The Canadian Alpha Particle X-Ray Spectrometer

For those looking to learn, here are some talking points, a couple of useful links and a bit of background information on the alpha-particle X-ray spectrometer (APXS), developed and funded by the Canadian Space Agency (CSA) as part of its contribution to the Mars Science Laboratory (MSL) Curiosity rover, which launched from the Kennedy Space Center on Saturday.

• According to the February 10th, 2010 BBC News article "Nasa rides 'bucking bronco' to Mars," the MSL "weighs almost a tonne, has cost more than $2bn and, in 2013, it will be lowered on to the surface of Mars with a landing system that has never been tried before." The article goes on to state that the first official cost estimate for the  project was set out in 2003 in a document published by the United States National Research Council (NRC), which said that the MSL would be a "medium price" project with a total cost of under $650M USD's. The size of the rover (comparable to a small automobile) was dictated by the need to "lay the foundations for future missions that will eventually bring pieces of the Red Planet back home to Earth."

• As for its Canadian component, BC based MacDonald Dettwiler (MDA) is prime contractor responsible for the engineering design and manufacturing of the APXS. The APXS science team includes members from the University of New Brunswick, the University of Western Ontario, NASA, the University of California at San Diego and Cornell University. University of Guelph scientist Dr. Ralf Gellert is acting as "principal investigator" for the project, according to the November 24th, 2011 GuelphMercury article "Going to Mars: University of Guelph researchers will see their work head to the Red Planet."

• It is expected that analysis of the data from APXS could help determine if Mars ever supported microbial life. According to wikipedia, the APXS will do this by analyzing samples of the Martian soil, irradiating them with alpha particles and then mapping the spectra of any re-emitted x-rays. The APXS uses a particle-induced x-ray emission (PIXE), which has previously been used by the Mars Pathfinder and the Mars Exploration Rovers.

• According to the CSA Backgrounder on "APXS: Canada’s contribution to Mars Science Laboratory" the APXS sensor head "will be mounted at the end of the rover’s robotic arm. It will be used regularly during the mission by being placed against the surface of a sample" then emitting alpha particles and x-rays from a Curium based source. Since each element in the sample is stimulated to emit well defined energy signature, "APXS then measures the characteristic x-ray radiation to determine the sample’s composition."

• The MSL is presently scheduled to land on Mars at Gale Crater between August 6th - 20th, 2012, according to the July 22nd, 2011 article "NASA's Next Mars Rover to Land at Gale Crater" on the NASA Jet Propulsion Laboratory website.