Curiosity chassis. What's inside the Curiosity rover

On August 6, 2012, the Curiosity spacecraft landed on the surface of Mars. Over 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 landing a man.

The main research tactic is to search for interesting rocks with cameras high resolution. If any appear, the rover irradiates the rock under study with a laser from afar. Result spectral analysis determines whether it is necessary to take out a manipulator with a microscope and an X-ray spectrometer. Curiosity can then extract and load the sample into one of the internal lab's 74 dishes for further analysis.

With all its large body kit and external lightness, the device has the mass of a passenger 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 service life of at least 14 years. On this moment it produces 2.5 kWh of thermal energy and 125 W of electrical energy; over time, the electricity output will decrease to 100 W.

There are several different types of cameras installed on the rover. Mast Camera is a system of two unequal cameras with normal color rendering that can take pictures (including stereoscopic) with a resolution of 1600x1200 pixels and, which is new for Mars rovers, record a hardware-compressed 720p video stream (1280x720). To store the resulting material, the system has 8 gigabytes of flash memory for each camera - this is enough to store several thousand pictures and a couple of hours of video recording. Photos and videos are processed without loading the Curiosity control electronics. Despite the manufacturer having a zoom configuration, the cameras do not have a zoom because there was no time left for testing.

Illustration of images from MastCam. Colorful panoramas of the surface of Mars are obtained by stitching together several images. MastCams will be used not only to entertain the public with the weather of the red planet, but also to assist in sample retrieval and 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 evaporating a tiny amount of the rock under study, a 5-nanosecond laser pulse analyzes the spectrum of the resulting plasma radiation, which will determine the elemental composition of the sample. There is no need to extend the manipulator.

The resolution of the equipment is 5-10 times higher than that installed on previous Mars rovers. From 7 meters away, ChemCam can determine the type of rock being studied (e.g., volcanic or sedimentary), the structure of soil and rocks, track dominant elements, recognize ice and minerals with water molecules in the crystal structure, measure signs of erosion on rocks, and visually aid in rock exploration with the robotic arm.

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 housing, the radiation to which is supplied via a fiber optic light guide.

The Mars Hand Lens Imager is installed on the rover's manipulator, capable of taking images measuring 1600 × 1200 pixels, on which details of 12.5 micrometers can be visible. The camera has a white backlight for operation both day and night. Ultraviolet illumination is necessary to trigger the emission of carbonate and evaporite minerals, the presence of which suggests that water took part in the formation of the surface of Mars.

For mapping purposes, the Mars Descent Imager (MARDI) camera was used, which recorded images of 1600 × 1200 pixels on 8 gigabytes of flash memory during the descent of the device. As soon as a few kilometers remained to the surface, the camera began taking five color photographs per second. The data obtained will make it possible to create a map of Curiosity’s habitat.

On the sides of the rover there are two pairs of black and white cameras with a viewing angle of 120 degrees. The Hazcams system is used when performing maneuvers and extending the manipulator. The mast houses the Navcams system, which consists of two black and white cameras with a viewing angle of 45 degrees. The rover's programs continually build a wedge-shaped 3D map based on data from these cameras, allowing it to avoid collisions with unexpected obstacles. One of the first images 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.

