STS-122 Atlantis

RedStreak · 2007-12-09 17:25:11

Their going to take these sensors off on Ares V right?
There should be an override for this. We know how much fuel there is, faulty sensor be dammed.

Agreed wholeheartedly. I don't recall unmanned rockets being scrubbed as often...

Whatever screws up the STS' ET and SRBs they ought to examine thouroughly and amend if they use both as a base for Ares V...and to an engineer both simplifying and improving tend to fall into the job description.

cIclops · 2007-12-13 18:32:48

NASA Targets Space Shuttle Atlantis Launch on Jan. 10 - 13 Dec 2007

HOUSTON - NASA's Space Shuttle Program managers have targeted Jan. 10 for the launch of shuttle Atlantis' STS-122 mission to the International Space Station.
"The workforce has stepped up to and met every challenge this year," said Wayne Hale, Space Shuttle Program manager at NASA's Johnson Space Center. "Moving the next launch attempt of Atlantis to Jan. 10 will allow as many people as possible to have time with family and friends at the time of year when it means the most. A lot has been asked of them this year and a lot will be asked of them in 2008."
The liftoff date from NASA's Kennedy Space Center, Florida, depends on the resolution of a problem in a fuel sensor system. The shuttle's planned launches on Dec. 6 and Dec. 9 were postponed because of false readings from the part of the system that monitors the liquid hydrogen section of the tank.

cIclops · 2007-12-19 09:58:18

Tanking Test Pinpoints Shuttle ECO Sensor Fault

Dec 19, 2007
By Frank Morring, Jr.
Troubleshooting with the space shuttle Atlantis fully fueled has narrowed the source of the problem that kept it stuck on the pad this month to a connector that passes through the walls of the big external fuel tank, raising hopes that International Space Station (ISS) assembly can resume as early as January.
Wayne Hale, NASA's shuttle program manager, said Dec. 18 a tanking test earlier in the day reproduced the problem with an open circuit in the engine cutoff (ECO) sensor system, and sophisticated Time Domain Reflectometry (TDR) gear traced the fault to the three-part pass-through connector at the tank wall.
Hale said the TDR gear - which sends an electrical pulse down a wire and measures the time before impedance in the circuit is reflected back - lacked the resolution necessary to determine if the fault is at the outside of the tank, inside the tank where wires leading to the five ECO sensors emerge from the wall, or in the metal and glass assembly that passes signals from ambient to cryogenic temperatures.

Tanking Test Briefing by Wayne Hale - video 28:05 mins December 18

cIclops · 2007-12-24 08:29:00

KSC-07PD-3656 (12/21/2007) --- KENNEDY SPACE CENTER, FLA. -- At Launch Pad 39A, a United Space Alliance technician removes foam insulation revealing the fastener holes on the covers over the feed-through connector box on the external tank for space shuttle Atlantis' STS-122 mission. The covers will be removed for access to the feed-through connectors.

cIclops · 2007-12-28 03:52:29

From NASA Shuttle main page:

Dec. 27
The Space Shuttle Program met Thursday to assess the progress made to troubleshoot an issue with the engine cutoff sensor circuit that occurred during the recent launch attempts and tanking test. Instrumentation installed for the tanking test indicate that there are one or more intermittent open circuits in the area of the feed through connector on the external tank’s liquid hydrogen tank.
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.

SpaceNut · 2007-12-28 11:03:41

What boths most about the ET is that it has been through several design changes and one would hope that a test process
was in place to have found this early on before mating it to the orbiter.

Sensor location

071227-shuttlesensor-vmed-3p.widec.jpg

A panel containing four engine cutoff sensors and suspect wiring, similar to the one causing problems inside the external fuel tank on the space shuttle Atlantis, is displayed at the Kennedy Space Center in Cape Canaveral, Fla., on December 8, 2007.

http://www.nasa.gov/missions/highlights/schedule.html

This particular shuttle should have launched on 12/05/07 but with the probability of the ET being unmated and swapped out for the next inline makes for a longer period to being able to launch the shuttle for the available window is Feb. 14 2008 for STS-123 (Endeavour), then april 24 for what would be STS-124 (Discovery )and more after august.

