Select Page

For over twenty years now, there has been continuous human occupation off our planet.

The International Space Station (ISS), launched in 1998, is a modular satellite in low orbit around the Earth, which is visible even with the naked eye.

Since November 2, 2000, the ISS has had a constantly revolving crew from a variety of nations, working on projects to further push the boundaries of our knowledge. Aside from their important scientific duties, these astronauts must live their daily lives like us – exercising, relaxing, cleaning, and sleeping – albeit in microgravity.

The International Space Station celebrated 20 years of constant habitation in November, 2020.

In October, an Antares rocket carrying a Cygnus resupply ship was launched by NASA at Johnson Space Center. This cargo ship carried an experimental system on board used to study the oxidation of ammonia under microgravity conditions to convert urine into water on the ISS.

Improving this waste management system has far-reaching repercussions for longer exploratory missions where the weight of the payload must be optimized with the amount of water needed (which is heavy) to sustain life during the trip. Given the limited resources aboard a spaceship, the recovery of water from all processes is of great importance.

Future missions which may benefit from this study include trips to the moon (Artemis) and eventually to Mars (Orion).

This system uses Metrohm DropSens screen-printed electrodes (SPEs). The novel nanomaterial coating of the electrodes was developed by researchers at the University of Alicante in Spain in collaboration with the University of Puerto Rico. In this article, we would like to introduce the people behind the project and elaborate on the research they are doing in space with Metrohm products.

Meet the researchers

Dr. José Solla Gullón (Ph.D. 2003, Chemistry)

Dr. José Solla Gullón in his laboratory at the University of Alicante, with Metrohm DropSens and Metrohm Autolab products on the bench.

I am currently a Distinguished Researcher at the Institute of Electrochemistry of the University of Alicante, Spain. My research mainly focuses on the synthesis, characterization and electrochemical properties of different types of nanoparticles with well-defined size, composition, shape, and surface structure. My overall publication record includes about 175 publications (h-index 53). I have also given more than 250 contributions in international and national meetings.

Ms. Camila Morales Navas

Camila Morales Navas holding the Nanoracks 2U, where the electrochemical equipment is kept inside.

I am a senior graduate student in the Department of Chemistry at University of Puerto Rico (UPR). I am working on a research project in collaboration with NASA, titled «Elucidating the Ammonia Electrochemical Oxidation Mechanism via Electrochemical Techniques at the ISS», or «Ammonia Electrooxidation Lab at the ISS (AELISS)» for short. The purpose of this project is to improve the water processing system and to identify new technology for long-term missions in space.

The project is attributed to NASA-ESPCoR, University of Puerto Rico, University of Alicante, NuVant Systems, and Nanoracks, with support from Metrohm DropSens.

Read more about the project on the NASA website:

The AELISS project

For a brief overview by Camila and her graduate advisor, have a look at the video provided below by NASA:

Here, you can see the Metrohm DropSens instruments used for this study: the screen-printed carbon electrode (SPCE8X110) and its corresponding flow-cell (FLWCL8X1C).

The Metrohm DropSens 8X110 carbon SPE (left) and the FLWCL8X1C flow-cell (right).
Instrumentation setup for the AELISS project which was launched to the ISS in October, 2020.

How did the AELISS project begin?

About five years ago, the groups from the University of Alicante and the University of Puerto Rico (UPR) began working together on microgravity experiments which led them to collaborate again for this project, which now resides on the ISS.

The electrochemical oxidation of ammonia using platinum as a catalyst is a well-established reaction, first published almost two decades ago by José’s group. The ammonia is extremely sensitive to the surface structure of platinum. However, this is well-known on earth. How does this reaction process behave in a microgravity environment? The groups sought to determine this by performing experiments in the US using a special airplane which mimics weightlessness for brief periods by flying in a parabolic motion.

SPE modification process: droplets of platinum nanoparticle ink provided by the University of Alicante deposited on the carbon SPEs. Platinum acts as a catalyst for the oxidation reaction. Click image to enlarge.

At first, this was purely for research, but later Camila’s group in Puerto Rico thought more about its potential use in space. Urea from urine is converted to ammonia, which then goes through the electrochemical oxidation process, resulting in N2 gas, water, and energy. Perhaps it was possible to use this technology to improve the onboard water recovery and recycling system in the ISS and other spaceships?

Because the UPR group often writes research proposals that are funded by NASA, they are quite knowledgeable in this area regarding the project requirements, as well as what materials are allowed on board a mission. The UPR group has been working in conjunction with NASA for about 20 years.