ChemCam is a set of tools for performing remote chemical analysis of various samples. The work proceeds as follows: the laser fires a series of shots at the object under study. The spectrum of light emitted by the evaporated rock is then analyzed. ChemCam can study objects located at a distance of up to 7 meters from it. The cost of the device was about 10 million dollars (overspend of 1.5 million dollars). In normal mode, the laser focuses on the object automatically.
MastCam: a system consisting of two cameras, and contains many spectral filters. It is possible to take pictures in natural colors with a size of 1600 × 1200 pixels. Video with a resolution of 720p (1280 × 720) is shot at up to 10 frames per second and is compressed by hardware. The first camera is the Medium Angle Camera (MAC), has a focal length of 34 mm and a 15 degree field of view, 1 pixel is equal to 22 cm at a distance of 1 km.
Narrow Angle Camera (NAC), has a focal length of 100 mm, a 5.1 degree field of view, 1 pixel is equal to 7.4 cm at a distance of 1 km. Each camera has 8 GB of flash memory, which is capable of storing more than 5,500 raw images; There is support for JPEG compression and lossless compression. The cameras have an autofocus feature that allows them to focus on objects from 2.1m to infinity. Despite the manufacturer having a zoom configuration, the cameras do not have a zoom because there was no time left for testing. Each camera has a built-in RGB Bayer filter and 8 switchable IR filters. Compared to the panoramic camera on Spirit and Opportunity (MER) that captures 1024 x 1024 pixel black-and-white images, the MAC MastCam has 1.25 times the angular resolution and the NAC MastCam has 3.67 times the angular resolution. higher.
Mars Hand Lens Imager (MAHLI): The system consists of a camera mounted on the rover's robotic arm and is used to take microscopic images of rocks and soil. MAHLI can capture an image of 1600 × 1200 pixels and a resolution of up to 14.5 µm 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 UV LED illumination for operation in the dark or using fluorescent lighting. Ultraviolet illumination is necessary to trigger the emission of carbonate and evaporite minerals, the presence of which suggests that water took part in the formation of the surface of Mars. MAHLI focuses on objects as small as 1mm. The system can take multiple images with an emphasis on image processing. MAHLI can save a raw photo without losing quality or compress a JPEG file.
MSL Mars Descent Imager (MARDI): During its descent to the surface of Mars, MARDI transmitted a 1600 × 1200 pixel color image with an exposure time of 1.3 ms, the camera began shooting at a distance of 3.7 km and ended at a distance of 5 meters from the surface Mars, took 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 viewing angle is 90 degrees. MARDI contains 8GB of internal memory that can store more than 4000 photos. Images from the camera 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 alpha particles and compare X-ray spectra to determine the elemental composition of the rock. APXS is a form of Particle-Induced X-ray Emission (PIXE), which was previously used in Mars Pathfinder and Mars Exploration Rovers. APXS was developed by the Canadian Space Agency. MacDonald Dettwiler (MDA) - The Canadian aerospace company that builds Canadarm and RADARSAT are responsible for the design and construction of 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 centimeter bucket that scoops up soil. In the internal cavities of CHIMRA, it is sifted through a sieve with a cell of 150 microns, which is helped by the work of a vibrating mechanism, the excess is removed, and the next portion is sent for sifting. 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 receptacle on the body of the rover, and the excess is thrown away. As a result, a 1 mm layer of soil is received from the entire bucket for analysis. The prepared powder is studied by CheMin and SAM devices.
CheMin: Chemin examines chemical and mineralogical composition using X-ray fluorescence 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 rocks, and the resulting powder will be collected by the tool. Then the X-rays will be directed at the powder, the internal crystalline structure of the minerals will be reflected in the diffraction pattern of the rays. Diffraction x-rays 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 captured by a specially prepared E2V CCD-224 matrix measuring 600x600 pixels. Curiosity has 27 cells for analyzing samples; after studying one sample, the cell can be reused, but the analysis carried out 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 Earth. They are needed to test the performance of the device in Martian conditions. The device requires a temperature of −60 degrees Celsius to operate, otherwise interference from the DAN device will interfere.
Sample Analysis at Mars (SAM): The SAM suite of instruments 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): This device collects data to estimate the level of background radiation that will affect participants in future expeditions to Mars. The device is installed almost in the very “heart” of the rover, and thereby simulates an astronaut inside spaceship. RAD was the first of the scientific instruments for MSL to be turned on, while still in Earth orbit, and recorded the background radiation inside the device - and then inside the rover during its work on the surface of Mars. It collects data on the intensity of two types of radiation: high-energy galactic rays and particles emitted by the Sun. RAD was developed in Germany by Southwestern research institute(SwRI) in extraterrestrial physics at the group Christian-Albrechts-Universität zu Kiel, with financial support from the Exploration Systems Mission Directorate at NASA Headquarters and Germany.
Dynamic Albedo of Neutrons (DAN): Dynamic Albedo of Neutrons (DAN) is used to detect hydrogen, water ice near the surface of Mars, provided by the Federal Space Agency (Roscosmos). It is a joint development of the Automation Research Institute named after. 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 remaining part of the neutrons is reflected and registered by the receiver. Accurate measurements are possible down to a depth of 50-70 cm. In addition to actively surveying the surface of the Red Planet, the device is capable of monitoring 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 Gómez-Elvira, of the Center for Astrobiology (Madrid) includes the Finnish Meteorological Institute as a partner. They installed it on a camera mast to measure atmospheric pressure, humidity, wind direction, air and ground temperatures, and ultraviolet radiation. All sensors are located in three parts: two arms attached to the rover, the Remote Sensing Mast (RSM), the Ultraviolet Sensor (UVS) located on the top mast of the rover, and the Instrument Control Unit (ICU) inside the body. REMS will provide new insights into the local hydrological state, the destructive effects of ultraviolet radiation, and underground 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 dense layers of the atmosphere, the heat shield separated - during this period the necessary data on Martian atmosphere. This data will be used in future missions, making it possible to determine atmospheric parameters. They can also be used to change the design of the lander 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 while the rover is moving and to safely point the manipulator at rocks and soil. The cameras take 3D images (the field of view of each camera is 120 degrees) and create a map of the area in front 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 a mast to track the rover's movements. The cameras have a 45 degree field of view and take 3D images. Their resolution allows you to see an object 2 centimeters in size from a distance of 25 meters.

