A special incubator designed to grow tissue samples in space is being used on Earth to help understand how breast cancer develops and provide clues about how its spread might be controlled.

Nasa scientists are growing healthy and cancerous cells in devices called bioreactors that fool the cells into believing they are in zero gravity.

Data from the experiments will help them learn what causes the growth of both healthy and malignant breast tissues.

Their findings could benefit women on Earth as well as women who may spend long periods in space, such as on a mission to Mars.

Beating malignancies

"We know that many things - radiation, certain chemicals, genetic makeup - can contribute to the cause of breast cancer," said Dr. Robert Richmond of Nasa's Marshall Space Flight Center.

"We are culturing noncancerous breast cells hoping to learn what controls their growth, and how we might use that knowledge to beat any malignancies before they are formed."

Space research could find a way to control the spread of cancerous cells

Scientists are growing a type of breast cells which are found in women who are likely to develop breast cancer, most probably because of radiation damage.

They have known for some time that cells in zero gravity can grow in different ways than those grown on Earth.

To investigate this, Nasa has developed the bioreactor.

As it turns, the cells inside it continually fall yet never hit the bottom of the vessel, thus simulating zero gravity.

Bioreactors have already been used aboard the Mir space station to study breast and colon cancer cells.

More research is planned aboard the new International Space Station in a few years' time.

Radiation

Astronauts sent on long-distance space missions, especially those beyond the Moon, will be exposed to increasing levels of radiation.

What scientists learn from these cells could help in the selection of female astronauts for a future Mars mission.

It is estimated that the radiation damage a 30-year-old male astronaut might sustain during a trip to Mars would increase their risk of getting cancer by 8%.

Scientists believe this is unacceptably high and are trying to reduce it.

Because the cancer risks for women are projected to be substantially greater, mission planners are leaning towards all-male crews.