J-2X Doghouse: Okay, So We Ain't That Smart

Diposting oleh vitto friend | 07.59 | , , | 0 komentar »

Back in the day -- back before I had the carefully regulated, federally mandated, and strictly enforced lobotomy that allows people into the ranks of management -- I was once an analyst.  And, since it seems so long ago that it doesn't sound like bragging anymore, I will admit that I was pretty good at it.  I absolutely loved the process of using fundamental physics or empirical correlations for fluid dynamics, thermodynamics, and heat transfer all together to simulate in computer coding how things function in the real world.  Whereas many people enter the field engineering because they like mechanical things or electronic things, there are some of us who relish the seeming purity of problem solving in abstraction.
 Over the years, working on many diverse projects and building many diverse mathematical models to simulate many diverse systems, I came to the realization that my models always appeared most unassailable and brilliant when there was no test data against which to compare them.  To put it bluntly, test data always proves that you simply ain't as smart as you thought you were.  But, that's okay.  If that wasn't the case, then you wouldn’t bother to test.  The whole point of testing to gather data and learn more. With all due respect to the Serenity Prayer, this ought to be the analyst's prayer relative to testing:
Grant me -- -- the results to validate that which I do understand -- the data to explain that which I did not understand -- and the openness to accept that I can always understand better
That last line is critical.  Ignoring data contrary to what your model output is a seductive, addictive, and dangerous path to follow.  We don't/won't do that. That brings us to the subject of test A2J003 of the J-2X development engine E10001.  This was our first test to mainstage operation.  The planned duration was to be seven seconds.  On Tuesday 26 July, right around five in the afternoon, the test ran for 3.72 seconds and then shutdown.  We did not accomplish the full duration.  Why?  Basically because we ain't as smart as we thought we were.  We had analytical models telling us that performance would be X, but the hardware knew better and decided on its own to perform to Y.  Here is a cool video of the test: A more detailed explanation of what happened is that the engine shutdown due to the measurement of a pressure too high in the main combustion chamber.  The measurement crossed a pre-set "redline" and the test controller unit took the automatic (and autonomous) action of shutting down the engine in a safe and controlled manner.  The high pressure in the main chamber was caused by higher than expected power coming out of the oxidizer pump.  This, in turn, was due to more power being delivered to the turbine side than expected.  It comes down to a fluid dynamics phenomenon (pressure drops) and what we have is not inherently bad, just different than expected.  So, in essence, we used our models to predict that the pressure in the main chamber would be at a certain level -- indicating a certain power level -- but the different performance of the hardware resulted in pushing us away from our analytical prediction.
  • Here is the good part:  We learned something.  We learned that our model needs to be updated and we collected the data that will allow that to happen.
  • Here is another good part:  We got enough data, despite the short duration, to recalibrate the engine for the next test thereby making it far more likely that we will hit our target. .
  • Here is yet another good part:  We had a successful demonstration of the test controller redline system by safely shutting down the engine.  The engine looks fine.  The controller did exactly what it was supposed to do and protected the hardware.  In fact, for these early tests we have the redlines clamped down pretty tight specifically to protect the hardware as we learn more about the engine..
  • And here is, finally, yet another good part:  Other than the power applied to the oxidizer turbopump, most of our other predictions with regards to hardware performance appear to be awfully darn good.  So, we've got a preliminary validation for much of our understanding of the engine.  Indeed, this is a brand new engine and we have just accomplished mainstage operation in the second hot-fire test.  That is truly unprecedented..
  • Here is the bad part: We have to spend a few minutes explaining to folks not directly involved that despite not achieving full duration, the test was in reality a total success.
If that, then, is the bad part, I can live with it.  I can live with admitting that we ain't as smart as we thought were.  Why?  Because now, after the test, we are indeed smarter.  And we will continue to get smarter and smarter about the J-2X design until, one day, we will be smart enough to say that, yes, we understand this engine so well that it is safe enough to propel humans into space.

