The Kaboom Case

Starting to work in Mission Control at JSC just before the first shuttle flight was a dream come true.  I was surrounded by old Apollo flight controllers who filled my days with space stories from the moon landings and before.  Those guys had seen a lot of action:  Apollo 13, Gemini 8, Skylab 1, and many more near disasters that had turned out all right due to hard work, solid preparation, ingenuity and not a little good luck.  And they also lived through “the fire” as it was universally known — Apollo 1; where all the preparation, ingenuity, and luck did not help.  My early days were a continuous seminar in the trials and tribulations of early space history taught by those who had earned their PhD in the school of hard knocks.

But the torch was being passed to a new generation of flight controllers and by the second shuttle flight there were a lot of us “new kids” training for the coveted front room positions in Mission Control.  I got to side saddle (that was the term) with the legendary Gary Coen who played a vital role in saving Apollo 13.  For shuttle, Gary was the senior Propulsion Officer, responsible for the hypergolic rockets that controlled the orbit and attitude of the shuttle.  My buddy Ron Dittemore, with a year’s seniority on me,  had already achieved orbit certification and was working on the even more difficult Ascent and Entry phase certifications as a front room Prop officer.  Following us was the new guy in the Prop section, a fellow that had transferred down from the Lewis Research Center:  Bill Gerstenmaier.  Seems like we would be working together for a long time to come.

Sitting with Gary during all the simulations and training was really outstanding.  He knew the systems, flight rules,  and procedures forwards and backwards.  Even more importantly, he had the judgment that comes with long experience to know what to do in a crisis.  And the simulations are nothing more than one crisis after another coming so fast that they pile up on top of each other.

The down side was that all the old Apollo guys were smoking fiends.  In those days nobody had heard of a ban on smoking in the workplace.  Gary was a chainsmoker of unfiltered cigarettes, so I got plenty of second hand smoke sitting right next to him.  On my other side, the GNC officer was Harry Clancy.  Harry was a pipe guy.  I’m surprised that I haven’t yet died of emphysema; as it was there were some days I thought I might asphyxiate. 

But we learned what it meant to be flight controllers from the pioneers.

One basic lessons was known as “loop discipline.”  Every position had a communications keyset which allowed the flight controller to communicate with different people.  The communications circuits were called “loops” and each one had its specific use and name.  The Propulsion team, front and back room, talked about our special problems on the “Prop loop.”  Everybody monitored the “Air to Ground loop” where the crew talked with the CAPCOM on the radio.  And everybody _ I mean EVERYBODY – listened to the “Flight Director loop” where all the important topics were discussed and decisions announced.  Drilled into your head was the requirement to “talk on the loop”  where everyone who had an interest in the topic could hear you — not only the members of your own discipline but the engineers over in the Mission Evaluation Room, the prelaunch team down at KSC, and your boss over in the office on the other side of the duck ponds at JSC.  Everybody who was anybody at NASA from the Administrator on down, had a box in their office to the Flight Director loop.  And the loops were recorded for posterity.  It was very important to pick your words carefully when talking on the loop.  Telling jokes or otherwise fooling around was not allowed.  But the worst sin was to “talk over the airwaves”, not on the loop, but where only the people physically around you could hear a conversation.  We were trained so to talk on the loop even if it was to the guy three feet away next to you.  The conversation was to be done “on the loop” so that others could follow it as well.  Loop discipline was one of the minor lessons, and there were many more difficult lessons in the school of flight controller training.

After working in the Staff Support Room (aka “the back room”) on the first shuttle flight, it was really a heady experience to be in the Flight Control Room for the second shuttle flight.  But I was just an “OJT” guy, Gary was at my side making sure I did all the right things at the right time.  On my very first shift, we had a minor problem:  the electrical feedback on a motor valve failed which cased the electric motor to stall.  I got to tell the CAPCOM to have the crew move a switch in the cockpit which kept the valve from overheating.  Whew, the first real crisis of my career.  Gary helped me with that problem from the first recognition, through the analysis, to the words to use on the Flight Loop.  Problem solved.  I started to relax.

Then Billy Moon, the EGIL started an excited conversation with the Flight Director that I didn’t quite follow.  The EGILs were responsible for the electrical systems onboard the shuttle.  This included the fuel cells which generated electricity.  The fuel cells are a marvel of modern technology; about the size and shape of a large trash can, they converted cryogenic hydrogen and cryogenic oxygen into drinking water and electricity.  They could loaf along at 3 or 4 kilowatts — about what my house uses when the kids leave the lights on and the airconditioner running — or up to around 18 kW in an emergency situation for limited periods of time.  And they only cost about $15 million apiece.  The shuttle runs on electricity; there are no batteries.  If the three fuel cells are turned off, the shuttle is dead; the computers don’t run, the hydraulics don’t run, the rocket engines don’t fire, nothing works.  So its kinda important to keep them healthy.

Billy Moon was telling the Flight Director that symptoms indicated one of the fuel cells was “breaking down”.  The catalyst material which separates the hydrogen and oxygen was developing holes.  Billy wanted to shut the fuel cell down and close the valves to the hydrogen and oxygen supply lines.  This was serious.  The Flight Rules required early termination of the mission if a fuel cell failed.  Flight had to be sure that EGIL knew what he was doing before taking a drastic step like that.  After all, this was only the second day of a planned five day mission.  This problem was clearly a lot more important than my little valve feedback circuit failure which had been resolved with no mission impact.

