Mars Radiation Environment Experiment
883646
196331295
2008-03-06T18:13:34Z
Seraphim Whipp
3369647
Reverted edits by [[Special:Contributions/168.9.48.254|168.9.48.254]] ([[User talk:168.9.48.254|talk]]) to last version by Aitias
[[Image:Mars_Radiation_Environment_Experiment.jpg|thumb|''MARIE'', designed to measure radiation, started malfunctioning shortly after a series of strong solar flares occurred in Autumn of 2003]]
The '''Martian Radiation Experiment''', or '''MARIE''' was designed to measure the radiation environment of [[Mars (planet)|Mars]] using an energetic particle [[spectrometer]] as part of the science mission of the [[2001 Mars Odyssey]] spacecraft (launched on [[April 7]], [[2001]]). It was led by [[NASA]]'s [[Johnson Space Center]] and the science investigation was designed to characterize aspects of the radiation environment both on the way to Mars and while it was in the Martian orbit.
Since [[Health threat from cosmic rays|space radiation]] presents an extreme hazard to crews of interplanetary missions the experiment was an attempt to predict anticipated [[radiation]] doses that would be experienced by future [[astronaut]]s and it helped determine possible effects of Martian radiation on human beings.
Space radiation comes from [[cosmic rays]] emitted by our local star, the [[sun]], and from stars beyond our solar system as well. Space radiation can trigger [[cancer]] and cause damage to the [[central nervous system]]. Similar instruments are flown on the [[Space Shuttle]]s and on the [[International Space Station]] (ISS), but none have ever flown outside of Earth's protective [[magnetosphere]], which blocks much of this radiation from reaching the surface of our planet. Ironically, in the Autumn of 2003 after a series of particularly strong [[solar flare]]s MARIE started malfunctioning, probably as a result of being exposed to the solar flare's intense blast of particle radiation. The instrument was never restored to working order.
==How the instrument works==
A spectrometer inside the instrument measured the energy from two sources of space radiation: [[galactic cosmic rays]] (GCR) and [[solar energetic particles]] (SEP). As the spacecraft orbited the red planet, the spectrometer swept through the sky and measured the radiation field.
The instrument, with a 68-degree field of view, was designed to collect data continuously during [[Mars Odyssey]]'s cruise from Earth to Mars. It stored large amounts of data for [[downlink]], and operated throughout the entire science mission.
==MARIE specifications==
[[Image:Orbiter-marie.jpg|right|200px]]
The Mars Radiation Environment Experiment weighs 3.3 kilograms (7.3 pounds) and uses 7 watts of power. It measures 29.4 centimeters (11.6 inches) by 23.2 centimeters (9.1 inches) by 10.8 centimeters (4.3 inches).
==Results==
[[Image:MARIEdoserates.nasa.png|center]]
MARIE found that radiation levels in orbit above Mars are 2.5 times higher than at the [[International Space Station]]. Levels at the Martian surface might be closer to the level at the ISS. Average in-orbit doses were about 22 [[rad (unit)|millirad]] per day (220 [[Gray (unit)|microgray]]/day or 0.08 gray/year)). However occasional [[solar proton event]]s (SPEs) produced much higher doses. SPEs were observed by MARIE that were not observed by sensors near Earth, confirming that SPEs are directional.
==External links==
* [http://mars.jpl.nasa.gov/odyssey/technology/marie.html NASA's site on MARIE]
* [http://marie.jsc.nasa.gov MARIE instrument site at Johnson Space Center]
[[Category:Spacecraft instruments]]
[[Category:Mars missions]]
[[Category:Cosmic rays]]