STS-122 Shuttle Mission - Page 2

01101001 · #31 (**permalink**) 09-December-2007, 08:32 PM

Quote:

Originally Posted by banquo's_bumble_puppy

I'd like to know why this problem keeps coming back...this is the 3rd. mission? to be haunted by this glitch.

I'm sure NASA would like to know the cause, too. It's been intermittent. It's hard to diagnose a problem that can't be reproduced on demand.

It sounded like engineers weren't making any commitments that it would be solved once and for all soon.

CBS News Space Place: current status:

Quote:

That's assuming, of course, engineers can track down and correct the ECO sensor problem by [January]. LeRoy Cain, director of shuttle integration at the Kennedy Space Center, said engineers plan to brief NASA managers Tuesday on possible troubleshooting options.
[...]
"We feel like we need to find root cause and we're going to make every effort to do that. Beyond that, as far as our path forward, it would be speculation for me at this point. Our main focus at this point is, given the repeat failure that we had today ... we're very hopeful it will repeat again in a fashion that we can capture it and be able to narrow down the area that's causing the problem, whether it be in the tank or outside of the tank or somewhere in the connectors. That's really our main focus right now."

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Links:
NASA Space Shuttle Mission Pages
STS-122 Mission Information
Space Shuttle Mission STS-122: The Voyage of Columbus
NASA Kennedy Space Center Shuttle Countdown Status
Wikipedia: STS-122
NASA STS-122 Launch Blog (active about 5 hours before liftoff)
CBS News Space Place
SpaceFlightNow STS-122 Mission Coverage BAUT Forum topic STS-120 (previous mission)
Watch NASA TV
NASA Shuttle Launch and Landing

KaiYeves · #32 (**permalink**) 09-December-2007, 09:09 PM

Well, better that they launch late and safe, then on time and have another disaster.

01101001 · #33 (**permalink**) 11-December-2007, 08:59 PM

NASA Space Shuttle Mission Pages

Quote:

Dec. 11 - 4:15 p.m. EST
Technicians and engineers in NASA's space shuttle program plan to test the engine cutoff sensor system onboard space shuttle Atlantis by pumping super-cold liquid hydrogen into the external fuel tank. The test is tentatively planned for Dec. 18. It will be conducted at the launch pad at Kennedy Space Center where Atlantis remains poised for launch.

Space Shuttle Program Manager Wayne Hale said additional instruments will be used during the test to pinpoint the problem that led to false readings during two previous countdown attempts for Atlantis.

Launch remains no earlier than January 2

01101001 · #34 (**permalink**) 12-December-2007, 04:14 AM

CBS News Space Place

Quote:

6:15 PM, 12/11/07, Update: Tanking test planned to help pinpoint ECO sensor problem
[...]
Shuttle Program Manager Wayne Hale said today engineers will tap into the engine cutoff - ECO - sensor circuitry near a control unit in the shuttle's aft engine compartment to hook up test instrumentation that should help locate any bad wiring or connectors in the 100 feet or so of cabling between the box and the sensors at the base of the external tank.

The tanking test is tentatively planned for next Tuesday.

"We think that we have some instrumentation we can put in an appropriate place in these circuits to observe what happens as we fill the tank," Hale told reporters during an afternoon teleconference. "If the erroneous condition repeats, which is what we think will happen, we can capture the location in the circuit of that opening with the use of some equipment and a technique known as time domain reflectivity, TDR.

"We have a high degree of confidence of pinpointing the location of where we're having our problems and once we know the location ... we'll be able to concentrate our go-forward efforts, presumably put together a fix and go fly. And again, our go-fly date is no earlier than Jan. 2. It could definitely be a little bit later than that, depending on the troubleshooting and the repair work involved."
[...]
Among candidate problem areas: Broken or damaged wires; a recessed connector pin/socket; contamination in a connector; wire splice damage; and a combination of problems leading to a tolerance "stack up" in a feed-through connector.

"If the erroneous condition repeats[...]"

Here's hoping it does.

Many details in the article.

BPCooper · #35 (**permalink**) 13-December-2007, 10:32 PM

NASA announced today a new target date of January 10th. Launch time would be 2:26am EST. The date has been chosen to allow holiday time for workers.

