So, how can you contact a rover on Mars? Think about it - even when Mars is at the closest distance from the Earth, the signal needs to travel fifty-five million kilometers! It's really a huge distance. But how does a small, lonely rover manage to transmit its scientific data and beautiful full-color images so far and in such numbers? In the very first approximation, it looks something like this (I tried very hard, really):
So, in the process of transmitting information, usually three key "figures" are involved - one of the centers of space communications on Earth, one of the artificial satellites of Mars, and, in fact, the rover itself. Let's start with the old Earth, and talk about the DSN (Deep Space Network) space communication centers.
Space communication stations
Any of NASA's space missions is designed to ensure that communication with the spacecraft must be possible 24 hours a day (or at least whenever it can be possible). basically). Since, as we know, the Earth rotates quite quickly around its own axis, several points for receiving / transmitting data are needed to ensure the continuity of the signal. These points are the DSN stations. They are located on three continents and are separated from each other by about 120 degrees of longitude, which allows them to partially overlap each other's coverage areas, and, thanks to this, "lead" the spacecraft 24 hours a day. To do this, when the spacecraft leaves the coverage area of one of the stations, its signal is transferred to another.One of the DSN complexes is located in the USA (Goldstone complex), the second one is in Spain (about 60 kilometers from Madrid), and the third one is in Australia (about 40 kilometers from Canberra).
Each of these complexes has its own set of antennas, but in terms of functionality, all three centers are approximately equal. The antennas themselves are called DSS (Deep Space Stations), and have their own numbering - antennas in the USA are numbered 1X-2X, antennas in Australia are 3X-4X, and in Spain - 5X-6X. So if you hear "DSS53" somewhere, you can be sure that it is one of the Spanish antennas.
The Canberra complex is most often used to communicate with the rovers, so let's talk about it in a little more detail.
The complex has its own website, where you can find quite a lot of interesting information. For example, very soon - on April 13 this year - the DSS43 antenna will be 40 years old.
In total, at the moment, the station in Canberra has three active antennas: DSS-34 (34 meters in diameter), DSS-43 (an impressive 70 meters) and DSS-45 (again 34 meters). Of course, over the years of the center's operation, other antennas were used, which for various reasons were taken out of service. For example, the very first antenna - DSS42 - was decommissioned in December 2000, and DSS33 (11 meters in diameter) was decommissioned in February 2002, after which it was transported to Norway in 2009 to continue its work as an instrument for studying the atmosphere.
The first of the mentioned working antennas, DSS34, was built in 1997 and became the first representative of a new generation of these devices. Its distinguishing feature is that the equipment for receiving / transmitting and signal processing is not located directly on the dish, but in the room below it. This made it possible to significantly lighten the dish, and also made it possible to service the equipment without stopping the operation of the antenna itself. DSS34 is a reflector antenna, its operation scheme looks something like this:
As you can see, under the antenna there is a room in which all processing of the received signal is carried out. At the real antenna, this room is underground, so you won't see it in the photos.
DSS34, clickable
Broadcast:
- X-band (7145-7190 MHz)
- S-band (2025-2120 MHz)
- X-band (8400-8500 MHz)
- S-band (2200-2300 MHz)
- Ka-band (31.8-32.3 GHz)
- 2.0°/sec
- Constant wind 72km/h
- Gusts +88km/h
DSS43(which has an anniversary soon) is a much older example, built in 1969-1973, and upgraded in 1987. DSS43 is the largest mobile parabolic antenna in the southern hemisphere of our planet. The massive structure weighing over 3,000 tons rotates on an oil film about 0.17 mm thick. The surface of the plate is made up of 1272 aluminum panels, and has an area of 4180 square meters. 
DSS43, clickable
some technical specifications
Broadcast:
- X-band (7145-7190 MHz)
- S-band (2025-2120 MHz)
- X-band (8400-8500 MHz)
- S-band (2200-2300 MHz)
- L-band (1626-1708 MHz)
- K-band (12.5 GHz)
- Ku-band (18-26GHz)
- within 0.005° (accuracy of aiming at a point of the sky)
- within 0.25mm (movement accuracy of the antenna itself)
- 0.25°/sec
- Constant wind 72km/h
- Gusts +88km/h
- Maximum design - 160km/h
DSS45. This antenna was completed in 1986, and was originally designed to communicate with Voyager 2, which was studying Uranus. It rotates on a round base with a diameter of 19.6 meters, using 4 wheels for this, two of which are driving. 
DSS45, clickable
some technical specifications
Broadcast:
- X-band (7145-7190 MHz)
- X-band (8400-8500 MHz)
- S-band (2200-2300 MHz)
- within 0.015° (accuracy of aiming at a point of the sky)
- within 0.25mm (movement accuracy of the antenna itself)
- 0.8°/sec
- Constant wind 72km/h
- Gusts +88km/h
- Maximum design - 160km/h
If we talk about the space communication station as a whole, then we can distinguish four main tasks that it must perform:
telemetry- receive, decode and process telemetry data coming from space vehicles. Typically, this data consists of scientific and engineering information transmitted over the air. The telemetry system receives the data, monitors its changes and compliance with the norm, and transmits it to the validation systems or scientific centers involved in its processing.
Tracking- the tracking system should provide the possibility of two-way communication between the Earth and the spacecraft, and calculate its location and velocity vector for the correct positioning of the saucer.
Control- gives specialists the opportunity to transmit control commands to the spacecraft.
