Cosmic Rays Postpone Mars Mission

[LIPTONW@detroitedison.com]

The attached Reuters dispatch may be of interest to RADSAFE subscribers.  
Perhaps astronauts would be a good cohort for an epidemiological study of 
radiation effects. 
Bill Lipton 
e-mail:  liptonw@detroitedison.com 
The opinions expressed are strictly mine. 
Here's to a risk free world, and other fantasies. 
 
Friday January 10 12:24 PM EST  
 
Cosmic Rays Postpone Mars Mission 
 
NEW YORK (Reuters) -- The first human visit to the Red Planet may be  
postponed until 
scientists determine the long-term effects of cosmic rays upon the  
health of astronauts. 
 
"At NASA's current rate of research in this area, more than 20 years  
will be needed to 
provide adequate data," says a statement from the National Research  
Council (NRC), 
who set up a panel to study the issue. They say this research "could  
delay a Mars 
mission beyond the next quarter century."  
 
Cosmic rays are a type of radiation found in space, born from the energy  
released by 
solar activity, or the birth of stars. The Earth's atmosphere shields us  
from most cosmic 
rays, but their effects on unprotected astronauts remains unclear.  
 
The projected round-trip visit to Mars would place humans in space for  
15 months. 
Valeriy Polyakov, a Russian cosmonaut, spent a total of more than 14 .5  
months 
aboard the space station Mir in 1994-1995.  
 
"The speculation is that these rays could result in cancer," said Dr.  
Frank Sulzman, 
Acting Deputy Director of NASA's Life Sciences Division. The NRC report  
also warns 
that exposure to cosmic rays could lead to a higher risk for cataracts  
and central 
nervous system disorders.  
 
Sulzman says current spacecraft offer crews little protection.  
"Spacecraft are made 
mostly out of aluminum, and this radiation can penetrate aluminum, at  
least the 
thicknesses that are normally used in spacecraft," he explains.  
 
The problem for NASA is that no one knows just how much protection may  
be needed. 
Shielding would probably require materials such as lithium hydride,  
adding bulk and 
weight to spacecraft.  
 
"If you were designing a radiation protection system for a spacecraft to  
go to Mars, in 
the absence of other data you would have to assume the worst," Sulzman  
explained. 
NASA researchers have estimated the cost of that worst-case scenario at  
up to an 
extra $30 billion.  
 
Time is another factor. At currently available NASA resources, it may  
take up to 20 
years to determine more exact health hazard and protection estimates,  
according to 
the NRC. They say the radiation facilities NASA needs to replicate the  
conditions of 
outer space here on Earth are currently unavailable. "Major radiation  
facilities... have 
been shut down in recent years," the report says, adding that "NASA can  
no longer rely 
on the Department of Energy and the Department of Defense for expertise,  
research, 
and facilities."  
 
One way to measure the effects of radiation exposure on tissue involves  
shooting 
particle beams at laboratory animals, beams generated by expensive  
'particle 
research accelerators'. The NRC panel is urging that NASA build its own  
accelerator, 
estimated to cost about $20 million. But they say it might provide  
answers allowing 
NASA to trim its radiation-shielding requirements, saving billions.  
 
The wait could still be a long one. "If the necessary facilities,  
expertise, and funding 
were available now," the panel concluded, "it would take approximately  
10 years to 
provide data that NASA needs to assess the best way to provide  
appropriate 
safeguards for its spaceflight crews."  
 
In the meantime, Sulzman says we can rest assured astronauts so far have  
not 
suffered from cosmic-ray exposure. "The missions to the moon, for  
example, were all 
fairly short in duration, and the longest exposures that people have had  
in space were 
on the Russian space station Mir." He says, so far, astronauts have not  
displayed any 
long-term health problems connected to cosmic rays.  
 
Sulzman says NASA is still reviewing the NRC report in an effort to plot  
an official 
policy on the issue.