Bright Fireball Flames in Southern Skies

Diposting oleh vitto friend | 05.34 | , , | 0 komentar »

Editor's Note: A rare snowstorm isn’t the only interesting thing that happened across the South this past week. On the night of Tuesday, Jan. 11, an extremely bright fireball meteor streaked over Jackson, Miss., and was visible across several southern states. NASA astronomer Bill Cooke of the Meteoroid Environment Office at Marshall Space Flight Center confirms the meteor below. Okay folks, can confirm that this was indeed a fireball or bolide. Unfortunately no video of the actual meteor has surfaced, so I requested an analysis of signals from North American infrasound stations. We had one very clear detection, from the ELFO station in Canada, and a marginal signal at another station east of the visual sightings. Unfortunately the marginal signal is too weak to permit extraction of much information or to triangulate. The ELFO signal arrived at 10:05:50 PM Central time, some 1 hour and 20 minutes after the event, and came in at an azimuth of 210 degrees. If you look at the attached plot, the black curved line shows the path of the ELFO signal, which intersects nicely with the bulk of the visual observations -- indicated by the red dot  -- around Jackson, Mississippi (ELFO az gives 32 deg N, 89 deg W -- Jackson is at 32 deg N, 90 deg W).
The infrasound signal at ELFO lasted some 2.5 minutes, and the amplitude permits an estimate of the meteor's energy at 40-80 tons of TNT. If we assume a speed of 15 kilometers per second, we can derive a mass of 171 kg or 376 pounds. Making a further assumption that the meteor was porous rock gives a size, or diameter, of 0.54 meters or 21 inches. That's the best estimate at this time -- if video data of the meteor itself shows up, please let me know. Don't hesitate to ask questions if you need clarification or more information.
Lunar Eclipse, Sprinkled With Fireballs
 Posted on Dec 23, 2010 12:43:21 PM | William Cooke 4 Comments | | Poor Fair Average Good Excellent
The 2010 solstice lunar eclipse is one for the books, but check out these images from two cameras in the Canadian all-sky meteor camera network.These cameras are similar to the ones used for observation at NASA's Marshall Space Flight Center: all-sky, black-and-white, and detecting bright meteors, or fireballs. Below are two stacked images of the eclipse:
Stacked image of the eclipse using images taken every five minutes from McMaster University
between 6:32 and 9:32 UT. A similarly stacked image, combining pictures every five minutes between 5:27-9:37;
it was taken from Orangeville, ON, Canada.
Just as a reminder, the eclipse event timings in UT were:
  • Partial begins: 6:33
  • Total begins: 7:41
  • Mid eclipse: 8:17
  • Total ends: 8:53
  • Partial ends: 10:01
So both cameras captured the full moon as it normally appears, then imaged it as it was eclipsed through the partial and total phases. Unfortunately, bad weather rolled in before the eclipse ended! The Canadian cameras also detected meteors during the eclipse. Here are a few good ones: The following two images were also taken from McMaster and Orangeville at about 7:38 UT, just before the total eclipse began, but after the partial eclipse had started. These pictures show an image of a meteor fairly close to the moon in the field of view.
The following three images were recorded from Elginfield, ON, Canada, McMaster, and Orangeville, respectively, at about 9:00 UT, just after the total eclipse phase ended, but before the partial eclipse ended. This meteor ablated by a height of 83 kilometers, or 52 miles.
Images courtesy of the Meteor Physics Group at the University of Western Ontario in London, ON, Canada Text courtesy of  Danielle Moser, NASA's Marshall Space Flight Center, Meteoroid Environment Office

Mercury Visible After Sunset

Diposting oleh vitto friend | 05.31 | , | 0 komentar »

NASA's Mercury MESSENGER spacecraft is preparing to insert itself into orbit tonight, Mar. 17. While you may not have a seat, you can still see Mercury tonight after sunset from the comfort of planet Earth.

Close-up image of a portion of Mercury’s surface, captured on a MESSENGER fly-by
on Oct. 6, 2008. (NASA/Johns Hopkins University Applied Physics Laboratory/
Carnegie Institution of Washington)
The key to seeing Mercury is having an unobstructed view of the horizon in the sunrise or sunset direction. You should look for Mercury about 30 to 40 minutes after sunset, as soon as the sky begins to darken.

