As NASA gears up for a manned Mars mission in 2030s, the agency is now building a menu for the planned journey.

The menu must sustain six to eight astronauts, keep them healthy and offer a broad array of food. That’s no simple feat considering it will likely take six months to get to the Red Planet, astronauts will have to stay there 18 months, and then it will take another six months to return to Earth. Imagine having to shop for a family’s three-year supply of groceries all at once.

“Mars is different just because it’s so far away,” said Maya Cooper, a senior research scientist who is leading the efforts to build the menu. “We don’t have the option to send a vehicle with more food every six months as we do for the International Space Station.”

Astronauts who travel to the space station have a wide variety of food available to them, with around 100 different options. However, it is all pre-prepared and freeze-dried with a shelf life of at least two years. While the astronauts make up a panel that tastes the food and gives it a final OK before it blasts off, the lack of gravity means smell and taste is impaired so the food tastes bland.

What's cooking in Mars?

Still, on Mars there is a little gravity, which allows NASA to consider significant changes to the current space menu. That’s where Cooper’s team comes in. Travel to Mars opens the possibility that astronauts can do things like chop vegetables and do a little cooking of their own. Even though pressure levels are different to those on Earth, scientists think it will even be possible to boil water with a pressure cooker.

One option Cooper and her staff are considering is having the astronauts care for a “Martian greenhouse.” They would have a variety of fruits and vegetables from carrots to bell peppers in a hydroponic solution, meaning they would be planted in mineral-laced water instead of soil. The astronauts would care for their garden and then use those ingredients - combined with others such as nuts and spices - brought from Earth to prepare their meals.

The top priority is to ensure that the astronauts get the proper amount of nutrients, calories and minerals to maintain their physical health and performance for the life of the mission, Cooper said.

The menu must also ensure the psychological health of the astronauts, Cooper explained, noting studies have shown that eating certain foods such as meatloaf and mashed potatoes or turkey on Thanksgiving improve people’s mood and give them satisfaction. That “link to home” will be important to astronauts on the Mars mission, and there are currently two academic studies looking further into the connection between food and disposition.

Jerry Linenger, a retired astronaut who spent 132 days on the Russian space station in 1997, said the monotony of eating the same thing day after day is difficult. “You just wanted something different. I didn’t care if it was something I wouldn’t eat in a million years on Earth. If it was different, I would eat it,” Linenger said, recalling with a laugh how he would even drink up a Russian sour milk-like concoction for breakfast or drink some borscht because it offered variety.

Go veggie in Mars

Cooper’s team of three has already come up with about 100 recipes, all vegetarian because the astronauts will not have dairy or meat products available.

To ensure the vegetarian diet packs the right amount of protein, the researchers are designing a variety of dishes that include tofu and nuts, including a Thai pizza that has no cheese but is covered with carrots, red peppers, mushrooms, scallions, peanuts and a homemade sauce that has a spicy kick.

To keep this menu going, and get the most out of any research about food sustainability on Mars, Cooper says it is possible NASA will choose to have one astronaut solely dedicated to preparing the food.

Cooper is also building an alternate pre-packaged menu, similar to the ones for crews that do six-month stints on the International Space Station. For this option, however, the food will need to have a five-year shelf life compared with the two years now available. NASA, the Department of Defence and a variety of other agencies are researching ways to make that possible, said Cooper.

Will NASA get the fund?

One of the biggest obstacles at the moment may be the budgetary constraints. President Barack Obama’s budget proposal in February cancelled a joint US-European robotic mission to Mars in 2016, and the rest of NASA’s budget has also been cut.

At the moment, Michele Perchonok, advanced food technology project scientist at NASA, said about $1 million on average is spent annually on researching and building the Mars menu. NASA’s overall budget in 2012 is more than $17 billion.

The mission is important - it will give scientists the opportunity for unique research on everything from looking for other life forms and for the origin of life on Earth to the effects of partial gravity on bone loss. It will also let food scientists examine the question of sustainability. “How do we sustain the crew, 100 percent recycling of everything for that two and a half years?” Perchonok said.

But first things first - none of this will happen without food.