So how can you communicate with a rover on Mars? Think about it - even when Mars is at its shortest distance from Earth, the signal needs to travel fifty-five million kilometers! This is truly 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 quantities? At a very first approximation, it looks something like this (I tried really hard, really):

So, in the process of transmitting information, usually three key “figures” are involved - one of the space communication centers on Earth, one of the artificial satellites of Mars, and, in fact, the rover itself. Let's start with old lady Earth, and talk about the DSN (Deep Space Network) space communication centers.

Space communication stations

Any of space missions NASA is designed to ensure that communication with the spacecraft should be possible 24 hours a day (or at least whenever it might be possible) basically). Because, as we know, the Earth rotates quite quickly around own axis, to ensure signal continuity, several points are needed to receive/transmit data. These are exactly the points that DSN stations are. They are located on three continents and are separated from each other by approximately 120 degrees of longitude, which allows them to partially overlap each other’s coverage areas and, thanks to this, “guide” the spacecraft 24 hours a day. To do this, when a 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 is in Spain (about 60 kilometers from Madrid), and the third 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 - 3X-4X, and in Spain - 5X-6X. So, if you hear “DSS53” somewhere, you can be sure that we are talking about one of the Spanish antennas.

The complex in Canberra is most often used to communicate with Mars 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 interesting information. For example, very soon - April 13 this year - the DSS43 antenna will turn 40 years old.

In total, the Canberra station currently 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 operation of the center, other antennas were used, which various reasons were taken out of service. For example, the very first antenna, DSS42, was retired 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 working antennas mentioned, DSS34, was built in 1997 and became the first representative of a new generation of these devices. Its distinctive feature is that the equipment for receiving/transmitting and processing the signal is not located directly on the dish, but in the room underneath it. This made the dish significantly lighter, and also made it possible to service the equipment without stopping the operation of the antenna itself. DSS34 is a reflector antenna, its operation diagram 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. For 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)

Reception:

X-band (8400-8500 MHz)
S-band (2200-2300 MHz)
Ka-band (31.8-32.3 GHz)

Positioning accuracy: Turning speed:

2.0°/sec

Wind resistance:

Constant wind 72km/h
Gusts +88km/h

DSS43(which is about to celebrate its anniversary) is a much older example, built in 1969-1973, and modernized in 1987. DSS43 is the largest movable parabolic antenna in southern hemisphere of our planet. The massive structure, weighing more than 3,000 tons, rotates on an oil film about 0.17 millimeters thick. The surface of the dish consists of 1272 aluminum panels, and has an area of 4180 square meters.

DSS43, clickable

some technical characteristics

Broadcast:

X-band (7145-7190 MHz)
S-band (2025-2120 MHz)

Reception:

X-band (8400-8500 MHz)
S-band (2200-2300 MHz)
L-band (1626-1708 MHz)
K-band (12.5 GHz)
Ku-band (18-26 GHz)

Positioning accuracy:

within 0.005° (accuracy of pointing to the sky point)
within 0.25mm (accuracy of movement of the antenna itself)

Turning speed:

0.25°/sec

Wind resistance:

Constant wind 72km/h
Gusts +88km/h
Maximum estimated speed - 160 km/h

DSS45. This antenna was completed in 1986, and was originally intended to communicate with Voyager 2, which studied Uranus. It rotates on a round base with a diameter of 19.6 meters, using 4 wheels, two of which are driving.