There are many launches by other rockets that may be limiting the available times to launch.

The gate though on launching shuttle is ET build which is quite lengthy.

cIclops · 2007-12-28 12:23:23

What boths most about the ET is that it has been through several design changes and one would hope that a test process
was in place to have found this early on before mating it to the orbiter.

Good point. Perhaps the tests done a few years ago when the problem first appeared showed it was fixed, so it wasn't necessary to retest each tank with cryogenics. The sensors are tested during tanking and have apparently worked every time before, but this time they failed. It's possible that they never worked properly but it wasn't detected.

dicktice · 2007-12-29 11:57:08

"It's possible that they never worked properly but it wasn't detected."

Cripes! Another unforseen "Russian roulette" type design detail to contend with--after all this time?

cIclops · 2008-01-03 16:16:04

Audio teleconference 3 Jan 2008 with John Shannon:

o External parts of the connector will be replaced while testing is done on the old connectors and the proposed new one

o Earliest launch will be 24 Jan 2008

o Expected launch date is 2 Feb 2008 only extending to 7 Feb 2008 because of range constraints and next Progress docking 9 Feb 2007

o No evidence that the sensor system had failed on earlier flights

From NASA - 3 Jan 2008

NASA flight control teams and ground operations teams have been requested to protect for a Jan. 24th launch date for Space Shuttle Atlantis. As work progresses, that date will be modified as required, says John Shannon, deputy manager for the Space Shuttle Program. The schedule depends on test results and modifications to a fuel sensor system connector on the external fuel tank Atlantis will use for launch on its STS-122 mission to the International Space Station. Other launch opportunities could come between Jan. 24th and the first week of February.
The connector suspected of prompting false readings during two previous launch attempts is undergoing intensive testing at NASA's Marshall Space Flight Center in Huntsville, Ala. Engineers also will test potential modifications to the connector to certify it for flight. Marshall has a test facility that allows the connector to be subjected to the same conditions it saw during the earlier launch attempts.
The modification and testing plans were discussed along with the launch preparation schedule during a meeting of Space Shuttle Program managers Thursday.
Technicians at NASA's Kennedy Space Center, Fla., will modify a replacement connector for the one that was removed. Metal pins inside the connector will be soldered to the socket, Shannon explained. The new connector is scheduled to be in place by Jan. 10.
"We're fairly confident that if the problem is where we think it is, that this will solve that," Shannon said.
Atlantis remains at the launch pad as the agency studies ways to modify the connector. The shuttle will carry the European Space Agency’s Columbus laboratory to the space station during the STS-122 mission.

cIclops · 2008-01-05 17:50:22

Video of work on the ET connector - 3:50 mins - 3 Jan 2008

A team of Lockheed Martin and United Space Alliance technicians removed the feed through connector from space shuttle Atlantis' external fuel tank Saturday and Sunday at NASA’s Kennedy Space Center's launch pad 39A. First, the external connector cable was cut, then a pair of support brackets were removed. A final cleaning was done to remove residual foam insulation. The connector assembly with its associated electrical harness was pulled away from the tank. Equipment was set up to take X-rays, then the feed through connector was disconnected and demated from the external tank. Next, a visual close-up pin inspection was performed. Finally, the connector was wrapped, placed in a shipping container and flown to NASA’s Marshall Space Flight Center in Huntsville, Ala., for further cryogenic testing.

cIclops · 2008-01-07 08:35:00

Soldering pins for the replacement feed-through connector - 3 Jan 2008

Hi-res image

cIclops · 2008-01-08 17:05:42

Six relaxed videos of the crew and support technicians - (YouTube about 7 mins)

cIclops · 2008-01-09 03:52:13

Two of nine pins soldered to the socket of the replacement feed-through connector - imaged 4 Jan 2008

Full story from Bill Harwood - 8 Jan 2008

Engineers plan to begin installing the upgraded connector on Atlantis' tank Thursday. Once it is in place, foam insulation will be reapplied. The shuttle's eventual launch date will depend, in part, on how long it takes the insulation to "cure," a process that can be affected by humidity, temperature and other weather issues. One internal estimate shows Atlantis being ready for launch 25 days after the connector hardware installation begins. But given the many variables involved, engineers say it's too soon to say when the shuttle might be ready to fly.

