STS-122 Mission Update

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STS-122 Mission Update
02.12.08
 
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Space shuttle Atlantis stands ready to launch the European-built Columbus laboratory to the International Space Station.

The crew has arrived and the countdown is under way. Live from NASA's Kennedy Space Center in Florida, this is the STS-122 Mission Update.

ALLARD BEUTEL: Good morning. Today is Wednesday, Feb. 6, and you are looking live at Launch Pad 39A.

Space shuttle Atlantis stands pointed toward space and a rendezvous with the International Space Station. I'm Allard Beutel, NASA news chief here at Kennedy. Thanks for joining us this morning before the launch of STS-122.

This is an exciting time for NASA as the agency launches its first mission of the year and adds a critical piece to the International Space Station.

The seven astronauts who will fly aboard Atlantis arrived here on Monday and the countdown is moving methodically toward a 2:45 p.m. Eastern time liftoff tomorrow. Commander Steve Frick and his crew will eat breakfast just before sunrise on launch day before putting on their orange pressure suits and heading to the launch pad. This is exactly the same thing they would have done in December if a faulty connector in the engine cutoff sensor system had not delayed two launch attempts before the external tank was completely filled in December.

Joining us this morning we have NASA Test Director Steve Payne to talk about that exact fix and what we're going to do now. Steve, thanks for joining us.

STEVE PAYNE: Thank you. Good morning.

BEUTEL: And just in case people don't know what a NASA test director does or is, besides you, what do you guys do for us?

PAYNE: Well, the NASA test directors are responsible for the planning and execution of the shuttle launch countdowns. So we, in effect, orchestrate and run the countdown.

BEUTEL: And which is going really well right now.

PAYNE: So far, so good.

BEUTEL: Well, let's see. We call it here at NASA the engine cutoff system. It goes by the acronym ECO. What is it and why do we need it?

PAYNE: Well, the engine cutoff system is one of two methods by which we tell the main engines when to shut off.

The computers on the main engine controllers are the primary system and they, after a certain amount of time, tell the engines it's time to shut down.

The backup system is this engine cutoff system and it consists of a number of sensors on the bottom of the external tank that, when they register that they are dry, they pass the signal to the engine controller to shut down.

BEUTEL: And we've had some intermittent problems with them.

PAYNE: Yes we have.

BEUTEL: And as anybody knows with a car or any kind of problem like that, something that's intermittent, that's some of the worst problems to deal with because you take it in, it's suddenly working, and that's what we had with several flights.

PAYNE: That's true. This was an unexplained problem for a couple of missions. We struggled to find out where the source was.

We thought initially that the sensors themselves were bad, but we couldn't find the source. Fortunately, or unfortunately, this last mission we were able to finally determine where the fault lay.

BEUTEL: And speaking of which, we happen to have what we think is actually where the fault lay, and in this case, what did you do to fix it?

And what is this?

PAYNE: Well, this is the feedthrough connector that goes between the inside of the external tank and the outside of the external tank.

And there's a connector on either side that connects on the inside to the engine cutoff sensors at the bottom of the tank, and on the outside to the avionics on the orbiter. What we found is that once we cooled the inside connector by filling the inside of the tank with liquid hydrogen, the outside part of the connector would also get cold and the airspace between the socket and the pins of the connector would, the air inside would freeze and it would be an insulator between the two metal parts. And so we'd have intermittent signals coming and going.

What was fortunate about the failure we saw last time is that we had many failing at the same time, which pointed directly to this being the cause of the problem.

BEUTEL: And in that particular case, what did you guys do to fix it?

PAYNE: Well, what we did, we did a little research and found that our folks across the river in the Atlas/Centaur Program had a very similar, identical problem practically. In their tank, they had the same issue with intermittent signals. What they have done, they removed that airspace by soldering the pins to the sockets. There's a video you're watching now.

We removed our feedthrough connector and the external connector, cut it off, spliced in a new one which was soldered solidly between the feedthrough and the connector. That way there was metal to metal contact and we no longer had the problem with air freezing inside and having an intermittent connection.

BEUTEL: And anyone at home who doesn't know about spaceflight hardware and the time it takes to do these fixes, you think, okay, it took you two months to be able to do that. But actually, when it comes to spaceflight hardware and modifications, that's pretty quick.

PAYNE: That was pretty quick. Fortunately, we had a couple of missions we've seen this, we didn't understand it but we had some data we had gathered. On the initial couple of launch attempts for STS-122, we gathered a lot more data.

And then we had a tanking test we performed in December, where we put instrumentation along the data path back and forth, and we were able to isolate it to this one connector. That was the smoking gun we were looking for and we were able to get the solution from our friends across the river.

BEUTEL: So other than having Atlantis safely in orbit and heading to the space station, when will you know that you really have gotten the fix done?

PAYNE: Well, we're pretty confident that this is the fix. Everything else had worked. We isolated to this and we implemented a known good fix.

But we'll know for sure after we tank on Thursday morning and give the system enough time to cool down.

Once we get beyond the point at which we would have seen these intermittent connections, we should be home free.

BEUTEL: A lot of news reports came out last week; we had another thing crop up that people may have heard about, flexible hoses in the cooling system for Atlantis. Tell me about those.

PAYNE: Out in space, you have to reject your heat through radiators in the payload bay doors. And the way that it works, we have Freon that flows through plates under our avionics, our electrical boxes, and they take the heat away, and we send it to via some hoses to the radiator panels on the doors. I believe we have video on the closing of our payload bay doors.

You see the radiators on either side of our Columbus module. There's a hose that carries the Freon from the body of the orbiter into these radiator panels, and when we closed the right side door, the starboard door, we noticed that the hose was not retracting into its box like it should have. In fact, it was bending. And you'll hear the term "omega bend," which is much like the Greek letter Omega, where rather than go into its case, it bent some.

We have analyzed it and, in fact, you see here, we used this homemade pole where we guided the hose back into its proper location.

We feel it's fairly safe to do and we don't expect to have any problems with this hose. It's been X-rayed and leak checked and we've had these in previous flights without any issue. So we have no concerns about it for this particular flight.

BEUTEL: And just have to mention that pole for a second. It looks suspiciously like a pool skimmer pole.

PAYNE: It looks a whole lot like a pool skimmer pole with some padding on it and some tape.

BEUTEL: I guess sometimes the best solutions are the simplest ones.

PAYNE: Absolutely.

BEUTEL: Actually, in that video, as well, we saw the Columbus laboratory. How has it held up in the past couple of months?

PAYNE: It has had a fairly easy time since they were ready to go during the first couple of launch attempts.

All they've really had to do is maintain a clean gas purge on their equipment to make sure it didn't get dirty.

They replaced the covers on the optics to make sure none of that got dust on it. But otherwise, they haven't had a whole lot else to do.

BEUTEL: Alright, well, Stephen, we appreciate you coming down and giving us a quick update on where we are, and we're in a good position to launch tomorrow, aren't we?

PAYNE: Absolutely.

BEUTEL: And from your words to both launch directors. A reminder now to stay with nasa.gov and NASA TV for all your mission information.

Launch coverage begins tomorrow at 5:15 a.m. Eastern on NASA TV and continues through liftoff.

You can also log on to www.nasa.gov/shuttle for continuous updates of the countdown on our launch blog.

There will also be video highlights and stunning photographs of the liftoff. Thank you for joining us this morning for the STS-122 mission update.

I'm Allard Beutel.

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