Effective Mass Properties Programs – Your Job is to Keep Me From Being Fired

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…


Leave a Reply

Your email address will not be published. Required fields are marked *