Monthly Archives: March 2011

J-2X Progress: Engine Assembly, Volume 3

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J-2X Progress: Engine Assembly, Volume 3

Assembly of J-2X development Engine 10001 “officially” commenced on Monday 21 February of this year, just about a month ago.  In even more important news, my own household had an eight-pound, eleven-ounce new arrival on Friday 11 February.  No, no, not that kind of arrival.  Rather, it’s a new puppy named Kate (…had ya fooled for a moment, didn’t I?).  

Thus, I have the great pleasure of spending this spring watching both J-2X Engine 10001 and Kate grow up and into what they will finally become.  Here is a picture of Kate cuddled with our cat Cassady to give you an idea of her size when first she came home.  By the way, the cats all thought that Kate was just swell so long as she was unconscious and inert.  Their opinion changed significantly when she woke up.

And here was the “engine” as a pup, newly weaned and delivered to Stennis Space Center.  It began as just the Main Injector stacked on the Main Combustion Chamber.  Humble beginnings.


Here is the engine today.  Awwwww, our little baby is growing up so fast!

The most noticeable additions since the last time that we checked in on the assembly progress are the two inlet ducts stacked on top of the two turbopumps.  More stuff has been going on, like the attachment of brackets and mounts for parts to follow, but those two ducts are the biggest items.  So, let’s talk about them…

In the picture of the stacked engine assembly, the inlet ducts are encased in protective coverings.  In the picture above, however, these coverings have been largely removed from the fuel-side duct for inspection purposes.  It looks kinda funky, huh?  Well, despite the oft-demonstrated good fashion sense and excellent taste of your average rocket scientist, we don’t usually make thinks look funky just so they look cool.  There is usually a function to our funky-ness.

Here is the function:  The engine has to gimbal.  What that means is that you have to be able to point the engine in slightly other directions besides straight down from the back of the vehicle stage.  You can think of gimballing as being like a rudder on the back of a boat but in three-dimensions.  Thus, the whole engine has to pivot around when pushed or pulled by two large hydraulic actuator arms from the stage.

In order to accommodate this movement of the engine, the inlet ducts need to be able to bend and flex and even twist a little bit.  So, in order to make super-duper-strong metal ducts flexible, you have to add the convolutions like you see above.  It’s very much like one of those twisty drinking straws that I absolutely loved as a kid (see, even then I was unconsciously thinking about rocket engine components).  If you bend a regular drinking straw, the thing collapses in on itself.  If you bend one of those twisty drinking straws with the convolutions, the straw remains useful as a duct.  The external structures in the picture of the inlet ducts, those shiny triangular brackets hinged together, hold the whole thing together under operational conditions. 

Here’s a neato little fact about the fuel-side inlet duct.  In order for the convolutions to do their job by allowing movement, you can’t have any ice buildup in the convolutions.  Liquid hydrogen is so cold that it can freeze nitrogen right out of the air.  If you don’t have some way to insulate this duct, it would be covered in nitrogen ice while sitting in compartment at the back of the stage.  But you can’t insulate it on the outside or, again, the thing can’t flex.  So, what we’ve done is make the whole thing into a Thermos® bottle.  There are actually two walls of convolutions, an inner wall and an outer wall.  In between is a vacuum and that vacuum provides the insulation.  This feature is not necessary on the oxidizer side since liquid oxygen will not freeze anything out of the air other than moisture.  Thus, so long as you keep the compartment free of humidity, the oxidizer side is fine with only one layer and bare metal (though special accommodations are necessary on the test stand where the ambient environment cannot be so carefully controlled).

So, that’s the status of the J-2X Engine 10001 assembly and a description of its inlet ducts.  The status of Kate is that she is growing like a weed.  Every day her legs look longer.  Of course, it was only after we adopted her that the shelter people seriously and openly speculated that the father might, in fact, have been a Rottweiler.  Oh dear.  She’s nearly 24 pounds at less than fourteen weeks old.  The cats are more displeased with each passing day.


