The first phase of the scientific research mission of the US Mars research vehicle Curiosity that in August 2012 landed near the Gale Crater located on the equator of the Red Planet has completed. The work of the NASA specialists and the Jet Propulsion Laboratory (Pasadena, California), who control the vehicle and designed its structure, including scientific equipment allowing it to operate on the Martian surface, has already been acknowledged as an "unprecedented technological breakthrough" and a "great step forward in studying the planets". Our country also made a contribution in the development of the Mars Science Laboratory project within the framework of the agreement between the NASA and the Federal Space Agency "Ros-kosmos". The latter ordered the RAS Space Research Institute* to design a special device--DAN (dynamic neutron albedo**) aimed to collect data on the reserves of water and hydrogenous compounds in the subsoil of

* See: L. Zeleny, K. Pichkhadze, "From Magnetosphere of the Earth to Martian Satellite"; L. Zeleny, Yu. Zaitsev, "Getting to Know the Universe", Science in Russia, No. 5, 2005.--Ed.

**Albedo (from Latin albus--white)--a characteristic of the reflecting (dispersive) power of the surface of a material.--Ed.

HD quality photo of the Mars taken by the CURIOSITY.

the Red Planet. This complex and the space experiment were developed with the active participation of the All-Russia Scientific Research Institute of Automatics named after N. Dukhov, RAS Institute of Machine Science named after A. Blagonravov (Moscow) and the Joint Institute for Nuclear Research (Dubna). According to the press service of the RAS Space Research Institute, regularly informing on the latest news from the Mars, the DAN experiment on the remote planet is conducted by a team of leading scientists from the JPL, Arizona and Tennessee State Universities and Brown University (USA).

The MSL project of the total value of USD 2.5 bln was launched in 2004. The key element of this project is Curiosity, a research vehicle representing the third generation of Mars vehicles significantly superior to its predecessors: the small Sojourner, larger Spirit and Opportunity, also designed at the JPL. The Curiosity has become the largest vehicle for the whole history of research of the Red Planet: its mass is 900 kg, it is about 3 m long, 2.8 m wide and 2.1 m high (with regard to the mast of camera attachment). The vehicle has a robotized arm operating in 5 regimes, three wheel pairs (50 cm diameter) driven individually by designated power units. The front and rear suspensions are equipped with special rotary mechanisms. The vehicle can overcome obstacles (75 cm high) and make a pivot turn. The motor unit can activate the vehicle to a speed of up to 3.5 cm/s, while nuclear power source can guarantee the work of Curiosity for at least one Martian year (686 earthly days). There are 10 scientific devices of the total weight of 75 kg aboard intended to carry out detailed geological and geochemi-cal studies, as well as studies of the atmosphere and climate of the Red Planet, search for water and organic substances. All these devices have been designed to solve a basic task--to confirm or refute the hypothesis on the existence of life forms on the Mars. As stated by the press service of the RAS Space Research Institute, the Mars research vehicle has already made a number of important scientific discoveries, including with the help of the Russian device.

According to the press release, DAN measured neutron elements of the natural radiation background of the Mars in the landing area and effected some tens of active measuring runs irradiating the Martian surface with short pulses of high energy neutrons in different spots along the route of the Mars research vehicle. Both blocks of the device are controlled by a group of Moscow specialists headed by Igor Mitrofanov*, Dr. Sc. (Phys. & Math.),

* See: I. Mitrofanov, "Unlocking Martian Enigmas", Science in Russia, No. 6, 2002; I. Mitrofanov, "Mastering the Moon". Science in Russia, No. 6. 2006.--Ed.

Chief of the Gamma Spectroscopy Laboratory of the RAS Space Research Institute, and are operating in a normal regime.

According to the press release, processing of the obtained data showed presence of hydrogen under the surface rock. Scientists believe it could be associated with the molecules of water or hydroxyl making part of the minerals found on the bottom of the Gale Crater.

After matching measurement results and numerical modeling, the specialists made a conclusion: in a thin layer of the soil up to 20-30 cm thick, water content is insignificant and does not exceed 1 percent in mass (if all available hydrogen is in water molecules, its weight will be 1 percent of the total volume of the soil). But under the dry soil layer, the experts emphasize, there is a substance with a relatively high water content that changes significantly along the route of the vehicle and in certain places even exceeds 4 percent in mass. The experimental results obtained by DAN have, in fact, confirmed first releases of NASA researchers stating that the vehicle landed in the bed of the ancient stream, which once flew into a large water body at the bottom of the Gale Crater.