The discussion on the Flight loop got more and more heated.  EGIL wanted action and Flight was waffling.  Billy Moon stood up and turned from his console to face Flight, only about eight feet away.  I had a front row seat since the Prop Console was almost directly between EGIL and Flight.  Bill’s tone of voice and volume were increasing.  Finally, Bill Moon did not key his microphone; he broke one of the fundamental Flight Controller Rules:  he said loudly and off the loop “THIS IS THE KABOOM CASE, FLIGHT!”  If the hydrogen and the oxygen mix improperly, the results would not be good.  The Flight Director got the point.

The Flight Director had also been standing up and at this point, he sat down and said:  “CAPCOM, tell the crew to shut down fuel cell 1 and close the reactant valves.”  While CAPCOM was repeating this message over the Air to Ground loop to the crew, we heard Flight dialing the phone and talking with senior management:  “You better get over here.”

So STS-2 became the first shuttle flight to be shortened.  Not many flights have been.  There have been more dramatic times in mission control, however.  This was just my first.

My drug of choice is the caffeine in the coffee, not the nicotine that the Apollo guys were all addicted to.  But some days in the MCC, you don’t need caffeine to get your heart rate going.


Management Training

I believe in continuous training for your job.  It is not enough to have earned a degree at one point in your life.  If you are to be good at your work, you need to have continuing education of one form or another. 

One of my very best short courses ever was a week-long training session for new supervisors that NASA held right at our center.  It was taught by a retired NASA manager and he was spot-on concerning what we needed to know, how we needed to make the transition from worker to supervisor, and how to motivate, encourage, and if necessary discipline our folks.  It was a great class, I soaked it all up, and I still fall back on that training from time to time.

My training records fill a bulging folder in my desk drawer and a similarly bulging computer folder in my office PC.  Some times this training has been practical (How to write User Friendly Software; How to deal with Difficult Co-Workers).  Sometimes it has been mandated (Government Ethics Training; IT Security).  Very few cases have been less than useful.  But even those classes were an opportunity to network, and to hear from folks in similar circumstances discuss their problems — which almost always turned out to be similar to my problems.

As a supervisor, I encouraged all my people to get all the training that they could.  This was never what you call excessive; at most it amounted to about two weeks a year, and for most people in most jobs it was really a lot less, sometimes just a few computer based refresher courses amounting to a few hours in a year.

But this is a story about an executive training course that I did not appreciate much at the time, but which had implications that I have pondered extensively.

To use the vernacular; most of my work is Left Brain work.  Engineering is probably the extreme example of Left Brain activity.  Logical, analytical, rational, and objective.  Very Left Brain.  However, when you work with people, you have to use the other hemisphere:  creativity, sensitivity, subjective thinking predominate.  How is a poor engineer to make the transition to supervisor?

A couple of years ago my very Right Brain human resources person came to my office and informed me that I was being a bad example to my troops.  What?!?  While I was encouraging — even requiring — my people to sign up for training classes right and left, over two years had passed since I myself had gone to any training class.  Everybody gets stale, she said, everybody needs a refresher.  And I knew she was right.  So I told her to bring me a list of recommended class options and I’d pick one.

And that is what we did. 

One class was very highly recommended by several NASA senior leaders that I knew.  It was taught by a distinguished professor from one of those big name eastern business schools.  Author of several books, well known on the lecture circuit, the professor was somebody you would recognize if you know anything about management theory and practice.  And not only that, the course — a whole week — was being held at a beautiful lodge in the mountains.  They offered a significant price discount for US government employees — it was within our training budget — so I signed up.

We got two thick books to read before class started.  They were chock full of good management and supervision techniques:  organization, motivation, delegation, etc., etc.  All good stuff.  Good to review even if you had heard it all before.

The class was held out of doors in a big tent in a mountain meadow in front of the lodge.  This made it hard to concentrate on the speaker.  Class members were from around the world; North and South America, Europe, Africa, Australia, Asia; and they represented many large industries and a number of non-profit organizations.  It was a truly eclectic group.  Listening to each participant describe the challenges that they and their organization faced was very revealing — their problems were much like mine.  Much creative discussion on how to solve those problems was extraordinarily useful.  All in all, a truly good course and I would recommend it to your senior leaders even today.  If you could put half of those good management principles into practice it would truly revolutionize your workplace for the better.

But there was this one extra thing.  And it is the part that will forever be first in my memory of this class.

Remember that I’m a Left Brain engineer trying to be a supervisor.  As it turns out, most of the executives in this class were pretty left brain, too.  One guy I kept getting teamed up with was an extreme Left-Brainer, an engineering supervisor from a German engineering firm.  Does it get more Left Brain than that?

The extra thing was a new part of the seminar; it came in the form of a modern dance teacher.  Seems that the professor had discovered that all of the executives taking the course over the years were pretty much left brain.  He felt we needed some right brain stimulation.  So he hired a lady who ran a modern dance studio in a big eastern city to come and help stimulate our . . . less developed hemisphere.