Grand_Lunar · #36 (**permalink**) 16-December-2007, 12:02 PM

I wonder if it can be something as simple as a ground circuit.

Can the sensors be replaced while at the pad?

Dave J · #37 (**permalink**) 16-December-2007, 02:36 PM

I believe replacing the sensors would involve a rollback and actually entering the tank, which involves removing the aft tank manhole cover, and all the insulation removal issues that entails.
No small task, they are probably hoping it doesn't come to that.

KaiYeves · #38 (**permalink**) 16-December-2007, 02:38 PM

Do they plan these launches to be on school days so I miss them completely?

01101001 · #39 (**permalink**) 18-December-2007, 07:39 PM

CBS News Space Place

Quote:

12:30 PM, 12/18/07, Update: Initial sensor troubleshooting work complete; engineers ready to drain tank

Engineers operating test equipment inside the shuttle Atlantis' mobile launch platform completed a battery of tests today in an attempt to locate the source of intermittent electrical problems with critical engine cutoff - ECO - sensors in the base of the ship's external fuel tank.

No results announced. A briefing is scheduled: 4:30 p.m. [EST; 1330 PST; 2130 UTC] - Post-Atlantis Tanking Test Briefing.

Watch NASA TV

01101001 · #40 (**permalink**) 18-December-2007, 08:38 PM

Quote:

Originally Posted by 01101001

No results announced. A briefing is scheduled: 4:30 p.m. [EST; 1330 PST; 2130 UTC] - Post-Atlantis Tanking Test Briefing.

Watch NASA TV

On now. I came in late.

Heard: Sensors exonerated. Problem in wiring. No promises on launch date. Q&A started.

Circuits open up. Some for minutes; some for hours. It's temperature related; doesn't happen unless chilled. A particular connector is being asked about. A socket connector inside tank is hard to get to. Would take more than a week. Pleased the particular connector has been indicated.

Sounds like it's an interface at the tank external surface, with wires leading from sensors to socket, with a plug that is inserted into the tank socket for analysis of signals. Sounds like problem may still be the plug into the socket or the socket external parts (both easy to get to) or the wires' attachment to socket, inside tank (which would be harder to get at). I'm unsure; just trying to piece it together.

It's a "feed-through" connector. Engineers now know what to look at. It's a relief to have that. Will talk about launch commit another day.

Will follow trail. Solve problem. Then fly. When it's fixed. No date offered. Again.

Time-domain pulse reflectometer helped nail it. (A little like sonar pings, to determine where a reflection is coming from.) Resolution not enough to say inside or outside the connector, just thereabouts.

01101001 · #41 (**permalink**) 19-December-2007, 01:00 AM

By the end of the briefing, I was fairly clued. From a reporter who was there:

CBS News Space Place

Quote:

6:00 PM, 12/18/07, Update:Sensor problem tracked to external tank wiring connector; corrective actions, impact on launch date not yet known

Precisely timing how electrical pulses moved back and forth through suspect engine cutoff sensor wiring during a fueling test today indicates intermittent open circuits that grounded the shuttle Atlantis on Dec. 6 and 9 were caused by problems in a critical-three part "feed-through" connector. The connector carries sensor data through the wall of the ship's external fuel tank.

While engineers do not yet know what will be required to fix the problem - or whether Atlantis can meet a no-earlier-than Jan. 10 launch date - shuttle Program Manager Wayne Hale said he was relieved today's tanking test exonerated the sensors themselves and isolated the problem to an area that is accessible at the launch pad.

Lots more detail there.

01101001 · #42 (**permalink**) 20-December-2007, 01:04 AM

CBS News Space Place

Quote:

06:30 PM, 12/19/07, Update: NASA managers assess ECO sensor options; additional review 12/27
[...]
The current "no-earlier-than" launch date is Jan. 10, but that target was announced before engineers had a good idea of what might be needed to fix the problem. It's not yet clear whether Atlantis can be ready by then even if the problem is, in fact, in the external part of the connector.