J-2X Doghouse: The Rocket Equation! Wahoo!

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J-2X Doghouse: The Rocket Equation!  Wahoo!

Welcome back to the J-2X Doghouse.  We’ve talked before about what a rocket actually is and we’ve talked about different kinds of rocket engine cycles and where J-2X fits in that family.  This time, in response to a couple of early requests on this blog, I’d like to talk about rocket engine performance characteristics and how they relate to successfully getting off the planet and into orbit.  Because this comes down to a matter of equations – and therefore at least half of the reading audience will click on their Facebook icon as soon as they see any equations – let me start with an old joke:

Q:  What do engineers use for birth control?
A:  Their personalities.

Of course you know that joke can’t be entirely true if you’ve read any of the articles profiling the J-2X office.  Just about everyone in the office have children.  But somewhere, deep down, in order for that joke to have lasted so long, there must be a tiny sliver of truth.  Okay, yes, I admit it, here it is: People who become engineers do so for a whole variety of reasons but typically share in common an aptitude towards mathematics and a desire to know how things work. 

For me, this whole “future-engineer” notion translated to an appreciation of physics and the representation of the real world, to some approximation, in equations.  Seriously, just think about that for a moment.  You can pick up a pencil, draw a simple sketch, apply some fundamental laws, and, boom, you’ve got a prediction right there on your paper for how the real world will function.  Now that’s darn exciting!  At least it is to me.  But, okay, word of advice:  Showing this level of enthusiasm regarding physics and neato equations is generally NOT good fodder for a first date.  Trust me.

However, since I’ve not had a “first date” in over a quarter of a century, I am now going to explain the derivation of the foundational equation for all rocketry:  The Rocket Equation.  Approximately 99.7% of the world’s population at large does not know this … and, yes, that is a 100% unverified, made-up statistic.  Regardless, today you will join an elite, exclusive, and fashionably eccentric club. 

[Warning:  Some of the mathematics gets a bit heavy here, but some of y’all asked for it.]

First, we start with a simple drawing.  Please note that my wife is the artist in the family; I “draw” in PowerPoint.  Sorry.

What you have is a thing, a blob, at time equal to t0 with a mass of M moving at a velocity of v.  At this point, don’t think of the blob as a rocket.  It’s just a thing in an imaginary space where there is no gravity, no friction, no environmental impacts at all.

We then go to the next step in time, time = t0 + dt, where dt is a small increment.

Our blob has ejected from itself a small piece of mass, dm, in the opposite direction from which it was moving.  The small mass has a velocity of vdm in the opposite direction of the original blob.  The blob, by the way, has a mass now diminished by dm and a velocity that has changed by some increment dv.

Do you want to play the gray blob at home?  Okay, do this.  On a smooth floor, tile perhaps, sit in a rolling chair holding a basketball.  Throw the basketball.  You, still in the chair, will roll in the opposite direction from the flight of the basketball.  Your initial velocity, v, was zero.  Your initial mass, M, included you, the chair, and the basketball.  Your new velocity is zero + dv.  Your new mass is now minus that of the basketball, dm, flying in the other direction.  Ta-da!

Now, how do we turn this simple concept and simplistic drawings into rocket science?  Simple, we call up the work of our friend Sir Issac Newton (1642 – 1727).  Newton’s First Law of Motion states: “An object at rest tends to stay at rest and that an object in uniform motion tends to stay in uniform motion unless acted upon by a net external force.”  I told you that there were no external forces acting on our blob and I drew the box around the whole thing, blob and small piece together.  Combining the philosophy of this First Law with the mathematics of the Second Law results in a simple conclusion that in absence of any external forces, momentum is conserved.  So, the total momentum in the first drawing is the same as the total momentum in the second drawing with momentum defined as mass × velocity.