Monitoring and control- I allow to control and manage the systems of the DSN itself
It is worth noting that the Australian station currently serves about 45 spacecraft, so the timetable for its work is clearly regulated, and it is not so easy to get additional time. Each of the antennas also has the technical ability to serve up to two different devices simultaneously.
So, the data to be transmitted to the rover is sent to the DSN station, from where they go on their short (5 to 20 minutes) space trip to the Red Planet. Let's now move on to reviewing the rover itself. What means of communication does he have?
Curiosity
Curiosity is equipped with three antennas, each of which can be used to receive and transmit information. These are UHF antenna, LGA and HGA. All of them are located on the "back" of the rover, in different places.
HGA - High Gain Antenna
MGA - Medium Gain Antenna
LGA - Low Gain Antenna
UHF-Ultra High Frequency
Since the abbreviations HGA, MGA and LGA already have the word antenna in them, I will not attribute this word to them again, unlike the abbreviation UHF.
We are interested in RUHF, RLGA, and High Gain Antenna
The UHF antenna is the most commonly used. With it, the rover can transmit data via the MRO and Odyssey satellites (which we will talk about later) at a frequency of about 400 megahertz. The use of satellites for signal transmission is preferred due to the fact that they are in the field of view of DSN stations much longer than the rover itself, sitting alone on the surface of Mars. In addition, since they are much closer to the rover, the latter needs to expend less power to transmit data. Transfer rates can reach up to 256kbps for Odyssey and up to 2Mbps for MRO. B about Most of the information coming from Curiosity passes through the MRO satellite. The UHF antenna itself is located at the rear of the rover and looks like a gray cylinder.
Curiosity also has an HGA that it can use to receive commands directly from Earth. This antenna is mobile (it can be directed towards the Earth), that is, to use it, the rover does not have to change its location, just turn the HGA in the right direction, and this allows you to save energy. HGA is mounted approximately in the middle on the left side of the rover, and is a hexagon with a diameter of about 30 centimeters. HGA can transmit data directly to Earth at about 160 bps on 34m antennas, or up to 800 bps on 70m antennas.
Finally, the third antenna is the so-called LGA.
It sends and receives signals in all directions. LGA works in X-band (7-8 GHz). However, the power of this antenna is quite low, and the transmission speed leaves much to be desired. Because of this, it is mainly used to receive information rather than transmit it.
In the photo, the LGA is the white turret in the foreground.
The UHF antenna is visible in the background.
It is worth noting that the rover generates a huge amount of scientific data, and not always all of them can be sent. NASA experts prioritize importance: information with the highest priority will be transmitted first, and information with a lower priority will wait for the next communication window. Sometimes some of the least important data has to be deleted altogether.
Odyssey and MRO satellites
So, we found out that usually, in order to communicate with Curiosity, an “intermediate link” is needed in the form of one of the satellites. This allows you to increase the time during which communication with Curiosity is generally possible, as well as increase the transmission speed, since more powerful satellite antennas are able to transmit data to Earth at a much higher speed.Each of the satellites has two communication windows with the rover every sol. Usually these windows are quite short - only a few minutes. In an emergency, Curiosity can also contact the European Space Agency's Mars Express Orbiter satellite.
Mars Odyssey
Mars Odyssey
The Mars Odyssey satellite was launched in 2001 and was originally designed to study the structure of the planet and search for minerals. The satellite measures 2.2 x 2.6 x 1.7 meters and weighs over 700 kilograms. The height of its orbit ranges from 370 to 444 kilometers. This satellite was actively used by previous rovers: about 85 percent of the data received from Spirit and Opportunity were broadcast through it. Odyssey can communicate with Curiosity on the UHF band. In terms of communications, it has an HGA, MGA (medium gain antenna), LGA and UHF antenna. Basically, for data transmission to the Earth, an HGA is used, which has a diameter of 1.3 meters. Transmission is carried out at a frequency of 8406 MHz, and data is received at a frequency of 7155 MHz. The angular size of the beam is about two degrees.
Location of satellite instruments
Communication with the rovers is carried out using a UHF antenna at frequencies of 437 MHz (transmit) and 401 MHz (reception), the data exchange rate can be 8, 32, 128 or 256 kb / s.
Mars Reconnaissance Orbiter
MRO
In 2006, the Odyssey satellite was joined by MRO - Mars Reconnaissance Orbiter, which today is the main interlocutor of Curiosity.
However, in addition to the work of a signalman, the MRO itself has an impressive arsenal of scientific instruments, and, most interestingly, is equipped with a HiRISE camera, which is, in fact, a reflecting telescope. At an altitude of 300 kilometers, HiRISE can take images with a resolution of up to 0.3 meters per pixel (for comparison, satellite images of the Earth are usually available with a resolution of about 0.5 meters per pixel). MRO can also create surface stereopairs with an accuracy of astonishing 0.25 meters. I strongly recommend that you familiarize yourself with at least a few of the pictures that are available, for example,. What is worth, for example, this image of the Victoria crater (clickable, the original is about 5 megabytes):
I suggest that the most attentive find the Opportunity rover in the image;)
answer (clickable)
Please note that most color shots were taken in an extended range, so if you stumble upon a shot in which part of the surface is bright blue-greenish, do not rush to engage in conspiracy theories;) But you can be sure that in different shots identical breeds will have the same color. However, back to communication systems.
The MRO is equipped with four antennas that are designed to match the rover's - a UHF antenna, an HGA, and two LGAs. The main antenna used by the satellite - HGA - has a diameter of three meters, and operates in the X-band. It is she who is used to transmit data to Earth. The HGA is also equipped with a 100-watt signal amplifier.
