The regular resupply missions to the International Space Station include the basics like food, but all sorts of new science toys as well. In the Dragon capsule that docked with the station several days ago, there was one particularly interesting device — a DNA sequencer. It’s called the MinION, and it’s tiny at just 120 grams. That’s probably lighter than your smartphone, but it could do some big science up there.
This will be the first time DNA has been sequenced in orbit, so part of the MinION mission will just be to prove that it works. NASA is considering a few other DNA sequencers for future space missions, but they will mostly be testing for targeted organisms. MinION is designed to analyze a full range of samples.
The MinION operates a bit differently than DNA sequencers on Earth, but that’s by design. NASA wants to be prepared for any kind of sample, even an alien one. When a sample is loaded into the MinION, it will encounter a barrier filled with small pores (nanopores) that allow charged particles (i.e. ions, that’s where the MinION gets its name) to pass through. This creates an electrical current that the device reads. When a larger molecule like DNA enters the channel, it reduces the current. That pattern can then be used to determine the sequence of the molecule.
NASA explains that any sufficiently large polymer could be analyzed by the MinION. If we did encounter some unknown life on Mars or some other planet, we don’t know for sure they will have DNA. However, if it’s something like DNA, the MinION should be able to provide some data on it. Perhaps the base pairs will be different or the sugar backbone will have a different configuration. There are a lot of possibilities.
The alien DNA eventuality is nice, but that’s not something NASA is expecting will come up right now. The MinION will primarily be used to see what microorganisms are growing around the space station (and if any of them happen the be aliens, all the better). Astronauts and NASA do their best to keep the station free of bacteria, but there’s only so much you can do.
The station is regularly sampled to make sure there’s nothing dangerous growing, but until now those samples had to be sent back down to Earth for analysis. The hope is that such samples can be sequenced on the station with the MinION. NASA will have to run some tests on the MinION in orbit before it can give the okay to use it regularly, but it’s already proven itself on Earth.