In February 2013, the device drilled the first hitch and took samples of the Martian soil for further analysis. John M. Grunsfeld, Administrator of NASA's Science Mission Directorate, called this event the most significant achievement of the mission from the moment of an epoch-making "procession" of the Curiosity along the Mars. The soil samples were taken from a small hollow named the Yellowknife Bay located 650 m away from the landing spot of the vehicle. The surface there is different from the place where the vehicle has landed: it is covered with pale veins containing, according to the experts, calcium sulphate and finest particles of what is called now sedimentary rocks. Earlier the observations conducted by the vehicle were focused on the near-surface layer (first of all, dust was analyzed); today they are concentrated on in-depth samples to analyze the rock composition that has never been exposed to atmospheric influence and solar radiation.

Drilling works were carried out on a fiat plate called John Klein in honor of the engineer of the mission who died in 2010. The sampling program envisaged several phases. During the first phase scientists checked up firmness of the chosen site: the drill operating in a chisel mode made small hollows in the stone. During the second phase, it made first a trial hole and then also the basic one by rotation (diameter--1.6 cm, depth--6.4 cm) in the rock. During the third phase, the obtained powder was collected in a special container, sorted out according to the size of particles and sent for an analysis to the on-board laboratories--CheMin (Chemistry and Mineralogy) spectrometer and a gas analyzer SAM (Sample Analysis at Mars).

The soil processing takes much time, but, the first results have shown traces of sulphur, nitrogen, hydrogen, oxygen, phosphorus and carbon in it--the basic construction materials for living organisms. This enabled scientists to assume that long ago, about 4 bln years ago, Mars like the early Earth was a kind of oasis with a temperature, pressure and atmosphere comfortable for the existence of living organisms. That is why the answer to the principal question of the mission--could the Mar-

tian environment be suitable for life?--can be considered positive.

However, John Grotzinger stated during the press conference held in Washington in March 2013, that the Mars research vehicle will have to carry out a number of drillings to confirm these results. He pointed out that samples taken in the subsurface layer differ drastically from those taken from the surface layer. The collected data have shown that the vehicle is really located in the estuary of the ancient river system or in the area of the ancient drying out lake. In those remote times, the humid environment could create conditions suitable for the existence of microbes. As for the found types of sulphur compounds, they could serve as energy sources for the microbes.

The sample contained 20-30 percent of smectite, a clayey mineral. High content of this mineral also evidences availability of fresh Martian water in the ancient times. Besides, it was either neutral or had a slightly acid reaction, which is proved by the presence of calcium sulphate in the rock composition. It is worth mentioning that it is the first time when NASA specialists are quite sure of the possibility of life on the Red Planet in the past.

After the Curiosity took first samples of the Martian soil, national specialists also commented on the obtained results. According to Maxim Litvak, Dr. Sc. (Phys. & Math.), leading research assistant of the RAS Space Research Institute, told the Rossiyskaya Gazeta, "In fact, there have been found prerequisites for the existence of life on the Mars, which exist on the Earth. But we still do not know whether it has originated on the Red Planet. No direct products of vital activities have been found. We are hardly surprised by regular statements that traces of life have been found on Mars, but they should be treated carefully. On the one hand, the NASA has made a lot: it is for the first time in history that scientists managed to take soil samples and study them in the laboratory directly on the surface of the Red Planet. This is a great achievement. But, on the other hand, they should understand that these studies are extremely complex. Even on the Earth scientists face many difficulties, let alone the automatic device on the Mars. That is why we must be very careful when interpreting the results. However, Americans do not make final conclusions, they are far from saying that they have discovered life. The wording is rather vague: conditions for its origination have been discovered."

The same standpoint, cited by the ITAR-TASS news agency, is supported by the research assistant of the DAN project Igor Mitrofanov. "First of all, I'd like to point out that no life as such has been discovered on the Mars", he pointed out. According to his point of view, the analysis of soil samples taken by the Curiosity showed only that "in the ancient times the planet was suitable for the existence of primitive life. But this does not mean that it has ever existed."

As stated by Mitrofanov, about 4 bln years ago, the Mars had much in common with the early Earth. But, as a result of the natural disaster, the environment has changed drastically. Most likely, the planet came up against a very big asteroid, after which lost almost everything: the strong magnetic field and the thick atmosphere and "gained" significant day and seasonal temperature variations. The Martian climate became cold and dry.

The scientist doubts that any traces of life can be found on the present-day Mars, but he does not exclude this possibility completely. He believes that "it is necessary to study new regions, move forward, and make new analyses in different areas of the Gale crater... If complex organic molecules that could form only in a primitive living organism are found, this will be a direct evidence of the existence of life on the Mars. But no such signs have been found yet."

In 2013 the NASA engineers are planning to carry out another drilling on the John Klein plate; then the Curiosity will move to the foot of the Sharp mountain, located in the center of Gale Crater, resembling puff-pastry made from sedimentary rocks. According to the experts, it can offer information on millions of years of history of the Red Planet. It will be come a final point in the journey of the Mars research vehicle.

Based on the materials of the press service of the RAS Space Research Institute

Photo NASA/JPL-Caltech/Malin Space Science Systems

Prepared by Marina KHALIZEVA