Space-relevant Bacteria

Space-relevant Bacteria

(Originally posted July 31, 2017 on Blogger)

There are bound to be millions of photos and videos of the solar eclipse coming August 21; the path of totality will pass over the homes of some 50 million people, with millions more making their way into the path of totality from other regions of the world. But even with tens of millions to be (protected) eye witness to this incredible event, there will be hundreds of millions more who will not be able to see it, save for seeing it via the millions of photos and videos that are likely to be uploaded online in the minutes, hours, and days after the event.

There is another unique way to see this event; it will be live-streamed by NASA from cameras set up on high-altitude balloons as part of NASA's Eclipse Ballooning Project. These balloons will be released by 57 teams of high school and college students positioned at 25 locations across the United States along the path of totality. To see live images and videos streamed online during the eclipse, be sure to visit this link:

http://eclipse.stream.live/

Each team will be responsible for the timely launch of a balloon, such that 57 high-altitude balloons will be released from Oregon to South Carolina. Each balloon will be equipped with GPS, a 5.8GHz modem for video transmission, a 900MHz modem for image transmission, and Raspberry PI 2 computers which will pair with ground station computers in order to stream this event online.

For any of my FAA-employed friends, these balloons will be tracked via the Iridium satellite constellation.

34 of the 57 balloons will have an additional payload in the form of highly-resilient (space relevant) bacteria, dried onto metal plates about the size of a dog tag as seen here:

Space-relevant bacteria are dried onto these metal plates. Each of the teams responsible for the 34 balloons charged with carrying this payload, will be given two plates. One to send up with the balloon, and the other to remain with them at the surface. The plate pairs for each of the 34 balloons will be compared at the end of the experiment.  Photo Credit:    NASA/Ames Research Center/Tristan Caro

Space-relevant bacteria are dried onto these metal plates. Each of the teams responsible for the 34 balloons charged with carrying this payload, will be given two plates. One to send up with the balloon, and the other to remain with them at the surface. The plate pairs for each of the 34 balloons will be compared at the end of the experiment.
Photo Credit:
NASA/Ames Research Center/Tristan Caro

I've tried to investigate what type of bacteria is being used in this experiment, but all I can find from NASA are "space-relevant", "harmless", and "highly-resilient". All other media outlets, the ones that are aware of the upcoming experiment, refer to it as "bacteria". Wow, that's some serious investigative reporting there.

NASA doesn't have to say what type of bacteria it is, and that's fine. My guess is they're using spores of Bacillus subtilis; Bacillus subtilis 168 and Bacillus pumilus SAFR-032 to be specific. NASA's stated purpose for this experiment is to "study [the] effect of [a] Mars-like environment on life". The experiment is dubbed Microstrat.

The high-altitude balloons in this experiment are expected to reach an altitude of about 100,000 feet above mean sea level (AMSL). That height along totality-path latitudes, will put these balloons into the upper half of the stratosphere, and above most of the ozone "layer". 

A high-altitude balloon burst. Photo credit: Kostas Tamateas

I use scare quotes around "layer" since it's generally 1 to 10 parts of ozone per million parts of 'air' which is hardly layer like. Also, ozone is not very stable, and to shorten its stratospheric life even further, UV radiation breaks ozone apart into its constituent oxygen atoms. Fortunately for us, and the rest of life on Earth not living beneath the ground or waves, that instability is balanced by recombination of free diatomic and atomic oxygen; in other words, ozone lost, ozone gained, to be lost again, to be gained again, etc... Ozone exists in the stratosphere in dynamic equilibrium... once again (thanks to the ban of chlorofluorocarbons); a reference to a relatively short period of time when human activities had a direct and detrimental effect on global atmospheric dynamics, and we did something about it.

At above most of the ozone in the stratosphere, the bacteria attached to the balloons will be exposed to more ionizing UV radiation than their cousins on the plate left with the student teams back on Earth's surface. This higher exposure to UV radiation is considered to be fairly similar to what reaches Mars' surface.

The total integrated UV flux on Mars falls between 200-400 nm, which is similar to Earth, however a much greater proportion of this flux falls within the shorter wavelength end of this range. Shorter wavelengths are more biologically damaging, and while UV radiation on Earth can give one a sunburn (or tan, which is the body's biological response to damage), UV radiation on Mars can give a person an early trip to the grave.

