So how autonomous is 3D printed construction, really?

After a week long reboot following our epic win in Peoria, IL, I had the opportunity to link up with AI SpaceFactory teammates Jeffrey Montes and Christopher Botham for a full mission debriefing. 

For those of you recently following us, MARSHA is our prototype Mars habitat, robotically 3D printed with materials indigenous to Mars. AI SpaceFactory was awarded in both the design and construction phases of NASA’s four year long, multi phase challenge, culminating in a thrilling 30 hour head-to-head final versus Penn State. We dubbed our 15-foot tall 3D printed prototype ‘MARSHA-alpha’, meaning it was our first attempt at constructing MARSHA, and certainly not our last.

“We were just happy to ooze.” - Jeff

Jeffrey and Christopher are original members of AI SpaceFactory’s design team who took up residence at Autodesk’s BUILD space in Boston, where they quickly learned the tools of the trade — and pushed it to new heights. If you saw the media coverage pouring out of Peoria, you might think Jeff and Chris had been 3D printing and operating robots for years. The reality is that they started from scratch eight months ago.

“Transitioning from architecture to robotics came naturally because I’ve always a technical bent to my architecture work,” explains Chris. “The type of software that I was familiar and intimate with from my architectural training happened to translate well to some of the robotics.” Added Jeff, “In the beginning, we were just happy to ooze.”

AI SpaceFactory’s First Print: “Arrival" - October 10, 2018

As their first 3D constructs climbed higher and higher, Jeff and Chris did more than build up their skills. They built up trust in each other: an ethos which they extended to new members as the team grew in size. Ultimately, that proved to be the decisive factor in narrowly edging out Penn State. The team’s ability to react and improvise meant having to spend a lot less time stopping the print. 

Explains Jeff, “NASA judged on the basis of autonomy. Each time we remotely intervened by adjusting the robot path, or physically intervened by stepping into the ring when things got really bad, NASA would time every second and deduct from our score.” The team became so efficient at making quick fixes on the fly that they resembled a Formula One pit crew more than a team of robot operators. “Chris was usually at the controls, and I was up on a ladder watching the print. There was no line-of-sight between us, so we had to rely on each other.” 

Chris and Jeff in the “Tub” after placing 2nd in a lead-up round to the Finals

The team benefitted from having rehearsed complex maneuvers back at the lab in Boston. Still, they had never printed a complete MARSHA before stepping into the spotlight of the NASA finals. Murphy’s Law kicked in almost immediately. Recalls Jeff, “Someone had forgotten the keys to the robot!” After one false start, the team got things back on track - but had lost minutes of valuable time.

As the clock ticked down to the final hour, the accumulation of tiny delays spread over 3 days of printing came to bear. Earlier in the day, Jeff and Chris noticed a potentially fatal slump in the print caused by overheating of the biopolymer material. In a carefully choreographed maneuver, the team slowed the robot to a crawl to deposit more material to level out the print.

Jeff takes his position on the ladder as MARSHA nears completion

Chris explains, “We had the same problem when we printed the Tub back in Boston. We fixed it then so we knew what had to be done.” Still, the slowing maneuver meant the print might not finish in time.Then came the dramatic final minutes. The 3D print was several layers short but the team had yet to robotically place a skylight to enclose the structure. At issue was whether the opening at the top was too large for the skylight, since the full taper had not been achieved. “I was up there begging the team for two more layers,” remembers Jeffrey, “and eventually we decided on one.”

"It came down to the final second." - Chris

Realizing there wasn’t enough time to adjust the code to place the skylight on a slightly shorter MARSHA, Chris stood up and grabbed his flex pendant to manually control the robot. “So the last moments, when I was piloting the robot, it was blind,” recalls Chris. “Per the rules, I couldn’t be looking at what I was doing. My team had to guide me through the process and yell out instructions. As soon as the skylight got into place, I heard somebody, which Jeff told me it was him, yell ‘Disengage’ meaning open the gripper and let the skylight go. I got it done with about two seconds left and maybe a second later I heard a big bang from the inside and it took me a few seconds to understand what it was, but looking up I couldn’t see the skylight anymore.”

The skylight had fallen through the hole and hit the ground; but for one brief, shining moment it was there. 

Chris piloting the skylight into position in the final seconds of the NASA Challenge

While the team had fallen ever so short in crowing their achievement, the final day of testing and awards validated the long days and nights Jeff and Chris spent in the lab away from friends and family. MARSHA’s unique 3D print material, a composite of biopolymer and basalt fiber, proved to be significantly stronger than its concrete competitor. In the final ‘crush test,' a 200,000 pound Caterpillar excavator bore its weight down on MARSHA. “After a while I heard a little cracking sound like a frozen lake but then nothing happened,” remembers Jeff, “then someone yelled that the Caterpillar treads were lifting up off the ground.”

Sure enough, the Caterpillar started lifting itself off the ground while MARHSA didn’t budge. It would take two Caterpillar machines doing a pincer move to eventually slice it into quarters. The machines drove away with the material, where the team used a saws-all to finish off the job. We put the pieces of MARHA back on our trailer headed for New York, where we will use it to demonstrate the most remarkable aspect of our super-strong material: it’s recyclable. AI SpaceFactory will be using the remains of the MARSHA-alpha prototype to 3D print our first Earth habitat, TERA, this Summer in upstate New York and open it to our first guests later in the year. 

Remains of the day: MARHSA-alpha headed for the recycling container

So looking back, what are the lessons learned from MARSHA-alpha? 

1. We developed a sustainable and recyclable material, made essentially of plants and rock, which outperformed concrete in every strength, durability, freeze-thaw, and quality test
2. Our material can be successfully extruded to create complex, high-performance forms with speed and precision. Since our material is recyclable, we can go out and print our Earth habitat version this summer
3. We can use a single robot to both 3D print the structure and to autonomously place pipes, windows, and (next time) a skylight
4. 3D printed construction is far from a fully autonomous process and requires human eyes on the print, practice, and improvisation
5. We succeeded in printing what is believed to be the world’s tallest in-situ 3D printed structure in just 30 hours. Chris believes, “As far as our material is concerned we could print taller. The height itself doesn’t seem to be the problem. Someday it will be possible to 3D print a skyscraper.”

Most importantly, we learned that despite the highly visible robotics and high-tech design, our success came down to the efforts of two young architects, who together with their team, stepped up to the plate and swung for the stars. From classmates at Columbia University to early recruits at AI SpaceFactory, Jeff and Chris are now champions of the NASA Centennial Challenge. As if winning wasn’t the best part, “Watching the Caterpillar lift off the ground was the highlight of my career,” says Jeff with a smile.

Jeff and Chris — your careers with AI SpaceFactory are just starting. Just wait until we build on the Moon.

This article first appeared on the AI SpaceFactory blog at https://www.aispacefactory.com/post/so-how-autonomous-is-3d-printed-construction-really

#nasa #mars #3dprinting #space #architecture #construction #technology