"That would obviously be the best scenario," said a NASA official. "If it's that, if you could somehow guarantee that's what it is, you don't have to be invasive to the tank. ... There's some optimism it's in the external part of the connector."

But if it turns out the problem is in the internal parts of the connector hardware, engineers would have to remove foam from the bottom of the tank, open an access port and work inside the structure. Such invasive work likely would require a rollback to the Vehicle Assembly Building, delaying Atlantis' flight well beyond Jan. 10.

And then there's that SARJ problem...

Quote:

A wild card in the discussion is what to do about fixing a recent problem with a space station solar array that is limiting the power available to the outpost. It appears a spacewalk by the station crew may be needed to replace a so-called beta gimbal assembly motor before Atlantis can fly regardless of work to fix the ECO sensors. While the station repair work could be added to the Atlantis mission, it would require major replanning.

As of this writing, no decisions have been made on how to proceed with either problem.

01101001 · #43 (**permalink**) 28-December-2007, 09:22 PM

More slip. No launch January 10.

NASA Space Shuttle Mission Pages

Quote:

The external parts of the connector will be removed and replaced with others that have been strategically soldered to ensure pin-to-socket connectivity and allow continuous electrical flow from sensors inside the external tank to the shuttle's computers.

This work will take some time to properly accomplish and to certify the redesigned configuration before flight. While a launch on Jan. 10 is no longer achievable, no launch date has been discussed. The program will take time to assess progress of the work before setting a target launch date.

CBS News Space Place

Quote:

Shuttle Program Manager Wayne Hale said today the work likely will delay Atlantis' launch "a few days to a couple of weeks" beyond the previous Jan. 10 target. But that "no-earlier-than" date was little more than a placeholder intended to ensure the launch team enjoyed a few days off over the Christmas holiday. As such, it was not based on any actual repair schedule.

NASA has now settled on a course of action, but Hale said today he was not ready to discuss when Atlantis might be ready for a third launch try. During an afternoon teleconference, he told reporters "I'm not going to make a launch date announcement ... because we're in the middle of troubleshooting and repair. Until that gets a little bit further along, I actually have no valid dates to give you."
[...]
But sources familiar with the discussion said the feed-through connector replacement and subsequent testing could delay launch to the last week in January when all is said and done, and that assumes the work goes smoothly.

KaiYeves · #44 (**permalink**) 28-December-2007, 09:52 PM

Not on the tenth- if NASA won't be there to cheer me up when I'm back in school, what will?

01101001 · #45 (**permalink**) 04-January-2008, 02:43 AM

CBS News Space Place

Quote:

7:45 PM, 1/3/08, Update: Shuttle launch no earlier than Jan. 24 as NASA pursues parallel ECO testing/hardware replacement

NASA managers today agreed to press ahead with work to replace suspect engine cutoff - ECO - sensor connectors on the shuttle Atlantis' external tank on the assumption parallel laboratory testing will confirm the root cause of open circuits that derailed two December launch tries. Assuming the replacement work goes smoothly, the weather cooperates and the lab testing goes as engineers hope it will, Atlantis could be ready for a third launch try by Jan. 24.

But John Shannon, deputy manager of the shuttle program at the Johnson Space Center in Houston, told reporters Jan. 24 is little more than a best-case crew training and planning target and that Feb. 2 is a more realistic launch date given the work required.

Similar news at NASA Space Shuttle Mission Pages

KaiYeves · #46 (**permalink**) 04-January-2008, 09:42 PM

They better stick to that one.

Maksutov · #47 (**permalink**) 05-January-2008, 07:46 AM

Let's see, a February 2nd launch. One wonders how many hogs would come out of the ground to see that one?

Then again, it may be one launch canceled (Imbolc).

KaiYeves · #48 (**permalink**) 05-January-2008, 08:01 PM

The most depressing aspect of all these prolongings of the launch was this conversation with a teacher in Greek School sometime in early December-

Quote:

Me: I can't wait to get home and look at NASA TV.
Her: Why?
Me: Space shuttle Atlantis is going to take off today. It was going to be yesterday, but there was a problem related to the fuel tank.
Her: Well, I hope they're careful. I know that there were a few bad accidents in the past.

Do most adults really associate the space shuttle with disaster?