Researchers evaluated the performance of the MinION DNA sequencer in-flight on the International Space Station (ISS) and benchmarked its performance off-Earth against the MinION, Illumina MiSeq, and PacBio RS II sequencing platforms in terrestrial laboratories. Samples like Escherichia coli (strain K12, MG1655) and Mus musculus (female BALB/c mouse). Nine sequencing runs were performed aboard the ISS over a 6-month period, yielding a total of 276,882 reads with no apparent decrease in performance over time. 

Benchmarking of the MinION sequencing data against MiSeq 

Duration for Mars missions is likely to range from 1.5 to 3 years, with 12 to 24 months of that time spent in transit between the planets, based on current propulsion technologies and planetary orbital dynamics. In response to spaceflight, the human immune response becomes dysregulated, and microbial pathogenicity can increase during spaceflight. 

Beyond gene expression-mediated virulence changes, it is unclear how microbial populations would evolve, both regarding population ecology and genetic mutations, over the course of a multi-year mission with increased exposure to ionizing radiation and microgravity during transit.

This ongoing microbial evolution could have a profound impact on crew health, as microbiome stability and dynamics are known to have significant effects on human health on Earth. 

Sequencing is a technology that could potentially address several critical spaceflight needs: infectious disease diagnosis, population metagenomics, gene expression changes, and accumulation of genetic mutations. Based on size, power, and ease of use considerations, the MinION™ DNA sequencer was the most spaceflight-ready of commercially available sequencers. 

This device sequences DNA and RNA by measuring current changes caused by nucleic acid molecules passing through protein nanopores embedded in membranes; the change in current is diagnostic of the sequence of the DNA or RNA occupying the pore at a given time.

Our results of the first-ever DNA sequencing in space indicate that the performance of the MinION sequencing platform was not adversely affected by transport to the ISS, nor by loading or operation in its microgravity environment. Ideally, all experiments on the ground and in-flight would have been performed by the same person; however, we prioritized performing near-simultaneous ground controls with reagents and materials of the same age over having all experiments performed by a single person.

They performed the sequencing operations before her sequencing on the ISS, successfully load samples aboard the ISS reinforces the robustness of the MinION sequencing platform in space. 

In future, the MinION holds the potential to greatly improve the rate at which ISS research can be performed by allowing researchers rapid access to data obtained in-flight, rather than having to wait for sample return. 

With robust experiment planning and some foresight, research projects that required multiple flights over several years could now be performed in a matter of months, as researchers could monitor experiment progress in real-time and make adjustments as needed (i.e., cadence of time points, identifying a subset of samples that should be returned to Earth for further analysis, etc.).