Koren: How did the experience compare to sequencing DNA on Earth?
Rubins: I was surprised at how well it worked. I had tried it out a few times on the ground just to see how the mechanics of loading everything would work, and then it’s pretty different in microgravity, right? You put the pipette on the sequencing flow cell, and you shoot back off in the opposite direction with the same amount of force that you put on the pipette. Anytime you’re handling something, you have to stabilize yourself, so that took a little bit to get used to. I brought some foot restraints over and got myself hooked in. The first time I did it, I had a head lamp on so I could see really well, and some magnifying glasses.
Koren: How many runs did it take before it worked?
Rubins: It was actually successful on the first try, so that was great. We had some extra samples just in case it didn’t work the first time, so we started actually changing the experiment a little bit. We altered a few parameters, like the length of time that the reaction runs. They all worked.
Koren: What was your reaction after that first successful run?
Rubins: I was extremely excited. I was really nervous loading it the first time. I’m usually not nervous when I’m just doing a normal bit of pipetting, but I didn’t want to screw it up. There was a little bit of adrenaline going. It’s within 10 minutes that you start to see the first sequence coming through.
Koren: Did it feel like 10 minutes? Because when you’re anticipating something, time can feel like it’s moving slowly.
Rubins: Oh, no! I was like, I can’t even be here. I’ve got to float away and try to keep myself busy. And then I’d come back and check again, and then I’d float away again. We had a communications loop open with the ground team, so when we did start to see everything come through, they put the speaker on so I could hear them all clapping and cheering.
Koren: You also spent some time culturing human heart cells on the ISS. What was that like?
Rubins: You’re tending to the cells—you have to change the media [in the cell culture], you have to resupply them with nutrients. Instead of having the open cell-culture plate, they’ve got lure locks that are designed for space, and you can change the media with a little syringe. It took quite a long time to do the cell-culture change. I was nervous because I didn’t want to contaminate the cell culture; if you get bacteria in there, it’ll overgrow your culture and kill the cells and ruin the experiment. You have to work on very sterile techniques. It’s like prepping for surgery. You don’t want any microbes getting in the patient.
Koren: You’ve said you watched the heart cells beat in unison. How many cells does it take to see that?
Rubins: You can see 20 to 100 cells. For the most part, they’re in sheets or forming clumps or groups of cells, so you can see them together just synchronize that beating.
Koren: And is that weird to see?
Rubins: It was very cool. When I pulled the microscope out, the cosmonauts would come down from the Russian segment of the space station and everybody would float past because they liked watching it. There’s something fascinating about seeing down to the microscopic level and actually watching these heart cells beat.