The Genetically Engineered Astronaut

Can we create people who are optimized for ultra-long space travel?


All astronauts need the right stuff. But to live on Mars or go even further in space, eventually it might be necessary to create the right stuff than to try to find people who have it.

In other words, what if you could make the ideal astronaut from scratch?

Even with advances in understanding the human genome and with editing tools like CRISPR, genetically engineering the perfect astronaut is still just a thought experiment. But the idea isn’t as wild as you may think.

Some researchers like Christopher Mason, a geneticist at Weill Cornell Medical College, are already looking into it. He has outlined a 500-year plan to edit and write entire genomes to make people better suited for colonizing outer space. The plan suggests we use synthetic biology to make other planets more like Earth and then, in the 24th century, “begin shipment of humans to these new worlds.”

Mason’s research so far focuses on enhancing physiological traits like genetic resilience to radiation. He’s tinkering with a gene called p53, which may provide protection from cosmic radiation. His team is also trying to learn from the genetic survival secrets of organisms like tardigrades — the tiny animal called a water bear — which can withstand radiation, temperatures near absolute zero, and even the vacuum of space.

But mental traits may be more important. To stay sane even on a relatively close trip to Mars, astronauts will have to get along well with other people in a confined space for a couple of years. They’ll have to be resilient, with the flexibility and creativity to solve unforeseen problems. They’ll also need to be introverts who are both comfortable socializing with crewmates and fine being alone when others don’t want to be bothered. And they’ll have to handle the isolation of being millions of miles from Earth.

Variants in six genes are correlated with extroversion, neuroticism, and conscientiousness.

What’s tricky is that genes don’t directly shape your personality. Instead, genetics “influences the way that environment shapes personality,” says Peter Suedfeld, a psychiatrist at the University of British Columbia who has consulted with NASA and the Canadian Space Agency. So engineering a genome could at least maximize the chances you’ll get an astronaut with the optimal personality. Combining that with the right environment and training, you could conceivably create the best possible astronaut.

Scientists have only recently begun to unravel the genetic basis for personality, scanning genomes and hunting for correlations between traits and differences in individual letters of DNA, called single nucleotide polymorphisms, or SNPs. Last year, researchers analyzed genetic data from about 200,000 people and found variants in six genes that are correlated to different extents with extroversion, neuroticism, and conscientiousness.

A smaller study, involving 2,500 people, identified a genetic variant that correlated with having positive emotions, an important component of psychological resilience. Yet another genomic study of 10,000 people looked at loneliness, estimating that it may be only 27 percent genetic at best, suggesting environment is the dominant factor.

These studies are preliminary, however. One limitation is that they rely on self-reported questionnaires. “So there’s a lot of noise,” says Aliza Wingo, a psychiatrist at Emory University who was part of the resilience study.

A personality trait likely involves hundreds or thousands of genes, and to find the rest, researchers will need much more data — which are now becoming available. The U.K. Biobank, for example, contains genomes and data on 500,000 people. The U.S. National Institutes of Health is recruiting a million volunteers to fill its own database as part of its Precision Health Initiative, launched in 2015.

Perhaps in a couple of decades, Wingo says, researchers will be able to identify all the genes responsible for personality. But while genomic information may help choose who goes to Mars, modifying those genes won’t be straightforward. Our genes are intertwined, each potentially influencing personality in many ways. “We don’t know the unintended consequences of editing so many genes,” says Chi-Hua Chen, a neuroscientist at the University of California, San Diego, who led the larger personality study.

One geneticist envisions that in the 24th century, it will be time to “begin shipment of humans to new worlds.”

The researchers found, for example, that extroversion was genetically correlated with attention deficit hyperactivity disorder. Openness was associated with schizophrenia and bipolar disorder, and neuroticism was linked to conditions like depression and anxiety. A different study looking at empathy — which is related to desired traits like agreeableness — found a genetic correlation with anorexia and schizophrenia. So even if you could balance every trait and engineer the optimal psyche for an astronaut, there’s no guarantee of a perfectly well-adjusted individual.

Then again, maybe that’s OK. The unpredictability and intangibility of personality are huge parts of what makes us human. If we want a drama-free mission to Mars, we should just stick with robots.