DSS45, clickable

some technical characteristics

Broadcast:

X-band (7145-7190 MHz)

Reception:

X-band (8400-8500 MHz)
S-band (2200-2300 MHz)

Positioning accuracy:

within 0.015° (accuracy of pointing to the sky point)
within 0.25mm (accuracy of movement of the antenna itself)

Turning speed:

0.8°/sec

Wind resistance:

Constant wind 72km/h
Gusts +88km/h
Maximum estimated speed - 160 km/h

If we talk about the space communications station as a whole, then we can distinguish four main tasks that it must perform:
Telemetry- receive, decode and process telemetry data coming from spacecraft. Typically this data consists of scientific and engineering information transmitted over a radio link. The telemetry system receives data, monitors its changes and compliance with the norm, and transmits it to validation systems or scientific centers that process it.
Tracking- the tracking system must provide the possibility of two-way communication between the Earth and the spacecraft, and carry out calculations of its location and velocity vector for the correct positioning of the satellite.
Control- gives specialists the opportunity to transmit control commands to the spacecraft.
Monitoring and control- allows you to control and manage the systems of the DSN itself

It is worth noting that the Australian station currently serves about 45 spacecraft, so its operating time schedule is clearly regulated, and you can get Extra time not so easy. Each antenna also has the technical ability to serve up to two different devices simultaneously.

So, the data that must be transmitted to the rover is sent to the DSN station, from where it is sent on its short (from 5 to 20 minutes) space trip to the Red Planet. Let's now move on to the rover itself. What means of communication does he have?

Curiosity

Curiosity is equipped with three antennas, each of which can be used to both 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 re-ascribe this word to them, unlike the abbreviation UHF.

We are interested in RUHF, RLGA, and High Gain Antenna

The UHF antenna is the most commonly used. With its help, the rover can transmit data through 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 preferable 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 energy to transmit data. Transfer rates can reach 256kbps for Odyssey and up to 2Mbps for MRO. B O Most of the information coming from Curiosity passes through the MRO satellite. The UHF antenna itself is located at the back of the rover, and looks like a gray cylinder.

Curiosity also has an HGA, which it can use to receive commands directly from Earth. This antenna is movable (it can be pointed towards the Earth), that is, to use it, the rover does not have to change its location, just turn the HGA in the desired direction, and this allows you to save energy. The 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 rates of about 160 bps on 34-meter antennas, or up to 800 bps on 70-meter antennas.

Finally, the third antenna is the so-called LGA.
It sends and receives signals in any direction. LGA operates in the 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 primarily used to receive information rather than transmit it.
In the photo, LGA is the white turret in the foreground.
A UHF antenna is visible in the background.

It is worth noting that the rover generates a huge amount of scientific data, and it is not always possible to send all of it. NASA experts prioritize what is important: information with the highest priority will be transmitted first, and information with 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 to communicate with Curiosity you need " intermediate"in the form of one of the satellites. This makes it possible to increase the time during which communication with Curiosity is possible at all, and also to 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. Typically these windows are quite short - only a few minutes. In an emergency, Curiosity could 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 intended to study the structure of the planet and search for minerals. The satellite has dimensions of 2.2x2.6x1.7 meters and a mass of more than 700 kilograms. The altitude of its orbit ranges from 370 to 444 kilometers. This satellite has been used extensively by previous Mars rovers: about 85 percent of the data received from Spirit and Opportunity was broadcast through it. Odyssey can communicate with Curiosity in the UHF range. In terms of communications, it has HGA, MGA (medium gain antenna), LGA and UHF antenna. Basically, HGA, which has a diameter of 1.3 meters, is used to transmit data to Earth. Transmission is carried out at a frequency of 8406 MHz, and data reception is carried out at a frequency of 7155 MHz. Angular size beam is about two degrees.

Satellite instrument location

Communications with the rovers are carried out using a UHF antenna at frequencies of 437 MHz (transmission) and 401 MHz (reception); the data exchange rate can be 8, 32, 128 or 256 kbps.

