STS-114 Mission Coverage and Discussion

srmeaney · 2005-08-01 10:55:15

NASA's plans for the next twenty years are Shuttle and Shuttle launch systems - Even the return to the Moon is tied to the shuttle - CEV switch over at the end of the decade, rather than tomorrow.
Once Discovery comes home, there will be no manned launches until the CEV greenlights in 2015? thats a ten year window of Unmanned Exploration.

As to the Discovery's current situation: Can they fix it without causing further damage? I'd rather it stayed in orbit that it might find a new mission, if the condition of the tiles continue to decay.

I'm sure there are lots of people who feel the same.

GCNRevenger · 2005-08-01 17:04:40

srmeaney, ISS probably wouldn't be finished, and though I would hate to say it in this context, ending the Shuttle program now would be the best thing for manned space travel.

Depends on what you call "finished"

Of course ditching Shuttle would be the best thing to do logistically, but unfortunatly the situation the way it is that isn't politically acceptable. Shuttle has too much support in Congress, it is needed to fulfill ISS launch commitments to make the diplomats happy, and NASA's credibility just couldn't take them cutting and running now after the "Return to Flight" fanfare.

Michael Bloxham · 2005-08-01 19:26:23

On the contrary, I think the media and the general public are starting to understand how pointlessly dangerous the shuttle has been all along, and at the same time are beginning to sympathize with the situation NASA is now in. If Griffin made the call to end the shuttle program soon after the successful return of Discovery, the public would atleast understand that decision a little better now than at any other time, past or future.

Commodore · 2005-08-01 19:39:02

You know, I wonder if NASA is allowing all these little quirks to have a little more media attention than they possibly deserve. That way they can milk the existing issues to put themselves in a better position to go to Congress and ask for an alternetive launch method for ISS pieces.

GCNRevenger · 2005-08-01 19:52:27

I disagree:

First off, although the gap filler issue is very likly inconsequential, overall the public scrutiny of NASA is not undeserved. The Shuttle design and both of its fatal failures have been the result of the way the agency thinks and runs. If Challenger and seven dead astronauts didn't change the way they aproach manned flight, seven more ought to... right?

Second, I would love to buy into your optimistic beliefe about the public Michael, but I bet that there are also alot of people who don't understand or don't care how flying Shuttle is so hard. To see NASA "triumphantly" (NASA's word) return to flight, only to cut-and-run now after so much money and time and political capital spent on it... no, NASA would not be forgiven that easily.

Then there are the purely political forces at work here, that Congress likes the Space Shuttle, and they like it alot. Neither Griffin nor even Bush could easily tell them to talk a long walk out a short airlock. Then there is the State Department folk who will not let NASA wriggle out of the ISS deal without a price to be paid.

RobertDyck · 2005-08-01 20:49:06

It's amazing how much influence one person can have, and how long lasting. NASA intended to build a space shuttle to be safer than capsules, much cheaper to operate, and provide routine access to space. Richard Nixon cancelled Apollo, Saturn 1B and Saturn V, and forced NASA to develop a bastardized shuttle with "just barely enough". That reduced development cost but increased operation cost, defeating the point of a reusable shuttle. Safety was glossed over to make it appear there was a space program while Nixon directed funds to the Vietnam War. He never told anyone his "secret" plan to end the war was to raid NASA's budget, until after he was elected. His efforts in Vietnam weren't successful anyway. That left NASA with a hobbled shuttle with questionable safety that had to work or NASA was out of the space business. How long has NASA been limping along with this thing? Tricky Dicky's legacy is still with us.

Oh how I wish NASA built the two-stage-to-orbit true shuttle, with aircraft skin over tank insulation, no SRBs, and a fly-back booster. They intended to keep operating Apollo until Shuttle had demonstrated itself. Skylab launched as a self-launching space station on a Saturn 1B, replaced by Skylab 2 which would be joined by another Skylab module to form the core of an international space station. Saturn 1B and Saturn V retained for heavy lift, and a shuttle just to service the station. Would-a could-a should-a, but we have what we have. Let's get on with it.

Rxke · 2005-08-02 02:21:50

re: the effect that protruding stuff can have, an interesting tidbit from a Slashdot poster:

Boundary layer transition is not a very well understood phenomenon to begin with, and in this case you pushing the limits of both flight experience and analytical capability. Going from laminar to turbulent flow above mach 18 results in some very serious heating, ultimately effecting not just the thermal system, but also the structural margins.
Most importantly, this trip would spill over the side of vehicle and run down streamlines into the wing leading edge. Analysts put the increased heat loads even in a "best case" situation at 80% increase. At those temperatures (almost 3300F), the SiC coating will start to degrade. Dispersion in the entry tajectory could lead to an additional 150F. At that temperature the SiC will ablate, exposing the carbon-carbon substrate. It will oxidize and the temperature will skyrocket to 4000F. At that temp kiss the wing goodbye.
That all being said, I think it could make it down - the uncertainty in this situation is increasing conservatism - but I sure as hell won't take that risk when the EVA is quick and relatively simple.

