Houston, We Have the Engine Remnants: How My Lab Pieced Together a Forgotten Part of an Apollo Rocket

Like many individuals, I had desires of flying into area as an astronaut once I was a toddler. That curiosity in aerospace and area exploration has continued all through my life. 

So when my colleague Tim Foecke, who was working at NIST on the time, invited me to help with a analysis mission involving the Apollo area program, I jumped on the probability. Tim has a protracted historical past in marine forensics and conservation.

Ten huge Saturn V rockets launched astronauts into area throughout the Apollo missions to the Moon. To succeed in the Moon, particular person rocket items, referred to as phases, had been discarded as they ran out of gas. The primary phases of the Saturn V rocket fell into the Atlantic Ocean and have been there because the Sixties and Nineteen Seventies. 

A decade in the past, Bezos Expeditions recovered a few of these artifacts from the ocean flooring. Conservators labored for years to protect these objects for examine.

Many of those items at the moment are on show in museums for the general public to view and keep in mind the Apollo program. Among the most intact objects had been the massive F-1 engines. The conservators decided the artifacts got here from Apollo 11, Apollo 13, Apollo 14 and Apollo 16 missions, based mostly on the place they had been discovered and serial numbers nonetheless seen on some components.

Tim and I initially labored with among the conservators to assist determine among the supplies used within the rocket engines. Nevertheless, the conservators had important challenges with one sort of piece — the turbine blades. They discovered many blades had been a lot lighter than they need to be and had been fragile to the touch.

After being retrieved from its longtime resting place on the Atlantic Ocean flooring, a turbine blade from the Saturn V’s rocket engine lately made its option to our lab in Gaithersburg, Maryland, for evaluation.

I used to be initially fairly puzzled by the point out of turbine blades. I knew they’re generally utilized in jet engines, however I initially struggled to determine how they match into rocket engines. Studying up on it extra, I used to be astounded to search out the generators had been a part of a jet engine hooked up to every rocket, with the only function of driving the gas and oxygen into the rocket engine!  

The Story of the Saturn V Rocket and F-1 Engines

The design for the F-1 rocket engine used within the Saturn V began within the Fifties. The designers imagined the most important capability engine that could be used within the subsequent decade. 

Rocket thrust is the power that determines if the rocket strikes in any respect, what cargo or devices the rocket can launch and the way shortly the rocket will speed up because it strikes by means of the air. The designers settled on the spherical variety of 1 million kilos of thrust (4.4 meganewtons) for this engine. 

On the time, most rocket engines produced about 120,000 kilos of thrust (530 kilonewtons). So, creating an engine with 10 occasions that quantity of thrust may need appeared a bit absurd. However with the creation of NASA in 1958 and the next area race all through the Sixties, the concept wasn’t so far-fetched anymore. NASA realized the necessity for high-thrust engines able to propelling astronauts all the best way to the Moon and again. 

By the point the Saturn V designs had been finalized, the F-1 engines had been upgraded to 1.5 million kilos of thrust (6.6 meganewtons). The Saturn V used 5 of those engines for a mixed thrust of seven.5 million kilos (33 meganewtons).  

All that thrust was wanted, because the Saturn V itself was taller than the Statue of Liberty and weighed over 6 million kilos (2.7 million kilograms). The overwhelming majority of the load was a mixture of kerosene, liquid hydrogen and liquid oxygen to feed the engines. The construction was largely a light-weight hole tube to carry every thing collectively. 

Finding out the F-1 Engine Turbine Blade 

Every intact turbine blade is in regards to the measurement of a soda can and appears like a twisted wing of a airplane. The form isn’t too shocking because it has an identical job to an airplane wing. Within the case of a turbine, as a substitute of producing carry like a airplane wing, the blades create rotation to maneuver gas and oxygen the place it must be. 

We had been initially despatched one intact blade, however our research had been restricted to statement and testing that wouldn’t harm the pattern. Our preliminary evaluation indicated it was probably a metallic alloy that can be utilized at excessive temperatures, referred to as a nickel-based superalloy. However this conclusion didn’t match any broadly recognized alloys on the time. Moreover, since we might solely study the floor of the blade, we weren’t certain the floor measurements had been the identical as contained in the blade.

