Avocados could be the missing element of a Mars shot


Carmel Johnston spent a year testing systems of habitation that could be used on the Red Planet. Andrew Masterson spoke to her about the experience.


The dome on the side of the Mauna Loa volcano in Hawaii was designed to test system we may use on Mars.
Carmel Johnston

“I really wanted an avocado,” says Carmel Johnston, revealing a potential stress point in NASA’s plans to send a crewed mission to Mars within the next two decades.

In August last year Johnston finished an important experiment designed by the space agency to monitor potential social and psychological pitfalls arising from sending astronauts on the long journey to the Red Planet.

She and five colleagues spent 12 months inside a small dome built on the barren heights of the Mauna Loa volcano in Hawaii. The facility is jointly administered by NASA and the University of Hawaii, and is explicitly designed to test how people cope in isolated, confined and extreme environments.

The six participants shared just 111 square metres of space, divided into a kitchen, shared area, two bathrooms, shower, and half a dozen tiny bedroom cubicles. Going outside onto the mountainside meant first donning a full spacesuit, of which there were only two, so strolls were few and far between.

Food was delivered every couple of months, all of it freeze-dried, powdered and processed. For any real Mars-based crews, the ability to foster at least some fresh produce is widely acknowledged as important for psychological and physical wellbeing.

Carmel was one of six people sharing just 111 square metres of space fro a year.
Carmel Johnston

“We did grow quite a few plants,” says Johnston. “Most of my work involved growing them, both for experiments and for general consumption, but it’s really difficult to grow the amount of food humans like to eat in such a small space.

“Because we were living in a culturally sensitive area in Hawaii, we couldn’t create acres and acres of garden outside. Ideally you would have the systems in place to grow all of the food you need. You have to think about fresh protein, too. Perhaps you would eat insects instead of ground beef – that’s a real possibility.”

For a multitude of practical reasons, therefore, steaks and tomatoes, not to mention avocadoes, were off the menu for 12 long months. She and her colleagues occasionally fell prey to dreaming of edible things that didn’t come out of vacuum-sealed packets.

The NASA experiment was primarily about living in close company without escape. It was not about a complete fine-grain simulation of life on Mars.

And that, in one aspect at least, was a blessing.

“We tried as best we could to feel like we were on Mars, but obviously we didn’t have a full life support system and we were still breathing the same air as everyone else on Earth,” she said.

“We did a phenomenal job of studying isolation and confinement. You can spend a lot of money on having the special machine that turns your urine and your sweat back into water but, you know, we left that for someone else to study.”

Carmel Johnston will take part in WOMADelaide’s Planet Talks in Adelaide on 11 March.

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Andrew Masterson is an author and journalist based in Melbourne, Australia.
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