She did three half-hour sessions over the course of about four days.  The first two session seemed sort of silly at the time; teaching elderly (ok, at least 40-something) managers some modern dance movements.  Now remember, this is taking place in a mountain meadow.  Do you get the picture?  I hope nobody had a camera!  But, hey, it was part of the course, so we did it.  Amazing what you can get people to do when you drag them off away from anybody they know and put them in a group of strangers.

The very last session on the very last day — right before we broke up to drive to the airport to go to our respective homes — was under the dance lady’s control.  Her instructions were simple:  pair up (I got the German engineer again), don’t talk, pick a spot in the meadow.  Chose one of the pair to go first; that person would make a modern dance move and stop, then the second person would make a modern dance move in response and stop, then the first person would make a move in response, and so on until time was up.

I can’t believe I’m telling you this story. 

Its all true, and there is no photographic evidence.  And if you ask me about it in person, I’ll deny it. 

It looked just about like what you can imagine it looked like.  A bunch of older executives in polo shirts and jeans doing modern dance steps silently in a mountain meadow. 

So my very Prussian partner came close by me and muttered quietly so the instructor could not hear us:  “Vat are ve doingk?”  That is a very profound question.  I almost doubled over in laughter.  But that looks like a modern dance move.  Probably the best response I had all day.

So why would I tell you this story?  The embarrassment alone has kept me silent on this subject for more than two years.  The reason is the same reason the professor had.  If you are going to manage people — lead them, really — you must be creative; you must be sensitive, you must be subjective, and you must exercise the Right side of your brain.

Have you ever met a teacher who knew a subject thoroughly and completely but couldn’t teach it?  I think we all have.  Have you ever had a supervisor who was an expert in your job, who could do it better than you even if he were blindfolded and had one hand tied behind his back — but was a lousy supervisor, couldn’t motivate a kid to eat a cookie, couldn’t delegate putting a postage stamp on an envelope, couldn’t organize people to walk to the cafeteria for lunch?  I bet you have.  I know I sure have.

So just like you have to go to the gym to improve your tennis serve, I guess you have to dance in the meadow to improve your people skills.

I can’t believe I wrote this.



Blogging: A new adventure!


I really appreciate the start to the conversation.  In fact, I am overwhelmed by it.  Pardon my ignorance of the technique, I hope to learn fast.

A couple of logistical notes:  all NASA Blogs, if comments are allowed, are moderated.  That means that if you write a comment, it comes to me and I have to approve it for posting.  So don’t send multiple copies of the same comment, please.  Also, posting comments is only one of my duties and sometimes (like this morning) it may be a couple of hours before I get back to this to read and approve posts.  Finally, there are a couple of rules, down at the bottom.  So far I have only not posted one comment because it derogated an individual by name.  I may need to keep folks on topic in the future.  I would really like NOT to play referee and post all the comments, but that is not the way the system works, so I’ll try to be as loose on the rules as I can be.

GREAT COMMENTS.  Wow.  Over the next several weeks I intend to explore many of the topics raised in these first few posts in some detail.  Bear with me if I don’t get to your favorite comment right away.

This is going to be fun and educational.  I am so impressed with this first day.  What a hoot.


Eating in the NASA Cafeteria

In my peripatetic ways, I have become a connoisseur of the cafeterias at almost all the NASA installations.  In some places there are great restaurants just outside the gates, but I’m cheap and the NASA cafeteria is almost always good basic food at a reasonable price. 

My absolute favorite NASA cafeteria is, or rather was, the White Sands Test Facility cafeteria.  Since I grew up in New Mexico, I really like the regional food and the WSTF cafeteria had the best.  I say ‘had’ because the operation there has changed.  For a long period they had nobody to run the cafeteria and now they have a new operator that I need to test.  I’ll give you an update after my next visit there.

The cafeteria at NASA HQ is one of the best buffets that I know of.  Very eclectic from oriental food to corned beef and cabbage.  Huge salad bar.  Also in the same building they have a small short order grill with very interesting sandwich wraps.

At MSFC they have down home cooking as you might expect in Alabama.  If you like beans and cornbread, greens, or other southern comfort food, go there.  Although, surprisingly, the GRC cafeteria runs a close race for comfort food. They have the best meatloaf of all the NASA cafeterias (and some of the other places make awful meatloaf. I think I’ve tried them all).

The best breakfast award goes to the JPL cafeteria.  They have short order cooks at the grill that make omelettes to order with a wide variety of fresh California produce to spice them up. 

I got the best seafood of any NASA cafeteria at Langley.  Must be because they can get it fresh in the local area.

Dryden serves really good soup — a plus for a place in the desert!

Ames gets the runner up award for the best view:  you can look out the windows at the huge wind tunnels and think about the glory days of aviation research there.  Nowadays Ames is all about computers but somehow the view of a room full of electronics just doesn’t compare with those magnificent wind tunnels.

The best view award goes to the KSC cafeteria at Launch Complex 39.  There are a lot of cafeterias at KSC and they serve great food, but for the view go eat breakfast at LC-39.  The big picture windows face east and you can watch the sun rise over the launch pads.  Wow.  Not to be missed.

And JSC?  Well, it used to be better.  There was a change in management and they went from good basic home food to foo-foo food with fancy names and servers that wear tall chefs hats (always a bad sign) — and the prices went way up.  Hmmm.