Mars Reconnaissance Orbiter

MRO

In 2006, the Odyssey satellite was joined by the MRO - Mars Reconnaissance Orbiter, which today is Curiosity's main interlocutor.
However, in addition to the work of a communications operator, the MRO itself has an impressive arsenal of scientific instruments, and, most interestingly, is equipped with a HiRISE camera, which is essentially a reflecting telescope. Located at an altitude of 300 kilometers, HiRISE can take images with a resolution of up to 0.3 meters per pixel (by comparison, satellite images of the Earth are usually available at a resolution of about 0.5 meters per pixel). MRO can also create stereo pairs of surfaces accurate to an astonishing 0.25 meters. I strongly recommend that you check out at least a few of the images that are available, such as . What is it 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 photographs are taken in an extended range, so if you come across a photograph in which part of the surface is bright blue-greenish in color, do not rush into conspiracy theories;) But you can be sure that in different photographs the same breeds will have the same color. However, let's return to communication systems.

MRO is equipped with four antennas, which are the same in purpose as the rover's antennas - 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. This is what 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 are mounted directly on the HGA)

Curiosity and MRO communicate using a UHF antenna, the communication window opens twice per sol and lasts approximately 6-9 minutes. MRO allocates 5GB per day of data received from the rovers and stores it until it is within sight of one of the DSN stations on Earth, after which it transmits the data there. Data transfer to the rover is carried out according to the same principle. 30 MB/sol is allocated for storing commands that must be transmitted to the rover.

DSN stations conduct MRO 16 hours a day (the remaining 8 hours the satellite is with reverse side Mars, and cannot exchange data, since it is closed by the planet), 10-11 of which it transmits data to Earth. Typically, the satellite operates with the 70-meter DSN antenna three days a week, and twice with the 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 speed can vary from 0.5 to 4 megabits per second - it decreases as Mars moves away from Earth and increases as the two planets approach each other. Now (at the time of publication of the article) the Earth and Mars are almost at their maximum distance from each other, so the transmission speed is most likely not very high.

NASA claims (there is a special widget on the satellite’s website) that during its entire operation, MRO transmitted more than 187 terabits (!) of data to Earth - this is more than all the devices sent into space before it combined.

Conclusion

So, let's summarize. When transmitting 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 an 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, all this happens in reverse order:

The rover stores its scientific data in internal memory and waits for the nearest communication window with the satellite.
When the satellite is available, the rover transmits information to it.
The satellite receives data, stores it in its memory, and waits for one of the DSN stations to become available.
When a DSN station becomes available, the satellite sends it the received data.
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 was able to more or less briefly describe the process of communicating with Curiosity. All this information (on English language; plus a huge pile of extras, including, for example, quite detailed technical reports on the principles of operation of each of the satellites) is available on various JPL sites, it is very easy to find if you know what exactly you are interested in.

Please report any errors or typos via PM!

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The science

NASA Mars rover Curiosity, which is already working on Mars more than one and a half years, managed to make many discoveries, expanding our knowledge and ideas about the Red Planet, especially about its distant past.

Mars and Earth, as it turned out, are on early stages existence, were quite similar. There was even an assumption that life first originated on Mars and then came to Earth. However, these are just guesses. There are many things we don't know for sure, but Very close We are approaching the solution.

Curiosity rover

1) Early Mars was inhabited by living things, perhaps for a long time

After a group of researchers who work with the rover Curiosity, found out that rivers and streams once flowed in Gale Crater, they reported that there were also the whole lake was splashing. This is a small elongated lake with fresh water probably existed approximately 3.7 billion years ago

This water is on the surface of the planet, like The groundwater that went deep several hundred meters, contained everything necessary for the emergence of microscopic life.

Gale Crater was warmer, wetter, and habitable approximately 3.5 - 4 billion years ago. It was then that the first living organisms began to appear on Earth, according to scientists.

Was Mars home to primitive extraterrestrial creatures? Mars rover Curiosity cannot and will never be able to give 100% accurate answer to this question, but the discoveries he made suggest that the likelihood that primitive Martians did exist is very high.

Gale Crater

2) Water once flowed in many parts of Mars

Until recently, scientists could not even imagine that there had once been places on Mars. wild rivers and large bodies of water liquid water. Observations using artificial satellites that orbit Mars allowed researchers to guess about this. However, it is the rover Curiosity helped prove that rivers and lakes really existed.

Photos taken by the rover on the surface of the Red Planet show many fossilized structures, which are traces of rivers and streams, canals, deltas and lakes that once existed here.

Mars rover news

3) Traces found on Mars organic matter

Search for organic ingredients based carbon- one of the main goals of the Mars rover mission Curiosity, a task he will continue to perform. And although the miniature chemical laboratory on board called Sample Analysis at Mars(SAM) has already discovered six different organic components, their origin still remains a mystery.

