Fruit Flies in Space Ruin Dreams of Colonizing Mars

As the UAE spacecraft orbits around Mars – mazel tov – it’s a good time to revisit how plausible life in outer space really is

Send in e-mailSend in e-mail
The Hope probe leaving Earth last July.
The Hope probe leaving Earth last July.Credit: HANDOUT - AFP

Conquering Mars and colonizing the Moon are such science fiction staples that one could be forgiven for assuming it will happen one day. Note though that vampires are also movie staples and they’re not real, and will never be. The United Arab Emirates’ Mars mission, which reached orbit around the red planet on Tuesday (mazel tov!), is a laudable scientific endeavor. But it also provides opportunity to revisit studies indicating why, lack of oxygen aside, outer space will kill us.

For instance, one recent study on fruit flies in space discovered they suffered spectacular heart damage.

The study looking at the effect of microgravity on the fruit-fly heart at the molecular level was published in Cell Reports. It adds to previous research demonstrating how hostile the conditions in outer space are to people.

We already knew from observing human astronauts by means of ultrasound in space that protracted exposure to microgravity causes the heart to change shape from oval to spherical. Like other muscles, the heart muscle also atrophies – which diminishes the circulation of blood. These are not good things. As The Guardian reported in 2016, moon astronauts were four to five times more likely to die of heart disease than their counterparts who ventured no further than low orbit.

But thanks to the insect astronauts who spent four weeks on the International Space Station, the changes to the heart could be studied at the microlevel. And changes there were.

A spotted-wing drosophila in a vineyard, a more hospitable setting than a box of fruit flies enjoyed on their recent space mission. Credit: Fredrik von Erichsen / dpa / AP

“Microgravity can have dramatic effects on the heart, suggesting that medical intervention may be needed for long-duration space travel,” said the lead author, NASA’s Sharmila Bhattacharya. Who knew Dr. McCoy was the most irreplaceable member of the Enterprise team?

By the way, fruit flies were chosen for the month-long mission because their heart is strangely like our embryonic ones, and humans and the drosophila share a lot of disease genes. In any case, one may extrapolate from entomological cardiac damage to ours.

Also, the astronauts didn’t have to spend any time taking care of the flies or keeping up their morale – the insects were housed in a box with everything they should need for the good life (minus independence, a view and gravity). Fortunately, fruit flies are largely self-sustaining, the team pointed out.

And during that month in space, the intrepid insects made merry and multiplied. Their several hundred babies experienced three weeks of microgravity, which the scientists say is the human equivalent of three decades. The results were heart-stopping.


After splashing back down on Earth off Baja California, the fruit flies born in space were recovered and hustled to the lab before Earthling gravity could “contaminate” the results. It transpired that the space flies had smaller hearts than normal that didn’t contract as well – reminiscent of certain symptoms observed in human astronauts. 

At the cellular level, the cardiac tissue was disrupted: normally parallel muscle fibers became misaligned, losing contact with the fibers that permit the heart to generate force, the team notes. That explains the impaired pumping and circulation. As the team adds, if that happens in humans, it’s a problem.

A dickey heart is just one of many potential problems in space. Bone mass gets lost, like in osteoporosis; astronauts have long been reporting vision impairment (apparently partly due to less blood and oxygen reaching the eyes), diminished internal organ functioning, some immune impairment – herpes in space, anyone? – and even genetic changes.

A composite photo of Mars using over 100 images taken by Viking Orbiters in the 1970s. Credit: /AP

Creating artificial gravity onboard spaceships, probably by harnessing centripetal forces (go watch a sci-fi movie involving rotating spaceships), could help alleviate some of the problems, if not all: it wouldn’t do a thing for the intense radiation to which the hapless spacefarers would be exposed, for instance.

Perhaps that could be a goal for the UAE’s extraterrestrial ambitions, even as it celebrates the arrival of its Hope spacecraft to Mars: to create an environment in which human beings, and fruit flies, could survive long trips in outer space. Let alone colonize anywhere but Earth.