But there is the real story apart from the food and prices.  Going to the cafeteria is a place to meet people.  Where else can you go to rub elbows with astronauts, flight directors, program managers, and real rocket scientists?  One table that I pass by almost every day has a rolling seminar in aircraft flight control.  When I was a young flight controller, I was able to sit at the table with the senior Flight Directors and learn the business first hand. 

Now I go to the cafeteria to escape from the office.  If I brown bag it to the office, inevitably the phone rings with some urgent problem and lunch is over before it begins.  Going to the cafeteria gives a respite in the middle of the day. 

But the funniest thing is how much “work” gets done in the cafeteria over lunch.  People that are not on my calendar just run into me in the cafeteria and vice versa.  We can have a 3 minute conversation while waiting in the checkout line and nip a critical problem in the bud.  There are young folks who join at my table and we have conversations about avoiding the mistakes I’ve made in my career and other important topics.  Personnel issues can be resolved over chicken and potatoes.  Technical issues get bubbled up over soup and salads to me long before the official communications chain processes the information. 

In short, going to the NASA cafeteria for lunch is often the best part of my day. 

Probably the most interesting thing is that most folks will tell you things that you need to know over pie and coffee that they would never do in a conference room.  Dissenting opinions can be thrashed out, alternatives explored, possibilities mulled over. 

So, if you see me in your NASA cafeteria, stop by.  Say hello and let me know what you are up to.  Some people feel its an imposition, but its not.  Actually, that is the best part of the day. 

The Radical Wrights

Yesterday was the 105th anniversary of the Wright brother’s first flight and I thought all evening about their accomplishment.  I dug out my dog-eared copy of Tom Crouch’s excellent biography “The Bishop’s Boys” and read a few paragraphs.  Whenever I can, I visit the Smithsonian’s Air & Space Museum on the national mall to see the second floor room where the “Flyer” is enshrined.

The Wright brothers are held to be the penultimate real-life historical proof that Horatio Alger was right; hard work, ingenuity, and courage can lead to success, fame, and fortune. 

Or maybe not. 

There were a huge number of people working on the problem of heavier than air flight in the early 20th century.  There are competing claims from supporters of many of those early inventers that some of them “beat” the Wright brothers to achieve the first flight.  None of these claims hold up under scrutiny however.  If the Wright brothers had not existed, or had been happy to be merely bicycle makers, someone else would have flow — the only question is how much later.  Based on my study, it probably would have been quite a lot later.  Literally everybody else was pursuing the dead end of making a perfectly stable aircraft. Today we know that is impossible.  The Wright brothers had a different idea: to build a purposely unstable aircraft with adequate controls to allow a human to manage that instability.  Of course that is not all, but imagine the consequences if the Wright brothers had not pursued their inherently unstable aircraft idea.  What would have happened during WWI with no aircraft?  No Red Baron, no Eddie Rickenbaker, no Hermann Goering, no Billy Mitchell, at least not as we know them today.  Only  tethered balloons for artillery spotters — not much different than the American Civil War — and the Zeppelins.  If the invention of the airplane had been delayed by 20 years, would Charles Lindberg Ameila Earhart be remembered today?  And  would the Japanese Imperial Navy have built aircraft carriers by 1941?  History would have been different in ways that we cannot even imagine.

Yet the Wright brothers succeeded because of a confluence of time, capabilities, and events.  If Octave Chanute had not published his work, if internal combustion engines had not sufficiently developed to generate 12 horsepower from an engine weighing less than 150 pounds,  if Bishop Milton Wright had not bought a 50 cent Penaud helicopter toy to bring home to his sons to play with, if the brothers had given up after the failure of their 1901 kite when Wilbur wrote “Not within a thousand years would man ever fly”, if, if, if, if any of a thousand events had unfolded differently, what would have happened?

The Wright brothers invention succeeded because they were the right people with the right knowledge at the right time in history — and because they worked really hard at making their dream a success.

In retrospect, history looks deterministic.  Everything happened as it was supposed to.  Events unfolded according to some cosmic plan.  In reality, we make our own history.  Decisions every day determine what the future will be.    Edmund Burke’s words ought to ring in our ears:  “All that is necessary for the triumph of evil is that good men do nothing.”

Recently there have been a spate of commentators that have decried our national plan to explore space as unrealistic.  That may be a topic for serious debate.  But one argument that they have advanced is nonsense.  The argument that Apollo was successful and could have only happened because of the historical influences of the times, and since the times and world events are different, the successor to Apollo cannot happen today.

Certainly the times and events influenced Apollo and the moon landings and caused certain decisions to be made in certain ways; events may have moved faster or slower had events been different.  All that I grant you.  But to leap from the historical record to the conclusion that no large national (or international!) exploration of space can take place today because the times are different is unwarranted.

This is a time when there is a confluence of capabilities and events.  All that is required is that innovative people work really hard to achieve their dreams. 

And in that way, these times are no different from 1969 or 1903. 






Factors of Safety

     Old joke:  “You see the glass as half empty, I see the glass as half full, but an engineer sees the same glass and says ‘it is overdesigned for the amount of fluid it holds.’”


     When an engineer starts out to build something, one of the first questions to be answered is how much load must it carry in normal service?  The next question is similar:  hom much load must it carry at maximum?  An engineer can study those questions deeply or very superficially, but having a credible answer is a vital step in at the start of a design process. 