Chemistry laboratory aboard the Sample Analysis at Mars rover

"There is no doubt that SAM detected organic substances, but we cannot say with certainty that these components are of Martian origin,"- say the researchers. There are several possibilities for the origin of these substances, for example, seepage in the SAM furnace organic solvents from Earth, which are necessary for some chemical experiments.

However, the search for organic matter on Mars has progressed greatly during the work Curiosity. Each new collection of Martian soil and sand contained increasing concentration organic substances, that is, different samples of Martian material show completely different results. If organics found on Mars were earthly origin, its concentration would be more or less stable.

SAM is the most complex and important instrument ever operated on another planet. Naturally, it takes time to understand what's the best way to work with it?.

Mars rover 2013

4) There is harmful radiation on Mars

Galactic cosmic rays and solar radiation attack Mars, and high-energy particles break the bonds that allow living organisms to survive. When a device called , which measures radiation levels, made the first measurements on the surface of the Red Planet, the results were simply stunning.

Radiation Assessment Detector

The radiation detected on Mars is simply harmful to microbes, which could live on the surface and at a depth of several meters underground. Moreover, such radiation was most likely observed here during the last several million years.

To test whether any living beings are able to survive under such conditions, scientists took an earthly bacterium as a model Deinococcus radiodurans, which can withstand incredible doses of radiation. If bacteria like D.radiodurans,appeared at a time when Mars was wetter and warm planet and when it still had an atmosphere, then theoretically they could survive after a long period of dormancy.

Living bacterium Deinococcus radiodurans

2013 Curiosity rover

5) Radiation from Mars interferes with the normal course of chemical reactions

Scientists working with the Mars rover Curiosity, emphasize that due to the fact that radiation interferes with the normal course of chemical reactions on Mars, organics are difficult to detect on its surface.

Using radioactive decay method, which is also used on Earth, scientists from Caltech found that the surface in the area Glenelg (Gale Crater) has been exposed to radiation for about 80 million years.

This new method can help find places on the planet's surface that were less exposed to radiation interfering with chemical reactions. Such places may be in the area of rocks and ledges that have been hewn by the winds. Radiation in these areas could be blocked by rocks that hung from above. If researchers find such places, they will start drilling there.

Mars rover latest news

Travel delays

Mars rover Curiosity immediately after landing was asked special route, according to which he must steer a course towards a scientifically interesting Sharpe's grief height about 5 kilometers, located in the center Gale Crater. The mission is already ongoing more than 480 days, and the rover needs several more months to get to the desired point.

What delayed the rover? On the way to the mountain was discovered a lot of important and interesting information. Currently, Curiosity is heading towards Mount Sharp almost non-stop, missing potentially interesting sites.

Having found and analyzed a potentially habitable environment on Mars, researchers Curiosity will continue to work. When it becomes clear where the radiation-protected areas are, the rover will be given the command to drill. In the meantime Curiosity approaching the original target - Mount Sharpe.

Photo from the rover

Taking samples

Photo taken by the rover during its work in the Rocknest area in October-November 2012

Self-portrait. The photo is a collage of dozens of images taken using the camera on the end of the rover's robotic arm. Mount Sharp can be seen in the distance

The first samples of Martian soil taken by the rover

The bright object in the center of the image is most likely a fragment of a ship that broke off during landing

The panorama glowing on the monitors is made up of frames sent by the rover to Earth. The blue sky should not be deceiving: on Mars it is a dull yellow, but the human eye is more familiar with the shades that are created by light scattered by our Earth's atmosphere. Therefore, the pictures are processed and displayed in unnatural colors, allowing you to calmly examine each pebble. “Geology is a field science,” Sanjeev Gupta, a professor at Imperial College London, explained to us. — We like to walk on the ground with a hammer. Pour coffee from a thermos, examine the findings 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 intrigued humanity for a long time, and the more we learn about it, the more often we discuss future colonization, the more serious the grounds for this curiosity.

Once upon a time, Earth and Mars were very similar. Both planets had oceans of liquid water and, apparently, quite simple organic matter. And on Mars, as on Earth, volcanoes erupted, a thick atmosphere swirled, but at one unfortunate moment something went wrong. “We're trying to understand what this place was like billions of years ago and why it has changed so much,” Caltech geology professor John Groetzinger said in an interview. “We believe there was water there, but we don’t know if it could support life.” And if she could, did she support? If so, it is unknown whether any evidence remains in the stones.” It was up to the rover geologist to find out all this.