SpaceNut · 2008-01-10 22:01:24

I noticed that the tech is soldering a crimped on pin that is attached to the wire. This allows for the least chance to cracking the ceramic glass material that the feed throughs pass through but any flexing of the feed through will cause cracks to occur and under pressure it can vent by the pin seal.

cIclops · 2008-01-11 14:04:02

Space Shuttle Launch Targets - 11 Jan 2008

HOUSTON - NASA Friday announced Feb. 7 as the target launch date for shuttle Atlantis' STS-122 mission to the International Space Station and mid-March for the launch of Endeavour on STS-123. Liftoff of Atlantis from NASA's Kennedy Space Center, Fla., will be at 2:47 p.m. EST.
A decision by the Russian Federal Space Agency to move up its Progress launch from Feb. 7 to Feb. 5 enables both STS-122 and STS-123 to launch before the next Russian Soyuz mission in early April. This allows astronauts assigned to the space station's Expedition 16 crew to complete the tasks they have trained for, including support of the launch and docking of Jules Verne, the first European Space Agency Automated Transfer Vehicle. Targeting Feb. 7 also allows time to complete modifications to the engine cutoff sensor system that postponed two shuttle launch attempts in December.

cIclops · 2008-01-12 07:16:57

TESTING OF ECO CONNECTOR AT MSFC - video 3:28 mins - 12 Jan 2008

Engineers at the Marshall Space Flight Center in Huntsville, Ala., are examining the external plug and feed through connector for the space shuttle's external tank. The components were removed from the external tank at the Kennedy Space Center, Fla., Dec. 29, and may be the source of recent faulty engine cutoff sensor circuit readings. The external plug and feed through connector are at Marshall for nondestructive and cryogenic testing, scheduled to occur over the next two weeks. New external parts are being soldered to ensure pin-to-socket connectivity and allow continuous electrical flow from sensors inside the external tank to the shuttle's computers. After this work is accomplished and certified, the redesigned configuration will be approved for flight. The Space Shuttle Program will take time to assess progress of the work before setting a target launch date.

Very nice X-ray imaging.

cIclops · 2008-01-14 14:13:15

Attaching the replacement feed-through connector onto the ET - imaged 13 Jan 2008

Connector installed: Tests verify soldering fix - 14 Jan 2008

A pass-through connector has been re-installed at Pad 39A, and tests in Alabama indicate that engineers were correct in their estimation of a proper fix for intermittent signals from low-fuel sensors that delayed Atlantis' launch by two months.
"It is installed and retested and we are into installing the re-application of the foam insulation," NASA spokesman George Diller said.
"It's a several-day process," said Diller. "We're not going to be reprocessing (the orbiter) for launch until they get the foam in."
Diller said cryogenic testing at Marshall Space Flight Center in Alabama produced evidence that the original connector, with friction pins and sockets, failed due to being cooled by liquid Hydrogen to 423 degrees below zero.
"It's a continuation for being able to repeat what we saw during the tanking test and two scrubbed launches," he said.
To make to fix, technicians soldered leads on the outside of the connector, where a diagnostic test showed the circuit was interrupted.
"The testing still has a while to go," added Diller. "It's encouraging so far that everything they're seeing supports what we've done to fix the connector."