The second term in the right-hand box is negative since the velocity of the small piece is in the opposite direction as the original movement of the blob.  Okay, now multiply this all out and eliminate redundant terms and – thanks to some niceties of differential calculus – eliminate second order terms to yield the following:

The dm = -dM switch-a-roo is possible since the incremental change in mass of the blob over the time period dt is exactly the negative of the piece ejected.

Rather than talking in terms of absolute velocity of the blob and the small piece, let’s instead talk in terms of ve, the “ejection velocity” of the small piece.  So, this is a relative speed.  Then the equation becomes:

Believe it or not, that’s it.  In its most rudimentary, simplified form, that the Rocket Equation expressed over a very small time increment dt.  If you add up a bunch of these very small time increments, or in other words integrate over a measureable time period [Oh no, integral calculus buried in a blog!  Call the blog police!], you get the following:

What does this say?  Equations always say something or they’re worthless.  It says that the change in velocity of a blob is equal to the relative ejection velocity of small pieces flung away from the blob times the natural log of the ratio of initial mass, M0, to final mass of the blob MF.  The natural log thing got in there thanks to the rules of integral calculus.  You’ll have to trust me on that one.

Now, what does this have to do with rockets?  Well, how about rather than ejecting small discrete chunks of mass we think about what a rocket engine does, which is spew out a continuous stream of mass in the form of high-speed hot gases.  The whole derivation above holds for that case with one modification.  The hot gases ejecting from the nozzle create a pressure field at the point of ejection.  That pressure field creates a force acting on the system.  Because there is a force involved now, momentum is not conserved.  The derivation is a bit more complicated, but it’s not too bad.  The result looks like this:

Where ueq is called the “equivalent exhaust velocity” and is defined as:

The first portion of that last equation deals with the pressure field.  Basically, it is the exhaust pressure at the end of the nozzle, Pe, minus the ambient pressure outside, Pa, times the exit area of the nozzle, Ae.  Force equals pressure acting over an area.  Simple.  The “m-dot” term is the mass flow of the hot gases out of the nozzle.

We’re almost there.  Really.  Hold on. 

Next, I want to define thrust.  We could have started this way by drawing a control volume around a rocket, but I like starting with the blob.  Thrust, T, is the force that the engine imparts on the vehicle.  So, it includes the pressure field aspect and it includes the aspect of ejecting hot gases at high speeds.  Here it is:

If you put a rocket engine on the test stand, fire it, and measure how hard it pushes against the stand, this is what you are measuring.  Sometimes you will see a rocket engine specification that will talk about “vacuum thrust” or “sea level thrust.”  The difference between those can be found in the ambient pressure term, Pa, in the equation above.  In a vacuum, Pa = 0.  At sea level, Pa = 14.7 pounds-force per square inch.  Note that depending on your system of measurements, there could be a “g-factor” conversion lurking in the mass flux term so be careful.

Substituting back into the Rocket Equation, we get this:

I have now cleverly introduced the concept of specific impulse, Isp, which is thrust divided by mass flowrate.  When talking about rocket engines, we typically describe this parameter as being analogous to gas mileage so that people can understand, but here you can see that it’s an integral part of the basic physics of the acceleration of a rocket vehicle.  (Again, beware of hidden g-factor conversions.)

Note that earlier I said that we didn’t have any gravity in our hypothetical situation and that we didn’t have any friction.  I can now add these things into our system a simplistic manner to facilitate the final discussion and to present the final equation:

That, right there, believe it or not, tells you 90% of the whole story about how rockets get into orbit and even how they go from there into the rest of the cosmos.  What do you need to get into and stay in orbit?  A lot of velocity.  And this equation tells you all about it.  Listen carefully to rocket scientists talking about “delta-v” in movies or the news or in documentaries.  “Delta-v” is everything.  You need so much delta-v to get to orbit.  You need so much delta-v to change orbits.  You need so much delta-v to get out of orbit and head towards the moon or anywhere else.  Whenever you hear this, they are referring to the Rocket Equation.