     Here is an example.  If you design and build a step ladder which just barely holds your weight without breaking, what will happens after the holidays when your weight may be somewhat more than it was before you eat Aunt Martha’s Christmas dinner?  You really don’t want to throw out your stepladder in January and build a new one do you?  Obviously you would should build a stepladder that can hold just a little bit more.  Don’t forget what might happen if you loan your stepladder to your coach-potato neighbor who weighs a lot more than you do?  Can you say lawsuit?


     So how do you determine what your stepladder should hold?  Do you find out who is the heaviest person in the world and make sure it will hold that person?  Probably not.  Better, pick a reasonable number that covers, say, 95% of all folks, design the ladder to that limit and put a safety sticker on the side listing the weight limit.  Yep, that is how most things are constructed.


     But that is not all.  Once you determine normal or even the maximum load it is a wise and good practice to include a “factor of safety”.  That means that you build your stepladder stronger than it needs to be.  This helps with the idiots that don’t read the safety sticker; it also helps protect for some wear and tear, and it also can protect if the actual construction of your stepladder falls somewhat short of what you intended.  So you might build your stepladder with a FS of 2.  That would cover 95% of all folks with plenty of margin for foolish people that try to accompany their friend climbing the ladder; or when your ladder has been in service for 25 years (like mine), or when your carpenter buddy builds the stepladder with 1/4” screws rather than ½” screws like you told him to.


     Factors of safety are not pre-ordained.  They have been developed over the years through experience and unfortunately through failures.  Some factors of safety are codified in law, some are determined by professional societies and their publications, and some are simply by guess and by golly.  Engineering is not always as precise as laypeople think.


     It’s a dry passage but I’d like to quote from one of my old college textbooks on this subject (Fundamentals of Mechanical Design, 3rd Edition, Dr. Richard M. Phelan, McGraw-Hill, NY, 1970, pp 145-7):


“ . . . the choice of an appropriate factor of safety is one of the most important decisions the designer must make.  Since the penalty for choosing too small a factor of safety is obvious, the tendency is to make sure that the design is safe by using an arbitrarily large value and overdesigning the part.  (Using an extra-large factor of safety to avoid more exacting calculations or developmental testing might well be considered a case of “underdesigning” rather than “overdesigning.”)   In many instances, where only one or very few parts are to be made, overdesigning may well prove to be the most economical as well as the safest solution.  For large-scale production, however, the increased material and manufacturing costs associated with overdesigned parts result in a favorable competitive position for the manufacturer who can design and build machines that are sufficiently strong but not too strong.

            As will be evident, the cost involved in the design, research, and development necessary to give the lightest possible machine will be too great in most situations to justify the selection of a low factor of safety.  An exception is in the aerospace industry, where the necessity for the lightest possible construction justifies the extra expense.”

            “Some general considerations in choosing a factor of safety are  . . . the extent to which human life and property may be endangered by the failure of the machine . . . the reliability required of the machine . . . the price class of the machine.”


            Standards for factors of safety are all over the place.  Most famously, the standard factor of safety for the cables in elevators is 11.  So you could, if space allowed, pack eleven times as many people into an elevator as the placard says and possibly survive the ride.  For many applications, 4 is considered to be a good number.  In the shuttle program the standard factor of safety for all the ground equipment and tools is 4.  


            When I was the Program Manager for the Space Shuttle, there were a number of times when a new engineering study would show that some tool either could be exposed to a higher maximum load than was previously thought, or that the original calculations were off by a small factor, or for some reason the tool could not meet the FS of 4.  In those circumstances, the program manager – with the concurrence of the safety officers – could allow the use of the tool temporarily – with special restrictions – until a new tool could be designed and built.  These “waivers” were always considered to be temporary and associated with special safety precautions so that work could go forward until the standard could once again be met with a new tool.


            In the aircraft industry, a factor of safety standard is 1.5.  Think about that when you get on a commercial airliner some time.  The slim factor of safety represents the importance of weight in aviation.  It also means that much more time, engineering analysis, and testing has gone into the determination of maximum load and the properties of the parts on the plane.


            For some reason, lost in time, the standard FS for human space flight is 1.4, just slightly less than that for aviation.  That extra 0.1 on the FS costs a huge amount of engineering work, but pays dividends in weight savings.  This FS is codified in the NASA Human Ratings Requirements for Space Systems, NPR 8705.2.  Well, actually, that requirements document only references the detailed engineering design requirements where the 1.4 FS lives. 


            Expendable launch vehicles are generally built to even lower factors of safety:  1.25 being commonplace and 1.1 also used at times.  These lower factors of safety are a recognition of the additional risk that is allowed for cargo but not humans and the extreme importance of light weight.


            It is common for people to talk about human rating  expendable launch vehicles with a poor understanding of what that means.  Among other things, it means that the structure carrying the vast loads which rockets endure would have to be significantly redesigned to be stronger than it currently is.  In many cases, this is tantamount to starting over in the design of the vehicle.


            So to the hoary old punch line:  Would you want to put your life on the top of two million parts, each designed and manufactured by the lowest bidder?

Riding the Phugoid

Phugoid, for the non-aviators, refers to a long term longitudinal oscillation in the flight path of a flying machine. More precisely it is the exchange of altitude for airspeed with constant angle of attack.  Whew, I had to look it up in my old textbooks to get it right.  One of the on-line helps says that the engineer that invented the term “phugoid” took it from the Latin but got the translation wrong.  That figures.  Most engineers don’t know that the ancient Romans studied aircraft control.