The Burp Test

Diposting oleh vitto friend | 05.30 | | 0 komentar »

On my very first home computer, I had a silly little program -- made by the marketers for the Monty Python brand name I believe -- that turned the keyboard into collection of funny or disgusting or borderline obscene simulated sounds of bodily functions.  Several keys triggered a variety of sneezing sounds.   Another set of keys activated a broad range of burping sounds.  Another set of keys set off sounds inappropriate for further discussion within a NASA blog.  And, of course, there were handful of sounds that simply left you scratching your head.  I guess that one should feel heartened by the notion that even at a time when the sterile realm of machines seem to be taking over our lives, we still revert to our childish fascination and amusement with the functions of our quirky bodies. 
And so, in that light, I give to you the J-2X Burp Test.  No, that is of course not the official name.  The official name is the "J-2X Ignition Test" or, even more formally: Test A2J001.  That really rolls off the tongue doesn't it? 
Etymological dissection of "A2J001"
     • "A2" because the test is happening on NASA Stennis Space Center test stand A-2.
     • "J" to distinguish this from 30 years of Space Shuttle Main Engine Testing data records related 
        to test stand A-2.
     • "001" because, well, it's the first test
The first test of the first J-2X development engine will have a duration of 1.9 seconds between the time that the engine receives a command to start and the time that the engine receives a command to shutdown.  That is not a long time.  It is, indeed, not a whole lot more than an extended, impolite belch considering that the engine is designed to ultimately roar for a full eight or ten minutes for full-duration tests.
So, why do such a seemingly silly little test?  That's a valid question and the answers back are just as valid.  We have a wide range of objectives for this test.  For example, this will be the first time that cryogenic propellants (liquid oxygen, liquid hydrogen) will have been loaded into the engine and the lowest reaches of the facility feedlines.  Remember, these fluids are so cold that they make metal shrink.  You have to design the engine and the facility to resist or accommodate this thermal stress.  And while you continuously check for leaks as you assemble the engine and the facility, nothing is ever quite like a good cryogenic chill for finding where seals might separate. 
Also, during a chill test you want to make sure that you can get the engine cold.  I know that that sounds funny, but it is possible to have enough ambient heat going back into the metal of the hardware such that it overwhelms the capacity of the cold fluids to take it away.  Essentially what happens is the cryogenic fluids boil when they hit warmer metal.  Boil?  Like water in a pot on the stove?  Yes, but remember that liquid hydrogen boils at about 420 degrees below zero and liquid oxygen boils at about 300 degrees below zero (both Fahrenheit).  What you want is for the hardware to get so cold that the boiling stops.  This is accomplished by continuously flowing new, fresh, cold stuff through the hardware via a bleed line.  During the chill test, you monitor the conditions within the engine and of the fluid coming out of the bleed line.  When you get to a suitably cold, steady state situation, then you’ve successfully chilled the engine.
Why is this important?  First, you run this test to make sure that you actually can chill the engine.  Not only do you design the engine to run, you have to design it to be able to get to this chilled state during a launch sequence.  Second, the engine needs to be chilled because if you have any boiling liquid in the pumps when it is time to start, that boiling represents voids in the fluid.  The movement of the pump will exacerbate these voids and potentially convert even more of the liquid into gas.  The pumps are not designed to pump gas and so the result is that the engine could go off mixture ratio, or it could fail to start, or it could even head rapidly towards a far more exciting failure situation.  Like a good martini, really chilled is really good.
Next, after the long chill, like a long, filling meal, comes the … BURP …
The 1.9 ignition test will demonstrate: the use of the helium spin-start system, ignition of the augmented spark igniter and the main injector, and the functioning of the start continue logic software.  Now, explaining one at a time --
In your automobile, you've got an electric motor that, when you turn the key (or push a button these days in some fancy cars), spins the motor to life.  We've got essentially the same thing on the J-2X.  There are different ways that this could be accomplished, but one of the cleanest and simplest is to use the inherent functionality of the turbines and provide a burst of power in the form of high-pressure helium.  The helium flows through the turbines, spins up the pumps, and thereby builds pressure throughout the engine making it primed for the rest of the start sequence.  The important features that will be demonstrated with the planned short test is the careful timing of the sequence and the tailoring of the pressure profile supplied to the turbines to yield the desired pressure build up on the other end, in the pumps.
The augmented spark igniter (ASI) is, effectively, a torch lit off by a pair of spark plugs.  This small hydrogen-oxygen torch resides in the center of the main injector and it is what lights off the propellants in the main chamber during the start sequence.  Just like you don't start a campfire by holding a match against the biggest log in the pile, the ASI provides the kindling to get the main fire going.  The burp test will demonstrate the effective discharging of our high-tech spark plugs and achieve ignition of the ASI and the main chamber.  They will not be lit for long, but just long enough to characterize the process.
Just like everything these days, the J-2X and the entire test facility element are run by software.  Streams of 1s and 0s are taking over everything.  And while J-2X does not have an exceptionally complex control system, there are a handful of absolutely critical feedback loops that must function properly.  The "start continue logic" is composed of a set of criteria that tell you, as the engine progresses through the start sequence, that it is okay to continue with the process.  Being not "okay" in this case means that you could be facing a catastrophic situation and that you must halt the engine starting process in order to ensure safety (of the engine, of the test stand, and, in flight, of the vehicle and crew).  Now, for this short test, it is extremely unlikely that we would be building up enough energy to damage much of anything even if things did go awry, but what is important is the demonstration of the closed loop of imposed software limits, measured parameters, the application of software logic, and the confirmation that all is well.  Considering that the engine and test facility is being entirely controlled by a group of people in a secured building that is hundreds of yards away, making sure that you’ve got complete control of the test facility and test article, and complete insight into what's going on via instrumentation, is pretty darn important.
So, that explains the strategy behind the first test of J-2X E10001.  What we will not be doing is lighting the gas generator.  That would be the next step in the start sequence: spin up the pumps, open the valves, light the main chamber, and then light the gas generator.  We will then be just one step away from ramping up to full power.  We’ll save that step for next test. 
To be entirely frank, this first won’t be very impressive for uninvolved bystanders, it probably won’t even be as much fun for a lot of people as would be the silly/disgusting bodily function sounds on my very first computer, but for those of us down in details, this burp test is a vital full -- dress rehearsal before the real fun begins of genuine, mainstage engine testing.  It represents yet another significant milestone on our path towards completing J-2X development.  Go J-2X!