Rxke · 2005-08-02 02:29:43

Someone nearly lost $100, from the look of the latest newsreports, heehee.

Glad no-o,ne took your offer, I bet!

Palomar · 2005-08-02 05:17:48

*Don't mind me:

http://www.spaceweather.com/swpod2005/0 … ]Discovery & ISS in this photo

-and-

http://www.spaceweather.com/swpod2005/0 … arz1.jpg]A "closeup" with markers

(The 3rd is a sunspot).

--Cindy

SpaceNut · 2005-08-02 05:23:10

GCNRevenger wrote:
although the gap filler issue is very likly inconsequential

This maybe so but if the crews of future ships are afraid to go out to fix what ever is wrong with there ships, all will view this media coverage as proof that we do not belong out there in space and that we are indeed waisting money as some would see it.

I for one see it as a chance to prove that no more life must be lost if we do the right thing with the tools that we have.

We all ready have played with the repair kits and there tools. Why not make use of what we have if need be to push the insulation back into the cracks with the putty knifes lets do so and make it safe for return.

Yang Liwei Rocket · 2005-08-02 05:55:12

Nasa managers have already noted an apparent 4cm-wide mark on the nose section of the shuttle. Discovery's astronauts have been using a 15m-long robotic arm with sensor and camera attachments to examine the shuttle's heat-resistant tiles. NASA says the protruding material could cause dangerous overheating during re-entry and lead to another Columbia-type disaster. The arm will be operated by astronauts inside the station, who will bend and wrap Robinson around so he can reach the shuttle's belly. Once there, he'll tug out the ceramic-fabric filler with his gloved hands. If that doesn't work, he'll cut away the material, which is sticking out about an inch from two spots near Discovery's nose. Shuttle astronaut Stephen Robinson says it should be a straightforward task to remove ceramic strips sticking out between Discovery's heatshield tiles.

Also with the American Shuttle crew there are two foreigners on this shuttle flight the Aussie Andrew Thomas and from Japan Soichi Noguchi as well as ISS crew. Soichi just said "I have considered coming home on the Russian Spacecraft (Soyuz)" when asked about the severity of the TPS damage. Collins butts in and says "She expects everything to be fine." NASA engineers have spent the past three days "working very hard" to assess the risk from the gap fillers, which are only about an inch (2.5 centimetres) long. He said the teams had "put together a very simple plan with good safety precautions and mitigations of any hazards that will allow a crewmember to go out and remove those two gap fillers."A team of managers, engineers and aerodynamicists has been working to address the issue for the past three days. They have been experimenting with the different techniques Robinson could use in his spacewalk

Rxke · 2005-08-02 05:58:58

Well you can't have too much EVA experience anyway, so it might be a good thing to try.

Pretty impressive though: both the EVA guys were rookies re: EVA missions prior this flight... Shows how good training has become. The stuff they pulled off so far were not minor tasks...

EVA's like these will eventually pay off for lon-time duration missions to Mars, I guess... So more hands-on experience in real-life problemsolving is in order. Working in a vacuum, in those clumsy suits, it ain't a simple job.

Palomar · 2005-08-02 06:12:31

*There's a first time for everything:

Spacewalk *beneath* shuttle never attempted before
A Discovery astronaut, working on the end of the space station's robot arm, will attempt to remove two protruding "gap fillers" sticking up from protective heat-shield tiles on the belly of the shuttle Discovery Wednesday during an already planned spacewalk, officials said Monday.

Even my sister is paying some attention to this situation. My sis, who is generally very UNinterested in astronomy, space exploration etc.

--Cindy

srmeaney · 2005-08-02 06:30:57

Apparently now theres a problem with the nose of the shuttle?

Rxke · 2005-08-02 07:30:39

@ Cindy, yes it's amazing how much coverage this mission gets.

Even in Belgium, Europe, it's headline news, day after day.

And friends and family actually calling me, emailing me for an opinion (I'm known as that space-freak guy, heh...)

A little bit more overdramatic press coverage, and the crew might come back, to get a ticker tape parade!