cIclops · 2008-01-17 10:46:23

Testing Validates Shuttle Fault Theory

Jan 17, 2008
By Frank Morring, Jr./Aerospace Daily & Defense Report
MARSHALL SPACE FLIGHT CENTER, Huntsville, Ala. - NASA engineers believe they have duplicated the failure mechanism that has plagued the space shuttle program with sporadic bad readings on engine cutoff (ECO) sensors in the orbiter's external tank.
The failure produced an intermittent open circuit in the pass-through connector that draws information from ECO sensors in the shuttle's liquid hydrogen tank.
This should allow NASA to try again Feb. 7 to launch STS-122/1E, when Atlantis will carry Europe's Columbus laboratory to the International Space Station.
Verification and testing will take another two weeks, but engineers believe the work done supports the theory that the super-cold temperatures of the liquid hydrogen produced the open circuit in two ways: When the tank was filled, the air around connector pins inside the wall of the tank apparently froze and produced an insulating layer in the connection. And when the tank contracted in the cold temperatures, the motion pushed the connection over the insulated space on the pin, breaking the circuit.
Stephen Cash, manager of the shuttle propulsion office here, said Marshall engineers sent the modified design to Kennedy Space Center, where engineers there made the modification in Atlantis' tank. The change involves soldering the connection together so it maintains integrity through the temperature cycle.
It'll take "the next couple of weeks" for additional testing and analysis of the results, Cash said. But unless something unexpected arises, that should clear this problem for Atlantis' launch.
The shuttle's four liquid hydrogen ECO sensors are designed to detect low propellant levels as a backup to cut off the three space shuttle main engines if vehicle computers try to continue and run the tank dry of fuel - an event that could cause an explosion. Different ECO sensor problems caused earlier delays in the STS-114, STS-115 and STS-121 launches in 2005-2006.

Root cause, good news!

SpaceNut · 2008-01-17 19:50:34

Actually Failure analysis but in either case the image tells the story on this page. circled is the crack
http://www.nasaspaceflight.com/content/?cid=5325

as meationed before...

I noticed that the tech is soldering a crimped on pin that is attached to the wire. This allows for the least chance to cracking the ceramic glass material that the feed throughs pass through but any flexing of the feed through will cause cracks to occur and under pressure it can vent by the pin seal.

mishandling an construction was bad....

In other words fire the personel that built it....

cIclops · 2008-01-18 03:40:15

Actually Failure analysis but in either case the image tells the story on this page. circled is the crack

Failure analysis leads to identifying the root cause. Frank's report clearly says "engineers believe they have duplicated the failure mechanism" and there was no mention of cracking. There should be a statement soon from the people doing the work.

cIclops · 2008-01-23 03:23:39

New foam around the replacement ECO sensor system connector on the external tank - imaged 17 Jan 2008

From NASA:

Jan. 22
Technicians are on pace to finish work Friday on new foam insulation applied over a replaced external wiring connector on space shuttle Atlantis' external fuel tank. The connector is part of the tank’s low fuel-level engine cutoff system, which experienced problems in December that caused two launch delays.

Friday is 24 Jan, perhaps the launch will be earlier than 7 Feb.

cIclops · 2008-01-23 08:22:01

NASA is confident sensor troubles fixed - 23 Jan 2008

BY PATRICK PETERSON
FLORIDA TODAY
CAPE CANAVERAL - NASA believes it has put sensor signal problems behind it, and next week the agency will begin moving toward the Feb. 7 launch of Atlantis on a construction mission to the International Space Station.
At Kennedy Space Center, technicians are shaping and coating foam over a replaced sensor connector at Pad 39A. The repair work will be finished by Friday, and normal shuttle processing will begin next week, NASA spokesman Candrea Thomas said.
Intermittent readings from low-fuel sensors in the external tank caused launches to be scrubbed on Dec. 6 and 9. However, two series of tests indicated that replacing the suspect connector and soldering the outside leads will solve the problem.
Cryogenic tests earlier this month showed the old connector failed where NASA engineers had suspected. During tests this week, a new connector with soldered leads maintained a circuit down to 423 degrees below zero, which the connector will encounter when the external tank is filled with liquid hydrogen.
"We have completed four cryogenic test runs of a test article (of the new design) and the circuit data looks good," said Steven Roy, spokesman for Marshall Space Flight Center, where the tests were conducted.
"Our confidence in the redesign with soldered pins and sockets is strengthening," Roy added.
Final approval of the Feb. 7 launch date likely will come Jan. 30 at an Executive Flight Readiness Review.

cIclops · 2008-01-24 03:39:28

STS-120 - ENGINE CUTOFF SENSOR ELECTRICAL CONNECTOR PREPARED FOR CLOSEOUTS - video (2:15 mins)