It's Raining Comet Halley!

Diposting oleh vitto friend | 05.28 | , | 0 komentar »

We at the Meteoroid Environment Office are hoping that you have clear skies on May 5/6 when we have the opportunity to see pieces of Comet Halley whiz through Earth's atmosphere!

Image of an Eta Aquarid meteor, taken the night of May 3, 2011. (NASA/MSFC)

Comet Halley (NASA)

Depending on your age, you may remember 25 years ago when people lined up for blocks to look through a telescope and get a glimpse of this popular comet. It will be another 51 years before the comet will pass close enough to earth for us to see it in its entirety, but the debris it has left orbit-after-orbit gives us a yearly show in the Eta Aquariid meteor shower.
Unfortunately the shower will not be seen in all its glory from the northern hemisphere. Our southern hemisphere friends will get a better show than us, seeing up to 60 meteors per hour if the skies are clear and dark. The radiant (the point in the sky that the meteors appear to come from) will not rise as high for those in northern latitudes, but we still may be able to see 20-30 per hour. Very few meteors will be seen if you live upwards of 40 degrees N latitude. Don't let the low numbers stop you, though! With the radiant being fairly low in the sky these meteors may be 'Earth grazers' which hit the atmosphere at a shallow angle resulting in very long and lingering trails. Earth grazers aren't numerous, but they are memorable. To see these meteors look straight up if you are in the southern hemisphere, and straight up but slightly to the east if you are in the northern hemisphere. Let your eyes adjust to the dark, and be patient.
Meteor showers are named after the constellation that their radiant is in, in our case the constellation Aquarius. Specifically the radiant is in the 'water jar' near one of the constellations brightest stars, Eta Aquariid.  The images below will help both southern and northern observers navigate the skies and locate the radiant (but don't look directly at the radiant in order to see the meteors; look up!).
The Eta Aquariids are not only interesting because of their comet of origin. The Eta Aquariids have quite the history, being first recorded in old Chinese annals from the 8th century! It was'’t until 1868 that people suspected that Comet Halley and the Eta Aquariids were related, and not confirmed until 1900 by William F. Denning.
Another interest to scientists is the complexity/inconsistency of the activity rates. May 4-6 is always the main peak, but other maxima are frequently seen around this time. This unusual activity is likely caused by thick and thin filaments within the stream that Earth passes through. These filaments could be from planetary perturbations as well as a refreshing of the stream by comet Halley. One sure thing is that the Eta Aquariids are one of the oldest known showers, yet still one of the most interesting to study.
Since you are going to be out anyways, why not check out what else is in the sky! Saturn will be setting on the opposite side of the sky as the Eta Aquariid radiant and in the early morning you may be able to catch a party of planets; Venus, Mercury, Jupiter, and Mars (in that order) will rise in the east just before the sun does. Using a small telescope or binoculars may aid in seeing the planets. Happy viewing!