Let’s break it down by starting with the last two terms on the right-hand side.  These are loss terms and that’s why they are negative.  First, as long as you are gaining altitude, you are fighting against gravity.  If we had some way to dial down gravity, we could launch rockets more efficiently because this term would lessen (we’d also all float away).  That’s intuitive.  It takes energy to lift something.  Second, as long as you have friction caused by drag against the atmosphere, you’ve got losses.  Compared to a vacuum, especially at high speeds, our atmosphere is like soup to a launch vehicle and you need energy to overcome it.  Thus, both of these loss terms tell you that for greatest efficiency, it’s best to get up high, out of the atmosphere, and level out to stop fighting gravity as fast as you possibly can.  And that’s exactly how we launch rockets.  It’s not an accident or a whim.  It’s physics.

Now, the first term on the right-hand side in that final equation has two pieces.  First, there is specific impulse, Isp.  That is a measurement of how efficiently the rocket engine produces thrust.  For a given amount of propellant the engine produces this much thrust.  Second, there is the ratio of masses within the natural logarithm.  What this says is that the lower the final mass of the vehicle is relative to the starting mass, the more velocity can be gained.  So, what you want is very low final, burn-out mass as compared to where you started.  When you get to the end, you don’t want much by way of leftover, unused propellants, and you want as little superfluous structure as possible.  Remember, part of your final mass is your payload, which is the satellite or your capsule filled with astronauts.  That’s the important stuff.  It’s this notion of discarding unnecessary and heavy stuff along the way that results in the reason why rockets typically have multiple stages.  As you go along, you toss off heavy structures that you no longer need:  The more stuff that you can shed, the less that you have to carry along, and the more velocity that you can pick up.  Again, it’s intuitive.

If you’ve made it this far and if you’ve grasped the basic concepts of the physics involved, you truly know more about rocketry than almost anybody you’ll meet.  And it’s amazing how intuitive it all ends up once you’ve plowed through the mathematics.  Good equations are those that can tell a good story.  The Rocket Equation is one such equation.

My recommendation is that you print this out and take it along with you on your next date.  Really, you’ll be a big hit!  (Or not.)


J-2X Progress: Engine Assembly Continues

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J-2X Progress: Engine Assembly Continues

Once upon a time, I used to consider myself reasonably handy with a saw and a drill and a miter box and various rudimentary woodworking tools.  I certainly knew my limits, so I never did anything too complex, but most of the fun from pursuing such projects was the creativity involved.  I didn’t plan out a great deal.  I preferred an evolving, organic (i.e., lazy) approach.  Given the nature of the forgiving materials involved, that was generally fine.  In my wife’s art studio, there’s a cat tree with six or seven beds that fills an entire wall.  I built it with no drawings, kind of on the fly, and it still turned out okay (or, at least, the cats seem to think so).

That is not, however, how you assemble a rocket engine.  You don’t wing it.  You plan everything.  The materials are not forgiving.  Just about everything is heavy and, if you drop it, or scratch it, or scuff it, or nick it, then you have the joyful experience of traipsing through a paperwork exercise to make sure that whatever you damaged is still usable.  In other words, rocket engine pieces are both extremely rugged and rigid yet also precisely machined and fragile.  Oh, and unlike two-by-fours, rocket engine parts aren’t cheap and as easily replaced as a trip down the street to Home Depot.  Thus, a great deal of time spent poring through the planning documentation and lifting and moving things with exceptional care.

You can think of a rocket engine as a large, three-dimensional jigsaw puzzle.  The pieces have to fit together exactly and properly.  To make this happen, you first have to have really well-manufactured parts, but then you also need good ground support equipment (GSE) and knowledgeable, competent, and dedicated technicians.  Below is a picture of one critical piece of GSE, the engine build dolly.  This is essentially a rolling piece of elevated floor onto which you build in the engine.  Considering with the engine sitting on it, plus tooling, plus the technicians themselves doing the work that the dolly could be holding well over 6,000 pounds, this is a stout piece of equipment.

