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Mike Leinbach, STS-116 Launch Director
You are listening to NASA Direct.
From the Kennedy Space Center in Florida, I'm Kay Grinter.
Space Shuttle Discovery is on the launch pad, ready for its third trip to the International Space Station since July of 2005.
With a launch planned for early December, the NASA launch team at the Kennedy Space Center in Florida is hard at work preparing.
One of the team leaders, NASA Launch Director Mike Leinbach, is here to tell us more about Discovery and a little bit about launching the space shuttle.
Mike, thanks for stopping by during such a busy time for the team.
Leinbach: It's my pleasure to be here.
Grinter: Mike, as we just mentioned, Discovery has flown twice already since NASA's return to flight in 2005, and Atlantis has flown once. Why was Discovery selected for this mission and will Endeavour fly again?
Leinbach: Well, I like the question about Endeavour flying again, and she absolutely will. Endeavour is set to fly in June of 2007, STS-118. She's been going through a major modification over the last couple or three years or so, and that's why you haven't seen Endeavour in the fleet. But that's a, that's a process we put all orbiters through about every three years or so. But she's just about done with that. Final preparations for her launch will begin in the springtime and, again, a liftoff STS-118 in June of 2007. And so that means we had to use Discovery and Atlantis for all the missions since the Columbia accident, and you look at things like the weight of the payload, the capabilities of the robot arms, those types of things, in deciding which orbiter to use. And so, while the orbiters look similar, almost identical from the outside, their weights are slightly different, the capabilities are slightly different, and we try to align an orbiter with a particular payload, and that's why we've flown Discovery three out of the last four missions. In particular, the last mission with the P3/P4 truss, that was such a very heavy payload, that Discovery had to fly that mission. Atlantis, Atlantis weighs a little bit more than Discovery, and so we had to use Discovery for that mission. But again, you'll be seeing Endeavour fly again before too long, and then we'll have all three orbiters remaining in the fleet for the rest of the shuttle program.
Grinter: STS-116 is a night launch. Are you worried at all that you may not see something that could cause harm to the space shuttle?
Leinbach: Well, as you well know, this is our first night launch since the Columbia accident. And after the accident, of course with the foam coming off the external tank and the video we had of that foam hitting the orbiter -- wasn't very good video, but nevertheless we were able to see what happened -- we levied a requirement on ourselves to launch only during the daytime so that we could see the ascent as best as possible and as long as possible, to see how the external tank was behaving, the modifications to the external tank.
The missions we've had since Columbia have all been very successful. The last two, in particular, have had extremely low amounts of foam coming off the external tank, well within the acceptable criteria. And so we feel, as a program, that it's OK now to go back to night launches. And you asked the question about, will we not see debris coming off, well, there's a chance we wouldn't see it coming off and hitting the orbiter if it hits the orbiter.
And part of your question has to do with not being able to see the orbiter during its full ascent and any type of debris that may be coming off the external tank. That's going to be true for this night launch, but again, our, our test of the health of the orbiter is after we've reached orbit. We do that full inspection of the belly of the orbiter and the leading edges of the wings, and really all surfaces of the orbiter, using the new boom system and using the pitch maneuver right prior to docking with the International Space Station. And so, while we may not see the source of the damage if we see one on orbit, the proof that the orbiter is healthy enough to come home, that the TPS system hasn't been damaged to the point that we couldn't reenter the atmosphere, those tests are done on orbit regardless of the time of day of launch.
And so, again, we may not see where the piece of foam came off of the external tank if it's late in the ascent, but we will know if the orbiter is safe enough for the astronauts to ride back down to Earth or not.
Grinter: Of course, everyone hopes for a picture-perfect launch and landing, but what would happen if the shuttle gets damaged during liftoff and it cannot get fixed in space?
Leinbach: Well, in the unlikely event that we do have a damaged orbiter during ascent, or if we suffer damage on orbit, the astronauts would go aboard the International Space Station and stay there until the next orbiter would come up to rescue them. We always have a second orbiter ready to go. It would launch within about 60 days or so, which is plenty of time for the on-orbit stay on the International Space Station. So the second orbiter would go up and rescue the astronauts, bring them back down, and then we would have to determine what we would do with the orbiter that suffered the damage.
And onboard the International Space Station, it is possible to have two shuttles docked to the station at the same time, obviously docking to different ports. But that's a capability that the International Space Station has and we would use if we had to.
Grinter: Here's a launch question for you: After the engines are fired at T-6.6 seconds, why does the shuttle look like it goes up and down before the solid rocket boosters fire?
Leinbach: Well, that illusion of the shuttle going up and down, it's really rocking back and forth. With the shuttle on the south side of the external tank, when the engines are fired, it tends to push the whole orbiter and the SRBs and the external tank slightly to the north and so the very top of the shuttle stack moves back and forth from north to south. And then when the top of the tank reaches a perfectly vertical position that equals RT-0 and the SRBs are ignited and the, and the whole system takes off.
Well, the shuttle doesn't actually go up and down after the main engines are ignited, but it does rock back and forth. With the orbiter on the side of the external tank and the, and the main engines of the shuttle at a slight angle to the vehicle itself, when the engines are fired, it tends to push the whole stack a little bit to the north. And so, if you look at the top of the external tank, the very tippy top does go back and forth, it goes, it goes north and then back down towards the south, and when the top of the tank reaches a perfectly vertical position that corresponds to RT-0 and the SRBs are ignited and the vehicle takes off.
Grinter: Discovery will be launched from Launch Pad 39B in early December. In fact, all of the launches since Columbia have been from this pad. Will Pad A ever be used again?
Leinbach: Well, the next launch off of 39A is expected to be STS-117 in March of 2007. Pad A has been going through a modification period. We need to upgrade its systems periodically. We need to do corrosion prevention and paint structures, etc., and that work is now winding down. And so, while it's not available for this mission, we do expect to launch STS-117 off pad A early next year.
Grinter: Mike, we know you've been doing this for years, but do you ever get nervous on launch day?
Leinbach: Am I nervous before launch? No, I'm not nervous. The feeling I tell everybody is that it's an intense feeling. We have so many criteria we have to meet. It's a, it's a feeling of excitement, it's a feeling of intensity, it's a feeling of immense pride when we do liftoff. Our training is so good that we don't have time to get nervous. We know the system so well that if we experience failures, we're able to deal with them. So nervous is not the right word; intensity, pride, excitement I think are better.
Grinter: Mike, thank you for stopping by and talking about launch with us.
Leinbach: Well, I appreciate you inviting me over and appreciate the interest from the folks around the country and around the world in the Space Shuttle System.
You've been listening to NASA Direct.
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