Characterize Human Forward Contamination Project

Let's face it: wherever we go, we will inevitably carry along the little critters that live in and on us. Conventional wisdom has long held that it's unlikely those critters could survive the space environment, but in 2007 microscopic animals called Tardigrades survived exposure to space and in 2008 Cyanobacteria lived for 548 days outside the International Space Station (ISS). But what about the organisms we might reasonably expect a crewed spacecraft to leak or vent? Do we even know what they are? How long might our tiny hitch-hikers survive in close proximity to a warm spacecraft that periodically leaks/vents water or oxygen—and how might they mutate with long-duration exposure? Unlike the Mars rovers that we cleaned once and sent on their way, crew members will provide a constantly regenerating contaminant source. Are we prepared to certify that we can meet forward contamination protocols as we search for life at new destinations? In FY15 we drafted an internal strategic plan to roadmap the test, analysis, and modeling needed to characterize human forward contamination, and in FY16 we prototyped and tested an EVA tool to collect samples for forward contamination analysis. In FY17 we proposed advancing the EVA swab kit's flight certification far enough to qualify for X-project flight funding to conduct external ISS life support system vent and EVA suit sampling/analysis. Understanding what life signatures may be leaking/venting from our current life support systems will inform exploration hardware designs going forward. The focus of this project's road-mapping effort was "what can we do now with what we have?" For example, the micro-organisms inside the ISS are well-characterized…but no one has ever swabbed an ISS external vent to find out what (if anything) has managed to get outside. We can swab ISS vents now, without having to develop new hardware. If we take a sample and find nothing, that's good news!—it means that our environmental control and life support (ECLS) systems may already meet forward contamination requirements. If we do find organisms outside the ISS, it will be interesting to see how they compare with what we typically find inside. Are they the same? Or have they mutated? What corrective measures can we take to prevent external contamination? Once we know what manages to escape a typical spaceship, we can expose it to various destination environments and see how it's likely to behave. We can go one step further, and test those organisms in a spacecraft-induced environment to understand whether proximity to a warm, venting spaceship makes a difference; that will tell us how far away we must land from a sensitive area to mitigate forward contamination. We can also bring the modeling community into play and overlay destination weather models onto bacterial growth models to estimate how far microbes could be transported by, say, a small dust storm on Mars. Another opportunity might be to take a sample from an Exploration Extravehicular Activity (EVA) Suit during development testing and follow similar steps as outlined above: what organisms come out of a suit vent or leak from the suit? How close can EVA crew be to a sensitive site without compromising the science objectives? Data would tell us what modifications might be required to the suit now--early in the development phase—and avoid an expensive redesign later. This project expected to produce a comprehensive test, analysis and modeling plan. To support future testing, we also needed to develop a specialized tool to collect swab samples. On Earth, this type of sampling is typically done with a simple swab, much like a sterile Q-tip®, that is wiped across a surface and stored in a sterile vial. But handling a small swab and vial while wearing spacesuit gloves is difficult and the swab itself will have to withstand extreme temperature swings combined with near vacuum pressures that can cause plastics to become brittle. What's more, keeping track of multiple samples--and preventing cross-contamination between--is even more challenging in microgravity, where items will float away if not restrained. In line with the project's "what can we do now with what we have?" theme, the team planed to repurpose existing flight hardware as much as possible, and to piggy-back onto other engineering evaluations to collect data as cost-effectively as possible.