When I built the big cat tree, I just moved around the mess in my garage and I pulled my pickup out of the driveway to lay out the bigger pieces.  The picture below is the J-2X assembly area.  Note that there aren’t any flower pots with last year’s dead petunias, or half-empty bags of bird seed, or cast-off, half-used rolls of duct tape scattered about the floor.  In other words, it doesn’t look like my garage.  It is extremely clean and orderly.  It is a FOD-free zone:  FOD = foreign object debris.  When assembling an engine, you do not want ANYTHING in the engine that does not belong there.  I will be showing you pictures below of various stages of engine assembly so far and you will notice that there is tape and/or plastic closures over every open hole where something might accidentally fall.  One dropped nut or hunk of wire or wad of tape and you’re either forced into a costly disassembly exercise to get the stuff out or, worst case should the FOD be missed and left in the engine, you could have an engine failure in test and the loss of tens of millions of dollars of hardware. 

The other thing that you will notice from the picture of the assembly area is how well the whole thing fits together.  Pieces of the floor retract to allow for the dolly to be positioned in the middle.  The kit carts have bays into which they can slide for convenient access to the necessary hardware.  There is an overhead boom with commodities available for when the assembly and checkout processes require gasses or electrical power or a hookup to a simulated vehicle stage computer.  And, of course, just above the boundary of the picture is an overhead crane for lifting operations. 

Now, can you just imagine the magnitude and glory of my cat tree if my garage was so neat, well organized, and fully equipped?  Difficult to fathom, huh?

So, where does the engine assembly stand?  Since I last reported the initiation of assembly, great strides have been made.  Let’s step through the biggest pieces of the sequence.  First, the birdcage was put into place on the build dolly.  Remember, the yellow birdcage is a simulator for the first portion of the nozzle.  Later, it will be replaced with the real nozzle.  The dolly was then wheeled into place in the assembly area. 

Below is the next sequence.  The picture farthest on the left is the MCE, i.e., the main combustion element (composed of the main injector attached to the main combustion chamber) sitting in its shipping box.  In the middle is a picture of the MCE with the turbopump arms installed.  From these four heavy arms will be hung the fuel turbopump and the oxidizer turbopump.  And, on the right, is a picture of this the whole assembly of MCE with the turbopump arms mounted on top of the birdcage.

Next, the two turbopumps were installed, first the oxidizer turbopump and then the fuel turbopump.  I can state that here quite simply in a single sentence, but go back to that series of pictures above: planning, lifting, moving, positioning, etc.  A great deal of careful work went into each step.

Now, I don’t know about you, but this is getting darn exciting for me.  If I squint hard at that last picture and add some ducts in my mind, then that really looks a whole lot like an honest to goodness rocket engine.  J-2X is coming together!  In another month or so, it will be fully assembled and early this summer we will be demonstrating the first new, human-rated NASA rocket engine since 1975 (…yes, 1975, think: the fall of Saigon, Patty Hearst still on the lam, the Thrilla in Manilla – Ali v. Frazier III, Tiger Woods and Kate Winslet born, sentences being handed down for Watergate, the very first episode of Saturday Night Live, and me as the star kickball player during fifth grade recess…). 

Two final notes for this article.  First, I would like to thank Brian West for all of the engine assembly pictures and background information for these pictures.  Keep up the great work!  Second, I would like to thank my cat Kesey for his starring role in the center of the cat tree picture.  Being that round and that lazy takes years of dedicated practice.

J-2X Extra: The Faces Behind J-2X, NASA MSFC, Part 2

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J-2X Extra: The Faces Behind J-2X,  NASA MSFC, Part 2

Several weeks ago, the article here on the blog featured the an introduction to the upper management of the J-2X development effort.  Now, I am going to introduce you to much of the next tier of our motley – yet talented – management crew, namely the subsystem managers here on the NASA side.

