Robert Hienz, a Johns Hopkins medical researcher, is studying the effects of radiation on the brain of astronauts on future deep-space exploration missions, thanks to a $400,000 grant from NASA’s Human Research Program and its
National Space Biomedical Research Institute.
Hienz, associate professor of behavioral biology, Johns Hopkins Medical School, and senior scientist for the Institutes for Behavior Resources, is continuing research he began in 2009 with previous grants from these NASA agencies.
Hienz says that NASA has identified three problems for humans on long-term space missions: bone and muscle deterioration, eyesight and radiation effects. A fourth potential problem is psycho-social, for astronauts who will be confined together in a small vehicle for several years in a row.
NASA requested proposals to study astronauts’ health and performance on long-term space flights. Of the 104 proposals received, it chose 29, for a total of $26 billion over a one- to three-year period.
Hienz’s proposal is to detect and prevent neurobehavioral vulnerability to space radiation.
The International Space Station is within the earth’s magnetic field, which deflects radiation, so it is not an issue for its occupants. However, once astronauts move beyond the station -- to the moon or Mars, for example -- they will be subject to radiation from the sun and interstellar space, even inside a spacecraft.
Says Hienz, “The astronauts will be exposed to naturally-occurring radiation and the longer out they are, the more they will be exposed. The longer they are exposed, the more likely they are to develop problems.”
Exposure to radiation is thought to increase the incidence of cancer and to accelerate the natural aging process. He says that NASA is currently engaged in a study of former astronauts to determine if they develop cancer in their later years but the results so far are inconclusive.
A round-trip flight to Mars would take about three years, including a short stay on the surface. With the possibility of a Mars mission in 2030, as Hienz has heard, it is expected that NASA will use more frequent trips to the moon, with longer stays on its surface, as a preliminary for a Mars flight.
Hienz says that other scientists are studying the effects of radiation on other parts of the body. A complication is that there are different kinds of radiation, from high-energy solar flares to the particles of interstellar space.
Hienz has reached a few preliminary conclusions. One is that exposure to radiation does appear to affect performance. The other, and more tentative, is that physical changes detected in the brain because of radiation may provide biological markers that can be determined ahead of time.
Such markers may be used to determine the radiation sensitivity of future astronauts for prevention and treatment purposes, according to Hienz.
Source: Robert Hienz, PhD, Johns Hopkins Medical School
Writer: Barbara Pash