1 - HGA, 3 - UHF, 10 - LGA (both LGAs mounted directly on HGA)
Curiosity and MRO communicate using a UHF antenna, the communication window opens twice per sol, and lasts approximately 6-9 minutes. MRO allocates 5 GB per day for data received from rovers and stores it until it is in line of sight of one of the DSN stations on Earth, after which it transmits the data there. Data transmission to the rover is carried out according to the same principle. 30 Mb/sol is allocated for storing commands to be transmitted to the rover.
DSN stations conduct MRO for 16 hours a day (the remaining 8 hours the satellite is on the far side of Mars, and cannot exchange data, as it is closed by the planet), 10-11 of which it transmits data to Earth. Typically, the satellite operates three days a week with a 70-meter DSN antenna, and twice with a 34-meter antenna (unfortunately, it is not clear what it does on the remaining two days, but it is unlikely that it has days off). The transmission rate can vary from 0.5 to 4 megabits per second - it decreases as Mars moves away from the Earth and increases as the two planets approach. Now (at the time of publication of the article) Earth and Mars are almost at the maximum distance from each other, so the transfer rate is most likely not very high.
NASA claims (there is a special widget on the satellite website) that over the entire period of its operation, MRO transmitted more than 187 terabits (!) of data to Earth - this is more than all the vehicles sent into space before it, combined.
Conclusion
So, let's sum up. When sending control commands to the rover, the following happens:- JPL specialists send commands to one of the DSN stations.
- During a communication session with one of the satellites (most likely it will be MRO), the DSN station transmits a set of commands to it.
- The satellite stores the data in internal memory and waits for the next communication window with the rover.
- When the rover is in the access zone, the satellite transmits control commands to it.
When transmitting data from the rover to Earth, it all happens in reverse order:
- The rover stores its science data in internal memory and waits for the next satellite communication window.
- When a satellite is available, the rover sends information to it.
- The satellite receives the data, stores it in its memory, and waits for the availability of one of the DSN stations
- When a DSN becomes available, the satellite sends the received data to it.
- Finally, after receiving the signal, the DSN station decodes it and sends the received data to those for whom it is intended.
I hope I have been able to more or less briefly describe the process of contacting Curiosity. All this information (on English language; plus a huge pile of extras, including, for example, fairly detailed technical reports on how each of the satellites work) are available on various JPL sites and are very easy to find once you know what you're interested in.
Please report any bugs and typos!
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On August 6, 2012, the Curiosity lander landed on the surface of Mars. In the next 23 months, the rover will study the surface of the planet, its mineralogical composition and radiation spectrum, look for traces of life, and also evaluate the possibility of a human landing.
The main research tactic is to search for interesting rocks with high-resolution cameras. If they appear, then the rover irradiates the studied rock with a laser from afar. The result of the spectral analysis determines whether the manipulator with the microscope and X-ray spectrometer needs to be taken out. Curiosity can then extract and load the sample into one of the 74 cups in the internal lab for further analysis.
With all its large body kit and external lightness, the apparatus has the mass of a car (900 kg) and weighs 340 kg on the surface of Mars. All equipment is powered by the decay energy of plutonium-238 from a Boeing radioisotope thermoelectric generator, which has a lifespan of at least 14 years. At the moment, it produces 2.5 kWh of thermal energy and 125 W of electricity, over time, the electricity output will decrease to 100 W.
The rover has several different types of cameras installed at once. Mast Camera is a system of two non-identical conventional color cameras that can take pictures (including stereoscopic ones) with a resolution of 1600x1200 pixels and, which is new for rovers, record a hardware-compressed 720p video stream (1280x720). To store the received material, the system has 8 gigabytes of flash memory for each of the cameras - enough to fit several thousand pictures and a couple of hours of video recording. Processing of photos and videos goes without load on the Curiosity control electronics. Despite having a zoom configuration from the manufacturer, the cameras do not have zoom because there was no time for testing.
Image illustration from MastCam. Colorful panoramas of the surface of Mars are obtained by gluing together several images already. MastCam cameras will be used not only to entertain the public with the weather of the red planet, but also as an aid in the extraction of samples by the manipulator and during movement.
Also attached to the mast is part of the ChemCam system. This is a laser-spark emission spectrometer and an imaging unit that work in pairs: after the evaporation of a tiny amount of the studied rock, a 5-ns laser pulse analyzes the spectrum of the resulting plasma radiation, which will determine the elemental composition of the sample. In this case, it is not necessary to extend the manipulator.
The resolution of the equipment is 5-10 times higher than that installed on previous rovers. From 7 meters, ChemCam can determine the type of rock being studied (e.g. volcanic or sedimentary), soil and rock structure, track dominant elements, recognize ice and minerals with water molecules in the crystal structure, measure erosion marks on rocks, and visually assist in the study of rocks with a manipulator.
The cost of ChemCam was $10 million (less than half a percent of the entire cost of the expedition). The system consists of a laser on a mast and three spectrographs inside the case, the radiation to which is supplied through a fiber optic light guide.
The rover's manipulator is equipped with the Mars Hand Lens Imager, capable of capturing 1600×1200 pixel images that can show details as small as 12.5 micrometers. The camera has a white backlight for both day and night operation. Ultraviolet illumination is necessary to cause the emission of carbonate and evaporite minerals, the presence of which suggests that water took part in the formation of the Martian surface.