We studied phugoidal motion a lot when analyzing shuttle re-entry.  It is most pronounced on an abort entry where the shuttle’s forward motion doesn’t create enough lift until the vehicle falls into the denser part of the atmosphere and then there is too much lift so it bounces upward to where there is not enough lift and then it falls down to where the dense air creates too much lift and causes it to climb up to where there isn’t as much air where . . . .   Well, you get the picture.  Not exactly a roller coaster, but somewhat disconcerting. 

If you are designing a re-entry vehicle with any lift at all, studying the aerodynamics so that lift and drag can be applied in the proper way at the proper time is crucial.  During the early portions of the shuttle entry, phugoids are to be avoided since they can lead to high heating which is . . . not a good thing.  Actually, the shuttle flies something called equilibrium glide for most of the entry phase.  This term refers to a state where the lift generated is exactly equal to the orbital mechanics forces and gravity.  In that state, the shuttle flies at a relatively constant altitude for a fairly long period of time, all the while bleeding off the incredible kinetic energy required to orbit the earth.

This is a good time of year to talk about how to fly through life:  are you riding the phugoid or are you in equilibrium glide?  I know where I am.  Yesterday was a real emotional high when the snow dusted my home and the shuttle flew over on its way back to Florida; then there were the stressful lows — like when I tried to untangle the Christmas tree lights . . . .

My job has continued to move away from the purely technical to a place where people skills are increasingly important.  One of my “other duties as assigned” is to represent the agency from time to time with the folks in the media.   The prospect of having this kind of interaction causes a lot of people in NASA to refuse promotions . . . engineering being generally considered to be more important than talking to the public or dealing with the media.

One of the new phenomenon in media is the blossoming of the blogosphere — exactly where we are today.  The neat thing about the internet and blogs is that anyone can spread a lot of knowledge and insight to many folks in a very rapid and inexpensive way.  The sad thing about the internet and blogs is that there is so much misinformation and personal opinion passing for fact out there.  In the last few months I have become much more involved in the new media. 

Some of it makes me miss the old media.  It is sad to see reputable old style news organizations in financial trouble laying off experienced and professional journalists, for example.  And being over the age of . . .. (ahem) 30 . . . I still prefer the feel of a real newspaper in my hands toreading streaming news off a computer screen.  But, OK, things change and we all have to learn to use the new tools.

My biggest problem with blogs and the internet — and I’m far from being the first to observe this — is the continual flame wars that go on.  Seems like everything posted attracts someone with a contrary view — that’s OK, in fact, that’s a good thing — but too frequently a contrary view stated in the most vituperative and inflammatory way.   A good exchange of views can be enlightening.  A rude exchange of person insults is just depressing.  Sigh.  Makes me want to repeat the old SNL line:  “can’t we just all get along?”  

To participate in this new world of internet interaction, you have to develop a thick skin.  Recognize the valuable components of a enthusiastic exchange of ideas and ignore the ad hominem and personal attacks and general lack of civility that seems to be rampant on the web these days. 

Its hard to avoid riding the phugoid between the highs that happen because of a great and productive exchange of ideas and information, and the lows that come with depressing and inappropriate personal attacks.

So my aerospace analogy, at least for the holiday season, is to avoid the phugoid and try to stay on the equilibrium glide as long as you have the energy. 

Hey, that probably applies to family get togethers for the holidays, too!  Don’t sweat the small stuff.



Real Engineers

I earned an undergraduate degree in engineering from a prestigious and notoriously competitive university.  After that I went on to do engineering research and complete a graduate degree in engineering from another major university with a reputation for excellence in engineering; along the way I wrote and defended a thesis and authored several papers which were published in professional engineering journals.

When I came to work for NASA, I was fortunate to get a job in the operations area:  mission control.  A thorough understanding of engineering principles and practices was mandatory for my job.

So I was floored just a few months later when I first heard it:  “you are not a real engineer”. I was just “an ops guy”.

In the NASA pantheon of heros, the highest accolade any employee can be granted is that they are a “real engineer”.  Not even astronauts rate higher.  The heart of the organization worships at the altar of engineering:  accomplishment, precision, efficiency.  What does it take to be a “real engineer”?

In the ethos and mythology of NASA, a real engineer is one who has several characteristics. 

First, they must have a superb grasp of the physics of their subject, a complete an total knowledge of the details of their specialty.  This almost goes without saying.  No nincompoops allowed; no fuzzy thinkers who are vague on the basic concepts.  A “real engineer” knows his arcane stuff forwards and backwards and from the middle out towards both ends and can recite it in his sleep.  “Let me tell you about the inviscid terms of the Navier-Stokes equation . . . ” a real engineer might say. 

Second, a “real engineer” must create something, taking it from original concept to working, functioning reality.  No view graph engineers ever get the title “real engineer”.  If it doesn’t fly or move or compute or generate power, or do some concrete something, you haven’t built something real and without building something real, you are never going to be a “real engineer.”  And the thing has to work; if it flops, then you are merely a tinkerer, not a “real engineer”.

Thirdly, “real engineers” are mild mannered; never needing to raise their voices, not loquacious, not given to long and convoluted discussions.  No, real engineers are soft spoken and terse; they are recognized by their brevity and the ability to concisely summarize a technical point in a way that admits to no further discussion.

