Q&A with long-time AEDC worker, aerospace expert

  • Published
  • By Philip Lorenz III
  • AEDC/PA
ARNOLD AIR FORCE BASE, Tenn. --  The Tennessee chapter of the American Institute of Aeronautics and Astronautics (AIAA) recently hosted a space and missiles lunch and learn presentation at the Arnold Engineering Development Center (AEDC) with a guest speaker who has a long history with Arnold.

Sam Dougherty is a former AEDC employee and is the Technical Fellow for Thermal and Fluid Dynamics with Jacobs Technology and ERC, Inc., at NASA's Marshall Space Flight Center in Huntsville, Ala., for the Engineering, Science and Technical Services Group.

Dougherty, who spent 22 years at AEDC and 20 years at Boeing and Rockwell International, gave a presentation on "The History of Simulated Altitude Liquid Rocket Testing at AEDC," based on his recent technical paper at the Joint Propulsion Conference.

Dougherty took the time afterward to share some of his professional experiences and his vision of AEDC going forward.

Q: Why did you choose engineering, with a focus on thermal and fluid dynamics, both academically and as a profession?

Dougherty: I was at McCallie School in Chattanooga and entered the Regional Science Fair my senior year. I built a Mach 2 supersonic wind tunnel. I wrote a letter to AEDC and was invited over for a whole day at VKF (the von Kàrmàn Gas Dynamics Facility). I then applied for the co-op program with ARO, Inc., at the University of Tennessee Knoxville and was fortunate enough to be accepted.

Q: Your biography says that you began your professional career as a co-op student at AEDC in June of 1958.

Dougherty: Yes. My 50 years coincides with NASA's 50 years.

Q: Who were some of your mentors?

Dougherty: My grandfather. He was dean of [the college of] engineering at [the University of] Tennessee and I was struggling with the idea, 'did I want to become an engineer?' He didn't pressure me, but he came to my high school graduation. He just quietly gave me a slide rule for a graduation gift - [an] $18.75 K&E slide rule. I still have it.

He (Nathan Washington Dougherty) came to AEDC when he retired at 70 and he helped establish UTSI, he was part of the establishing of the curriculum at UTSI. He retired in 1956, came to AEDC right at that same time I was a high school graduate in 1957.

I started in 1958 and [AEDC was] just a major place to go for us in Tennessee, we knew it. There was Alcoa; there was ARO, Sverdrup, Oak Ridge National Laboratory and AEDC.
I had many great AEDC mentors. AEDC was among the best of assignments anywhere. I then went to UTSI part-time after my B.S. My major professor was Dr. Jimmy Wu.

Q: What was it like to be a college student working at AEDC during such a pivotal time in its history and in those early years of the space race?

Dougherty: It was exciting to come to work every day. My first project was in design with Joe Reavis on the Atlas Missile Model Base Heating Investigation in T-1 Test Cell.

To go out to a test cell and touch flight hardware was just an exciting, fantastic experience. [This included] the people who you were with - the AEDC people and user representatives who came in to test. It was very purist, engineering in its purest kind of sense. And it was all new and there were so many firsts in our facilities.

Q: What was your most significant first while at AEDC?

Dougherty: There were three - Apollo 7, 8 and 9. Apollo 7 - the first manned Apollo flight. Apollo 8 - the first human Saturn V flight and we went to the moon circum-lunar. Apollo 9 - the first manned flight of the Lunar Module [LM]. We tested the Apollo Service Propulsion Engine in J-3, the LM Ascent and Descent Engines and Reaction Control System thrusters in the J-2A, and the S-IVB Stage in J-4 Test Cell.

Q: How significant a role is computational fluid dynamics [CFD] currently playing in the study and ground testing of rocket motors at places like NASA and AEDC?

Dougherty: We routinely perform CFD analyses of everything along with fluid dynamic and aero physics experiments and tests. I cannot overemphasize the importance of CFD in our propulsion and vehicle work. But we still verify by test.

Q: What are some of the newest technologies, materials and sources of rocket fuel on the horizon or in the near future - ones that are the most promising for improving space mission capabilities as this country goes forward?

Dougherty: Looking forward to the 2020s and the 2030s, for some missions to Mars, we will need nuclear electric or nuclear thermal propulsion and nuclear power. In a decade or two, the TRL [technology readiness level] for fusion drive may become acceptable.

For Earth-to-orbit we need chemical propulsion and there is LOX (liquid oxygen) -hydrocarbon heavy lift and LOX-hydrogen upper stage in-space. There are storable hypergolic in-space and LOX-methane in-space. I suspect we still have solid rocket motors to test - boosters and small solids for stage separation and ullage settling. [Ullage is the space within a fuel tank above the liquid propellant].

But much of the testing on the ground may be at the component level instead of the engine system or full stage level, and nuclear testing may take place entirely in space. So transfer everything we know about how to conduct systems-level testing in a ground facility, but figure that we might be doing it robotically in space, acquiring data in space and tele-metering it all back down to the ground.

Q: What is the value in giving presentations at AEDC like the one you just gave? How do you hope your peers at AEDC will use what you have to share with them?

Dougherty: Lessons learned - I come from a test background. I grew up in test and analysis. I have been on the prime contractor side and therefore a user of the test facilities. [I would also say] insight from [the] inside and as a user, and insight from NASA as sponsor and customer. NASA was the USAF's customer using the AEDC facilities. Plus I was there, I lived it and I am one of the few still around to tell about it. So many have retired and passed on.

Q: As budgets, both commercial and DoD, shrink, tighten or however you might want to characterize it, how can places like AEDC remain viable in the area of rocket motor testing from both the leadership/management side and from the project engineering side of the house? 

Dougherty: There have always been the AIAA and JANNAF (Joint Army Navy NASA Air Force) forums to exchange ideas and technologies and there is the National Rocket Testing Alliance to preserve our mutual interests in testing capabilities nationwide. NASA and the USAF remain in a long-standing partnership to preserve and advance our test capabilities.

My point in the lecture is that generations of us come and go and our facilities are our great crown jewels. Take care of our facilities. Maintain and upgrade our facilities.