STS-114 Mission Coverage and Discussion

Palomar · 2005-07-16 22:12:32

I'm not feeling too good about the competance of the Michoud folks anymore (who build the ET)... it was originally their sloppy work that caused the destruction of Columbia, and now their fault that the tank sensors are faulty.

*I'd ask -why- they weren't released/fired from contract after the Columbia incident, but not knowing the ins and outs of NASA contracts and etc...

Or are they the same tank sensors installed on Discovery prior to the Columbia tragedy?

Sorry if the questions seem "fuzzy" or whatever...it's far too late in the evening (since 4:00 a.m.).

--Cindy

GCNRevenger · 2005-07-16 22:29:18

They wern't "deselected" because:

-They are the only factory that can make the external tank
-They employ alot of people that Congress wants kept
-They bring in a large sum of federal money to the state
-They are an extended "part of the family" of the Shuttle Army

Palomar · 2005-07-17 22:17:13

*Okay, thanks GCN.

Will post this here, rather than create a new thread.

Back-to-back top headlines at spaceflightnow.com for today's date:

Top Story
Baffling problem could prompt shuttle fueling test
After a long weekend of troubleshooting, engineers have not found an obvious problem that might explain why one of four hydrogen fuel sensors failed to operate properly during the shuttle Discovery's aborted countdown Wednesday.

***
Video Flashback

Voyage of Apollo 11
One of the defining moments of the 20th century was mankind's voyage to the moon. This video selection allows you to relive the mission of Armstrong, Aldrin and Collins on Apollo 11.
FULL REPORT

Ironic. :-\ Puts new meaning into the phrase "blast from the past."

--Cindy

SpaceNut · 2005-07-18 21:32:28

A little tid bit on the windows : Corning Inc. windows used on all spaceflights

each shuttle window - they range in size from 14ì by 11-inch viewing windows to 42-inch diagonal front windows - consists of three panes of glass. The panes range in thickness from less than half an inch to 1.3 inches.
The inner pane is made of an aluminosilicate glass that Corning Inc. no longer manufactures.
"Corning doesn't make them any more, but we have a large enough inventory, an ample supply, to last through the life of the (shuttle) program," Filson said.
The center (the thickest) and outer panes are made of high-purity fused silica. The outer pane can withstand temperatures of about 800 degrees Fahrenheit. It is also exposed to temperatures as low as 250 degree below zero.

The we have the question of whether or not the idea of the ISS as a safe haven is the best alternative to rescue from rather than safe return options.

New Device Will Allow Shuttle Crews Longer Station Visits

U.S. space shuttle crews will soon be able to stay at the international space station longer with the installation of a new power-transfer system that allows docked shuttles to use solar power from the space station instead of solely relying on electricity produced by the orbiters' fuel cells.
The Station-Shuttle Power Transfer System (SSPTS) will make it possible to use the space station's solar arrays to supplement the orbiter's electrical power. The additional power will decrease the need for power output from a shuttle's fuel cells, which require liquid hydrogen and oxygen to operate. With this new capability, shuttles can stay docked at the station for nine to 12 days instead of the six- to seven-day period available with the current power transfer system.

Commodore · 2005-07-18 21:43:20

On Wednesday while they were booting up the 4 redundant main computers, the NASA TV people were saying that each computer did its own calculation and then compared notes. The majority could vote out a bad result.

Why can't we do this with sensors? We know darn well when the tank gets empty. When the one gives a bad reading, the others should be able to tell it the shut up.

SpaceNut · 2005-07-18 21:56:16

While I am not sure of the type of sensor that it has for the ET or of there placement. It may not be possible to ignore if these are used to give a wet contact closure as the tank empties. Then again these could also be pressure style. I am just not in the know of which type they are.

Palomar · 2005-07-19 05:37:58

Wont]http://www.space.com/missionlaunches/050717_sts114_update.html]Won't launch before July 26

“We’re still looking for the problem,“ NASA’s shuttle program manager Bill Parsons said during an evening press conference. “This team is trying everything it can to launch in the July window.”

Someone else is hopeful the problem will be resolved within 24 to 48 hours.

--Cindy

GCNRevenger · 2005-07-19 06:34:01

On Wednesday while they were booting up the 4 redundant main computers, the NASA TV people were saying that each computer did its own calculation and then compared notes. The majority could vote out a bad result.
Why can't we do this with sensors? We know darn well when the tank gets empty. When the one gives a bad reading, the others should be able to tell it the shut up.

Parinoia basically... probobly not without good reason though.

If the computers fail, then Shuttle may at least be able to seperate from the ET manually and the crew might be able to bail out. If the fuel tank sensors fail and the SSME engines run "dry," the back half of the Shuttle will disintegrate and the crew will die almost immediatly.