Eta Aquariid radiant in the water jar of Aquarius -- orientation for northern observers
(Starry Night). Constellations as seen from Huntsville Alabama, 4 am local time
(UTC-5 hours) May 6.

Eta Aquariid radiant in the water jar of Aquarius -- orientation for southern observers
(Starry Night). Constellations as seen from Brazil, 4 am local time (UTC-3 hours) May 6.

Quick facts on the Eta Aquarids:
  • Parent body: Comet 1P/Halley
  • Velocity:  66 km/s or 152,000 miles/hr
  • ZHR (meteors per hour): 60 max
  • Radiant constellation: Aquarius
  • First time recorded: 8th century by the Chinese, though the connection to Comet Halley wasn’t made until1900.

Courtesy of Rhiannon Blaauw, NASA's Meteoroid Environment Office, Marshall Space Flight Center, Huntsville, Ala.

J-2X Extra: The Rocket Engine Development Life Cycle

Diposting oleh vitto friend | 05.20 | | 0 komentar »

Everyone has in their personal histories certain events that they can look back on and say, "That's where things changed for me."  Some of these could be planned rites of passage like the first day of kindergarten, joining a little league team, getting your driver's license, and high school graduation.  Others are not necessarily foreseen or planned but seem in retrospect like inevitable events such as a championship football game, falling in love, or your child being born.  Everyone has a history, a story.  It is the narrative of how we come to be who we are.  Believe it or not, rocket engines also have a life story of how they come to be.
Below is a timeline of a rocket engine development life cycle (and, yes, that is actually what we call it: "life cycle").
The first thing that you'll notice from the drawing is that there are a bunch of NASA-typical three-letter abbreviations.  Sorry for that, but I promise that I will explain them.  Generally, think of these three-letter abbreviations as milestones or as gates through which the engine development project much pass.  For the rocket engine, these are its planned rites of passage.  The gray bars below the timeline of milestones describe the general activities during different phases of the development effort.  Note, however, that these are general notions and every engine development project is different.  For example, if what you’re doing is a change to an existing engine or if you have components already developed lying around and waiting to be incorporated into an engine, then perhaps you could do earlier component testing.  Also, not shown on here are such things as subscale or laboratory testing.  These too can often occur earlier in the life cycle thereby informing the design of the system.  On the other hand, if you’re starting entirely from scratch, then you've got to do a good bit of work before you would even know what to wring out in the laboratory.  In that case, everything can get pushed outwards to the right.
The first milestone gate in the life cycle is Authority to Proceed (ATP).  For activities as substantial as rocket engine development, we don’t go off willy -- nilly and decide for ourselves when to start such a thing.  While that might be fun for a little while, it is a generally accepted and overarching rule -- of -- thumb that prison is something we should to endeavor to avoid.  There is a whole chain of command that ultimately flows down from Congress and the Administration.  Thus, at ATP we essentially get a formal charter to fulfill certain objectives such as, in this case, develop an engine.  Also, with that charter comes the authority to spend time and money in pursuit of the objectives.  The authority part is key.  And so, not much can happen until ATP.
Next, you have the milestone of the System Requirements Review (SRR).  Before you can design something, you need to know what it is that you need and expect it to do.  Now, some requirements development had better have happened at a higher level before you even began the project -- otherwise, how would you even know that you need to start developing a rocket engine versus, say, a rocking chair? --  but getting a set of valid, system-level functional, performance, physical, and safety requirements is extremely important.  In addition to the system requirements pertaining to the engine, the other stuff that is part of the SRR is a whole slate of the programmatic documentation that forms the infrastructure for the organization responsible for the development effort.  This review therefore establishes the foundation of the product and the processes for the development effort to follow.
For all of these "reviews," what these represent is, usually, one great -- big meeting, sometimes taking several days, multiple smaller meetings, detailed review, comment, and response periods on documentation and drawings and analyses and test data, and a final, formal series of technical and programmatic board meetings airing any issues found, citing accomplishments identified, and declaring the success or failure of passing through the gate.  They are periods of intense activity and high internal and external scrutiny.
The next milestone in the timeline, the System Definition Review (SDR), is sometimes combined with the SRR.  The objective of the SDR is to demonstrate that you have a concept for the rocket engine that is plausible, feasible, and achievable given programmatic constraints.  However, since you need to have something in your head that is plausible, feasible, and achievable as part of the validation of your requirements set, separating SRR and SDR does not always make sense.  For J-2X, for example, we conducted the two of them as a joint review.