For mapping purposes, the Mars Descent Imager (MARDI) camera was used, which during the descent of the vehicle recorded images of 1600 × 1200 pixels in size on 8 gigabytes of flash memory. Once the surface was a few kilometers away, the camera began taking five color photographs per second. The data obtained will make it possible to map the Curiosity habitat.
On the sides of the rover are two pairs of black-and-white cameras with a viewing angle of 120 degrees. The Hazcams system is used when manipulating and extending the manipulator. On the mast is the Navcams system, which consists of two black and white cameras with a viewing angle of 45 degrees. The rover programs constantly build a wedge-shaped 3D map based on the data from these cameras, which avoids collisions with unexpected obstacles. One of the first shots from Curiosity is a picture from the Hazcam camera.
A monitoring station was installed on the rover to measure weather conditions. environment(Rover Environmental Monitoring Station), which measures pressure, atmospheric and surface temperatures, wind speed and ultraviolet radiation. REMS is protected from Martian dust.
NASA launched another rover to the Red Planet. Unlike projects related to this planet in our country, American researchers manage to quite successfully carry out such missions. Recall that the Russian analogue of Curiosity - Phobos-Grunt failed due to a software error when entering low Earth orbit.
Objectives of the Curiosity mission. Curiosity is not just a rover. The project is carried out as part of the Mars Science Laboratory mission and is a platform on which a lot of scientific equipment is installed, which was prepared to solve several problems.
The first task facing Curiosity is not original - the search for life on this harsh planet. To do this, a new generation rover will need to detect and study the nature of organic carbon compounds. Find substances such as hydrogen, nitrogen, phosphorus, oxygen, carbon and sulfur. The presence of such substances suggests the prerequisites for the origin of life.
In addition, other tasks are assigned to Curiosity. The rover, with the help of its equipment, will have to transmit information about the climate and geology of the planet, as well as prepare for the landing of a person.
Characteristics of the Curiosity rover. Curiosity is 3 meters long and 2.7 meters wide. It is equipped with six 51 cm wheels. Each wheel is powered by an independent electric motor. The front and rear wheels will help the rover turn in the right direction. Thanks to the special design and optimum diameter, Curiosity is able to overcome an obstacle with a height of 75 cm and accelerate to 90 meters per hour.
The rover is powered by a mini-reactor. The plutonium-238 embedded in it will last for 14 years of operation. From solar panels decided to refuse because of the problem of large dustiness of the atmosphere of Mars.
Flight and landing of the Curiosity rover. Gale Crater was chosen as the landing site for the Curiosity rover. Pretty flat place that shouldn't pose a problem.
The rover was launched into geostationary orbit by a two-stage Atlantis-5 541 rocket. From where the station will proceed to Mars. And here a very interesting moment begins - the landing of Curiosity.
The atmosphere of Mars is quite complex. Its dense layers do not allow landing engines to correct this process. Because of this, a rather interesting technology has been developed that should bypass these difficulties.
During entry into the atmosphere, Curiosity will be folded inside a special protective capsule. From high temperatures when entering the dense layers of the atmosphere at high speed, it will be protected by a special coating of carbon fibers impregnated with phenol-formaldehyde resin.
In the dense atmosphere of Mars, the speed of the device will decrease from 6 km / s to twice the speed of sound. Dropped ballasts will correct the position of the capsule. The heat-shielding "veil" will shoot off and at a speed of 470 m/s the supersonic parachute will open.
When passing a height of 3.7 km above the planet, the camera installed at the bottom of the rover should start. It will take pictures of the surface of the planet, high-resolution frames will help to avoid problems with the place where Curiosity should land.
All this time, the parachute acted as a brake, and at an altitude of 1.8 km above the Red Planet, the rover is separated from the descent unit, and further descent will occur using a platform equipped with landing engines.
Variable thrust motors adjust the position of the platform. At this point, Curiosity should have time to decompose and prepare for landing. In order to make this process quite smooth, another technology was invented - the “flying crane”.
The “flying crane” is 3 cables that will smoothly lower the rover to the surface of the planet while the platform will hover at a height of 7.5 meters.
Equipment of the Curiosity rover. The Curiosity rover has a large amount of scientific equipment. Among them there is also a device that was developed by Russian specialists. The rover is equipped with a robotic arm that is quite sensitive. A drill, a shovel and other equipment are mounted in it, which will allow collecting soil and rock samples.
The rover has 10 instruments, some of which we will describe below.
MastCam is a camera located on a high mast above the rover. She is the eyes of the operators who, receiving a picture on Earth, will control the apparatus.
SAM is a mass spectrometer, a laser spectrometer and a gas chromatograph “in one bottle”, which allow you to analyze soil samples. It is SAM that must find organic compounds, nitrogen, oxygen and hydrogen.
The robotic arm should deliver samples to a special place on the rover, where they will be examined by the SAM instrument.
CheMin- another device for the analysis of rocks. It defines chemical and mineral compounds.
checam is the most interesting piece of equipment aboard the Curiositi rover. In simple terms, this is a laser that is capable of melting soil or rock samples at a distance of 9 meters from the rover and, having examined the pairs, should determine their structure.
APXS- a spectrometer that, by irradiating samples with X-rays and alpha particles, will be able to identify them. APXS sits on the rover's robotic arm.
DAN- a device developed by our compatriots. It is able to detect the presence of water or ice even at a shallow depth below the surface of the planet.
RAD- will determine the presence of radioactive radiation on the planet.
REMS is a sensitive weather station aboard Curiosity.
The Curiosity rover is humanity's ambitious project that will take us to new level the study of Mars. Landing and studying the Red Planet with this apparatus will help answer two questions that have haunted mankind for a long time: is there life on Mars and is it possible to colonize this planet in the near future.