After dialogue of our findings, the conservators gave us 4 blade fragments that we might lower open and analyze what they appeared like inside. It was obvious simply by dealing with the fragments that they weren’t the strong metallic they was once; they had been a lot too mild. We positioned the half in a vacuum chamber to assist the inner construction and poured an epoxy combine over it. Then, we allowed air into the vacuum chamber, which pushed epoxy into lots of the open areas contained in the blade. 

Once we appeared inside, it was stunning how porous the blades had been as a result of the within had corroded away. The outer surfaces had been principally intact, however the inside was now stuffed with epoxy, the place metallic was once 40-plus years in the past. The clear epoxy supported the delicate metallic pores whereas holding the inexperienced corroded metallic remnants in place, just like the clear ice on a pond that I noticed in lots of winters within the Midwest. 

We then used a specialised microscope and different superior gear to concurrently see what was being corroded and the way the assorted components had been distributed all through the blade. This allowed us to substantiate that it was probably an alloy developed particularly for this mission. 

As researchers, we didn’t have any background info on what supplies had been used within the engine. I think about the corporate that constructed the engine a long time in the past solely needed to meet NASA’s necessities, and so they might not have needed to disclose precisely what supplies had been in it. It’s additionally doable these data have simply been misplaced through the years. 

One of many different mysteries on this mission was that within the 4 turbine assemblies that had been discovered, two of the turbine assemblies had been discovered with their protecting masking hooked up. The opposite two had been discovered with out the quilt. 

Opposite to expectations, the turbine blades with the protecting masking intact had been extra badly corroded. Studying by means of different literature on corrosion, I realized this could usually happen, the place a stagnant atmosphere contained in the masking may cause extra corrosion than materials simply uncovered to the weather.   

What Our Analysis Means for Conservation 

The analysis supplied some further context in just a few areas, together with: 

• what supplies had been used within the Saturn V engines,
• what was the reason for the corrosion (and how one can forestall it),
• which supplies or environments could be extra inclined to this sort of corrosion for future conservators, and 
• concepts on how one can assist fragile samples like this in different functions. 

Additionally distinctive is that these engines had been immersed in an atmosphere (sitting for many years on the ocean flooring) fairly completely different from the one they had been meant for (spinning quickly in a movement of scorching gasoline in a rocket engine). 

There haven’t been plenty of conservation alternatives for issues created so lately, so the outcomes of this work had been printed as a paper in Studies in Conservation.

One other space the place we’re hoping to make an affect is by making use of conservation concepts to the information and metadata from our work, in addition to the artifacts themselves. Along with writing the paper, we’ve additionally ready a data publication that features further pictures, information, strategies and details about our work for future researchers to construct upon the work. This mission allowed me to make use of my data and construct upon the numerous work the NIST workers has executed to make information publicly accessible over the previous decade. We hope the publication helps exhibit a few of what we’ve realized to a broader neighborhood. 

The conservation of Apollo rocket components might not appear to overlap a lot with my major space of analysis, which incorporates growing new checks and requirements to include advanced, lighter-weight materials into automobiles for power and gas effectivity. However one of many issues I like about NIST is that we regularly get requested to do some fascinating and strange issues. Working at NIST has inspired me to assist folks with their technical issues. I get plenty of gratification from fixing the issue after which with the ability to share what we study freely with the analysis neighborhood and the general public. 

It was fairly an thrilling alternative for me as an aerospace engineer to be a small a part of the historical past of the Apollo area exploration program. It was additionally neat to go along with my household to the Smithsonian Air and House Museum in Washington, D.C., to see among the objects. In the course of the video loop introducing the artifacts, the narrator thanked “supplies scientists” who labored on the restoration. That was gratifying to listen to. 

I used to be born too late to be a part of the Apollo program when the rockets had been being launched, however it’s good to have the ability to nonetheless contribute to part of area exploration in my very own means.

Writer’s word: Adam Creuziger want to thank co-authors Claudia Chemello, Paul Mardikian and Jerrad Alexander for permitting him to meet a childhood aspiration of being concerned within the area program by supplying the assorted rocket components to analyze, and Megan King for editorial help in drafting this text. Adam additionally acknowledges the substantial contributions to this mission and paper from Dr. Tim Foecke previous to his retirement from NIST.