the three field 
joints on each booster"
<EDIT SOME MORE>
"NASA says the gas went only several inches into the J-joints, where for 
a length of 3.5 inches a pressure-sensitive adhesive bonds together 
nitrile-butadiene rubber insulation attached respectively to the field 
joints tang and clevis.  No damage was done, says a NASA spokesma, and 
the gas did not pass the field' joint's capture feature O-ring to reach 
the primary and secondary O-rings. "The flight safety of the shuttle was 
not compromised'".
"Upon investigation NASA concludes 'the most probable cause of this 
seepage was related to the use of a new adhesive and cleaning fluid'.  
The adhesive used until then, Morstik 132, is a styrene-butadiene rubber 
base dissolved in trichloroethane (TCA).  TCA is known to deplete the 
earth's ozone laye and is being phased out under international 
agreements.  NASA and booster contractor Thiokol have won an "essential 
use exemption" for the use of TCA through 2001 for lack of proven 
alternatives."
"But the curbs on TCA led the adhesive supplier to stop making the 
adhesive last year.  NASA and Thiokol 'wanted to meet the new [ozone 
depleting] regulations as soon as feasable'.  They thus replaced the TCA-
based adhesive with Morstik 227, a water-based acrylic emulsion made by 
the same supplier.  In addition, they had previously used TCA as the 
baseline solvent for cleaning the joint before applying the adhesive.  On 
Colombia's field joints, they replaced TCA with an environmentally safer 
degreaser made of 97% kerosene and 3% d-limonene."
"NASA's investigation finds the risk of field joint failure is of field 
joint failure is 'improbable', and boosters 'assembled with the new field 
joint cleaning process and adhesive are safe to fly'.  Nevertheless, NASA 
officials decided against the new materials on Atlantis 'to provide an 
opportunity to better understand the J-joint failure and to improve the 
safety margin of the joint'."
{MY COMMENT: NOW WE GET TO THE 100 GALLONS REMAINING}
"Therefore technicians are now replacing Atlantis' boosters with rockets 
that were slated for use on the next shuttle flight in November.  And 
those boosters are being assembled using the TAC-based adhesive and 
cleaning fluid.  NASA still has more than 100 gal of this old adhesive 
and only a few gallons are used per shuttle mission, notes the spokesman.  
So 'there's enough for a while' until NASA figures out whether it can use 
the new materials or will have to find, test and certify alternatives."

{MY COMMENTS:  As a practising chemist, it is well known that emulsion-
based coatings can often be somewhat more permeable than coatings applied 
from a single-phase (dissolved) solution.  Emulsion-based coatings become 
non-permeable only if they are properly applied within a carefully 
specified temeprature range so that the emuslified particle deposits in a 
uniform manner and has the opportunity to properly reflow before too much 
curing/evaporation occurs.  Perhaps it is not so surprising therefore 
that the Morstik 227 failed}



Date:	27-Jul-1996
Posted-date: 27-Jul-1996

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    This seem to be a firm date & time :-
    
    Scheduled Launch: September 12, 1996, 6:26 a.m. EDT (target date) 
    

    Except for the fact that there is another launch also scheduled
    for that day by the military. I think I saw it mentioned somewhere.
    Maybe there is some negotiation going on, and meanwhile NASA has
    picked that date in anticipation that they can get priority over
    the range for the shuttle launch.
    
    Bob

    
	Following is an extract from the shuttle status reports, I take
        the conflict is with the military launch as in -.7 ?


NOTE: The crew of mission STS-79 (image)are at KSC for the Terminal
Countdown Demonstration Test which concluded today. A TCDT is held
prior to each Space Shuttle flight providing the crew of each mission
opportunities to participate in simulated countdown activities and
emergency egress training exercises at KSC. The crew will return to
Johnson Space Center at about 2 p.m. today to continue their
training.

        The Flight Readiness Review is scheduled to begin Thursday
morning at KSC. One issue to be discussed is the launch date,
currently targeted for Sept. 12, and a scheduling conflict with the
Eastern Test Range. If this conflict remains, the earliest Atlantis
could launch is Sept. 14 at about 5:39 a.m.


        Managers are keeping a close watch on the tropics and the
weather systems that have developed over the past several days.
Hurricane Edouard continues to move northwest followed by Tropical
Storm Fran. Managers are discussing options for a potential rollback
of Atlantis (image) to the VAB if the storms show signs of becoming a
threat to central Florida.

I think it is a GPS launch.

Burns

    
    
    
    LAUNCH DATE/TIME: Sept. 14 at about 5:39 a.m. (EDT)
    LAUNCH WINDOW: 7-10 minutes
    MIR DOCKING: About 12:39 a.m., Sept. 16
    TARGET KSC LANDING DATE/TIME: Sept. 23 at 9:34 a.m.
    MISSION DURATION: 9 days, 3 hours, 55 minutes
    

Actually, because of the hurricane-induced round trip to the VAB, the launch is
now set for Sept 16 at 4:54.  This is good for us NE residents.  Before sunrise
we have a chance of seeing MECO.

Burns

    From: [email protected] (Bruce Buckingham)
    Date: Thu, 05 Sep 1996 12:41:46 -0400
    Subject: 9-5-96 status
    
    
    KENNEDY SPACE CENTER SPACE SHUTTLE STATUS REPORT
    THURSDAY, SEPTEMBER 5, 1996  (12:02 PM EDT)
    
    KSC Public Affairs Contact: Bruce Buckingham (fax 407-867-2692)
    E-mail: [email protected]
    
    MISSION: STS-79 -- 4th MIR DOCKING & SPACEHAB DM
    
    VEHICLE: Atlantis/OV-104
    LOCATION: Pad 39A
    LAUNCH DATE/TIME: Sept. 16 at about 4:54 a.m.
    LAUNCH WINDOW: about 7 minutes (possibly less)
    MIR DOCKING: Sept. 18 (late evening)
    TARGET KSC LANDING DATE/TIME: Sept. 26 at about 8:49 a.m.
    MISSION DURATION: 10 days, 4 hours
    CREW: Readdy, Wilcutt, Akers, Blaha (up), Lucid (down), Apt, Walz
    ORBITAL ALTITUDE and INCLINATION: 196-245 statute miles/51.6 degrees
    All times are EST
    
    NOTE: The Space Shuttle Atlantis was returned to Pad 39A today following
    mission managers determination that the threat of Hurricane Fran to central
    Florida had passed. First motion from the Vehicle Assembly Building back to
    the pad occurred at about 2:51 a.m. The vehicle was hard-down on the pad at
    about 8:30 a.m.
    
        Because of the delay in processing experienced when Atlantis was sent
    back to the VAB, managers have reassessed the time it will take to prepare
    the vehicle for launch. The new official launch date for mission STS-79 is
    Sept. 16. The launch window opens at about 4:54 a.m.
    
        The Rotating Service Structure has been placed around the vehicle and
    orbiter power-up is scheduled for about noon today. Later this afternoon,
    operations will begin for early stowage of equipment and supplies in the
    Spacehab double module. Also, orbiter aft engine compartment close-outs will
    begin today. Work to complete hypergolic propellant loading will begin this
    weekend.
    
        This is the third time Atlantis has been rolled-out to the pad for this
    mission. Atlantis was returned twice to the VAB due to two separate
    hurricanes. The first return to the VAB was due to Hurricane Bertha which
    threatened the east coast of Florida on July 10. Two days later, managers
    decided to keep Atlantis off the pad in order to replace the solid rocket
    boosters before launch. STS-79 roll-out dates are: July 1, Aug. 20, and
    Sept. 5.