NASA is full of “real engineers”. 

So us poor ops guys, who never had a drafting table, who never went into the machine shop to hand blueprints to a tech, who never got to blow up anything on the test stand; we failed miserably on the standard of being a “real engineer”.  We merely operated the stuff that the real engineers built.

Along the same lines . . . .

I have been privileged to watch the advanced concept boys at work.  They are marvelous.  Through the study of all past and current rockets they have developed a number of “empirical models” — rules of thumb if you will — that can help in the initial ideas about building spacecraft.  If you want to lift a certain number of metric tonnes to low earth orbit, given a particular rocket type (solid, liquid, hypergolic, cryogenic, hydrogen, kerosene, etc.) the advanced concept boys can give you a variety of options based on known ratios of structure weight to propellant weight, burn out mass, etc.  And they can give you a rough guess at the cost.  And they can evaluate multiple options and compare them one to another in very short order. 

In the summer of 2002, I got to participate in an exercise for about two months of possible design options of manned missions to Mars.  The advanced concept boys generated a new heavy lift launch vehicle about every other day and could compare all the designs against each other on a number of figures of merit.  Its heady work to invent new Saturn V class rockets in the computer lab.  Taller, shorter, with solid boosters or not, using kerosene or hydrogen or whatever.  One engine, two engines, five engines, twenty engines; two stages, three stages, four.  Whew.  At the end of two months the team had a great list of options and the pros and cons for every launcher.  And I found out that the advanced concept boys have been studying this problem for 40 years!  They have evaluated hundreds, thousands of various options.  Then they refined their studies, re-examined the basis for their methodologies and started in again. 

But you know what?  Advanced concept folks, even with all their knowledge of engineering principles, they are not “real engineers”. 

Real engineering starts after the viewgraphs stop.  Real engineers take the concept — boiled down as it may have been from hundreds of starting options — they take the concept and start making it real.  When you have to really design and build the rocket in its detailed glory; when you have to take the subsystems out to the test stand and start them up and see if they hang together; when you go from weight estimates to actual plans and find out what the gizmo really does weigh — that is real engineering. 

That is where you find out if the concept really will work or not; what the real problems are and how to solve them. 

When the rocket really flies you have proof positive of the real stuff of engineering — and whether you have it or not.

That is what real engineering is all about.


Black Zones – Part 4

I keep meandering around on this topic and if you get confused, I’m sorry about the writing style. 

Just to review the story:  Mercury, Apollo, Soyuz, Shien-Zou, and the Orion all use launch escape towers for crew safety.  Gemini used ejection seats.  The shuttle famously does not have a crew launch safety system although it had ejection seats for early flights for problems during entry and now has a bail-out pole and parachutes for problems resulting in not being able to reach a runway.

I will discuss re-entry safety in a later post; I know a lot of folks are interested in that, too.

Of course a launch escape tower does not provide complete safety.  For example, off the pad or very early in the launch of a Saturn rocket, the launch escape system would get the astronauts away from the rocket, but the Apollo capsule would land on the beach.  Those capsules were not rated for anything other than a water landing so crew injury potential was high.  Similarly, there was a tremendous concern about running into the launch umbilical tower shortly after liftoff.  In some of those scenarios, the launch tower might not be effective in getting the capsule away. 

At a certain point in the launch sequence the escape tower is jettisoned.  Survival here depends on several factors.  First of all, that the launch vehicle failure still results in the spacecraft being pointed in the direction of travel.  As we saw in the Soyuz 18A story, the third stage firing with the second stage attached resulted in large attitude excursions and a subsequent flight direction that resulted in far higher loads than a controlled abort at that point should have.  A real spin up of a launch vehicle would probably overwhelm any of the launch escape systems ever designed.

Second, after launch escape tower jettison, for multi-engine rockets, the capability must exist for all the running engines to be shut down.  So if you have an engine out case and everything is still holding together but you cannot shut the remaining engines down perhaps due to an electrical fault, generally the capsule cannot get away.  There must be a rocket engine to separate the capsule from the failed launch vehicle, but many times these are relatively small.  For example, the Gemini Orbit Adjust Maneuvering System (OAMS) provided such slow acceleration that even with one engine out on the Titan II second stage, the capsule could not get away.  Mercury used very small separation rockets with the option to fire the solid retro rocket package, but these could not overcome the acceleration of even the Atlas sustainer engine burning alone.  So attitude control upsets which in themselves can be caused by electrical faults, coupled with the inability to shut down the upper stage engine(s) – again could be the same electrical fault – could lead to very bad outcomes.  On the other hand, Apollo with its huge Service Propulsion System (SPS) engine — designed to launch the CSM off the moon when direct flights were envisioned — had enough oomph to get the Apollo capsule out of almost any circumstance.

All that being said, a capsule with moderate rocket engines and a launch escape tower on top of a long slender rocket is much safer than any tandem design like the space shuttle. 

The space shuttle is safe if any single SSME prematurely shuts down and both of the other engines keep running AND the attitude control system is functional AND there was no debris generated in the engine shutdown that affects the orbiter’s heat shield.  That is quite a bit of difference.  One of the reasons for the difference is that the cargo – up to 30 tons – goes everywhere the crew goes. 

