Subject Matter Expert:
Jitendra Joshi, Michele Perchonok and Debbie Berdich
Food. Water. Air. Shelter. All living
things have these basic needs.
On Earth, we know where to find them. In space, these items
usually have to be carried from Earth. While in space, an
astronaut usually needs 30.60 kg (67.32 lb) of food, water,
and air per day to be healthy. Imagine that a crew of three
astronauts for a 1-year mission would need 33,000 kg (70,000
lb) of food, water, and air. It would be impossible to carry
that many supplies from Earth. Recycling is one solution
to this problem.
Cleaning and recycling the air is a big concern for NASA
scientists as we plan for longer trips in space. In space
and on Earth, human beings breathe out carbon dioxide (CO2).
Too much carbon dioxide, especially in a small, enclosed
space, can be poisonous. Air inside the spacecraft must be
“cleaned” to remove excess carbon dioxide. Some of the excess
carbon dioxide is released into outer space. Oxygen may be
removed and used from some of the carbon dioxide. Back-up
systems are in place to ensure that excess carbon dioxide
isn’t trapped in an astronaut’s living space.
Other gases trapped in the spacecraft can also be dangerous.
The gases may come from chemicals, leaks, and outgassing from materials. Outgassing happens when gases trapped inside
materials slowly leak out of those materials and into the
air. Stuffed animals, DVD labels, and some electronics cannot
be carried into space because they have outgassing issues.
The trace contaminant control
system removes these trace
odors and gases because they could accumulate and harm a
Currently, each astronaut aboard the International Space
Station (ISS) uses about 3 gallons of water daily. The average
American on Earth uses about 35 gallons of water per day.
An astronaut on an extended stay on the ISS could use up
to 10.6 tons of water per year. A crew of four on a 3-year
trip to Mars is expected to use 127.5 tons of water. That
much water is too heavy to carry on a spacecraft.
Water will have to be recycled in space. One method of recycling
water uses catalytic oxidation, a process that kills bacteria
and viruses. Unwanted materials are removed from the water,
and the water is cleaned. It will be necessary to collect
water from bathing, washing, sweating, urine, and the air’s
humidity. Through this process, NASA can make the collected
water even cleaner than water that flows from your faucet
Currently, all food astronauts need during their mission
is carried into space—1.83 kg— (slightly more than 4 pounds)
of food and packaging is carried on the ISS for each astronaut.
Of this amount, 1.56 kg (a little less than 3 ½ lb) is food;
the rest is packaging. Based upon these amounts, a 1000-day
mission to Mars would require 1830 kg (4,035 lb – more than
2 tons) of food and packaging for each astronaut! Carrying
this much food would be nearly impossible.
To avoid carrying such large amounts of food, scientists
are working on ways to grow or “create” that food. Plants
may be a food source. They may also help recycle carbon dioxide
Food. Water. Air. Shelter. A human being’s basic needs will
not change whether we live on Earth or travel to Mars. What
will change is how we meet these needs. NASA researchers,
scientists, and engineers are working to find new ways to
supply all that we’ll need for long-duration space flights.