GCNRevenger · 2005-08-02 08:18:20

GCNRevenger wrote:
although the gap filler issue is very likly inconsequential
This maybe so but if the crews of future ships are afraid to go out to fix what ever is wrong with there ships, all will view this media coverage as proof that we do not belong out there in space and that we are indeed waisting money as some would see it.
I for one see it as a chance to prove that no more life must be lost if we do the right thing with the tools that we have.
We all ready have played with the repair kits and there tools. Why not make use of what we have if need be to push the insulation back into the cracks with the putty knifes lets do so and make it safe for return.

Fixing the dangling filler as proof? Iiii don't think so... although it sounds trivial, it most certainly is not something NASA decided to do lightly. What if the unlucky spacewalker accidently smashes a few tiles while he is down there? Or pulling out the gap filler yanks a few tiles out with it?

Shuttle is unique in that it is so delicate, and doing delicate things with a space suit on is a difficult proposition. And if the gap filler won't pull out? Hacksaw time... "Oops... un oh"

Palomar · 2005-08-02 08:26:46

GCNRevenger wrote:
although the gap filler issue is very likly inconsequential
This maybe so but if the crews of future ships are afraid to go out to fix what ever is wrong with there ships, all will view this media coverage as proof that we do not belong out there in space and that we are indeed waisting money as some would see it.
I for one see it as a chance to prove that no more life must be lost if we do the right thing with the tools that we have.
We all ready have played with the repair kits and there tools. Why not make use of what we have if need be to push the insulation back into the cracks with the putty knifes lets do so and make it safe for return.
Fixing the dangling filler as proof? Iiii don't think so... although it sounds trivial, it most certainly is not something NASA decided to do lightly. What if the unlucky spacewalker accidently smashes a few tiles while he is down there? Or pulling out the gap filler yanks a few tiles out with it?
Shuttle is unique in that it is so delicate, and doing delicate things with a space suit on is a difficult proposition. And if the gap filler won't pull out? Hacksaw time... "Oops... un oh"

*Thanks GCN. I had doubts, which you addressed. And cautious thoughts along the "whoops" line too. delicate things with a space suit on is a difficult proposition. Yep. ::shakes head::

Doubtless the reports of NASA furiously debating whether or not TO weren't dramatized.

Talk about a real potential "damned if you do, damned if you don't" scenario. If they don't and the unthinkable happens, there'll be recriminations and guilt. If they do and the unthinkable happens, it'll be the same...and added to that, "what if we'd left it alone?"

I am very glad the decisions being weighed and made by NASA bigshots on this aren't up to me.

--Cindy

Admiral_Ritt · 2005-08-02 09:03:38

Collins: "There be no shirkers on this ship (holding a cutlass)"

Fearfull crewmembers: "But were in danger"

Collins: "Do you know how dangerous a hard vacuum is?" (motioning to the airlock)

SpaceNut · 2005-08-02 10:14:29

I can not see how the shuttle tiles are so fragile as you have made out. They must be more robust than that since they must under go such dynamic thermal stresses while in orbit say nothing about re-entry.
Are these not a few inches thick?

GCNRevenger · 2005-08-02 11:52:38

They are indeed that fragile. The original Shuttle tiles were so brittle, that you could literally crush them in your hand. They have enough total strength to avoid damage during reentry from high pressure across their surface, but their problem is that they cannot withstand impacts very well (like from a flailing astronaut or a slipped tool). Oh, and they are held onto the orbiter by nothing but a layer of GLUE for goodness sakes'.

Heads up: Dennis Tito is in NASA-bashing mode.

Palomar · 2005-08-02 11:59:16

They are indeed that fragile. The original Shuttle tiles were so brittle, that you could literally crush them in your hand. They have enough total strength to avoid damage during reentry from high pressure across their surface, but their problem is that they cannot withstand impacts very well (like from a flailing astronaut or a slipped tool). Oh, and they are held onto the orbiter by nothing but a layer of GLUE for goodness sakes'.

*I actually sort of laughed when I read your post. -Not- a happy, humorous laugh but rather a shocked, somber, "you MUST be joking," sardonic sort of laugh. Not at you, GCN.

--Cindy

SpaceNut · 2005-08-02 12:47:35

[url=http://www.flatoday.com/apps/pbcs.dll/article?AID=/20050802/NEWS02/508020344/1007/news02]Crew gets go-ahead to try risky repairs

Unprecedented spacewalk to cut fabric from shuttle is Wednesday[/url]

As part of an already-planned spacewalk Wednesday morning, Robinson will venture outside toting forceps, a modified hacksaw and special spacewalk scissors with holes big enough to fit the chubby fingers of his pressurized gloves.

