Lee Norbraten: Most of the shuttle program activity is operations activity – doing the planning to get ready for the specific missions we fly, conducting those missions, and getting the vehicles ready to fly for the upcoming mission. That’s the day-to-day activity of the program, and that’s 90 to 95% of what the program does.

The program does have a development activity, and that’s the part I’m responsible for that has to look into the future a little bit and look at overall what the future needs of the program are. Are there systems we need to improve? Are there other systems that might be deteriorating that we need to replace? Is there a way overall to improve the vehicle in such a way that it flies safer than it currently flies today? That’s the focus of my activity.

NTB: How are the shuttles safer today than they were five or ten years ago?

Norbraten: The main improvements that have been made in safety over the last five or ten years have been improvements in the main engines themselves. We’re talking about the three engines at the base of the orbiter that burn the propellants from the external tank. That is high-speed turbo-machinery dealing with hazardous chemicals and it represents the most risk during ascent. Therefore, the most likely to have failure modes that could end in the loss of the mission, the loss of the vehicle, or the loss of the crew. Those are the things that have been the focus of improvement.

There was a significant development activity over that period of time that was improvement of the turobpumps that feed both the hydrogen and the oxygen into the combustion chamber of the main engine. In addition, we redesigned the powerhead to eliminate linear cracking and also the heat exchanger to minimize welds. We’re talking major development activities that were spread out over a number of years that significantly increased the overall safety of the vehicle during the ascent phase, when those engines are in motion.

NTB: When did a formal program of shuttle upgrades and safety improvements begin?

Norbraten: The shuttle program has always had some amount of development activity going on in the background, and we have always looked at, to the best of our ability, do we understand the likelihood of failure and are there things we can do to improve that.

In late 1999, there was a significant effort to improve the overall safety of the vehicle that was proposed by some of the NASA leadership at that time. It was developed through Congress in such a way that there was a commitment made by Congress that pertained to the fiscal 2000 year budget and subsequently, to fund on the order of $1.6 billion worth of upgrades over a period of six years. That was the re-infusion of interest in the overall upgrades program at that time. There were several candidate upgrades that were then put under consideration at that time, and of those candidates that were put in place, four of the eight candidates are things that are well on their way to completion. The others either did not have adequate funding or there were some problems with whether the technology itself was ready to go do the thing we were trying to do. Not everything was ultimately approved, but we have proceeded with four of the eight projects that were approved.

NTB: What is the new “glass cockpit” in the orbiters, and how has it helped the shuttle pilots?

Norbraten: There are two activities in place where the term “glass cockpit” has been used. One is the MEDS (Multifunction Electronic Display Subsystem) activity. It is a display system that emulates the glass cockpit. What we’ve done is follow-on behind that in the Upgrades Program with a project called the Cockpit Avionics Upgrade (CAU), which basically is redesigning all of the displays that the crew sees throughout the flight, but especially at critical phases of ascent, so that they have access to more current information, better information, information that can be displayed more readily on the screens in front of them.

We’re talking about going back into the information that is updated to make sure that the information base is improved significantly over what was there. Part of it is physically changing out gauges for displays, but the second part of it is building the logic that gives the displays their maximum effectiveness.

It is real-time information the pilots receive, and that’s why the term “situational awareness” is always used. What you don’t want to have is the commander or pilot during a critical flight phase simply reacting to alarms, trying to interrogate the information in order to try to understand the nature of the problem. You want to give the pilot the ability almost to anticipate the problem by virtue of the information that is displayed during those flight phases. You’ve got better information, more readily accessible. Things like during the ascent phase being able to anticipate if an engine fails, where is the abort site that would be currently in play if you had an engine out. You are already aware without having to wait for a call from the ground to react. You’re trying to save a substantial amount of time in a critical time phase to make the right decision onboard.

NTB: What technologies are being investigated to improve shuttle systems such as the main engines, hydraulic power, and the fuel tanks?