- ChemCam is a set of tools for conducting remote chemical analysis various samples. The work is carried out as follows: the laser conducts a series of shots on the object under study. Then the spectrum of light emitted by the evaporated rock is analyzed. ChemCam can study objects located up to 7 meters away from it. The instrument cost about $10 million ($1.5 million overrun). In normal mode, the laser focuses on the object automatically.
- MastCam: A dual camera system with multiple spectral filters. It is possible to take pictures in natural colors with a size of 1600 × 1200 pixels. 720p (1280 × 720) resolution video is captured at up to 10 frames per second and is compressed by hardware. The first camera, the Medium Angle Camera (MAC), has a focal length of 34 mm and a 15 degree field of view, 1 pixel equals 22 cm at a distance of 1 km.
- Narrow Angle Camera (NAC), has a focal length of 100 mm, 5.1 degree field of view, 1 pixel equals 7.4 cm at a distance of 1 km. Each camera has 8 GB of flash memory capable of storing over 5500 raw images; there is support for JPEG compression and lossless compression. The cameras have an auto focus feature that allows them to focus on subjects from 2.1m to infinity. Despite having a zoom configuration from the manufacturer, the cameras do not have zoom because there was no time for testing. Each camera has a built-in Bayer RGB filter and 8 switchable IR filters. Compared to the Spirit and Opportunity (MER) panoramic camera that captures black and white images of 1024 × 1024 pixels, the MAC MastCam has 1.25 times the angular resolution and the NAC MastCam has 3.67 times the angular resolution. above.
- Mars Hand Lens Imager (MAHLI): The system consists of a camera attached to the rover's robotic arm, used to take microscopic images of rocks and soil. MAHLI can capture an image of 1600 × 1200 pixels and up to 14.5 microns per pixel. MAHLI has a focal length of 18.3mm to 21.3mm and a field of view of 33.8 to 38.5 degrees. MAHLI has both white and ultraviolet LED backlight for working in the dark or using fluorescent lighting. Ultraviolet illumination is necessary to cause the emission of carbonate and evaporite minerals, the presence of which suggests that water took part in the formation of the Martian surface. MAHLI focuses on objects as small as 1 mm. The system can take multiple images with emphasis on image processing. MAHLI can save the raw photo without quality loss or compress the JPEG file.
- MSL Mars Descent Imager (MARDI): During the descent to the surface of Mars, MARDI transmitted a 1600 × 1200 pixel color image with an exposure time of 1.3 ms, the camera started at a distance of 3.7 km and ended at a distance of 5 meters from the surface Mars, shot a color image at a frequency of 5 frames per second, the shooting lasted about 2 minutes. 1 pixel is equal to 1.5 meters at a distance of 2 km, and 1.5 mm at a distance of 2 meters, the camera's viewing angle is 90 degrees. MARDI contains 8 GB of built-in memory that can store over 4000 photos. Camera shots made it possible to see the surrounding terrain at the landing site. JunoCam, built for the Juno spacecraft, is based on MARDI technology.
- Alpha-particle X-ray spectrometer (APXS): This device will irradiate with alpha particles and correlate X-ray spectra to determine the elemental composition of the rock. APXS is a form of Particle-Induced X-ray Emission (PIXE) that was previously used by the Mars Pathfinder and Mars Exploration Rovers. APXS was developed by the Canadian Space Agency. MacDonald Dettwiler (MDA) - The Canadian aerospace company that builds the Canadarm and RADARSAT are responsible for the design and construction of the APXS. The APXS development team includes members from the University of Guelph, the University of New Brunswick, the University of Western Ontario, NASA, the University of California, San Diego, and Cornell University.
- Collection and Handling for In-Situ Martian Rock Analysis (CHIMRA): CHIMRA is a 4x7 cm bucket that scoops up soil. In the internal cavities of CHIMRA, it is sieved through a sieve with a cell of 150 microns, which is helped by the operation of the vibration mechanism, the excess is removed, and the next portion is sent for sieving. In total, there are three stages of sampling from the bucket and sifting the soil. As a result, a little powder of the required fraction remains, which is sent to the soil receiver, on the body of the rover, and the excess is thrown away. As a result, a soil layer of 1 mm comes from the entire bucket for analysis. The prepared powder is examined by CheMin and SAM instruments.
- CheMin: Chemin examines the chemical and mineralogical composition, using an X-ray fluorescence instrument and X-ray diffraction. CheMin is one of four spectrometers. CheMin allows you to determine the abundance of minerals on Mars. The instrument was developed by David Blake at NASA's Ames Research Center and NASA's Jet Propulsion Laboratory. The rover will drill into rocks, and the resulting powder will be collected by the instrument. Then X-rays will be directed to the powder, the internal crystal structure of minerals will be reflected in the diffraction pattern of the rays. X-ray diffraction is different for different minerals, so the diffraction pattern will allow scientists to determine the structure of the substance. Information about the luminosity of atoms and the diffraction pattern will be taken by a specially prepared E2V CCD-224 matrix of 600x600 pixels. Curiosity has 27 cells for sample analysis, after examining one sample, the cell can be reused, but the analysis performed on it will have less accuracy due to contamination from the previous sample. Thus, the rover has only 27 attempts to fully study the samples. Another 5 sealed cells store samples from the Earth. They are needed to test the performance of the device in Martian conditions. The device needs a temperature of -60 degrees Celsius to operate, otherwise interference from the DAN device will interfere.
