Biology in Deep Space: the BioSentinel Mission
By: Gunnar De Winter
Tags: Biology, Science, Space, Future, NASA

Biology in Deep Space: the BioSentinel Mission

BioSentinel, a small satellite designed to test the effects of deep space cosmic radiation on living organisms, will be part of NASA’s Artemis I mission

(Wikimedia commons, NASA)

Unfriendly space

Space is not a friendly place.

No gravity, vacuum all around, radiation aplenty… Not exactly an environment where biological life (as we know it?) thrives.

No wonder robotic mission are the preferred means of space exploration. Cheaper, less mess, less chance of people dying. In fact, there are several voices who suggest that (deep) space exploration is better left to our artificial colleagues.

And yet.

Some of us are not satisfied with seeing the marvels of the cosmos through a robot’s eyes. We want to go there, plant our feet on the moon, or watch a double sunset on an exoplanet.

But getting there is not without its challenges. Distance and time are probably the biggest ones.

Orbits of important satellites and the ISS (Wikimedia commons, cmglee)

Even if we figure out how to bend the laws of physics or curb our enthusiasm to remain close to home, we’ll have to cross the sea of deep space. So far, we don’t really have a lot of experience with that. The farthest out humanity has been in person is the moon, and that was a relatively short trip. Longer stays have taken place on the International Space Station (ISS), but that is still in a low Earth orbit and well-buffered against the onslaught of cosmic radiation by Earth’s atmosphere.

Biology in deep space

If we persist in our vision of sailing the sea of stars, it’s probably a good idea to understand the potential effects of deep space travel on biological organisms.

Many things, such as zero gravity and vacuum-like conditions, can be tested very well on the ISS, but deep space radiation is not one of them. Sure, there are facilities on earth where we can try to mimic the cosmic rays eager to smash our DNA. Getting our metaphorical hands on the real deal, though, can be very helpful as well.

BioSentinel (Wikimedia commons, NASA)

Thus, BioSentinel.

BioSentinel is a proposal for a low-cost CubeSat (aka mini-satellite). It is being developed by NASA to be one of the thirteen CubeSats that will tag along with the Artemis I mission as secondary payload. The Artemis I mission will test NASA’s Space Launch System and was originally planned for 2020. Now, the tentative launch date is sometime during November 2021.

Oriiginal plan for Artemis 1 (Wikimedia commons, NASA)

The primary aim of Artemis I is to bring the reusable Orion capsule into a six-day orbit around the moon. This will officially certify the Orion capsule and the SLS system for manned flights, such as the 2023 (planned) Artemis II mission.

Yeast and radiation

But before human beings will be the Orion’s crew, it’s yeast’s turn.

Once BioSentinel is deployed, it will:

…first undergo a ∼700-km lunar fly-by, then enter into a stable heliocentric orbit. As it orbits the sun, BioSentinel will conduct science experiments for 6–12 months, accumulating doses of radiation analogous to that of a potential human Mars mission. At the 6-month nominal mission duration, it will be ∼0.2 astronomical units (0.2 AU, ∼30 million km) from Earth.

These science experiments involve Saccharomyces cerevisiae, or baker’s yeast, a veritable workhorse in current (molecular) biology. Two strains of this yeast will be part of the BioSentinel experiments: a ‘normal’ strain, and a strain which has a faulty DNA repair mechanism.

Even though yeast and humans are quite far apart in the web of life, the genes and cellular processes that control DNA damage and repair show many similarities. In other words, studying how deep space radiation affects yeast DNA can help us hypothesize about what it might do to the DNA of human spacefarers.

Microfluidics card for the yeast strain on BioSentinel (Wikimedia commons, NASA)

In preparation for the mission, the yeast strains will be desiccated. Once they enter the experimental phase, they will be rehydrated with a nutrient-rich broth.

Then, the science begins. Different batches of yeast strains will be rehydrated at different times. Cell growth and metabolism will be monitored, as well as the amount and type of radiation, and the data will be beamed back to earth. Another BioSentinel payload will be delivered to the ISS, and a third one will stay on earth for comparison.

The data is expected to teach us more about the effects of deep space cosmic radiation on DNA and its repair mechanisms. Maybe, it will help us develop tools and procedures to prevent DNA damage during long spaceflights.

From there, to the stars.