Curiosity is regularly and carefully photographed, allowing itself to be examined and assessed for its general condition. This "selfie" is made up of pictures taken with a MAHLI camera. It is located on a three-joint manipulator, which, when combining images, turned out to be almost invisible. The impact drill, a ladle for collecting loose samples, a sieve for sifting them, and metal brushes for cleaning dust from stones were not included in the frame. The MAHLI macro camera and the APXS X-ray spectrometer for analysis are also not visible chemical composition samples.

1. Solar batteries are not enough for the rover’s powerful systems, and a radioisotope thermoelectric generator (RTG) provides power to it. 4.8 kg of plutonium-238 dioxide under the casing supplies 2.5 kWh daily. The cooling radiator blades are visible. 2. The laser of the ChemCam device produces 50-75 nanosecond pulses, which evaporate 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 shoot through various IR filters. 4. The REMS weather station monitors pressure and wind, temperature, humidity and ultraviolet radiation levels. 5. Manipulator with a set of tools and devices (not visible). 6. SAM - gas chromatograph, mass spectrometer and laser spectrometer for determining the composition of volatile substances in evaporated samples and in the atmosphere. 7. CheMin determines the composition and mineralogy of crushed samples from the X-ray diffraction pattern. 8. The RAD radiation detector started working in low-Earth orbit and collected data throughout the flight to Mars. 9. The DAN neutron detector allows you to detect hydrogen bound in water molecules. This Russian contribution into the work of the Mars rover. 10. Antenna casing for communication with the Mars Reconnaissance Orbiter (about 2 Mbit/s) and Mars Odyssey (about 200 Mbit/s) satellites. 11. Antenna for direct communication with the Earth in the X-band (0.5−32 kbit/s). 12. During the descent, the MARDI camera captured high-resolution color photography, allowing a detailed look at the landing site. 13. Right and left pairs of black and white Navcams 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 ladle are poured into this tray for study with a MAHLI macro camera or an APXS spectrometer. 17. 20-inch wheels with independent drives, on titanium spring spokes. Using the tracks left by the corrugation, you can evaluate the properties of the soil and monitor movement. The design includes Morse code letters - JPL.

Beginning of the expedition

Fierce Mars is an unlucky target for astronautics. Since the 1960s, almost fifty devices have been sent to it, 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 rovers. In 1997, a 10-kilogram Sojourner rode on Mars. The twins Spirit and Opportunity have become legends: the second of them has heroically continued to work for more than 12 years in a row. But Curiosity is the most impressive of them all, an entire robotic laboratory the size of a car.

On August 6, 2012, the Curiosity lander released a system of parachutes that allowed it to slow down in the thin 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 Sanjeev Gupta, it was here that all the conditions were found to better understand 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 (Aeolid) promised the opportunity to see layers of ancient rocks. The fairly flat surface looked safe. Curiosity successfully contacted and updated the software. Part of the code used during the flight and landing was replaced with a new one - from an astronaut, the rover finally became a geologist.

Year one: traces of water

Soon the geologist was stretching his legs with six aluminum wheels, checking numerous cameras and testing equipment. His colleagues on Earth examined the landing point from all sides and chose a direction. The journey to Mount Sharp was supposed to take about a year, and during this 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. Exchanges with them occur thousands of times faster, allowing hundreds of megabits of data to be transferred daily. Scientists analyze them in the Data Observatory, look at the 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 adapt to a slightly longer day. Today for them is “tosol”, tomorrow is “solvtra” (solmorrow), and a day is simply sol. So, after 40 sols, Sanjev Gupta made a presentation at which he announced: Curiosity is moving along the channel ancient river. Small stone pebbles ground by water indicated a current of about 1 m/s and a depth of “ankle- or knee-deep.” Later, data from the DAN instrument, which was produced for Curiosity by the team of Igor Mitrofanov from the Space Research Institute of the Russian Academy of Sciences, was also processed. By shining through the soil with neutrons, the detector showed that up to 4% of water is still retained at depth. This is, of course, drier than even the driest of Earth's deserts, but Mars was still full of moisture in the past, and the rover could cross that question off its list.