- Sample Analysis at Mars (SAM): The SAM toolkit will analyze solid samples, organic matter, and atmospheric composition. The tool was developed by: Goddard Space Flight Center, Inter-Universitaire Laboratory, French CNRS and Honeybee Robotics, along with many other partners.
- Radiation assessment detector (RAD), "Radiation assessment detector": This device collects data to estimate the level of background radiation that will affect members of future expeditions to Mars. The device is installed almost in the very "heart" of the rover, and thus imitates an astronaut inside the spacecraft. The RAD was turned on by the first of the scientific instruments for MSL, while still in Earth orbit, and recorded the radiation background inside the device - and then inside the rover during its operation on the surface of Mars. It collects data on the intensity of irradiation of two types: high-energy galactic rays and particles emitted by the Sun. RAD was developed in Germany by the Southwestern Research Institute (SwRI) for extraterrestrial physics in the Christian-Albrechts-Universität zu Kiel group with financial support from the Exploration Systems Mission Directorate at NASA Headquarters and Germany.
- Dynamic Albedo of Neutrons (DAN): The Dynamic Albedo of Neutrons (DAN) is used to detect hydrogen, water ice near the surface of Mars, provided by the Federal Space Agency (Roskosmos). It is a joint development of the Research Institute of Automation. N. L. Dukhov at Rosatom (pulse neutron generator), the Space Research Institute of the Russian Academy of Sciences (detection unit) and the Joint Institute for Nuclear Research (calibration). The cost of developing the device was about 100 million rubles. Photo of the device. The device includes a pulsed neutron source and a neutron radiation receiver. The generator emits short, powerful pulses of neutrons towards the Martian surface. The pulse duration is about 1 μs, the flux power is up to 10 million neutrons with an energy of 14 MeV per pulse. Particles penetrate into the soil of Mars to a depth of 1 m, where they interact with the cores of the main rock-forming elements, as a result of which they slow down and are partially absorbed. The rest of the neutrons are reflected and registered by the receiver. Accurate measurements are possible down to a depth of 50 -70cm In addition to active survey of the surface of the Red Planet, the device is able to monitor the natural radiation background of the surface (passive survey).
- Rover environmental monitoring station (REMS): A set of meteorological instruments and an ultraviolet sensor were provided by the Spanish Ministry of Education and Science. The research team led by Javier Gomez-Elvira, Center for Astrobiology (Madrid) includes the Finnish Meteorological Institute as a partner. We installed it on the mast of the camera to measure atmospheric pressure, humidity, wind direction, air and ground temperatures, and ultraviolet radiation. All sensors are located in three parts: two booms are attached to the rover, the Remote Sensing Mast (RSM), the Ultraviolet Sensor (UVS) is located on the upper mast of the rover, and the Instrument Control Unit (ICU) is inside the body. REMS will provide new insights into local hydrological conditions, the damaging effects of ultraviolet radiation, and subterranean life.
- MSL entry descent and landing instrumentation (MEDLI): The main purpose of MEDLI is to study the atmospheric environment. After the descent vehicle with the rover slowed down in the dense layers of the atmosphere, the heat shield separated - during this period, the necessary data on the Martian atmosphere were collected. These data will be used in future missions, making it possible to determine the parameters of the atmosphere. They can also be used to change the design of the descent vehicle in future missions to Mars. MEDLI consists of three main instruments: MEDLI Integrated Sensor Plugs (MISP), Mars Entry Atmospheric Data System (MEADS), and Sensor Support Electronics (SSE).
- Hazard avoidance cameras (Hazcams): The rover has two pairs of black-and-white navigation cameras located on the sides of the vehicle. They are used to avoid danger during the movement of the rover and to safely aim the manipulator on rocks and soil. The cameras make 3D images (the field of view of each camera is 120 degrees), map the area ahead of the rover. The compiled maps allow the rover to avoid accidental collisions and are used by the device's software to select the necessary path to overcome obstacles.
- Navigation cameras (Navcams): For navigation, the rover uses a pair of black-and-white cameras that are mounted on the mast to track the rover's movement. The cameras have a 45 degree field of view and produce 3D images. Their resolution allows you to see an object 2 centimeters in size from a distance of 25 meters.
Before us is a desert, naked and lifeless. The horizon is marked by the edge of the crater, in the center rises a five-kilometer peak.
Before us is a desert, naked and lifeless. The horizon is marked by the edge of the crater, in the center rises a five-kilometer peak. The wheels and panels of the rover gleam right at our feet. Don't be alarmed: we're in London, where the unique Data Observatory allows geologists to step into the Martian wilderness and work side by side with Curiosity, the most sophisticated robot ever to go into space.
The panorama glowing on the monitors is made up of frames sent by the rover to Earth. The blue sky should not deceive: on Mars it is a dull yellow, but the human eye is more familiar with the shades that are created by the light scattered by our Earth's atmosphere. Therefore, the images are processed and displayed in unnatural colors, allowing you to calmly examine each pebble. “Geology is a field science,” explained Sanjev Gupta, professor at Imperial College London. - We love to walk on the ground with a hammer. Pour coffee from a thermos, examine the finds and select the most interesting for the laboratory.” There are no laboratories or thermoses on Mars, but geologists sent Curiosity, their electronic colleague, there. The neighboring planet has been intriguing mankind for a long time, and the more we learn about it, the more often we discuss future colonization, the more serious the reasons for this curiosity.
