Roger Wacker

Sorry about the font all. Yes, eyes are 67 yrs old. My worked at NASA spanned Shuttle, ISS, X-38 and Artemis, specifically the Orion spacecraft. BTW, I built the Lego Saturn V rocket with NO issues. My worked focused primarily in control. I did receive a masters and stopped my PhD work to start making money. I worked both on- orbit and entry for all vehicles ( yes I even did one of the first studies in de-commissioning ISS). I would say my expertise is in flight control. That discipline still demanded systems knowledge of sensors, actuators, effectors as well as guidance & navigation. Myself and an a colleague designed a complete entry flight control system using dynamic inversion to control aero surfaces. Successfully tested it 4 times launched from a B52. I did the entry flight control design for Artemis. Pretty simple because you only have one degree of freedom (roll) to control the lift vector. I will mention that achievement of guidance trajectory commands of a spacecraft in LEO, cis-Lunar and LLO that carry many different types of engines (RCS, AUX and OME) in the face of rigid-body, flex and slosh dynamics with imperfect Navigation (we do use GPS when we possible) can present challenges. I worked using various effectors alone and in concert to achieve flight objectives (delta-V, pointing, rendezvous & docking, etc). Good luck with your studies. Aerospace is a very exciting field to be in if that’s your goal!

Lego post A Warning to Prospective Buyers of LEGO 10341 NASA Artemis Space Launch System I want to share my experience with the LEGO 10341 NASA Artemis Space Launch System because I think prospective buyers should know what they may encounter. I purchased this set approximately two months before the planned Artemis II launch. My goal was simple: build the model and have it completed in time for the launch. I was particularly excited about this set because Artemis is not just an interesting subject to me—it has been a significant part of my professional life. I spent 40 years working for NASA and as an engineer, and I personally designed a number of systems associated with the Artemis spacecraft’s GN&C effort. So when I saw LEGO’s 3,601-piece Artemis model, I couldn’t resist. LEGO describes it as an accurate replica of the Artemis Space Launch System, and at $259.99, it is certainly positioned as a premium adult model. Unfortunately, my experience has been extremely disappointing. I have now encountered nearly 100 missing pieces in my set. To be clear, LEGO has been willing to replace the missing pieces at no charge. I appreciate that. The problem is the turnaround time. I have been told that replacement pieces can take approximately three weeks to arrive. And there is an even bigger problem: I don’t yet know how many additional pieces are missing. I have not inventoried all 3,601 pieces against the approximately 300 pages of building instructions. Doing that would essentially require me to go through the entire instruction book in advance, identify every part required at every stage, and create my own inventory spreadsheet. That isn’t a reasonable expectation for someone who purchased a LEGO set expecting to build it. Instead, I discover missing pieces as I progress through the build. When I reach a step and the required piece isn’t there, the build stops. I request a replacement, wait several weeks, and then continue—until I encounter the next missing piece. At this rate, a project I bought specifically to complete before the Artemis II launch could potentially take close to a year. That is profoundly disappointing. I’m not posting this because I expect LEGO to give me special treatment because of my NASA background. I’m posting it because people considering purchasing this $259.99 set deserve to know about my experience before they spend the money. This is a 3,601-piece premium adult model representing a subject of enormous historical and engineering significance. For me, it was supposed to be a fun and meaningful way to celebrate a program I have spent much of my career working on. Instead, I’m spending a significant amount of my time troubleshooting LEGO’s parts inventory. I hope LEGO will take this experience seriously. Providing replacement pieces eventually is appreciated, but it doesn’t completely solve the problem when the customer has to repeatedly stop a 3,601-piece build and wait weeks for individual replacement shipments. If you are considering buying LEGO 10341, I would strongly recommend that you understand this potential issue before purchasing it. I would also be very interested in hearing from other owners of the 10341: Have you experienced significant numbers of missing pieces? If so, how many, and how far into the build did you discover them? I’m interested in documenting the experience objectively rather than simply complaining. — A retired NASA engineer who really wanted to see his LEGO Artemis launch before Artemis II