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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 Progress: Engine Assembly Starts!

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After so many requirements reviews and concept reviews and safety reviews and design reviews, and after so many trade studies and analyses and assessments, and after so much paperwork generation and processing, and after so many programmatic meetings and technical interchanges and integration exchanges and formal boards, after all that, we have finally begun assembling the very first J-2X, Engine 10001, at the NASA Stennis Space Center (SSC) in Building 9101.

In the end, truly, it all comes to this: the hardware.  Everything that we do – and it is an astonishing amount of work – comes down to an operational piece of space launch hardware, a rocket engine (albeit a development unit first example).  It is sometimes quite easy to forget that fact after being buried in the mountains of necessary details for several years.  Yet that day has now arrived.

The Main Combustion Element (MCE), consisting of the Main Combustion Chamber (MCC) and the Main Injector (MI) mated together, arrived at NASA on 22 February 2011.  While a number of piece parts and components have been arriving at SSC for weeks, it is the arrival of this sub-assembly that marks the start of assembly.  It would not be too much of stretch to say that the rest of the engine, one way or another, hangs off the MCE.  So you need that part to get the whole process started in earnest.

The drawing below shows the first steps in stacking the whole thing together.


Your first question should be, “What’s a Birdcage?”  It’s actually a simulator for the nozzle.  Because this is the first build of the engine and because the various components are not completing fabrication in the optimal sequence, we have found ways to expedite engine assembly such as the use of this nozzle simulator.  The whole engine will be stacked and assembled with the Birdcage acting as the effective pedestal for the process.  Then, when the nozzle does arrive, the assembled upper part of the engine will be lifted, the Birdcage will be removed, and then the assembled pieces will be lowered onto the actual nozzle assembly to be used for Engine 10001.  Below is a photograph of the actual Birdcage sitting in its packing box at NASA SSC.

(Now, I’m not going to burst anyone’s bubble, but whoever first started calling this thing a “Birdcage” perhaps has a frightening impression of how large are the birds of southern Mississippi.  Those are some awfully large holes.)  Later, the Birdcage will be reused as the structural foundation for the assembly of the J-2X PowerPack Assembly to be tested next year.

The next picture is of the assembly area where the whole thing will be brought together.  There is a raised floor on which the technicians will stand and there is a recessed area where the dolly will fit on which the engine is assembled.  On the silvery metal carts shown – the so-called “bread carts” – the kits will be laid out for the next stage of assembly as the engine comes together.

One interesting little note about that picture of the assembly area is that in the upper left-hand corner you can see another engine within a big yellow piece of ground support equipment.  That is an RS-68 engine that flies on the Delta IV vehicle.  The J-2X assembly area sits right next to the RS-68 assembly area though they are distinctly separated.

Here are some other really cool pics:

Okay, so maybe “really cool” is a slight exaggeration.  On the left is a corner of the kit staging area where, on a pallet in the back (can you see it?), sits the first pre-arranged kit of engine parts to arrive at NASA SSC.  On the right are the two turbopumps for Engine 10001 still sitting in their shipping crates.  Trust me, as the assembly process moves forward, the pictures will get better.  Really.

So, J-2X is coming together.  Over the next several weeks, I will be posting pictures and descriptions of the process.  I do have to say, from a personal perspective, seeing this thing finally becoming a reality is quite gratifying.  Thank you all for coming along and sharing the ride.