This may be more then a faulty sensor... sensors on TWO different tanks have both failed in the same way. Either the problem is actually with Shuttle's miles of wiring, or else the manufacture of the sensors has a systemic fault... which is sufficent cause to worry, and cancel launch.

GCNRevenger · 2005-07-21 05:46:13

NASA will fuel up Discovery and prepare for launch on Tuesday, and perhaps fly with bad guage or no bad guage, says CNN.

I am kinda split... Shuttle is too complex a beast to ever be 100% operational (not including its flaws) so it is only rational to fly it with some issues, but this sounds an awful lot like the "oh it'll be okay" thinking that caused the Challenger disaster.

SpaceNut · 2005-07-22 20:21:23

It would appear that scheduel and need for missions to the ISS are putting safety on the back burner again.
I saw one article in the past few days that talked of how Nasa used a freon based foam in the past but had opted not to use its clout to continue using it. Even though it did not shed as much debri. Meaning that last shuttle accident did not need to happen. :evil:

GCNRevenger · 2005-07-22 20:56:34

"Freon based" foam? Huh? I question if there is such a thing, since you can't make polymers with it. Maybe you mean Lockheed changing the technique they used to apply foam, which they did. If done properly I am sure that it works okay... but errors have been made and documented.

Foam has always fallen off the external tank, just nothing ever as big as the chunk that doomed Columbia. Even Atlantis took a similar hit from a smaller piece.

RobertDyck · 2005-07-22 22:36:12

http://www.nasa.gov/pdf/63758main_TPS_F … T.pdf]This PDF document states "The tank's foam is polyurethane-type foam composed of five primary ingredients: polymeric isocyanate, a flame retardant, a surfactant, a blowing agent, and a catalyst. A surfactant controls the surface tension of a liquid and thus cell formation. The blowing agent – originally CFC 11-- creates the foam's cellular structure by making millions of tiny bubbles or foam cells."

It says that BX-250 used CFC 11 as the blowing agent, but has been replaced by BX-265 that uses HCFC 141b instead.

GCNRevenger · 2005-07-23 08:04:54

Ahhh. Well, that really shouldn't make much difference if they are both used as a gas. As I understood it, the flaw that doomed Columbia was due to the method the foam was applied and insufficently rigerous quality control.

RobertDyck · 2005-07-23 08:56:34

I heard a couple individuals express verbally a concern about bubble size and consistency with the new blowing agent. I haven't found any technical documents about this, but that is the concern SpaceNut is talking about. The rumour is that the new blowing agent produces large bubbles that create voids within the foam, weakening it. GCNRevenger, are you able to find any confirmation of this? Or is it just rumour?

By the way, those interested in using a Shuttle ET as a module in orbit should take note. This article says the foam is "closed cell". That means each bubble of foam is sealed; as the shuttle ascends pressure inside the bubbles will blow out the foam bubble walls causing it to crumble. There aren't any reports of foam causing problems at high altitude, just during launch. An open cell foam wouldn't have this problem but would accumulate Florida coast humidity that would freeze in contact with the cryogenic tank. I thought this was what happens, causing ice to accumulate inside the foam. Or is there some infiltration of humidity? Or does foam break off during supersonic/hypersonic flight? The more I learn the more confusing it gets. I'm amazed a closed cell foam works at all for hypersonic flight during rapid ascent into extremely low air pressure.

Stormrage · 2005-07-23 09:08:09

I'm getting bad vibes. I just hoep that NASA don't screw up this time. If a disaster happens in this flight it could be the end of space travel (for the US that is).

SpaceNut · 2005-07-23 18:12:10

Rather than editting the previous page, Privatize Space Exploration contains the info I was referencing.

There is reason to believe that the political nature of the space program may have even been directly responsible for the Columbia disaster. Fox News reported that NASA chose to stick with non-Freon-based foam insulation on the booster rockets, despite evidence that this type of foam causes up to eleven times as much damage to thermal tiles as the older, Freon-based foam. Although NASA was exempted from the restrictions on Freon use, which environmentalists believe causes ozone depletion, and despite the fact that the amount of Freon released by NASA's rockets would have been trivial, the space agency elected to stick with the politically correct foam.

Stormrage · 2005-07-24 02:31:35

Rather than editting the previous page, http://www.americandaily.com/article/8352]Privatize Space Exploration contains the info I was referencing.
There is reason to believe that the political nature of the space program may have even been directly responsible for the Columbia disaster. Fox News reported that NASA chose to stick with non-Freon-based foam insulation on the booster rockets, despite evidence that this type of foam causes up to eleven times as much damage to thermal tiles as the older, Freon-based foam. Although NASA was exempted from the restrictions on Freon use, which environmentalists believe causes ozone depletion, and despite the fact that the amount of Freon released by NASA's rockets would have been trivial, the space agency elected to stick with the politically correct foam.

