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Lab Notes | Cells in Space!

Reaching new heights, stem cells from the Allen Institute for Cell Science were flown into space for the first time ever. 

By Rachel Tompa, Ph.D., and Rob Piercy / Allen Institute


9 min read

Cells in Space!

Reaching new heights, stem cells from the Allen Institute for Cell Science were flown into space for the first time ever. In 2023, astronauts from Axiom Space studied genetically engineered cells, derived from human skin cells, in microgravity aboard the International Space Station. Axiom Space’s astronaut Dr. Peggy A. Whitson and Chief Scientist, Dr. Lucie Low; along with Professor Arun Sharma from Cedars-Sinai share the experience and science behind the out-of-this-world mission.  


Peggy A. Whitson

I was the first scientist to fly into space… and they named me the first science officer and since I’m a Trekkie from long, long ways back, they consider that a compliment.


Rachel Tompa

That’s Peggy Whitson, an astronaut, scientist and commander of the Ax2 mission, the second private mission to the International Space Station. The mission is run by Axiom Space, a leading commercial space company building the world’s first commercial space station.


Peggy A. Whitson

It was my fourth flight. I’ve worked at NASA for 37 years before that, and the last couple of years I have been working with Axiom Space. And I’m very excited about the potential for a new space station in the future and I’m really looking forward to be a part of that.


Rachel Tompa

Earlier this year. Peggy along with three other astronauts from Axiom Space launched into orbit… among the many pieces of cargo aboard their rocket were some vials of cells engineered by researchers at the Allen Institute. Peggy and her crew were carrying those little vials all the way to the International Space Station… to observe the effects of microgravity on cell proliferation. I’m Rachel Tompa. And this is Lab Notes, a podcast from the Allen Institute.

Today, we’re bringing Lab Notes into orbit, talking with two leading space experts: an astronaut Dr. Peggy Whitson, who’s logged more hours in space than any other American astronaut. Peggy is also a biochemist and has spent much of her career as an astronaut conducting experiments in orbit.

Astronauts have been running experiments on the International Space Station for many years. It’s a really interesting environment to learn more about ourselves and our planet by removing the constraint of gravity… And we’re also thrilled to welcome Lucy Low, Chief Scientist at Axiom Space.


Lucie Low

The absence of gravity in itself just allows this really unique insight into some of the very fundamental processes that drive our understanding of ourselves and our world and science and technology. So it’s just a tremendous place to do all kinds of research and really try and understand where we came from and where we’re going.


Peggy A. Whitson

You know, a lot of people refer to being in space as zero gravity. But the closer you are to Earth, the more you have just a bit of gravity. And we’re at 250 miles that we’re attending to minus six G’s. So that’s why we call it microgravity. Microgravity is actually a tool. Without gravity, you don’t have convective forces. So there’s some types of experiments like combustion experiments, where a flame no longer has the shape of a flame, and it forms a ball.

You know, liquids move differently, gas liquid mixtures react differently. And the human body is changing in space too. And so some of the research is to try and understand all those changes and how we might mitigate some of the detrimental effects of being in space. Of course, there’s lots of great things about being in space, and then it’s way easy to move around. But it’s, you know, one of the things you have to learn how to deal with because there are lots of things they can also get away from you if you have a very complex experiment with lots of piece parts.

This mission was really important for us it was the second axiom mission to the International Space Station. It demonstrated that we can fly not only private astronauts but government astronauts as well. And so we had to Saudi space commission government astronauts represented on the crew.

Coincidentally, one of those was the first Saudi woman to fly in space. And so it was really great to have another first on the mission. But long-term goal for Axiom Space is to build the first commercial space station. We have run it won a contract with NASA to attach our modules to a forward node of the International Space Station, the one that’s currently been up there for 23 years.

And before the International Space Station is decommissioned, we should have four modules attached. And we will detach from the International Space Station before they bring it in and burn it up in the atmosphere.


Rachel Tompa

The Ax2 astronauts performed experiments on the Allen Institute’s human-induced pluripotent stem cells, which are human adult cells that are reprogrammed to revert back into their stem cell form. These cells were chosen for the experiment by a team of scientists at Cedars Sinai Medical Center.


Arun Sharma

My name is Arun Sharma, I am an assistant professor at the Cedar Sinai Medical Center in Los Angeles. I’m a stem cell biologist by training. We believe that we might be able to utilize microgravity for a positive effect. Typically, microgravity exerts a negative effect on the human body, we know that as astronauts spend more and more time in space, their bones and their muscles and even their hearts can degrade and lose some of their mass over time. And this has been established for decades now in the in-astronaut studies and physical astronaut studies for many years. But recently through experiments that have been done in the last 10-ish years, we’ve also gotten understanding of the way cell biology can be impacted, perhaps not in a negative fashion but in a positive way in microgravity by just placing the cells in the right low-gravity context.

