VOA慢速英语听力：NASA为火星飞行开发食品吧[1]

When astronauts go to the planet Mars years from now, they will need the right food to stay strong and healthy.

At NASA, the American space agency, scientists are working to create food products that provide nutrition without weighing down the spacecraft.

For the first step to Mars, NASA plans to send astronauts past the moon on what are called deep space missions. They will travel in the Orion spacecraft, which has limited space for food and other supplies.

This is different from the International Space Station (ISS). Its crew members can choose from about 200 food products.

Another difference is that Orion’s flights into deep space will not involve other vehicles carrying supplies, or taking away trash. The Orion crew will have to take everything they need with them, and then bring everything back home.

Limit to what can fly on Orion

Going past the moon means NASA must limit the mass on Orion. That is because a heavier spacecraft needs more fuel and energy to get to where it needs to go.

But astronauts need to eat, so for now, NASA is developing breakfast food bars. Food adds weight to the spacecraft, explains NASA engineer Jessica Vos.

“When you have 700 to 900 calories of something, it’s going to have some mass regardless of what shape it’s in,” she said. “So we’ve taken a look at how to get some mass savings by reducing how we’re packaging and stowing what the crew would eat for breakfast for early Orion flights with crew.”

“When you think about multi-week missions in Orion, having just one package for breakfast items for crew will help us limit the space we need to store them.”

Sometimes Americans eat a protein bar instead of a meal. NASA says the bars available now are not good enough.

“There’s no commercially-available bar right now that meets our needs. So we’ve had to go design something that will work for the crew, while trying to achieve a multi-year shelf life,” said Takiyah Sirmons, a fo英语听力