On the external tank of space shuttle Atlantis for mission STS-122, during the week of Jan. 14 – 18, technicians sand and trim reapplied foam insulation around the box containing the engine cutoff sensor electrical connector. Primer was then applied to the lid and connector box and the cover installed in preparation for spraying of two layers of foam insulation. The connector was reinstalled into the tank Jan. 13 at Launch Pad 39A at NASA's Kennedy Space Center, Fla.

cIclops · 2008-01-30 16:56:52

Jan. 30
NASA managers formally set the launch of space shuttle Atlantis for Feb. 7 at 2:45 p.m. EST, pending analysis of a flexible hose in the shuttle's radiator cooling system.
The bent hose was discovered Tuesday on Atlantis during inspections of the payload bay doors. Engineers want to determine whether the braided metal hose, which carries Freon to cool the shuttle's systems while in space, will work as planned. The hose in question runs from the shuttle body to the radiator panels on the cargo bay doors.
The problem was first uncovered during inspections of space shuttle Discovery.
"We're heading for the seventh of February for launch and we'll continue to look at the radiator hose issue," said Bill Gerstenmaier, NASA's associate administrator for Space Operations.
Officials will meet again Saturday to evaluate testing and other data related to the hose.
"Right now, that hose is perfectly functional," Space Shuttle Program Manager Wayne Hale said. "Since the hose is not leaking now and the sister hose on Discovery didn't leak on a number of flights, I'm feeling very positive we'll come to a good conclusion. But we have to do our work here, the engineers have to do their work and we want to make sure we know what we're doing before we go fly this vehicle."

cIclops · 2008-02-01 16:41:38

Testing work for the ECO sensors - (video 2:23)

Testing has isolated the source of electrical problems on connectors retrieved from external tank ET-125, and a redesigned, soldered configuration has passed tough cryogenic and vibration tests. Erratic readings from the engine cut off sensor system led to two launch postponements in December 2007. The sensor system's external plug and feed through connector were removed from space shuttle Atlantis' external tank and shipped to Marshall Space Flight Center in Huntsville, Ala., for tests. A modified connector was designed, with pins and sockets soldered together. Both the original and modified connector configurations were subjected to temperature, pressure and vibration environments identical to those experienced during a space shuttle launch.

Ahh duct tape, a sign of real testing!

New Mars Forums

Announcement

#26 2007-12-09 17:25:11

Re: STS-122 Atlantis

#27 2007-12-13 18:32:48

Re: STS-122 Atlantis

#28 2007-12-19 09:58:18

Re: STS-122 Atlantis

#29 2007-12-24 08:29:00

Re: STS-122 Atlantis

#30 2007-12-28 03:52:29

Re: STS-122 Atlantis

#31 2007-12-28 11:03:41

Re: STS-122 Atlantis

#32 2007-12-28 12:23:23

Re: STS-122 Atlantis

#33 2007-12-29 11:57:08

Re: STS-122 Atlantis

#34 2008-01-03 16:16:04

Re: STS-122 Atlantis

#35 2008-01-05 17:50:22

Re: STS-122 Atlantis

#36 2008-01-07 08:35:00

Re: STS-122 Atlantis

#37 2008-01-08 17:05:42

Re: STS-122 Atlantis

#38 2008-01-09 03:52:13

Re: STS-122 Atlantis

#39 2008-01-10 22:01:24

Re: STS-122 Atlantis

#40 2008-01-11 14:04:02

Re: STS-122 Atlantis

#41 2008-01-12 07:16:57

Re: STS-122 Atlantis

#42 2008-01-14 14:13:15

Re: STS-122 Atlantis

#43 2008-01-17 10:46:23

Re: STS-122 Atlantis

#44 2008-01-17 19:50:34

Re: STS-122 Atlantis

#45 2008-01-18 03:40:15

Re: STS-122 Atlantis

#46 2008-01-23 03:23:39

Re: STS-122 Atlantis

#47 2008-01-23 08:22:01

Re: STS-122 Atlantis

#48 2008-01-24 03:39:28

Re: STS-122 Atlantis

#49 2008-01-30 16:56:52

Re: STS-122 Atlantis

#50 2008-02-01 16:41:38

Re: STS-122 Atlantis

Board footer