Once upon a time, Earth and Mars were very similar. Both planets had oceans of liquid water and, apparently, fairly simple organic matter. And on Mars, as on Earth, volcanoes erupted, a thick atmosphere swirled, but at one unfortunate moment something went wrong. “We are trying to understand what this place was like billions of years ago and why it has changed so much,” said John Grötzinger, professor of geology at the California Institute of Technology, in an interview. “We believe there was water, but we don't know if it could support life. And if she could, did she support it? If so, it is not known whether any evidence has been preserved in the stones. It was up to the rover geologist to find out all this.
Curiosity is photographed regularly and carefully, allowing you to inspect yourself and assess your general condition. This "selfie" is made up of pictures taken with the MAHLI camera. It is located on a three-joint manipulator, which turned out to be almost invisible when the images were combined. The impact drill, the ladle for collecting loose samples, the sieve for sifting them, and the metal brushes for cleaning stones from dust did not get into the frame. Also invisible is the MAHLI macro camera and the APXS X-ray spectrometer for analysis. chemical composition samples.
1. Powerful rover systems will not have enough solar panels, and it is powered by a radioisotope thermoelectric generator (RTG). 4.8 kg of plutonium-238 dioxide under the casing delivers 2.5 kWh daily. The blades of the cooling radiator are visible.
2. The laser of the ChemCam device produces 50-75 nanosecond pulses that vaporize the stone at a distance of up to 7 m and allow you to analyze the spectrum of the resulting plasma to determine the composition of the target.
3. A pair of MastCam color cameras are shooting through various IR filters.
4. The REMS weather station monitors pressure and wind, temperature, humidity and UV levels.
5. Manipulator with a set of tools and devices (not visible).
6. SAM - gas chromatograph, mass spectrometer and laser spectrometer
to establish the composition of volatile substances in evaporated samples and in the atmosphere.
7. CheMin finds out the composition and mineralogy of ground samples from the X-ray diffraction pattern.
8. The RAD radiation detector was still in operation in near-Earth orbit and collected data throughout the flight to Mars.
9. The DAN neutron detector can detect hydrogen bound in water molecules. This is the Russian contribution to the work of the rover.
10. Antenna housing for communication with satellites Mars Reconnaissance Orbiter (about 2 Mbps) and Mars Odyssey (about 200 Mbps).
11. Antenna for direct communication with the Earth in the X-band (0.5-32 kbps).
12. During the descent, the MARDI camera took high-resolution color footage, allowing a detailed view of the landing site.
13. Right and left pairs of black and white Navcams cameras for building 3D models of the surrounding area.
14. A panel with clean samples allows you to check the operation of the rover's chemical analyzers.
15. Spare drill bits.
16. Prepared samples from the bucket are poured into this tray for examination by the MAHLI macro camera or the APXS spectrometer.
17. 20-inch wheels with independent drives, on titanium springy spokes. According to the traces left by the corrugation, it is possible to assess the properties of the soil and follow the movement. The pattern includes Morse code letters - JPL.
Start of the expedition
Ferocious Mars is an unfortunate target for astronautics. Starting in the 1960s, almost fifty vehicles went to him, most of which crashed, turned off, failed to enter orbit and disappeared forever in space. However, the efforts were not in vain, and the planet was studied not only from orbit, but even with the help of several planetary rovers. In 1997, a 10-kilogram Sojourner drove across Mars. The twins Spirit and Opportunity have become a legend: the second of them has been heroically continuing its work for more than 12 years in a row. But Curiosity is the most imposing of them all, an entire robotic lab the size of a car.
On August 6, 2012, the Curiosity lander ejected a parachute system that allowed it to slow down in a rarefied atmosphere. Eight worked jet engines braking, and a system of cables carefully lowered the rover to the bottom of Gale Crater. The landing site was chosen after much debate: according to Sanjev Gupta, it was here that all the conditions were found in order to better know the geological - apparently very turbulent - past of Mars. Orbital surveys indicated the presence of clays, the appearance of which requires the presence of water and in which organic matter is well preserved on Earth. The high slopes of Mount Sharp (Eolid) promised the opportunity to see layers of ancient rocks. The fairly flat surface looked safe. Curiosity has successfully contacted and updated the software. Part of the code used during the flight and landing was replaced by a new one - from an astronaut, the rover finally became a geologist.
Year one: traces of water
Soon the geologist "stretched his legs" - six aluminum wheels, checked numerous cameras and tested the equipment. His colleagues on Earth considered the landing point from all sides and chose a direction. The journey to Mount Sharp was to take about a year, and during that time there was a lot of work to be done. The direct communication channel with the Earth is not very good. throughput, but every Martian day (sol) orbiters fly over the rover. Exchange with them is thousands of times faster, allowing you to transfer hundreds of megabits of data daily. Scientists analyze them in the Data Observatory, view images on computer screens, select tasks for the next Sol or several at once, and send the code back to Mars.
Working practically on another planet, many of them are forced to live according to the Martian calendar and adjust to a slightly longer day. Today for them is "sun" (tosol), tomorrow - "solvtra" (solmorrow), and the day is just sol. So, after 40 sols, Sanjeev Gupta made a presentation at which he announced: Curiosity moves along the bed of an ancient river. Small, water-turned stone pebbles indicated a current at a speed of about 1 m / s and a depth “ankle- or knee-deep”. Later, data from the DAN device, which was made for Curiosity by the team of Igor Mitrofanov from the Space Research Institute of the Russian Academy of Sciences, were also processed. By scanning the soil with neutrons, the detector showed that up to now, up to 4% of water is retained in it at a depth. It is, of course, drier than even the driest of Earth's deserts, but in the past, Mars was still full of moisture, and the rover could cross this issue off its list.
in the center of the crater
64 high-definition screens create a 313-degree panorama: The KPMG Data Observatory at Imperial College London allows geologists to be transported directly to Gale Crater and work on Mars in much the same way as on Earth. “Look closer, there are traces of water here too: the lake was quite deep. Of course, not as Baikal, but deep enough,” the illusion was so real that it seemed as if Professor Sanjev Gupta was jumping from stone to stone. We visited the Data Observatory and talked to a scientist as part of the UK and Russia Year of Science and Education 2017 organized by the British Council and the British Embassy.
