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Detecting radiation on lunar, Mars missions

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FLUID FLOW: This image shows the Becquerel Crater on Mars as photographed by the HiRISE (High Resolution Imaging Science Experiment) camera on board NASA's Mars Reconnaissance Orbiter. The orbiter images show alternating layers of dark- and light-toned rock within which are a series of fractures, surrounded by what researchers call `halos' of light-toned bedrock. These halos are believed to indicate where fluids, probably water, passed through the bedrock.
FLUID FLOW: This image shows the Becquerel Crater on Mars as photographed by the HiRISE (High Resolution Imaging Science Experiment) camera on board NASA's Mars Reconnaissance Orbiter. The orbiter images show alternating layers of dark- and light-toned rock within which are a series of fractures, surrounded by what researchers call `halos' of light-toned bedrock. These halos are believed to indicate where fluids, probably water, passed through the bedrock.

The instrument collects, stores and transmits data to the ground

ASTRONAUTS ARE exposed to radiations from different sources including particles trapped in the Earth's magnetic field, cosmic rays and energetic solar events. Radiation negatively affects missions in a number of ways. Radiation exposure can lead to fatigue, hair loss, cataracts, vomiting, central nervous system problems, changes in physiology and genetic make up, and cancer, among other diseases.

Effects on spacecraft

On the spacecraft, it could cause reduced power generation, background noise in sensors and the failure of electronic devices. Astronauts on lunar and Mars missions will need to continually assess their radiation risk and exposure. The faculty and midshipmen at the United States Naval Academy (USNA) are developing a small device to do exactly that, as well as alert crews during high-radiation events."Radiation on the moon and on a three-year mission to Mars is dangerous and uncertain. Since the moon and Mars have negligible or thin atmosphere and no global magnetic field, astronauts will not have the protection from radiation that we have on Earth and in low-Earth orbit," said Dr. Vince Pisacane, a researcher on the National Space Biomedical Research Institute (NSBRI)'s Technology Development Team."Travel away from the Earth's surface makes it essential to monitor the types and levels of radiation exposure."Pisacane, along with other faculty and midshipmen of the USNA, is developing a radiation detection and assessment system, called a microdosimeter, in partnership with NSBRI. The instrument will measure radiation doses on the cellular level and help determine regulatory dose limits for scientific and medical purposes. "In space, we can't predict when radiation events occur nor their severity.So it's crucial to develop a rugged, light-weight, portable system that can make real-time measurements of radiation environments," said Pisacane, R.A. Heinlein Professor of Aerospace Engineering in USNA's Aerospace Engineering Department.

Providing warning

"Spacesuits and spacecrafts integrated with microdosimeter sensors can help assess risk, provide warning at the onset of enhanced radiation so astronauts can take protective action, and help crews determine safe locations during these periods." Pisacane and his colleagues have developed two systems; one for ground-based lab testing and one for use in space. The goal of the project is to reduce the size of the sensors to the size of a deck of cards, according to a press release from the National Space Biomedical Research Institute. The flight instrument consists of three sensors and an electronic output module that collects and stores data for transmission to the ground.

The capabilities

One sensor will be near the exterior of the spacecraft and the other two housed at different locations inside. Of the interior sensors, one resides in a block of polyethylene, which will simulate the effect of radiation on tissue."The sensors measure the deposition of radiation energy in tiny microscopic elements similar in size to a red blood cell," Pisacane said.On Earth, the microdosimeter's capabilities will be useful for nuclear material clean up, in detecting radioactive devices, and to monitor patients undergoing radiation treatment. — Our Bureau


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