The first true design review is the Preliminary Design Review (PDR).  The question at this review is, at its root, pretty simple:  Do we have the right design?  Now that we've spent some time doing analyses, performing trade studies between subsystem design concepts, perhaps running component or subscale tests, laying out the initial drawings, can we say with sufficient confidence that we have a functional design that meets our technical requirements within the limits of the time and money we've been allocated?  To me, more than at any other moment in the development life cycle, this is that pivotal point.  If you fail here, everything stops, as it should.  It means that you've been working on the wrong design.  Start over.  However, if you are successful, then you start ordering materials to start building the engine and you commit to completing the design.  The stakes are very, very high.
The next milestone is an interesting one.  For many, many development efforts other than rocket engines, the Critical Design Review (CDR) is The Design Review.  For these other projects, it represents a true completion point for the final, to-be-flown design and it often takes place after prototype fabrication and testing.  But for a rocket engine development effort, the CDR takes on a somewhat different flavor.  This is because just building a rocket engine for testing can take several years and the necessary extensive test program that can also consume a couple of more years of activity.  Thus, for a rocket engine, the CDR is focused on getting the right design into the test stand.  The question to be answered is this:  Are we still on the right path, with the design essentially finished, to commit to the rest of the effort?  Therefore, you review not only the design (and associated matured analyses) but also all of the planning documentation that explains how the engines that you are already building will be used to demonstrate that the design meets all of the imposed requirements.  In essence, you have to prove that all of your ducks are in a row because now you're getting into some serious welding, grinding, shaping, and cutting of metal. 
Note that because CDR is not the final review of the flight design for a rocket engine, there can be a handful non-milestone check-point meetings during the years that follow the CDR.  For J-2X, we held one such meeting about a year after CDR in order to help come to closure on any actions lingering from the design phase and to review our maturing go-forward plans.  We may have another one prior to going into what we call certification testing with what we believe to be the true final, to-be-flown design of the engine.
The final, formal milestone for a rocket engine development project is the Design Certification Review (DCR).  At the end of this review process, the engine is declared to be certified for spaceflight.  So, what is reviewed?  It is a combination of several things.  The first part is known as a physical configuration audit.  This is basically a demonstration that you can (and have, and will continue to in the future) build what the design drawings prescribe.  The second part is known as the functional configuration audit.  This is a review of all of the collected evidence demonstrating that the engine fulfills all of the functional, performance, physical, and safety requirements imposed at the very beginning.  The evidence is a wide array of test data, analyses, and/or inspection results.  And the final portion of the DCR is a review and approval of all of the other products related to the engine design.  These include operational manuals and, most importantly, all of the reliability and safety analyses and assessments, plus an assessment of the quality and configuration management systems in place to ensure continued high standards during subsequent engine production.  Overall, when you complete a successful DCR, you are stamping the entire development effort as a success and pointing towards a future of successful launch operations.  It is therefore both an endpoint and a point of transition.
So, how long does all this activity take?  Well, that depends strongly on whether you're just making limited modifications to an existing design or if you're starting from scratch.  Using these scenarios as extremes, you usually can get to PDR in one or two years.  At PDR you start the process of test engine fabrication.  For very simple engines, fabrication can be as short as a couple of years.  For other, complex and large engines, fabrication for a first unit can take as long as five years or more.  Again, depending on how much new stuff you have to prove out, your test program could be as short as a year or as long as three years or more.  Thus, the duration between ATP and DCR could be as short as three or four years or as long as seven or eight (or, historically speaking for truly new and different stuff, even longer).  And that is all dependent on getting an appropriate funding stream…but that's a discussion for another time…
If you've made it through to the end of this article, you now have a high -- altitude perspective of what makes up the life cycle for a rocket engine development effort.  Successfully guiding that whole process from one rite of passage to another, from ATP through DCR (within budget and schedule), the entire development life cycle, sometimes seems like herding cats, but that's the essence of project management.  Luckily, as you can see from the picture above, I've had some experience with the whole clowder of cats thing.