Take everything from Fox News with a grain of salt. They say alot of bullshit sometimes.

GCNRevenger · 2005-07-24 09:57:54

I heard a couple individuals express verbally a concern about bubble size and consistency with the new blowing agent. I haven't found any technical documents about this, but that is the concern SpaceNut is talking about. The rumour is that the new blowing agent produces large bubbles that create voids within the foam, weakening it. GCNRevenger, are you able to find any confirmation of this? Or is it just rumour?
By the way, those interested in using a Shuttle ET as a module in orbit should take note. This article says the foam is "closed cell". That means each bubble of foam is sealed; as the shuttle ascends pressure inside the bubbles will blow out the foam bubble walls causing it to crumble. There aren't any reports of foam causing problems at high altitude, just during launch. An open cell foam wouldn't have this problem but would accumulate Florida coast humidity that would freeze in contact with the cryogenic tank. I thought this was what happens, causing ice to accumulate inside the foam. Or is there some infiltration of humidity? Or does foam break off during supersonic/hypersonic flight? The more I learn the more confusing it gets. I'm amazed a closed cell foam works at all for hypersonic flight during rapid ascent into extremely low air pressure.

I am beginning to get a picture of how this stuff is supposed to work. The freon mixed in with the other foam componets is as a liquid I bet, and it is used as a propellant much like for various canned products, like the bottled foam insulation for houses you can buy from hardware stores. In fact, I bet this stuff is remarkably similar... anyway, HCFC-141 has a much higher vapor pressure then freon, so when it comes out it probobly does so at a higher pressure, which could lead to making larger bubbles.

However I was under the impression that the problem was with voids forming in the bulk of the foam, but rather against the tank due to improper application, and air infiltrated and caused the disaster when the air pressure outside the foam dropped. The cryogenic tanks are so cold, that air in contact with them would liquify (nitrogen, oxygen, etc) at normal pressure. However, during acent the ambient air pressure falls, and this liquid air would boil and become a gas again... and blow out the foam on top of it.

Open-cell foam is the very last thing you would want, you want to avoid getting air against the tank as much as is possible... I think here is where the poor quality control at Michoud caused the Columbia disaster, that they were not sufficently rigerous about ensuring that the foam stuck to the tank.

As far as the voids in the bulk of the foam themselves exploding, don't worry about that, the foam is mechanically strong enough to prevent that.

srmeaney · 2005-07-26 04:22:08

So they are going ahead with the shuttle launch even though the damn fuel light still doesnt work...

"Hey, we've got a red light on the intake valve!"
"Ignore it!"

Rxke · 2005-07-26 04:26:43

It works now. They tested it and it came up ok. Stop trolling.

srmeaney · 2005-07-26 04:32:26

Who'se Trolling? I just caught the News, Light still not working, launching without it...

Rxke · 2005-07-26 05:33:17

Then check your sources.
Several sources stated the sensor is working fine. Hours ago.
But... They don't know why

Josh Cryer · 2005-07-26 05:45:30

Hey, sounds like this forum software sometimes.

Just kidding. I'm up for this though, can't wait to see the launch! Woohoo!

Rxke · 2005-07-26 05:50:13

Anyone know of good feeds?
This verrrrrrry probably will not be aired live in Belgium...

Stormrage · 2005-07-26 05:55:35

Seen it on the News. If the fuel gauge doesn't work NASA will bend their own rule and still go ahead.

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#51 2005-07-16 22:12:32

Re: STS-114 Mission Coverage and Discussion

#52 2005-07-16 22:29:18

Re: STS-114 Mission Coverage and Discussion

#53 2005-07-17 22:17:13

Re: STS-114 Mission Coverage and Discussion

#54 2005-07-18 21:32:28

Re: STS-114 Mission Coverage and Discussion

#55 2005-07-18 21:43:20

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#56 2005-07-18 21:56:16

Re: STS-114 Mission Coverage and Discussion

#57 2005-07-19 05:37:58

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#58 2005-07-19 06:34:01

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#59 2005-07-21 05:46:13

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#60 2005-07-22 20:21:23

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#61 2005-07-22 20:56:34

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#62 2005-07-22 22:36:12

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#63 2005-07-23 08:04:54

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#64 2005-07-23 08:56:34

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#65 2005-07-23 09:08:09

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#66 2005-07-23 18:12:10

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#67 2005-07-24 02:31:35

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#68 2005-07-24 09:57:54

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#69 2005-07-26 04:22:08

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#72 2005-07-26 05:33:17

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#73 2005-07-26 05:45:30

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#75 2005-07-26 05:55:35

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