Unassembled equipment: plastic protector frame (grey), Metrohm DropSens FLWCL8X1C electrochemical flow-cells with 8X110 carbon SPEs (blue/white), and Nanoracks 2U (green). Click image to enlarge.

Combining the expertise in ammonia oxidation research from José’s lab in Spain with the knowledge of Camila’s group in Puerto Rico about NASA’s engineering and safety requirements made the construction and realization of the complex AELISS project possible. However, launching something to the ISS isn’t without its issues…

Has the COVID-19 pandemic had a significant effect on the research? 

Camila Morales Navas assembling the AELISS equipment in the UPR laboratory. Click image to enlarge.

Aside from the usual problems and delays that can pop up during collaborative research projects, the introduction of a global pandemic at the last stages did not help the situation. The COVID-19 pandemic affected the timeline of the AELISS project, especially when it came to traveling and working within the extremely regulated environment of NASA. Additionally, Puerto Rico had already dealt with several large earthquakes and hurricanes in this period.

Keeping each other on track became difficult at times, particularly when Camila had to bring the entire setup back home to finish the engineering. In June, she was able to return to the laboratory and complete the project. However, the stressful part was not yet over because there was still a flight to NASA in the US, and with that the ever present threat of COVID-19 infection during travel.

One positive test result would mean a denial of entry – there can be no chance of infecting the ISS crew.

Ultimately, everything went to plan before and during the launch, and the instrumentation was sent to the International Space Station in October along with other precious cargo for the astronauts. Now that this part of the puzzle is finished, the rest of the work begins…

How will AELISS differ from similar experiments on Earth?

The final goal of this research is to determine how gravity affects the oxidation of ammonia, and also to test out different catalysts for the reaction in microgravity. While several other parameters can be adjusted in the lab such as pH, nanoparticle shape, and more – gravity is a universal constraint we cannot avoid. On Earth, we are only able to mimic the effects of microgravity for a few seconds with freefall. The previous collaboration between the groups in this project also involved performing experiments on special flights that allowed weightless conditions for less than 15 seconds at a time. This is certainly not enough time to draw long-term conclusions, and hence the push to launch the project into orbit. Only then can a true comparison be made, and conclusions drawn about the effects of gravity and the future applicability of this technology.

Dr. José Solla Gullón shown in his lab at the University of Alicante depositing Pt nanocubes on the 8X110 substrates which are used in the FLWCL8X1C electrochemical cell. Click image to enlarge.

One of the major concerns regarding this project is to achieve the most efficient conversion of waste urine into usable water for long-term space missions. Here, water recycling is a critical point. Also, it is important to note that the product of the oxidation of ammonia is nitrogen gas, but the behavior of gases is not the same on Earth as in space. Understanding how the N2 bubbles behave in the absence of gravity is a critical step to study.

Camila’s doctoral research project aims to answer these questions and more, using the realistic conditions of space rather than short periods of weightlessness in flight. So how did the researchers come to use Metrohm products?

There’s Something About Metrohm

So, why choose Metrohm over other providers? I asked José and Camila just what it was that drew them to our products.

«In my case, I have been working with Metrohm DropSens for many, many years. We have a very good collaboration, not only in the in the case of the nanomaterials, but also in the electrochemical cells, and the use of the screen-printed electrodes for electroanalysis. So, we have a very long history together

Dr. José Solla Gullón

Distinguished Researcher at the Institute of Electrochemistry, University of Alicante

Additionally, José mentioned that it was the fact that the electrochemical cells from Metrohm DropSens were very small, perfectly fitting into their conceptual system, which was another critical point. In fact, only cosmetic changes were needed to the products to be used in this project – all of the used materials were already approved for use by NASA..

For Camila, this was her first time using these products, and she found their out-of-the-box usage incredibly helpful.

«This was my first experience since José suggested it. And I trust them because they’re the people that really know about this subject

Camila Morales Navas

Senior graduate student in the Department of Chemistry, University of Puerto Rico

In the past, José has asked Metrohm DropSens several times to custom design SPEs for his research needs, and has always found them responsive and agreeable.

«I know that I can send an email and in two hours, I will have some response. This is wonderful for me. They are always open to new solutions

Dr. José Solla Gullón

Distinguished Researcher at the Institute of Electrochemistry, University of Alicante

We wish the very best to the research groups behind the ambitious AELISS project at the University of Puerto Rico and the University of Alicante. We at Metrohm are proud that our products can contribute to space exploration.

Post written by Dr. Alyson Lanciki, Scientific Editor at Metrohm International Headquarters, Herisau, Switzerland.

Special thanks go to Dr. José Solla Gullón and Ms. Camila Morales Navas for their important research and taking time to contribute to this article.

%d bloggers like this: