Today we will dive into some details on the prep phase –
After experimental methods and seed selection, the most important part of the Prep stage is planting the seeds that will be germinated on orbit. This is an important step because we need to place the seeds in their growth medium (in this case a .5x MS Phytagel nutrient gel media instead of soil) but we need them to not begin to grow until they have made it to the ISS, and have been installed in the hardware where they will grow. This time period can be anywhere between 2-4 weeks. We prepare these “dormant” plates of seeds by first sterilizing the seeds in ethanol to ready them for planting out on Petri plates containing sterile Phytagel growth medium. Step two is then test the sterilized seed batches to ensure they are indeed sterile, and that they have high germination rates when activated. Once we are confident in our seed quality, we can move into the next phase of preparation – Planting.
Planting for flight takes about half a day to set up, and then the remainder of the day to do the actual planting, providing you have the help of two additional lab members. To plant, the seeds are suspended in a small amount of sterile water to facilitate dispersing onto the surface of the nutrient gel in the Petri plate, and then the plates are immediately wrapped in black out cloth; keeping them in the dark inhibits germination until they are unwrapped on the space station. It is important that this all is done in a fully sterile environment and that from the time the water is added that only 10 minutes elapses before the plate is wrapped (take a look at the time-lapse video below – it shows Anna-Lisa Paul (left) and Jordan Callaham (right) planting in the laminar flow hood, and Eric Schultz (far right) outside the hood photographing and wrapping the plates.
[ Now you might ask – why is Eric photographing plates full of dormant seeds? I mean, they are just seeds, they all look exactly the same…The answer is that these are official “close-out photographs” required by NASA. Absolutely everything that goes to the space station is documented, cataloged and controlled. Because our plates are wrapped in black cloth when they are turned over, we need to provide documentation of what lies inside each black-wrapped packet. A non-flight example is shown below. ]
Plates containing 15-40 seeds are then stored in a refrigerator until the beginning of the experiment in space. We plant about twice as many plates as we will need for the flight (for the flight we need 27 plates, we plant 45-48). These extra plates serve as back up and test plates, so we can monitor them before the experiment is launched. And the flight experiment is comprised of more than just the set of plates that fly… 48 and 96 hours after the first set of plates are planted, second and third sets of plates are planted to serve as ground control and back-up (in case of launch delay.) These plantings require the same high level of attention that the flight plates receive – note, the ground control set is absolutely as important to the experiment as the set that flies!
Once all sets of plates are planted and stored in the refrigerator we monitor the test plates for any signs of problems before launch. As long as all plates look healthy and good to go, they will be turned over to NASA 48 hours prior to launch. These plates are then transported by NASA to the SpaceX Dragon capsule to be launched.
[ Now you might ask – why is Eric photographing plates full of dormant seeds? I mean, they are just seeds, they all look exactly the same…The answer is that these are official “close-out photographs” required by NASA. Absolutely everything that goes to the space station is documented, cataloged and controlled. Because our plates are wrapped in black cloth when they are turned over, we need to provide documentation of what lies inside each black-wrapped packet. A non-flight example is shown below. ]
Plates containing 15-40 seeds are then stored in a refrigerator until the beginning of the experiment in space. We plant about twice as many plates as we will need for the flight (for the flight we need 27 plates, we plant 45-48). These extra plates serve as back up and test plates, so we can monitor them before the experiment is launched. And the flight experiment is comprised of more than just the set of plates that fly… 48 and 96 hours after the first set of plates are planted, second and third sets of plates are planted to serve as ground control and back-up (in case of launch delay.) These plantings require the same high level of attention that the flight plates receive – note, the ground control set is absolutely as important to the experiment as the set that flies!
Once all sets of plates are planted and stored in the refrigerator we monitor the test plates for any signs of problems before launch. As long as all plates look healthy and good to go, they will be turned over to NASA 48 hours prior to launch. These plates are then transported by NASA to the SpaceX Dragon capsule to be launched.
More to come soon about turn over operations and launch – as well as what is happening on flight!
