If the research works out the way it is intended, physicians will be able to deterimine if an astronaut who has spent months in space is about to get cancer and intervene with a treatment before the deadly disease appears.
"What we're trying to do is to make sure that our astronauts don't incur unacceptable risks from exposure to radiation," said Walter Schimmerling, NASA's program scientist for space radiation research in Washington, D.C. Radiation is one of the key health hazards for anyone traveling in space. Over-exposure can lead to damaged cells and cancer.
More specifically, Colorado State researchers will study how acute myelogenous leukemia (AML) develops and in the process learn how to predict when cancer might form under certain conditions.
AML is a form of cancer that occurs in bone marrow and is one of the most common types of cancer that results from radiation exposure.
"Our research team is looking at leukemia development and searching for molecular markers of pre-cancerous cells prior to the development of overt cancer," said Robert Ullrich, director of the Cancer Biology Group at Colorado State and principal investigator of the project. "Once those specific alterations are identified, we hope to be able to determine possible steps to reduce that risk."
People on the Earth's surface are protected by the planet's magnetic field, and generally speaking that's true for astronauts traveling in low Earth orbit aboard either a spacecraft like the space shuttle or the International Space Station.
But far beyond the safety of Earth's natural defenses -- such as by going back to the Moon or on to Mars -- the situation changes dramatically.
"The radiation environment outside the confines of our atmosphere is quite a bit different for astronauts than what we are exposed to on Earth," Ullrich said.
The radiation found within interplanetary space is more intense, but scientists still have more questions than answers about its effects.
"We have some idea from biological studies that these types of radiation may be more harmful and may be more particularly effective in inducing cancer than the types of radiation we're normally exposed to on Earth, and for which we have quite a bit of information," Ullrich said.
NASA officials clearly understand there is a risk to astronauts from radiation and flight surgeons carefully track each crew members' total radiation dose from all sources during his or her lifetime.
But with still much to be learned about space radiation and the risk of cancer, the limit for crew selection is very conservative -- meaning that some astronauts whose total dose is near the current redline might never fly in space again unless those limits are changed.
For example, although astronauts' medical histories are private, the case of Don Thomas became public in 2002 when he was pulled from the Expedition Six crew to the ISS and replaced with Don Pettit, essentially at the last minute.
The reason: Thomas' lifelong radiation exposure was deemed as being high enough that the risk of sending him on a long-duration station mission would put him over the arbitrary safety limit. The numbers were argued and ultimately Thomas lost.
Schimmerling couldn't comment on that specific incident but said that, in general, the work that is to be done at Colorado State should help provide the information that would have made it easier to decide to allow Thomas to fly.
"The major emphasis of our research is to narrow our margins of safety and perhaps show that the risks are less than they are estimated to be," Schimmerling said. "So that we can assure that all of our astronauts, regardless of gender and age, are able to go at least on three 180-day missions, that is our goal."
Officials acknowledge that one potential medical breakthrough with this research -- being able to predict who will get cancer from space radiation -- could be used to prevent an astronaut from being assigned to a crew, but that is not the intent of the Colorado State studies, they say.
"We're not interested in coming up with some idea on how to select or de-select astronauts. We're more interested in coming up with better ways of monitoring the astronauts when they get back. And identifying which ones ought to be monitored more closely," Ullrich said.
For the most part, NASA's Schimmerling agreed.
"It will not be used in generic astronaut selection, but it will enable us to provide information to the people who do crew assignments so that they can make rationale decisions, and so that they can inform the crew members themselves of what the actual risks are with a much higher degree of accuracy," Schimmerling said.
"But what the total risk is is something that obviously is an ethics question that the medical people have to resolve. What we need to tell them is how accurate is our estimate, what's the margin of safety they have to include in their methods to make the decision."
Although there are no formal plans or programs yet approved for sending humans to Mars, the research still needs to be done, Schimmerling said.
"The knowledge that we're going to gain will be available forever, so when a decision is made to send humans beyond low Earth orbit, we will have the knowledge required to do so."
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