We’ve seen prior studies where stem cell proliferation and cell division could be altered and perhaps even enhanced in in microgravity context, cell differentiation similarly, could be changed in microgravity. And so what we’re hoping to investigate as part of this NASA in space manufacturing award that we received recently here at Cedars Sinai and have to mention my co-PI on this award is Dr. Clive Svendsen and who is also an Allen-funded investigator. What we’re hoping to investigate is exactly that: to see if we can actually harness microgravity for stem cell proliferation stem cell division, enhancing these abilities. So that perhaps down the road, we can manufacture biomedical products and biological tissues in space.


Rachel Tompa

That experiment was one of many that astronauts conducted in space for research teams back on Earth during their ten-day mission.


Peggy A. Whitson

We were visualizing different aspects of the stem cell growth also under the fluorescence microscope. Being in microgravity causes some things to accelerate and change. And so this is one way to use that lack of gravity as a tool. One of my favorite ones was looking at cancer cell growth—breast cancer, colorectal cancer, and we were also testing a drug therapy to try and reduce that cancer growth. And they found it was particularly helpful with a breast cancer.


Lucie Low

There were lots of physical sciences projects as well, there was a project looking at cloud seeding. So looking at how clouds can be seeded with silver crystals that could potentially be used in drought conditions, that was very important to our partners from the Kingdom of Saudi Arabia, for example. So it’s really team science. I know, there’s a huge emphasis on collaborative teamwork and science at the Allen Institute. And I think Ax2 is a real testament to that, because we had two countries, we had 19 different research partners, we had over 20 projects, we had all of these theme projects, we had so many different people, 1000s of people on the ground, making sure that this happened. And I think that’s probably the definition of team science there is getting that research into space.


Peggy A. Whitson

Lift of his back plate, probably the most exciting part of the mission. As a crew we all trained in a centrifuge to get used to the fact that as you accelerate from zero to 17,500 miles per hour over about eight and a half to nine minutes. There’s some acceleration involved. So you get to feel that in a centrifuge. And the profile goes up to around four and a half Gs. In the Dragon, the SpaceX Dragon vehicle, you don’t feel the G forces immediately. It’s built gradually over time. So it’s this pressure of what we call three and a half to four and a half Gs and then I always explain it as you know, three dudes sitting on your chest kind of feeling because it’s all going through your chest, which is the way the body takes g forces the best.

Being in space is just a lot of fun, but it is a learned way of working. What’s really cool is when you adapt to it, and it all seems natural that you know, something will float and you can, you know, float something in front of you, but you don’t take your eyes very far off of it or it’ll float away with ventilation and other forces acting on it.

But as a technique, you have to have, you know, Velcro or gray tape with the sticky side out that you can put if you have lots of little pieces, you know, something like that to try and contain all the piece parts that you need to do your investigation. And so a lot of prep time goes into actually developing the experiment.


Rachel Tompa

Peggy says that one of the most impactful things about spending time in space is a renewed appreciation for what’s below not above the Earth’s atmosphere.


Peggy A. Whitson

And I do like to call it Spaceship Earth because it keeps us you know, alive protects us provides the oxygen removes carbon dioxide, maybe not enough but it tries to remove carbon dioxide for us. It provides us with the water that we need thermal control. It’s our spaceship and up in space you’re trying to develop all those same things, and you find out how hard that is and makes you want to protect planet Earth. It’s just overwhelming the sense of perspective that you gain from our life and you know where we are and you know what’s out there that we need to understand even better.


Rachel Tompa 

And hopefully observing life outside our planet will help us better understand life on it… I’m Rachel Tompa. For more Lab Notes episodes and other science news, visit our website at  Thanks for listening

About the Allen Institute

The Allen Institute is an independent, 501(c)(3) nonprofit research organization founded by philanthropist and visionary, the late Paul G. Allen. The Allen Institute is dedicated to answering some of the biggest questions in bioscience and accelerating research worldwide. The Institute is a recognized leader in large-scale research with a commitment to an open science model. Its research institutes and programs include the Allen Institute for Brain Science, the Allen Institute for Cell Science, the Allen Institute for Immunology, and the Allen Institute for Neural Dynamics. In 2016, the Allen Institute expanded its reach with the launch of The Paul G. Allen Frontiers Group, which identifies pioneers with new ideas to expand the boundaries of knowledge and make the world better. For more information, visit

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