CHOMIK Will Sink Its Teeth Into Surface of Enigmatic Martian Moon Phobos

The Space Research Centre of the Polish Academy of Sciences in Warsaw has started work on developing a geological penetrator CHOMIK (the Polish word for hamster), intended for the Russian space mission Phobos Sample Return. The return spacecraft will reach Earth in mid-2014 with a soil sample collected by the penetrator on the surface of the Martian moon Phobos.

A unique geological penetrator dedicated for the Phobos Sample Return space mission will be designed and manufactured at the Space Mechatronics and Robotics Laboratory, Space Research Centre of the Polish Academy of Sciences (SRC PAS) in Warsaw. One of the most important goals of the mission is to collect a soil sample from Martian moon Phobos, and deliver it to Earth. The sample will be collected from the surface of the moon by the Polish penetrator and deposited in a container that is planned to land in 2014 in Kazakhstan, encased in the Russian re-entry capsule. "Assuming everything goes according to the plan, in a few years we will be in possession of the first object acquired from a different planet's moon" -- said Dr. Karol Seweryn, of SRC PAS.

An agreement regarding the development of the penetrator CHOMIK, co-signed by the Russian Space Research Institute of the Russian Academy of Sciences and the Lavochkin Association (one of the biggest entities of the Russian space industry), took effect in April of this year. As a result, Polish scientists will be able to be a part of the international team that is going to analyze Phobos' soil sample. Furthermore, it is agreed that the container designed and developed by SRC PAS will be returned to Poland.

Phobos, the larger and the innermost of the two Martian moons, is a small, irregular body -- 27×22×18 km in dimensions, with of low density (1.9 g/cm3). Low gravity makes it a very appealing target for space missions. The escape velocity of 11 m/s is close to that of a sprinter; therefore, landing and takeoff maneuvers are relatively easy to perform. Phobos orbits around Mars at a distance of only 9,400 km, about 40 times closer than our Moon orbits above Earth.

"For the operators of a spacecraft low gravity is an advantage. However, in case of a device that is supposed to insert into the soil it becomes a major problem," pointed out Jerzy Grygorczuk, an engineer at SRC PAS. Every action has a reaction, which means that every insertion into the soil would result in a repulse of the lander away from the surface. Thanks to its unique design, the Polish penetrator is able to insert into the soil by itself, and the lander's assistance is only needed during the first few strokes. "CHOMIK will collect the sample in the case that the moon's surface is too hard for other manipulators designed for loose soil," remarked Grygorczuk. The penetrator will also measure thermal and mechanical properties of the Phobos surface.

Phobos has long attracted the attention of scientists from around the world. Its low density and unusual orbit led to a theory formulated in mid-twentieth century, maintaining that the moon could be in fact an artificial object -- a metal crust made by hypothetical Martians. Currently we know that Phobos is a natural object, most probably of solid and porous structure. There is opinion that it is similar to the outer part of the main asteroid belt that is between Mars and Jupiter. However, another viable theory suggests Phobos was not captured by Mars, but was created in orbit after the planet was formed, which would make it a second-generation Solar System object. "The results of analysis of the sample collected by our penetrator will be crucial in solving the mystery of Phobos' origins," observed Dr. Joanna Gurgurewicz, of SRC PAS.

According to the existing plan, the Phobos Sample Return mission will be launched in November 2011 aboard the launch vehicle Zenit. About a year later (11 months), the vehicle will reach the Martian orbit. It is anticipated that it will land on Phobos in the beginning of 2013. A take-off back to Earth will take place a month later and the re-entry module containing a capsule that will hold the soil sample enclosed in a container will be on its way back home. The 11 kg re-entry capsule with the container will land in Kazakhstan in mid-2014. Once the mission will be over and following a mandatory quarantine, the Polish container will be returned to the Space Research Centre PAS.