It's one of the Big Questions when it comes to considering travel through the enormity of space; how can the human body survive outside the chemical comfort and time constraints of Earth.
While a manned trip to Mars might soon become a reality, it would, given current technology, take something like eight months. Given that Mars is a nearby planetary neighbor, that's quite a long time. But what if the astronauts of the future wished, and they surely will, to explore much further into the beyond?
It's questions like those which formed the crux of a symposium hosted by the Harvard Medical School Department of Genetics called Genetics, Biomedicine, and the Human Experience in Space.
The co-organizers of the symposium, Ting Wu and Susan Dymecki, both Harvard professors of genetics, say that the secret to such travel in the future is genetics.
"We are a medical school," Wu said. "Whether or not you agree with sending people into space, we are responsible for their health on and off the planet."
The answer to covering those vast differences may well come down to not sending astronauts at all, but sending instead the code needed to reproduce those astronauts on distant planets via bioprinting.
Gary Ruvkun, a genetics professor, proposed just such a solution at the symposium. His Ruvkun lab uses "C. elegans molecular genetics and genomics" and is engaged in developing protocols and instruments to search for diverse microbes from extreme environments. A long term goal of the project? Sending a robotic thermal "cycler" to Mars in search of microbial life.
His talk, entitled What's True For E. coli Is True for the Elephant, was a musing centered on how mankind might one day travel to another planet by printing ourselves (or versions thereof) at the final destination. The current assumption is that deep space travel might well be "laughable," Ruvkun said, but could it be replaced by a system where exact copies of astronauts could be made on site?
"Our best bet for space exploration could be printing humans, organically, on another planet," Steltzner told an audience during the Smithsonian Magazine Future Is Now conference in Washington.
As it stands, the idea of printing space travelers runs something like this: encode human genetic information within bacteria and then use those simple packages to transport the necessary information to far-flung locales. As researchers have found that microbes are capable of surviving the relatively short trip from Earth to Mars, some postulate that they could then use that material as the building blocks of life to "reassemble" a complete, functioning human being.
"Once you propose terraforming, you might as well propose sending bacteria with human sequences. That's not that crazy," Steltzner says. "Maybe we'll colonize other worlds – not with astronauts in space suits – but with bacteria. Those considerations seem beautiful, fantastic."
While Ruvkun is the man responsible for the initial idea, his wild notion has traction among various elements of the scientific community. According to Ruvkun, encoding segments of DNA in bacteria is akin to "using bacteria like computer memory, and the bacteria can store information very densely."
While the technology to do it is currently beyond our reach, how much imagination does it take to see that the future might provide an entirely different tool kit?
"We're only fifty years into the DNA era. Five thousand years in, we'll probably think of that as a piece of cake," Ruvkun says.
And Steltzner goes the idea one better. He imagines that it might be possible to avoid sending a physical specimen entirely. In his scenario, it might become possible to send digital instructions once the DNA-encoded bacteria have already arrived on the scene.
"The idea of 3D printing is, something's created out of matter at the location, just with the information," Steltzner said recently."That's kind of what we're talking about here. That kind of feels like a very fancy 3D printing to me."