UV radiation at Mars' surface is most abundant in the UVC (200-280 nm) and UVB (280-315 nm) range (Catling et al., 2014), which is particularly biologically damaging. Such UV radiation can be found in the upper stratosphere, which can be Mars like to a degree, but temperatures in the stratosphere increase with height, such that they won't be all that Mars like (save for a 'hot' summer day along Mars equator perhaps). But, the eclipse will cause temperatures to drop to more Mars-like temperatures. Also, NASA has stated that certain ultraviolet rays which are less abundant in the Martian atmosphere, will be blocked by the moon. Since UVC and UVB rays are in greatest proportion of the total integrated UV flux, we can assume they mean UVA is blocked. They don't elaborate on how certain wavelengths of UV are blocked while others aren't.

White light image of the solar corona during totality of a solar eclipse.

Photo credit: NASA's Goddard Space Flight Center

In addition to Mars-like temperatures, and a Mars-like UV radiation environment, atmospheric pressure at 100,000 feet AMSL is almost as low as what exists at Mars' surface; a bit less than twice the pressure experienced on Mars' surface (around 1.12 kPa at 100,000' over Earth vs. 0.636 kPa on Mars' surface). That's incredibly thin air on Mars, and a reason why getting human to Mars may very well be considerably easier (as hard as it will be) than getting humans on Mars... nice and gentle like.

So during the eclipse, bacteria attached to these balloons, will experience Mars-like'ish conditions... for about 2 minutes. If they're working with Bacillus subtilis, then it should be interesting to see what sort of information is learned. B. subtilis was used in the experiment PROTECT during the EXPOSE-E mission on the International Space Station (ISS).

The EXPOSE-E mission was one of three such missions on board the ISS between 2008 and 2015. Over the course of 1.5 years, B. subtilis were mounted as dry layers on metal plates. Some plates were subjected to expected conditions one might expect in a trip to Mars, while the other plates were subjected to conditions one might expect on Mars. These were labelled "trip to Mars" plates, and "stay on Mars" plates. Very creative.

The "trip to Mars" bacteria had the pleasure of experiencing space vacuum, cosmic and extraterrestrial solar radiation, as well as temperature fluctuations. The "stay on Mars" bacteria enjoyed simulated Martian conditions (UV and cosmic radiation, as well as atmospheric pressure and composition). The results are no surprise; short wavelength UV radiation was the single-most "deleterious factor applied" (Horneck et al., 2012). All other environmental factors applied in both the "trip to Mars" and "stay on Mars" samples did little harm to the spores (Ibid.).

UV radiation is an extraordinarily serious threat to life. In a 2010 paper, Horneck et al. discovered that spores of B. subtilis were capable of surviving in space for up to 6 years if shielded from UV radiation.

So once again my friends, this all harks back to my "To Mars or Bust - Pt. III" blog, in which I state the need to develop ways to protect humans both going to, and on the stranded planetary embryo we call Mars. Yes; planetary embryo. Mars, like Ceres, formed in the material-starved asteroid belt... not in the terrestrial feeding zone enjoyed by Earth, Venus, and to a lesser extent, Mercury. But that was another blog... "To Mars or Bust - Pt. IV.

NASA's balloon bacteria may well mirror results concluded at the close of the PROTECT experiment on board the ISS years ago, but more data is always a good thing, and this experiment is as inexpensive as they come. Before I conclude this blog entry, I have to state a glaring irony; in my first blog on Mars, "To Mars or Bust - Pt. I", I argued that Mars is not the most Earth-like environment in our solar system. The upper atmosphere of Venus is.

While all eyes are on Mars, and NASA even states directly that this balloon experiment has been designed with consideration of the Martian surface environment, fact remains that they are doing an upper atmospheric experiment in order to ascertain life's environmental limits. Yet no mention of Venus' upper atmosphere whatsoever. Quite frustrating if you ask me. Venus' upper atmosphere has several major benefits over Mars' surface. I blame "surfacism"; a term coined by astrophysicist, Gabe Perez-Giz. People see images of Mars' surface, and think, "Wow, that looks like Earth!" But looks don't necessarily equate to being Earth-like. I'd hardly consider perchlorates' bacteriocidal enhancement of UV radiation on Mars' surface an "Earth-like" feature (Wadsworth and Cockell, 2017).

This, along with considerations of solar luminosity over geologic time scales, the Jovian Grand Tack theory, and more will be addressed in my "To Mars or Bust - Pt. V" blog... coming soon. I won't be including this blog in that series, because most of what I've written here has already been addressed in my earlier blogs.

Before I conclude, I'd like to add that even at 100,000 feet, the bacteria attached to the eclipse balloons will still be within Earth's protective magnetic field, and under the umbrella of the Van Allen belts; belts that trap the solar winds (thereby shielding us from them) and protect our atmosphere from highly-ionizing cosmic radiation. No such shield exists over Mars.

                                                           "Put your hand down Mars."

                                                           "Put your hand down Mars."

As always, thanks for reading.

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