Category: Effective Mass Properties Programs

The Orion spacecraft recently underwent mass properties verification in Houston in preparation for the second Launch Abort System test.  NASA Langley Research Center was intimately involved and LaRC engineers Amanda Cutright and Anjie Emmett were on hand for the operations.

Here is a video clip of Anjie and Amanda explaining the testing:

http://www.dailypress.com/visuals/video/95951602-132.html

Knowing the mass and the CG of the Orion spacecraft is a safety of flight issue.  The AA-2 (Ascent Abort – [test] Two) test flight will test the Launch Abort System during the critical boost phase of the Space Launch System.  The LAS must safely remove the Orion capsule with its crew away from a failing booster if there is a launch mishap. The earlier PA-1 (Pad Abort – [test] One) test performed a similar function, but from a stationary simulated launch pad.  The AA-2 capsule is an actual Orion Command Module, instrumented and mass simulated for this test. The fixture seen in the videos was built to enable multiple weight and CG measurements to be made in multiple orientations and is reusable on subsequent Orion vehicles.

The Houston Chronicle also posted an article on the verification test at:

https://www.houstonchronicle.com/news/nation-world/article/NASA-s-Orion-spacecraft-test-module-passes-13152137.php#photo-16006303

Amanda and Anjie traveled to Johnson Space Center in Houston for the testing.   They are seen in the background of the video above.

The Norfolk, VA area newspaper The Daily Press also ran a story about the testing:

http://www.dailypress.com/news/science/dp-nws-nasa-langley-orion-test-20180215-story.html

Both Amanda Cutright and Anjie Emmet are members of the Hampton Roads Chapter of the SAWE.  Amanda is co-chair of the upcoming 78th International Conference on Mass Properties Engineering in Norfolk, VA  from May 18 – 23, 2019.

 

Robert Zimmerman

SAWE Vice President – Technical Director

In 1986 I was seemingly drifting from project to project on a short-term basis when I was asked to report to a program known only as Program B.  I arrived at the locked door on the fifth floor of a building we jokingly referred to as “The Six Story Building”.  After knocking on the door, I was greeted by a secretary who looked at my badge, checked my name against a list, and let me in.  I was shown a desk, where I dropped my briefcase, and then followed the secretary to what proved to be the program manager’s office.

Inside, there were a small group of people standing around.  The secretary left and came back a few minutes later with another person.  This continued for about 15 minutes, then a slight, balding man arrived and shut the door.  He introduced himself as the program manager, whom I will call Doctor E.  Doctor E went around the room asking each of us to state our names and areas of expertise.  Then he explained what we were doing.

The government was looking to launch a satellite that would use an infrared device, cooled by a Dewar jar filled with liquid methane.  We were to design this satellite, incorporating the various instruments and this quite large and heavy Dewar.  And then we were hit with the kicker – the launch vehicle was already designated, and it did not have a large payload capacity.  And the deployment stage would spin for stabilization.

I went back to my desk and began listing what this satellite would need – structure, electronics, tubing, cabling, power, etc., and going over the specs we had been given for the instrumentation and the Dewar.  Then I conceptually created a satellite and came up with a weight estimate that I took to the structures lead.  He called in the thermodynamics engineer to look at what I had come up with just as the power engineer arrived with his concept of how to power the satellite.  The power engineer envisioned a satellite surrounded by solar panels, and I still recall the thermal engineer’s initial reaction, namely “Don’t put me in a box!”  The four of us sat there in structure lead’s office and hashed out a top-level packaging scheme and I ran a quick calculation to see what that would weigh.  Just then Doctor E came in and looked at my figures with dismay.  He shooed us out and closed the door to the structures lead’s office.

The next morning the structures lead came to me and said he ran his own calculations overnight and agreed with what I’d come up with.  We marched into Doctor E’s office and presented a united front.  His reaction was “OK, but we have to keep the weight down to allow for specification creep.”  The three of us looked at each other and the structures lead had this look on his face that said “Duh!”

The next few weeks were hectic, 7 days/week for 10-11 hours a day as we breezed through refining the design, looking to minimize cabling, tubing, and electronics while I also spent a lot of time with component placement to keep the spin axis aligned with the deployment stage’s spin axis.  As time went on, my constantly updated mass properties database converged with my “back of the envelope” calculation to within a few pounds.  This was done by constantly questioning every part and any change the various groups decided belonged on the spacecraft.  With a cohesive group of dedicated engineers who shared a common purpose in winning this proposal, keeping the weight under control was relatively easy.  Finally, as the deadline for delivering the proposal neared, the company held a “Black Hat Review” of our proposal, meant to uncover weaknesses in our design and proposed methodologies.  This was held over a Saturday and Sunday, meaning most of the team finally got some time off while the upper management met with the “Black Hats” and walked through the proposal’s many pages.