Year two: getting more dangerous
Curiosity celebrated its first anniversary on Mars and played the tune “Happy Birthday to You” by changing the frequency of vibrations of the ladle on its heavy 2.1-meter manipulator. With the bucket of the "roboruk" he picks up loose soil, levels it, sifts and pours a little into the receivers of his chemical analyzers. A drill with hollow interchangeable bits allows you to work with hard rocks, and the rover can stir up the pliable sand directly with its wheels, opening up the inner layers for its tools. It was these experiments that soon brought a rather unpleasant surprise: up to 5% of calcium and magnesium perchlorates were found in the local soil.
Substances are not only poisonous, but also explosive, and ammonium perchlorate is used as the basis of solid rocket fuel. Perchlorates have already been detected at the landing site of the Phoenix probe, but now it turned out that these salts on Mars are a global phenomenon. In an icy oxygen-free atmosphere, perchlorates are stable and harmless, and the concentrations are not too high. For future colonists, perchlorates could be a useful source of fuel and a serious health hazard. But for geologists working with Curiosity, they can put an end to the chances of finding organics. While analyzing the samples, the rover heats them up, and under such conditions, perchlorates quickly decompose organic compounds. The reaction proceeds violently, with burning and smoke, leaving no distinguishable traces of the starting materials.
Year three: at the foot
However, Curiosity also discovered organics - this was announced later, after on Sol 746, covering a total of 6.9 km, the geologist rover reached the foot of Mount Sharp. “After receiving this data, I immediately thought that it was necessary to double-check everything,” said John Grötzinger. Indeed, as early as when Curiosity was working on Mars, it was found that some terrestrial bacteria - such as Tersicoccus phoenicis - are resistant to cleanroom cleaning practices. It was even calculated that by the time of launch, the rover should have had between 20,000 and 40,000 resistant spores left. No one can guarantee that some of them did not make it to Mount Sharpe with him.
To check the sensors, there is also a small supply of clean samples of organic substances on board in sealed metal containers - is it possible to say with absolute certainty that they remained sealed? However, the graphs that were presented at a press conference at NASA did not cause doubts: during the work, the Martian geologist recorded several sharp - tenfold at once - jumps in the methane content in the atmosphere. This gas may well have a non-biological origin, but the main thing is that it could once become a source of more complex organic substances. Traces of them, primarily chlorobenzene, were also found in the soil of Mars.
Years Four and Five: Living Rivers
By this time, Curiosity had already drilled a dozen and a half holes, leaving along its path perfectly round 1.6-centimeter tracks that would someday mark the tourist route dedicated to his expedition. The electromagnetic mechanism that forced the drill to make up to 1800 strokes per minute to work with the hardest rock failed. However, the studied outcrops of clays and hematite crystals, layers of silicate spars and channels cut by water already revealed an unambiguous picture: once the crater was a lake into which a branching river delta descended.
The Curiosity cameras now had a view of the slopes of Mount Sharp, the very sight of which left little doubt as to their sedimentary origin. Layer after layer, for hundreds of millions of years, the water either arrived or retreated, causing rocks and leaving to erode in the center of the crater, until it finally left, having collected the whole peak. “Where the mountain rises now, there was once a pool, filled with water from time to time,” John Grötzinger explained. The lake was stratified in height: the conditions in shallow water and at depth differed in both temperature and composition. Theoretically, this could provide conditions for the development of various reactions and even microbial forms.
The colors on the Gale Crater 3D model correspond to the height. In the center is Mount Aeolis (Aeolis Mons, 01), which rises 5.5 km above the plain of the same name (Aeolis Palus, 02) at the bottom of the crater. The landing site of Curiosity (03) is noted, as well as the Farah Valley (Farah Vallis, 04) - one of the alleged channels of ancient rivers that flowed into the now disappeared lake.
Journey continues
The Curiosity expedition is far from over, and the energy of the onboard generator should be enough for 14 Earth years of work. The geologist has been on the road for almost 1750 sols, covering more than 16 km and climbing a slope of 165 m. As far as his tools can see, traces of the sedimentary rocks of the ancient lake are still visible higher up, but who knows where they end and what else they indicate ? The geologist robot continues its ascent, while Sanjeev Gupta and his colleagues are already choosing a landing site for the next one. Despite the loss of the Schiaparelli descent probe, the TGO orbital module successfully entered orbit last year, launching the first stage of the European-Russian ExoMars program. The rover, due to launch in 2020, will be next.
There will already be two Russian devices in it. The robot itself is about half the weight of Curiosity, but its drill will be able to take samples from a depth of up to 2 m, and the Pasteur instrumentation will include tools for directly searching for traces of past - or even preserved - life. "You have cherished desire, a find that you especially dream about? we asked Professor Gupta. “Of course, there is: a fossil,” the scientist answered without hesitation. But this, of course, is unlikely to happen. If there was life there, then only some microbes ... But, you see, it would be something incredible.