64 high-resolution screens create a 313-degree panorama: The KPMG Data Observatory at Imperial College London allows geologists to travel directly to Gale Crater and work on Mars in much the same way as on Earth. “Look closer, there are also traces of water here: the lake was quite deep. Of course, not like 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 spoke with a scientist as part of the events of the UK-Russia Year of Science and Education 2017, organized by the British Council and the British Embassy.

Year two: it becomes more dangerous

Curiosity celebrated its first anniversary on Mars and played the tune “Happy Birthday to You,” changing the vibration frequency of the scoop on its heavy 2.1-meter manipulator. The robotic arm scoops up loose soil with a scoop, levels it, sifts it and pours some into the receivers of its chemical analyzers. A drill with hollow replaceable bits allows you to work with hard rocks, and the rover can stir up pliable sand directly with its wheels, revealing the inner layers for its tools. It was these experiments that soon brought a rather unpleasant surprise: up to 5% calcium and magnesium perchlorates were found in the local soil.

The substances are not only toxic, but also explosive, and ammonium perchlorate is even used as the basis for solid rocket fuel. Perchlorates had already been detected at the landing site of the Phoenix probe, but now it turned out that these salts on Mars were a global phenomenon. In an icy oxygen-free atmosphere, perchlorates are stable and harmless, and the concentrations are not too high. For future colonists, perchlorate could be a useful source of fuel and a serious health hazard. But for geologists working with Curiosity, they could end their chances of finding organic matter. When analyzing samples, the rover heats them, and under such conditions, perchlorates quickly decompose organic compounds. The reaction proceeds violently, with combustion and smoke, leaving no discernible traces of the original substances.

Year three: at the foot of

However, Curiosity also discovered organics - this was announced later, after covering in total 6.9 km, the Mars geologist rover reached the foot of Mount Sharp. “When I received this data, I immediately thought that everything needed to be double-checked,” said John Grötzinger. In fact, already when Curiosity was working on Mars, it turned out that some terrestrial bacteria - such as Tersicoccus phoenicis - are resistant to clean room cleaning methods. It was even calculated that by the time of launch there should have been from 20 to 40 thousand stable spores left on the rover. No one can guarantee that some of them did not reach Mount Sharp with him.

To test 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 presented at a press conference at NASA did not raise any doubts: during his work, the Martian geologist recorded several sharp - tenfold - jumps in the methane content in the atmosphere. This gas may well have a non-biological origin, but the main thing is that at one time it could have 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 holes, leaving perfectly round 1.6-centimeter traces along its path, which will someday mark a tourist route dedicated to its expedition. The electromagnetic mechanism that forced the drill to make up to 1,800 strokes per minute to work with the hardest rock failed. However, the studied clay outcrops and hematite crystals, layers of silicate spars and channels cut by water revealed an unambiguous picture: the crater was once a lake into which a branching river delta descended.

Curiosity's cameras now revealed the slopes of Mount Sharp, the very appearance of which left little doubt about their sedimentary origin. Layer by layer, over hundreds of millions of years, the water rose and fell, depositing rocks and leaving them to erode in the center of the crater, until it finally left, collecting the entire peak. “Where the mountain now stands, there was once a pool that filled with water from time to time,” explained John Grötzinger. The lake was stratified by height: conditions in shallow and deep water differed in both temperature and composition. Theoretically, this could provide conditions for the development of a variety of reactions and even microbial forms.

The colors on the 3D model of Gale Crater 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 marked, as well as the Farah Vallis (04) - one of the supposed channels of ancient rivers that flowed into the now disappeared lake.

The journey continues

The Curiosity expedition is far from over, and the energy of the onboard generator should be enough for 14 Earth years of operation. The geologist has been on the road for almost 1,750 sols, covering more than 16 km and climbing the slope by 165 m. As far as his instruments can see, traces are still visible above sedimentary rocks ancient lake, but how do you know where they end and what else they will point to? The geologist robot continues its ascent, and Sanjeev Gupta and his colleagues are already choosing a place to land the next one. Despite the death of the Schiaparelli lander, the TGO orbital module safely entered orbit last year, launching the first stage of the European-Russian ExoMars program. The Mars rover, due to launch in 2020, will be next.

There will already be two Russian devices in it. The robot itself is approximately half the weight of Curiosity, but its drill will be able to take samples from depths of up to 2 m, and the Pasteur instrument complex will include tools for directly searching for traces of past - or even still preserved - life. “Do you have a 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, it would only be some kind of microbes... But, you see, it would be something incredible.”