Monday morning, as we came in, we heard that there would be an all hands meeting in the conference room.  A few minutes before the appointed time we filed in and were surprised to see the company President sitting up front next to the program manager.  Also present were other senior level executives.  Doctor E started speaking, telling us that the Black Hats, who were sitting in front of us, had never seen a stronger proposal.  There were a couple of nits, but these were truly insignificant items that were easily fixable.  We all started to smile, then the company President rose from his chair and walked to the podium.  He told us that the value of this particular project was small, and in a few months’ time the same government customer would be evaluating another proposal the company was working on.  The Program A proposal was worth more than ten times as much as Program B.  It was the consensus of the Black Hats that we would win the Program B proposal, at which point the government could (he said “possibly would”) award the other proposal to a different company, as we would already have won one.  Therefore, the Black Hats had decided to tell this customer that our company was a “No Bid” on Program B and this winning proposal team was hereby transferred to the Program A proposal.  You could see the disbelief on everyone’s face as we filed out of the room to pack up our belongings and head to the facility where Program A was already underway.

Arriving at the other facility, I went in and found my new supervisor.  I knew that there was already a mass properties engineer assigned to this proposal, which had been in conceptual design and pre-proposal activities for over a year.  I was told that the other engineer would temporarily report to me while the company found a place for him – in other words there was only budget for one mass properties engineer and I was to be it.  I didn’t like the feeling that I was taking someone else’s job away, but I went and found the outgoing engineer who had already heard what was happening.  He turned over his files to me, went through a quick overview of Program A, and left.

I went to my new desk, started going through the reams of paper and the mass properties database, and was shocked at what I found.  The program was seriously overweight.  There was a hard requirement for launch capability and the mass properties database showed our design was over by hundreds of pounds, fully 50% over the launch capability.  Obviously, we weren’t meeting requirements, with the trade-off being a severe shortage in range.  My first stop was with the flight design group to verify range versus payload and compare that to what the database said we were carrying.  Next, I went to my new supervisor and told him what I had found and questioned why he hadn’t told me about this when I had first met him.  Amazingly, he was unaware how severe the situation was, although he knew we were overweight.  I went to Doctor E, who was now the deputy program manager on Program A and explained what I’d found.  He said two words, “Fix it!”

Going back to my supervisor, I asked for a copy of the technical proposal.  He said it wasn’t finished, and I said then get me what we have.  I started going through the proposal subsystem by subsystem, checking what was in the proposal against the mass properties database, and verified that the database was generally accurate.  Moreover, it looked like the known unknowns were accounted for.  That, at least was good news – we weren’t worse off than I thought we were.  Next, I went to each lead, subsystem by subsystem, and introduced myself, explained that we had a severe technical challenge, and that I wanted to verify that what I had in my proposal document was the current design.  There were a few differences, but overall everything checked out.  Then I went to the vehicle architect and spent several hours with him and the systems lead going over what I knew, and with Doctor E’s admonishment behind me, explained that we had to “Fix it!”  Shaving a few pounds here and there was not going to give us a viable technical proposal – this needed a rethinking of what we were trying to achieve.

With the words, “If we remove an item, we achieve a 100% weight reduction of that item,” I shocked the system architect into action.  Together we called a mandatory meeting of all subsystem leads, where I repeated what I’d said and then went on to say that unless we could prove we needed an item, it was off the vehicle.  There was, of course, consternation.  We went single-string on many subsystems.  Structural pieces were pulled, the size of the whole vehicle shrank as space was no longer required for this or that box.  Cabling mass came way down.  We shaved material from component boxes, structural members, skins, insulation, combined functions of multiple electronic boxes into one component – anything to get the weight down.

I was on that proposal for six weeks without taking a day off, although I admit I did work half days on Sundays (five hours versus 10 or 11).  We passed our Black Hat Review.  We turned the proposal in but did not win the contract.  The customer said we were in technical compliance but that other companies had better cost and management proposals.  BUT – we did not lose on technical grounds, which we surely would have if we had been 50% overweight.  I can count that as a “win”.  Losing a proposal is not unusual, it happens a lot, just as a company’s decision to “No Bid” a proposal is not unusual.  These are part of corporate life, and corporate life lives on despite these setbacks.

The lesson learned is that a mass properties engineer is much more than a clerk.  Yes, we have to keep track of the mass properties, but that is only part of the job.  Know what your requirements are.  Keep your management informed.  Interact with your subsystem compatriots.  Don’t let a small problem become a big problem.  Look at the overall picture and determine if what you are doing supports that vision.  And most importantly – you may be the “Weights Person”, however, keeping mass properties under control is everyone’s responsibility, so enlist others in the quest to maintaining a technically sustainable design.

Robert Zimmerman

Message from the SAWE President:

So what does it take to have an effective mass properties program?

Our society’s publications provide insights into the elements and mechanics, but organizational behavior is one element we barely address.  This is the first in a collection of stories from fellow mass properties engineers who want to share their most memorable experiences of a robust mass properties effort.  Take note over the course of these stories what the common denominator or behaviors were that led to a favorable outcome.