050801_shuttle_hmed_5p.h2.jpg

An engineer wearing astronaut gloves tries out a technique to cut away a protruding strip of gap-filler material while holding it steady with a forceps. Astronaut Stephen Robinson may use a similar technique on Discovery during a Wednesday spacewalk.

Trying to do a little home work on the tiles:

[url=http://science.ksc.nasa.gov/shuttle/technology/sts-newsref/sts_sys.html]SPACE SHUTTLE ORBITER SYSTEMS
THERMAL PROTECTION SYSTEM[/url]

While some of the silica tiles are made with nextel.
Superhero Ceramics!

Stronger than aluminum, fireproof and able to withstand meteoroids, Nextel is the wonder ceramic fabric that protects NASA's Space Shuttles

The black High-Temperature Reusable Surface Insulation Tiles

Note that the tiles cannot withstand airframe load deformation; therefore, stress isolation is necessary between the tiles and the orbiter structure.
The RTV silicon adhesive is applied to the orbiter surface in a layer approximately 0.008 inch thick. The very thin bond line reduces weight and minimizes the thermal expansion at temperatures of 500º F during entry and temperatures below minus 170º F on orbit. The tile/SIP bond is cured at room temperature under pressure applied by vacuum bags.

Nomex felt material insulation is used to prevent tile-to-tile contact since the tiles swell upon re-entry heat.

New foam is focus on shuttle tank as spacewalk planned

The ramp on Discovery's tank was made with a new type of foam called BX-265, NASA spokeswoman June Malone said. Every other tank that has flown in space had a ramp made with an older foam called BX-250. NASA is phasing out the older foam because it contains chemicals harmful to the ozone layer.

GCNRevenger · 2005-08-02 16:21:28

So now NASA's stupidity has a name: BX-265

I think a personal visit to Michoud by M. Griffin with a breifcase full of pinkslips and an executive order to buy a heckload of BX-250 is in order... Right after he personally oversees them ripping the PAL ramps and other manually/incompetantly applied foam.

Hey NASA... why exactly does the spacewalk have to be done with the arm on the ISS? I thought the Shuttle's extended arm was supposed to reach.

John Creighton · 2005-08-02 16:39:49

Hey NASA... why exactly does the spacewalk have to be done with the arm on the ISS? I thought the Shuttle's extended arm was supposed to reach.

You man it doesn't :shock: :?

RobertDyck · 2005-08-02 16:46:38

Details, details. GCNRevenger said tiles are glued on. Actually commercial airliners are put together with glue. This is not normal elementary school glue, this is special glue that requires special treatment resulting in a stronger bond than rivets or bolts. Bolts can come unscrewed and both bolts and rivets require holes punched in the metal, glue doesn't. Aircraft adhesive requires special treatment of the surface before applying the adhesive, and the adhesive itself often requires treatment to set: baking, humidity control, etc.

In fact, I discovered you can get a much stronger bond with normal 2-part epoxy by carefully cleaning the surface with isopropyl alchohol. I bonded a rubber flap for a one-way air valve to a smooth stainless steel surface. That was in a temperature chamber that regularly cycled from -40°C to +70°C. The chamber cooled by splashing around liquid nitrogen and baked with 460 volt, 46 amp heaters, and used two very large circulation fans to distribute the heat, each as big as a car radiator fan and each driven by a 460 volt motor. The epoxy hasn't come loose after a year of use.

SpaceNut quoted from a NASA web page that described how HRSI tiles are applied. The quote missed a detail. The aluminum skin expands more than the tiles, so the gap prevents aluminum deformation from breaking the tiles. A nomex felt pad is applied between the aluminum skin and tile, and held with RTV silicone adhesive. The adhesive is 0.008 inch thick, but nomex felt is 0.090, 0.115 or 0.160 inch thick depending on location.

That's a very interesting web page. It details exactly how to make HRSI tiles and how to apply them. I used RTV silicone adhesive at Micropilot.

Silly me, I would have assume they used something more than adhesive to hold filler strips. Yes, RTV silicone can seal the felt to make it water proof, but felt can pull apart. They did a lot of processing to ensure the felt is strong: crimp fibres, carting to orient fibres, cross-lapped, "lightly needled" into a batt, two batts are "needled together" to form felt, "multineedle pass" to increase strength, "calendered" by passing through heated rollers at selected pressures, and heat-set at approximately 500º F to thermally stabilize the felt. But after all that they simply glue the filler strip to the felt pad. RTV silicone adhesive is good stuff, but it's strength is over a surface, not focussed on a single point. That means a tile can not pull off its backing, but a narrow filler strip can be pealed back. I would have assumed they stitch filler strips to the felt pad.

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