|Question and Answer Board
|Aren from Vermont
Did you have to take the payloads out of Columbia after the summer launch delay?
| Actually, Aren, we didn't have to do that. This particular payload, the SPACEHAB Research Double Module that you saw just a few seconds ago, doesn't need to be removed for an extended period of time. In fact, for this payload, we're actually just installing the time-critical payload complement right now at the launch pad. We get down inside there on basically a hoist type arrangement, and load all the critical experiments right in the countdown. So when we delayed this summer, the Research Double Module stayed inside Columbia and stayed inside the OPF (Orbiter Processing Facility). Every once in a while we powered it up to make sure all the electronics and cooling systems worked, and they did very nicely. So not too much to do with that particular module.
Host: Now is there ever a case when we do have to remove payloads?
Expert: There are some cases. There are some payloads that have to be removed frequently. They may have a unique component that has to be replaced, or if we had a technical problem on the launch pad that necessitates us getting inside the payload bay - and of course some payloads are so large, they take up the entire payload bay - we might have to remove them. Sometimes we can do that at the launch pad, and sometimes we have to take the vehicle off the pad and take it all the way back to the OPF to take out the payload and do the work.
|James from Cananduagia, New York
The problem with the ball valve with Columbia on the pad - which ones can be checked out?
|Well, the Ball Strut Tie Rod Assembly that we're having problems with, that's really a gimbaling mechanism that has a metal ball in the center of it that's inside the main propulsion system lines. And at the pad we cannot inspect it adequately. We have to do all that back at our orbiter hangar, the OPF, to do that type of work.
Host: Is there a plan or a procedure in place now to check the remaining balls?
Expert: We sure have a plan. What we're going to do, we have a team looking at this particular problem over the past few weeks, and that team says we're safe to fly, but we need to keep an eye on it over the long term. Of course, the shuttle is planning on launching over another 20 years. So we're going to keep an eye on it, and in fact there's a fellow at JSC (Johnson Space Center) who came up with an idea, sort of a device that can insert into the main propulsion system tube, and this device goes up to the Ball Strut Tie Rod Assembly, and the ball is actually captured by two cups. And he's able to spread the cups apart and put a little gimbaling mechanism that rotates the ball and allows us to do a full, complete video inspection. It's a pretty clever device, and we're using it here at Kennedy Space Center right now, and we have plans in the future to do it periodically for all the vehicles upcoming.
|Matt from Wellington, New Zealand
In my job I come under a lot of stress but I can't imagine how much it is compared to the amount you guys come under. How do you deal with it?
|Well! I'm sure there's stress at every job, but I will have to be honest with you, Matt. The space shuttle activities are really something that we try to control stress, and we do that by a lot of practice and a lot of training. And in our training, our launch countdown simulations, we have people in another room that throw problems at us. We don't know what the problems are until we get there. We call them "gremlins," and they throw the problems out at us, and try to stress us out. And we've been doing this so often for so many years, we feel we're trained to handle that. So our job is not too stressful. There are lots of other stressful jobs in the world, and I don't think ours ranks up with them. Like everybody else, training helps relieve the stress.|
|Jonathan from Louisville
Since Columbia is the oldest of the orbiter fleet, what special challenges does she offer during processing versus the rest of the fleet?
|You're right, Jonathan. Columbia was the oldest one, it was our first. And it kind of holds a special place here - the first vehicle to fly. You know, it's the oldest one, but it's not the one with the most flights. Columbia has 27 flights; Discovery, OV-103, has the most flights with 30. And then we have OV-104 Atlantis, with 26. So Columbia's about equal with the other orbiters, and we always pay attention to the age of the orbiters and we're concerned about it. You know, these things were first flown in 1981, and we expect to fly them another 20 years. So we're doing a lot of efforts to make sure that the hardware is safe to fly, and every eight flights, we take an extended stand-down period we call OMM, Orbiter Maintenance and Modifications. And we go into each orbiter and almost tear it apart looking for corrosion or problems with fluid systems or electrical systems. In addition, we incorporate new technology when we can. For instance, Columbia, although it's the oldest orbiter, does have a Multi-function Electronic Display. Just like the 777s of today, it's a completely glass cockpit that we updated just a short while ago. So we do our best to make sure the orbiters are safe by constantly upgrading them. So right now, Columbia is in the same category with the other orbiters, we maintain them. And for your information, Endeavour is the youngest of the orbiters, and it only has 19 flights on it.|
|Wayne from Hampton
What is the radius of the restricted airspace around the Cape during a mission? When does the Temporary Flight Restriction (TFR) go into effect and how long does it stay in effect? (I am a private pilot who wishes to make a trip through Florida and I want to AVOID the TFR.) ...Wayne
|You know, Wayne, we want you to avoid the TFR as well. That's something new we're doing, and the TFR, Wayne, which you're familiar with, is a temporary flight restriction which the FAA can issue to lots of folks, particularly pilots they send that out, and you can check on those yourself. And Wayne, for this case what we're doing is about a 40-mile radius around the Space Center, and that's all documented in the TFR, and it goes into effect nine or ten hours before the planned launch time or period. My best advice to you, Wayne, is to please check the TFR, the times can change, the distances can change, and of course you're a pilot and you know how to do that. But we would like you to come down and visit us sometime, though.
Host: Let me ask you a question. Is this restricted airspace something new since Sept. 11, or has this always been in place?