J-2X Progress: Road Trip, Baby!

Diposting oleh vitto friend | 05.17 | | 0 komentar »

It wasn't too many years ago that there was this thing about asking sports heroes after winning the big game, "So, what's next?"  They would always dutifully answer "I'm going to Disney World!"  I guess that that whole thing is passĂ© since I've not heard it in awhile, so I am going offer an alternative.  Maybe it'll catch on and be the BIG THING this summer…

…or, well, maybe not.
But that is what happens next.  Our little engine is pulled out of the air-conditioned confines of its assembly area and trucked across the NASA Stennis Space Center to its test stand.  No more pleasantly cool and dry air for you, E10001.  This is Mississippi in June.  Thus, in order to make this trip out in the open like this on the back of the truck (don't try this at home!), the engine has to be sealed up tight against the humidity (and bugs) hanging in the air.  Anywhere where there is an opening, there is a cover, a closure, or a plug.  From the lot at the assembly building in picture (1) below, down the road towards the engine testing area in pictures (2) and (3), and finally arriving at the lot behind test stand A-2 in picture (4).  In picture (5), you can see that the truck backs in alongside the test stand for the next operation.

The next operation is to get the engine up into the test stand.  Years ago, this test stand was built for testing the Apollo Program S-II stage (the second stage of the Saturn V vehicle that was powered by five J-2 engines).  Back then, they basically picked up the whole stage (from a canal barge, not a flatbed truck) high into the air and lowered it down from above into the stand.  When it was converted to be an engine-only test stand for Space Shuttle Main Engine testing in the early 1970's, propellant tanks were added on top of the stand.  So you can no longer lower the test article in from way up above.  Rather, you lift it up about four or five stories and then pull it in laterally.  This is the "engine deck," the level where the engine will be installed into the stand.  In the pictures below you can see the operation of pulling the engine off the transport truck and up to the engine deck level of test stand A-2.

After the engine is lifted to the correct height, it is brought laterally into the stand and set down on the "porch."  That's what the folks on the test stand call it: the porch.  The other day somebody (obviously from out of town) mistakenly referred to it as the "veranda."  We'll have none of that fancy talk around here!  The thing onto which the engine is set is the Engine Vertical Installer (EVI).  This is a hydraulic lift table that will be used to raise the engine into place when it is to be bolted to the test stand.  So, here is the sequence: you lift the engine up to the engine deck level, you pull it into the stand and set the engine down on the EVI sitting on the porch, then you slide the EVI horizontally into the heart of the test stand (the EVI is on rails for this purpose), you then raise the engine into the test position, bolt it in place, and then you slide the EVI back out of the way.  Ta-da!  Now you've installed an engine for test!
In the pictures below you can see the technicians positioning the engine onto the EVI on the porch.  In the bottom picture of the set, you can see in the background to the left test stand A-3 still under construction and, to the right, test stand A-1 where, early next year, J-2X powerpack testing will be conducted.

So, our little baby engine is all grown up and ready to see the great big world from high up in the test stand.  The next phase of our development program is now begun: the testing phase.  After the engine is installed and the test stand is readied for hot fire, J-2X development engine E10001 will be used to demonstrate basic operations such as start, mainstage, and shutdown, to verify main chamber combustion stability, and to provide initial validation of numerous systems-level simulations and models.
Okay, somebody go carefully poke the Datadogs because soon we're going to have genuine, full-up rocket engine test data from J-2X.  And, as a final note, I offer an extra special tip of the hat to all of the folks at SSC (NASA, Pratt & Whitney, and support contractors) for doing an amazing job in terms of engine assembly and test stand readiness preparations.  Don't ever think that your extraordinary efforts go unrecognized or unappreciated.  Bravo!