In the current design for Ares/Orion, the cargo goes up on a separate rocket.  This allows for improved crew safety, but at some operational cost — the crew capsule must rendezvous with the cargo on orbit before any work can commence.

Two other quick points.  One person wrote a comment that the SSMEs are so reliable that we could quit worrying about one shutting down in flight.  While the engine designers and builders are justifiably proud of the extraordinary reliability of the SSMEs, nobody that has studied them in detail rests easily.  Too many parts are rotating at too high speeds, combustion is taking place at too high temperature and pressure for anybody to not keep their fingers crossed for the entire duration of engine firing. 

Second, a number of folks have wondered why we did not put a crew escape system on the shuttle.  Various systems have been proposed, a number have been studied to a high level, and a couple of designs have been looked at in detail.  Ejection seats have been rejected for reasons I mentioned earlier.  Putting the crew in a capsule in the payload bay that could be separated has received a detailed examination.  Some of the limitations associated with this proposal can be easily imagined.  Another idea was to separate the crew module with large solid rockets away from the rest of the shuttle in a launch emergency.  And there have been others.  The problem with designing in these solutions to an already flying vehicle is that none of them are as reliable as we would like; all of them are very heavy and drive the center of gravity out of an acceptable region, and they all cost an incredible amount of money to retrofit in.  So, none of them have been implemented. 

Any winged orbital vehicle under consideration needs to have a serious capability for crew escape designed in from the beginning.  As to vehicles which are carried aloft by other aircraft for their launch; crew (and passenger) safety in that environment has its own challenges and is going to be neither a simple nor cheap capability to design into that type of vehicle.

I think this rounds out my discussion on Black Zones for launch and how they affect spacecraft design.  All you guys out there working to design a spacecraft, keep these points in mind.

Black Zones – time out for Q&A

I have really appreciated all the questions and comments to my mini-series of blogs on Black Zones.  I am not done with the series yet, but I thought it was time to address some of the questions and comments.

First of all, not to be too grumpy, but I have to set a couple of new blog comment rules.  I have received a number of comments that are frankly undecipherable.  They are either written by non-English speakers or some type of computer program that strings together English words at random.  So my rule is if the comment is unintelligible and/or the grammar and spelling are so bad that most readers could not understand them — I won’t post them.  Clear enough?  My grammar and spelling aren’t perfect and I won’t hold you to perfection either, but it has got to make sense or it doesn’t get posted.  If your comment didn’t get posted, that is most likely why.

Second grumpy new rule:  I don’t do UFO comments.  I have no patience for these things, don’t even try to start here.  Go someplace else with your UFO comments.  I will not post them here.  This is my personal preference and should not reflect on the agency or anybody else. 

Thanks, I’m glad to get those off my chest.  On to serious comments.

No, there was no serious entry guidance anomaly on STS-1.  There was a significant lofting during ascent, but nothing to speak of during entry.  STS-2, 3, and 4 entries were flown automatically not manually with the exception of some short duration pilot test inputs to stimulate the entry flight control system to verify its robustness.  Some of these type of manual test inputs continued for a number of flights.  But there have been no manually flown entries of the space shuttle — its all been automatic until subsonic speeds.

At this date in the shuttle program, it is my belief that the bugs have been worked out of all the intact abort modes.  That is, for any single SSME premature shutdown, there is a very high confidence level that the vehicle and crew can successfully execute an RTLS, TAL, ATO.   The big assumption, though, is that nothing else goes wrong.  The shuttle requirement — which I believe it meets — is that any single premature SSME shutdown at any point in the trajectory will lead to an intact abort — safe landing by the orbiter on a runway and safety for the crew. 

I was pleased to see a post with the details of the Gemini ejection seats, but I would think that landing a mere 700 feet from an exploding Titan II rocket would not be a good thing.  Survivable if the wind was blowing the right way probably.  And I do agree that Schirra showed that he had the right stuff when he did not pull the ejection handle on Gemini 6A pad abort.

I probably should have started the series of posts with a definition of ‘black zone’ so here it is:  a portion of a manned rocket launch trajectory where the premature shutdown of any or all running booster engines will lead to loss of the re-entry vehicle and crew subsequently due to the over temperature or structural loads incurred from the resulting trajectory.  Is that too muddy?  Black zone does not mean what is going to happen in a normal case, only if an engine (or two or three) quits.  Black zone does not take into account the weather at the proposed abort landing site which is another way to kill a crew.

As to why EELVs were not chosen by the Exploration team early on — I don’t think black zones had a lot to do with it, but I really don’t know.  I should ask and I will ask and I will report to you at a later day.  However, the standard trajectory design for EELV launches would result in extensive black zones — which can be either greatly reduced or eliminated by adjusting the trajectory — which in turn leads to significant reductions in the mass which the EELV could place in orbit. 

The two early American suborbital flights — Shepard and Grissom — had carefully designed trajectories to keep the entry G level and heating relatively low.  If they had flown the type trajectory that the redstone rocket used as a weapon, that would not have been the case.  Similarly, the Soyuz T-10-1 high altitude abort had an extreme entry G level because the rocket staging went so poorly that the entry was steeper than it would have been for a clean abort — as if the 3rd stage engines had merely failed to light off. 

Well, that’s all for today folks.  The series resumes tomorrow.