Norbraten: Where we deal with engine technologies, almost all the advancement of the technology exists under industry projects that NASA has funded, rather than by directed NASA research. However, at the base of almost any program are those places where NASA would have invested money in university departments to do the fundamental research that may ultimately lead to a breakthrough. Examples include avionics, hydraulics, battery design, fuel cells, digital technology, and advanced materials. But when we talk about trying to uprade the shuttle systems, we’re talking about something where not only is the technology there, but it could be adapted to the flight use. That’s when we rely on our contractor community.

NTB: NASA stated that it would like to double the shuttle’s safety by 2005. How will that be accomplished?

Norbraten: We have in place a PRA (Probabilistic Risk Analysis), and the output of that particular tool is a mean time between failures, which we measure in two ways. One way is during the ascent phase, which is considered to be the most risky flight phase. The other number addresses the overall mission risk. If right now we say, for example, that during ascent the risk of a catastrophic failure is one in 556, that means in 556 missions we’d have one catastrophic failure. That’s not good enough. We’re under the charge to try and double that to improve it by 100%, which would mean somewhere on the order of one in 1,000 would be the direction we’d want to move in.

There are several potential projects that we could invest in that begin to move that risk from the 1 in 556 toward 1 in 1,000. One of the things that currently is funded and on its way to final approval is an Advanced Health Monitoring System (AHMS). It’s a box attached to the main engines that is used as a means of monitoring vibration, and a means of shutting down an engine before it experiences a catastrophic failure. You have a smart box looking at something that even if it begins to depart from its normal profile, you’ll send a signal to shut it down in a safe mode rather than have some kind of critical vibration get out of hand.

That moves things in the right direction. On the solid rocket boosters, we have the system that controls the direction of thrust. That is a hydrazine fuel system. Hydrazine is a toxic chemical and the potential for fire that exists with hydrazine is one of those things that makes it a risky component to fly. If we could replace the hydrazine with helium under pressure – helium being a non-toxic gas – that would result in an overall improvement in ascent flight risk.

The corresponding capability on the orbiter itself is the auxiliary power units that drive the control surfaces of the vehicle, also fueled by the combustion of hydrazine. If you have a leak in that system, you have the potential of a catastrophic fire and explosion. If you’re able to replace hydrazine with battery power, that would represent a significant improvement in safety. If we were able to spend the next amount of development money to do a project called Channel Wall Nozzle – the channel wall is a better way of cooling the nozzle on the main engines, preventing the potential for a burn-through. A redesign of the main combustion chamber would make it safer and less risky. All of these are sizable technological investments, but they all tend to drive that number from the neighborhood of 1 in 500 up to the neighborhood of 1 in 1,000.

What you have to do at any given time is look at what technologies and what capabilities are ready and how much that is going to cost to implement, and whether the current version of the budget that we ultimately get back from the Administration and Congress is sufficient to pay for some of those things and then it competes with everything else that the program wants to do in terms of overall priorities.

NTB: NASA’s 2020 Upgrade Study identifies what’s required to keep the shuttle flying through the year 2020. Is there still a plan to replace the shuttle fleet with a new, reusable craft?

Norbraten: What we have had is a significant statement from NASA Administrator Sean O’Keefe that is overall supportive of the space shuttle as being the primary means of human space transportation. The fact is that we believe it will be required to fly well into the next decade. Before the current NASA administration, we were looking at the shuttle potentially going out of business in the year 2012. It was understood at that time through the Space Launch Initiative that whatever the replacement for the shuttle might be, it would be ready to fly in that time frame. That does not look like it’s going to come to pass.

Therefore, there will be more reliance on the shuttle as being the primary means of getting humans into space. If that’s true, and Mr. O’Keefe has said this, then we need to do whatever it takes to be sure that the shuttle continues to operate safely and effectively. That means two things: the kinds of safety upgrades we’ve talked about, and also the overall infrastructure of the program in terms of the launch site facilities, the process facilities, the tools, the labs, the critical skills – all of the resources that are there, all the assets that it takes to fly the shuttle safely. We need to then go in and make sure we don’t have any deterioration of those assets.