Rick Ballard is the systems engineering and integration manager.  He is a product of the great Southwest U.S. and is therefore  (it would seem to follow) a connoisseur and master chef of chili in multiple forms and variations, including some formulations can also be either eaten or used to scour barnacles from the hulls of ships.  Rick is a graduate of Texas A&M who worked for support contractors, starting in 1987 first for Martin Marietta and then Sverdrup Technologies, before joining NASA over ten years ago.  He is widely known for having an encyclopedic knowledge of space propulsion systems and is quite active in professional aerospace industry associations.  When not working or spending time with his wife and two daughters, he can either be found participating in fencing or, as he puts it, “chilling” at his farm north of Gurley, AL.

Gary Genge, subsystem manager for Turbomachinery, like our chief engineer Eric Tepool, is also an Auburn University graduate and, like our chief engineer, began work at NASA in the turbomachinery branch.  He started working for NASA in 1987.  Back then, of course, the turbomachinery branch was immersed in Space Shuttle Main Engine (SSME) support.  He was also the lead systems engineer for the Advanced Space Transportation Program and the NASA-side project manager for the Integrated Power Demonstrator (IPD) engine, which was a really cool technology demonstration engine using a full-flow staged-combustion cycle engine.  Gary has three daughters and so, of course, has become an expert in attending dance recitals and gymnastics meets in his off hours.  When not exercising this expertise, he has been known to golf, or play pool, or, once upon a time, far, far away from here, scuba dive.

The business office for the Upper Stage Engine Element office is led by Joan Presson, originally from Pulaski, TN.  While “business” is not technically a J-2X subsystem, without the flow, control, and accounting of the dollars and cents, nothing else can happen.  The interesting thing about Joan is that, strictly speaking, this is her first gig as a “business manager.”  It is not, however, her first time dealing with all that business stuff given that over her nearly 24 years with NASA she was manager or deputy manager for a variety of small projects in the space sciences area where business management was part of the role for the project manager.  Joan has a bachelor’s degree in English, another bachelor’s degree in Electrical Engineering, a master’s degree in project management, and coursework complete towards a doctorate in systems engineering.  It was during her graduate work that she met her husband and today they have a 12-year-old boy.  When not helping with his homework, or engaging in other activities with her son, Joan loves to get deep into hands-on house renovation projects. 


Twenty years ago, Mike Shadoan started here at NASA MSFC straight out of the University of Kentucky graduate school.  He’s still here, working hard, as always, but now diligently plugging away as our combustion devices manager.  He started as a designer in the area of control systems and mechanisms and that’s where he earned the accolade of co-inventor of the year for MSFC for a selectively-locking knee brace design.  For the last ten years, though, he’s worked all facets of combustion devices development.  On the COBRA engine project, he was the subsystem manager for the thrust chamber assembly.  On IPD, his job was geared more towards the manufacturing processes.  On the Fastrac engine project, he was back focusing on design.  In other words, he’s perfectly suited for his current job.  But when not doing that, you can find him pursuing his hobby as a beekeeper or coaching either fast-pitch softball or basketball for any one of this three daughters.


The Upper Stage Engine Element office has set aside a management block dedicated to J-2X production.  The person managing this block has the responsibility to establish what is necessary beyond the J-2X development effort in terms of supporting a flight program.  Bill Jacobs, native of Rochester, New York and graduate of the University of Alabama, is the J-2X production manager.  He began working here at NASA as a co-op in the mid-1980’s.  His technical specialty back in those days was control system electronics.  Working out of the engineering laboratory, Bill supported an alphabet soup of different projects and programs, from the Orbital Maneuvering Vehicle program to the National Launch System to the Fastrac engine development project.  From there his career transitioned towards systems engineering and for quite some time Bill was stuck with the moniker of “Requirements Guru.”  When not at work, Bill brews beer, plays tennis, and works on his photography.  Those things are only possible, of course, when not spending time with wife and three daughters.  Finally, Bill is one of those rare guys who played in his high school band 30 years ago and can still competently toot his trumpet when the mood strikes him.

