Even before Neil Armstrong stepped foot on the moon people have looked to the stars and wondered if we would ever be able to colonize outer space. Thanks to new imaging technology like the Transitioning Exoplanet Survey Satellites (TESS) we have been able to find a wide range of planets orbiting other stars. It seems as if any day now, we will find one capable of supporting life as we know it.
Yet even if we found a planet that could double as Earth’s twin, the challenges of how we would get there are immense. At this time, we don’t have a propulsion system capable of taking a manned mission to Mars, let alone out of our solar system.
Even with the promise of Ion engines and the science of gravity assist, we likely couldn’t achieve a speed that would make it possible to arrive on another planet in a single human lifetime. This has left many scientists, and even a few philosophers to wonder if it would be possible to send an unmanned space vehicle to another world with cryogenically preserved sperm, eggs, or embryos, which could be thawed and used to repopulate the new world.
Of course, before we start to wonder just who would raise these interstellar babies, we first need to find out if it’s possible for human reproductive tissues to withstand the ravages of long-term space flight and “Zero-G” environments.
Frozen Sperm Samples Might Survive Space Flight
At the 35th Annual Meeting of ESHRE (European Society of Human Reproduction and Embryology), researchers said that the lack of difference in a range of sperm characteristics observed in frozen sperm samples exposed to microgravity remained as viable as those that had been maintained on Earth.
This interesting little piece of information opens the door to the possibility of safely transporting male genetic material into space with the possibility of creating an “Extra-Terrestrial Human Sperm Bank.”
The study was originally pioneered by Dexeus Women’s Health based in Barcelona, Spain. The group worked with microgravity engineers from Barcelona’s Polytechnic University as well as the Aeroclub Barcelona-Sabadell of Spain. In these tests, they used parabolic flights to essentially replicate the microgravity conditions found in low Earth orbit.
The Effects Of Microgravity On Cryogenically Preserved Space Flight
The study explained that while the effects of microgravity on the central nervous, cardiovascular, and musculoskeletal system has been extensively tested in space flight. Many of the results are well-known, and some of the long-term effects are still a challenge for experts.
Yet very little is known about the effects of different gravitational environments on the human reproductive system, sperm, and eggs. There have been some inconclusive studies that suggest a significant decrease in the motility of fresh sperm samples in the past. Yet nothing has been reported on the potential effects of gravitational differences and microgravity on cryogenically preserved human gametes.
The Dexeus Women’s Health study was performed in a lightweight aerobatic training aircraft, known as a CAP10. This particular craft was chosen for its ability to provide short-duration hypo-gravity exposure. The aircraft then executed a series of 20 parabolic maneuvers, each of which yielded 8 seconds of microgravity per parabola.
The craft carried ten sperm samples which had been obtained from ten healthy male donors. Each was analyzed before and after exposure to the different micro-gravitational conditions found in space as well as at near sea level gravity on Earth.
The sperm analysis included a full range of measurements. It included:
- Sperm concentration
- Sperm morphology
- Signs of any DNA fragmentation
- Interpreting The Test Results
After careful analysis, the Dexeus Women’s Health found that there was no discernible difference in any of the tracked parameters between the sperm samples that were exposed to replicate microgravity and the sperm samples of the control group that remained on Earth. One researcher noted that there was a 100% concordance in DNA fragmentation rate and vitality. There was only a 90% concordance in sperm concentration and motility. These minor discrepancies were more likely related to the heterogeneity of the sperm sample than to the effect of exposure to changes in gravity or microgravity exposure.
What’s The Next Step?
Now that we know frozen sperm samples can survive microgravity and changes in gravity, the next step is to measure how larger sperm samples, which will be exposed to longer durations of microgravity or perhaps even the Zero-G of Earth orbit in space.
With companies like SpaceX and planned government missions to other worlds, the 21st Century if full of the promise of one day colonizing space. It’s not out of the question to consider the possibility of human reproduction beyond the confines of Earth and its 1G gravity. If or when that time comes, it will help to have a working knowledge of how the environment of space can affect human reproductive material.
For instance, radiation may be a major factor causing fertility issues for anyone who is considering conceiving in space. The Earth’s atmosphere and magnetic field block most of the solar radiation and cosmic rays that bombard our planet. Out in the depths of space radiation levels increase steadily.
Understanding how cosmic rays and solar radiation affect sperm and eggs will most likely play a role. Certainly, there is an increased chance of DNA fragmentation, which could render sperm non-viable for procreation. We can’t know how to properly shield against these potential problems without further testing.
This might involve including cryopreserved sperm samples in special cryo-straws or cryo-tanks that can then be transported into space as part of a new research mission. This would be able to test the impact of massive gravitational changes on sperm quality, as well as long-term exposure to the radiation of space.
Unfortunately, access on these missions is very limited, and often cost-prohibitive. One can only hope that as we continue to expand our search to colonize other worlds, that we will leave room for this important field of study.
Source – Science Daily