Let me give you an example. We received notice two or three weeks ago that an asbestos supplier in Canada was going out of business. It was not anticipated. There was nothing in the wind that predicted this would happen. Asbestos is required as the lining in the insulation for the solid rocket motors. It is an excellent material for that use and is benign. The manufacturing processes they use does not carry any risk. It’s relatively cheap and effective for what it does. When the company decides they’re going out of business, the first indication was that there might be six months to a year of residual material there that could be purchased. What was the shuttle supposed to do after that? You’ve got to invest in a significant thought process to decide if you look for alternative sources of asbestos, or do you look at developing a new insulation material and what kind of material would that be?

We have to put some investment into studying what our options are and then if asbestos is not a viable option long term, then how do you develop an alternative material for that particular use? That could be an expensive proposition. But those are the kinds of things that would have to be invested in in order to keep the shuttle viable through 2015 or 2020.

The jury is still out on exactly what might end up being the replacement for the evolution of the space shuttle itself. Certainly when the Space Launch Initiative was driving it, it had certain concepts of what that vehicle should look like, when it might be ready, what the characteristics of it would be. A lot of that has been the subject of some very intense debates over the last few months. I don’t know what the outcome of that will be.

But in the background, it certainly would have been on the part of the shuttle program important to us as part of contingency planning, to make sure we were not going to do anything that might put us in a posture where we could not fly beyond 2012. That was the basis of the charge we were given in March, to go examine what it would take to be able to fly to at least 2020. A lot of our effort has been looking not just at the safety improvements but also at all the systems that might be becoming obsolete. There are tape recorders, for example, that are carried on the orbiter that record critical data during flight and are brought back. Tape technology is becoming obsolete. Therefore, the state of the industry is such that we should be moving to all solid-state digital capability. But that costs money to effect that kind of change and to be able to produce a system that could withstand the rigors of space flight. It is a good example of something that would have to be done if we’re really going to proceed with a vehicle that’s viable after 2020.

NTB: So, with proper funding, does it look like NASA can keep the shuttles flying for another 15 to 20 years?

Norbraten: There is no brick wall in front of us that says we cannot continue to fly. What we have instead is probably going to be a sequence of little hurdles that have to be overcome from time to time. You can’t always predict what things will show up as the next problem. When we stood down the fleet for four months this summer leading up to the last flight, it was because of a tiny crack found in the flow liner that’s routing liquid hydrogen to the main engines. The condition wasn’t even understood until it was discovered. It wasn’t anticipated as something that was in a state of deterioration.

Hopefully, most of the things that are moving in the direction of obsolescence are things that we do understand and that we continue to inspect from flight to flight. Even then, you can’t always anticipate how much longer something is going to last. It’s like driving a car that’s ten years old. You know that a lot of the systems require attention but you can’t really fully predict when the brakes will go or when you’ll have transmission problems. You continue to have it serviced, and you inspect things, and you try to keep things running as long as possible. You do preventive maintenance. In one sense of the word, most of the 2020 upgrade strategy is really a preventive maintenance strategy on the fleet to try to be sure that we make the changes and replace the obsolete systems before they become problems and not after they become problems.

We want to improve that mean time between failures, but at the same time put equal emphasis on looking at these obsolescence issues and trying to make sure that the assets don’t deteriorate while we’re waiting to fly. Keeping those two things in balance is really where the artistry comes in the program.

It’s almost impossible at any one point in time in the shuttle program to predict the environment five, ten, 15, or 20 years out. If anyone declared today, ‘here are the specific 175 things we need to do to keep the shuttle flying until 2020,’ that would not be in earnest. The better strategy is to continue to evaluate the program year by year. Always continue to address those things that are the most urgent issues, and understand that those things will change over time. And some things that you thought were badly deteriorating might end up not being as big a problem as you thought, other things might surprise you, and some other things you may have perfectly predicted. The point is to always keep looking.

Lee Norbraten can be reached at g.l.norbraten@nasa.gov.