A man with a diverse background within government employment is our manager for engine controls, valves, and instrumentation, Jeremy Richard.  While he’s only been with NASA for about eight years, his total government service with Space and Missile Defense, the Army, and the Army Corps of Engineers comes in at 17 or 18 years (depending on how you add it up).  Previously with NASA, Jeremy worked in the SSME office and even there sought a diverse experience spending a year and a half in California at the prime contractor site acting as a safety and mission assurance representative and also a year at the NASA Stennis Space Center in southern Mississippi in the SSME project resident office.  He is a graduate of the University of Alabama in Huntsville, has four quite active children, and spends most of his off-hours time with his kids or working on his house and six acres of country land.  An interesting additional fact about Jeremy is that he is a licensed preacher so should the need arise for an emergency, in-office wedding, we’re covered.

Our subsystem manager for engine systems hardware is Andy Hardin.  If you’re wondering about what “gine system hardware” is, it’s basically everything not covered by the other hardware subsystems, which means that it consists of lots and lots of various piece parts.  It’s probably appropriate then that Andy is our manager here given his diverse background.  Andy spent several years in the Army, living in Louisiana and then three years in Fairbanks, Alaska.  After the Army, he went back to school, earned his degree and pursued several jobs in the telecommunications field, working as engineering manager and program manager, including management of the establishment of a cellular network along the Gulf Coast.  Andy has been working in support of NASA since 2003.  He’s a golfer gifted with a broad spectrum of emotional display on the course, an excellent pool player, the world’s greatest collector of gadgets, and general household tinkerer/putterer.  And, on top of that, he has two very young children.  Busy man.


Like the business office, the Upper Stage Engine Element procurement office is not technically a J-2X subsystem.  But considering that NASA as an agency buys products and services from the private sector to the tune of well over 80% of our budget, having competent procurement specialists in place is an absolute necessity.  Luckily, we have Kim Adams leading our procurement office.  Kim is an Auburn University graduate with a degree in management.  She’s been with NASA for a total of 18 years and in her spare time dabbles in real estate.  Trust me, if there was anyone that you’d want to take into a tough negotiation, it’s Kim.  That’s not just because of her experience and intelligence, but because, as she says, she has a great poker face when needed.  I’m sure that that has also been helpful in raising two sons, one of whom is a freshman at Auburn and the other is a tenth-grader and avid soccer player.  When given the opportunity, Kim loves to travel, attends many Auburn football games, and is eagerly looking forward to a trip to Key West in May.  And while she only keeps up today with some keyboard playing for fun, back in high school she played saxophone, xylophone, and piano.


Much earlier in this blog series, I provided a definition for “Datadog.”  If, with that definition I’d wanted to include a photograph, I would have included an image of Marc Neely, our subsystem manager for assembly and test.  Marc has spent the largest portion of his career, starting with NASA in 1985, supporting the various incarnations of the engine systems branch here at MSFC, the native home of those feral beasts known as Datadogs.  In so doing, there are very few engine projects over the last two decades that Marc has not touched.  Beyond that, he has interests in woodworking (he was once a carpenter) and art (once a subject of his collegiate studies as a younger man).  Marc just recently got back from a trip to Nicaragua where his soon-to-be-doctor son got married to his soon-to-be-doctor and now daughter-in-law from that Central American country. 

So, that’s just a further sampling of our office.  These are my coworkers and friends.  Beyond these folks, there are literally hundreds of people behind the J-2X development effort and they span the country.  As we progress, I hope to tell you about more of the people involved.