Your Job is to Keep Me From Being Fired 

Submitted by an Honorary Fellow of SAWE

After several years of study, a large aerospace company received the go-ahead to respond to an RFP for a class of rockets to be used as target vehicles for the Missile Defense Agency (MDA) to test various Ballistic Missile Defense weapons.  As a result of already being assigned to the missile defense group, a mass properties engineer found himself now working on multiple programs, including the new target vehicle program.

Of particular interest to the MDA was for the company to create a (relatively) inexpensive surrogate missile that would emulate a class of threat missiles with a longer range than SCUD-class missiles.  The company already had studied such a design, and proposed this to the customer, who accepted the proposal with one additional request.  Since the design was using existing mothballed assets to simulate this threat to keep the cost down, the design utilized solid rocket motors.  The threat class did not, and so the end-of-flight behavior of the motors would deviate significantly from the desired behavior, as non-volatile material could be unceremoniously and randomly ejected from the spent motor, imparting momentum to the stage.  A solution would be to spin up the stage, thereby pinning this non-volatile material in the stage and adding predictability to the missiles flight path, just like the threat vehicle it was supposed to emulate.

You can see where this is going – this is a huge mass properties nightmare in the making.  Spinning along the long axis is unstable, yet that is what is necessary to keep the vehicle going where you want it to.  The amount of “leftover” material in the motor is variable, as is its location, which affects CG, and more importantly, Products of Inertia.  Each test flight would have different equipment, meaning even if you could come up with a set design to keep the spin axis pointed correctly, this would have to be recalculated for each flight.  So, the mass properties engineer (MPE) had a real problem to work on when the go ahead to go for this class of threat targets was received.  And to complicate matters, as happens so often, a new management team came in. This was emplaced on top of the skeleton proposal management team, and the team started to hear about this new Program Manager, whose name we will call Oscar (not his real name), in unpleasant terms from those the MPE reported to, including the person who had been the proposal manager and now was reconfigured into the engineering manager.  He emerged from one high level meeting and stated, “I’ve been Oscarized!”  Soon, the whole team started hearing of others who had been Oscarized.  None looked particularly happy about it.

A week after the management insertion, when the MPE had introduced a possible solution to the variable product of inertia (POI) problem and was busy trying to get the design team to understand that the mechanism proposed had to be configurable right up until the payload was attached, the MPE received a call from Oscar’s secretary, saying that Oscar wanted to speak with him.  “Uh-oh, here comes my Oscarization,” he thought to himself.  The dreaded “BOHICA” that had been the talk 20+ years earlier.  Nevertheless, he prepared for the one-on-one with Oscar, set for 10AM the following morning.  The MPE showed up at Oscar’s door few minutes before 10 AM and was told to wait. Ten minutes went by.  Fifteen, then the door opened and the Engineering Manager came out, looking uncomfortable and mouthing at the MPE, “I’ve been Oscarized”.  “Come in,” the MPE heard Oscar say, and “shut the door.”

The MPE had his proposed solution to the POI problem, as well as what he was proposing to keep the other mass properties under control, and was prepared to go over everything.  Instead, Oscar said to sit down, and proceeded to talk.  Oscar went through his career, where he had spent the majority of it on space launch vehicles, having started on the company’s mainline program.  He had risen through a succession of positions which put him on the management track, eventually reaching the company equivalent of a brigadier general.  He worked directly for a Vice President on a program that had several problems.  One of those problems was mass properties – in this case the weight carrying capacity of the launch vehicle.  At this point Oscar looked right at the MPE.  He said “You are in charge of the mass properties of this program.  If there are any problems I need to know about them.”  The MPE started to pull out his papers and Oscar said, “Not yet!  I’m not done.”  He continued with his narrative – somewhat familiar via hallway talk.  Turns out this launch vehicle program from his past promised certain customers that the vehicle could perform certain missions, and then failed to do so.  This caused multiple investigations, both by the company and the customer, where it became obvious that the promised capability was not there, and this was not known to everyone.  The Vice President was asked to resign, in other words he was fired, being ultimately responsible for the program.

Oscar looked at the MPE.  He stood up and paced.  Then he said, “I’ve seen what messed up mass properties can do.  Mass properties is a hot ticket item to the company and to our customer.  As far as I am concerned, you are the lead of the mass properties team, and I know we have challenges, so you do whatever it takes to keep mass properties in line.  Your job is to keep me from being fired!  Do that and everyone will be happy.”

The MPE realized he was being offered a favorable hand, even if it was carrying a stick.  He also realized that he had an opportunity to really affect the program.  Properly cued, he went through what he thought had to be done to ensure the program would not have weight or POI problems.  Oscar looked at the proposed mass properties control program and the POI solution, and told the MPE to get with the engineering manager and tell him he approved the concept.  And then he stood up and opened the door to his office and said to the person sitting outside his office, “Come in, and shut the door.”

The program was successful.  The vehicle flew successive multiple missions, maintaining the desired pointing of the spin axis.  Additional class vehicle programs came the company’s way, each with their own idiosyncrasies to contend with.  And Oscar was not fired, but instead was able to retire, vindicated.  Everybody was happy.  Well, except for the usual grumbling…