Expert: This is something new. Something we have had a restricted airspace aroung the Kennedy Space Center, but it was very small, just to keep basically to the Space Center itself. The new restricted airspace has been greatly expanded, 40 miles away, and that also includes Orlando International Airport.
|Scott from Mineola, New York
How long does the shuttle have to be on the pad before launch?
|It varies each time. The shuttle goes out to the launch pad, usually 20-25 days is the time period it needs to be out there. And when we're out there we load ordnance onto a variety of components: the ordnance that separates the orbiter from the external tank, the solid rocket boosters from the external tank - all that stuff is checked out there. One other key item we do out there is load hypergolic fuels. Once the orbiter's on orbit, it maneuvers with about 44 little jets that allow us to do a variety of yaw, pitch, and roll motions with the orbiter to mate it to the space station, for example. And that fuel is loaded out at the pad, it takes several days to do that. It is a hazardous commodity. The crew comes out and does a TCDT (Terminal Countdown Demonstration Test) that I mentioned earlier. So we think about 20-25 days, and about 20 days is our best.
Host: What is our longest?
Expert: Oh! The longest? It really depends. Sometimes we have technical problems, and that keeps us out there awhile, but generally it's not much longer than that. Some of our payloads are installed at the pad versus this particular one, that was installed in the OPF.
|Kathy from Palm Harbor, Florida
What happens to the external tank after it separates from the shuttle during launch?
|The external tank, once we reach orbit and have main engine cutoff - and that's about eight and a half minutes after launch - is no longer necessary. And it makes no sense to pull all that hardware around with the orbiter as it does all its maneuvering and raises its orbit to get to the space station, so we discard it. The flight profile is designed so the external tank, when it's discarded, it reenters the Earth's atmosphere and actually starts tumbling a little bit and breaking apart. A lot of it burns up, but the stuff that doesn't burn up actually lands in the Pacific Ocean, near Hawaii, the nearest land mass, but there's a nice area that's outside of shipping channels that the debris can get to safely. It'll come down and of course we tell folks out in that area when those events are going to happen so they can make sure they're not there.|
|Jonathon from Citra, Florida
Where are the external tanks built, and how do they get to the Cape?
|Okay, Jonathan. The external tanks, or really the components, the fuel lines, the feed lines, the electronics to them, are all built in the U.S. They are shipped to Michoud Assembly Facility (MAF), and that's a facility just outside New Orleans. Once there, they're all assembled into the larger external tank that you see. They assemble it, weld all the pieces and parts and components, the two major cryogenics tanks, and then they put the foam on with a special machine that applies it at just the right thickness to keep the cryogenic temperatures inside the tank from warming up from the external environment here at the launch pad. Once the foam is applied, we put them on a special barge that takes the external tank from Michoud, just outside New Orleans, and takes it around the coast of Florida, and brings it into the Port of Canaveral. And not far away from the Vehicle Assembly Building here at Kennedy Space Center we have a turn basin, and that barge can make it all the way up. And it's on a really long, skinny transporter, so once it gets here, we just roll it right over to the VAB, and our cranes take care of the rest.
Host: Typically, how long does it take for the external tank to come from MAF all the way to Kennedy?
Expert: Well that trip is normally about five days. Sometimes it takes a little bit longer - we do pay attention to the trip during hurricane season, and we have had to alter those plans if we have bad weather.
Host: And I understand the SRB retrieval ships are the ones who actually bring it from MAF to the Cape, right?
Expert: Yes! Yes, we have tugboats and we recently modified them so the recovery ships that are on the NASA inventory can currently do the job, and that saves us money.
|Doug from Coldwater Canyon
Does it damage a shuttle on the pad when the temperature drops below freezing?
|Well, on a regular day when we go below freezing, no, it doesn't hurt the shuttle at all. It can withstand cold temperatures. On the facility side of things, the launch structure you see out there does have a lot of systems with water in them, and not all those systems have heaters. So we do have a team that goes out and does a special inspection of all the water systems, makes sure there are no leaks, like you might do at your house if you looked at the water entry into your home during freezing weather. On launch day, obviously, we do have special weather criteria. Today, between 43 and 36 degrees, there's a chance we could launch if the winds are right, if the temperature's right, and the humidity is correct. There's a matrix we look up to see if it's OK to launch. And of course, we have heaters around the SRB joints. When it gets really cold, we activate the heaters and make sure the joints maintain their warmth. And the shuttle doesn't really need a whole lot of external heaters. It can get cold enough to where we have heaters on the propulsion systems for on orbit activities to turn on the heaters. But in general the cold weather doesn't bother us too much. But on launch day we have some special criteria.
Host: Do we consider scheduling launches such that we don't target some very cold parts of the year?
Expert: Actually the launch manifest is planned independent of the weather seasons. We try to do the best we can to get the shuttle out there as early as we can, and accommodate either our customers' needs or the assembly sequence for the space station. So we don't let cold weather bother us.
|Jenny from Omaha, Nebraska
Who on the ground is closest to the shuttle during liftoff besides the astronauts on borad, and how far away are they?
|Okay! Well, a few hours before launch, everybody is cleared away from the shuttle, at least to three and a half miles. And that's where we are in the Launch Control Center, as well as observers and distinguished visitors, they get that close. However, we do have a special team, a fire-rescue team, that's closer in. In fact, they're just a few thousand feet away from the shuttle. They're housed in an armored personnel carrier that could protect them if something happened on the launch pad, and they're there just in case. If we have a bad day and have an emergency on the launch pad, then that team can go straight up the launch pad very quickly, and help out the astronauts if they need to do that.|