Mars Science Laboratory (MSL), also known as:“Curiosity”Mars rover.It is an integral part of NASA's Mars exploration plan in 2009, twice the size of Mars Exploration Rover Spirit and Opportunity, and three times the weight of Mars Science Laboratory to collect Martian soil samples and rock cores, and then analyze the organic compounds and environmental conditions that may support the existence of microorganisms now or in the past.Mars Science Laboratory inUS Eastern TimeAt 10:25 on November 25, 2011 (23:25 Beijing time on November 25)Cape Canaveral Air BaseLaunch.
Mars Science Laboratory (MSL) Curiosity is a NASA probe vehicle program. At 10:25 on November 25, 2011 (23:25 Beijing time on November 25)Cape Canaveral Air BaseIt is expected to land on Mars in the autumn of 2012.This rover is three times heavier and twice longer than the Mars rovers Opportunity and Spirit that landed in 2004.It carries more advanced scientific instruments than other previous Mars missions.The international community provides some instruments.The Mars Science Laboratory was launched by the Optimus V 541 rocket.Once landed, Curiosity analyzed dozens of samples, dug out soil and drilled powder from rocks.Operate for at least one Mars year (about two Earth years), and explore a wider area than any previous Mars rover.It investigates the possibility of life support on Mars.
It is NASA's convention to name the rover by children.On November 18, 2008, a race to name a Mars rover for students aged five to eighteen across the United States began.From March 23 to 29, 2009, the general public had the opportunity to vote for the names of the nine entry decisions and use the final names of the rovers as a reference.On May 27, 2009, NASA announced that Ma Tianqi, a sixth grader, had won the competition with "curiosity".
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The Mars Science Laboratory is mainly composed of three parts: cruise stage, entry, descent and landing system and Curiosity rover.The cruise stage plays a role in the interstellar navigation phase of the probe, and can use up to six orbital positive opportunities to transport the probe to the designed Mars entry route;The entry, descent and landing system is mainly composed of three parts: heat shield, parachute and overhead crane landing system.The heat shield is mainly responsible for isolating the high temperature generated when the Curiosity rover passes through the Martian atmosphere. The parachute is mainly responsible for reducing the descent speed of the Curiosity rover from about Mach 2 to 0.75 m/s. The overhead crane is mainly responsible for helping the Curiosity rover land on the Martian surface at zero speed.The Curiosity rover is 3 meters long, 2.8 meters wide and 2.1 meters high.The mechanical arm is 2.1 meters long, the wheel diameter is 0.5 meters, and the weight is 899 kilograms. It carries 10 kinds of detection instruments, including "mast camera", "Mars handheld lens imager", "Mars landing imager", "alpha particle ray spectrometer", "chemical camera", "chemical and mineralogical analyzer", "neutron albedo dynamic detector", "Mars sample analyzer""Radiation Assessment Explorer" and "Mars rover environmental monitoring station" can carry out a series of scientific research from the physical, chemical and biological perspectives[1]。
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The "Mars Science Laboratory" is a part of NASA's "Mars Exploration Program" (MEP), and all the missions carried out serve the four strategic objectives of the program.The four strategic objectives are[1]：
Determine whether there was life on Mars;
Describe the climatic characteristics of Mars;
Describe the geological characteristics of Mars;
Prepare for manned detection.
In addition, the "Mars Science Laboratory" has a specific goal, that is, to determine the habitability of Mars.In order to accelerate the realization of the above goals, the "Mars Science Laboratory" has defined eight specific goals, which belong to four major fields.The objectives of the biological field are:
Determine the nature and inventory of organic carbon compounds;
Cataloging the chemical components of life: carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur;
Identify features that may represent biological processes.
The objectives of geology and geochemistry are:
To study the chemical, isotopic and mineralogical composition of the surface and near surface regions of Mars;
Explain the formation process of rocks and soils.
The goals of planetary evolution are:
Assess the atmospheric evolution process in a long time range such as 4 billion years;
Determine the state, distribution and circulation process of water and carbon dioxide.The goal of the field of surface radiation is to determine the broad spectrum characteristics of surface radiation, including cosmic rays, solar proton events and secondary neutrons.
Main technologies
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Expandable heat insulation design
The heat shield of "Mars Science Laboratory" uses a material called "Phenolic Resin Impregnated Carbon Ablator" (PICA), and consists of 113 PICA heat insulation tiles in 27 different shapes.Compared with the thermal shield of previous Mars landers, the technical progress of the new thermal shield mainly includes the following two aspects: one is splicing expansion.PICA materials have applied integral molding technology in "Stardust"Comet detectorHowever, the 4.5 meter diameter of the "Mars Science Laboratory" made it impossible to implement the above scheme.The heat shield of the Mars Science Laboratory is the first spliced heat ablation heat shield in the world.The spliced thermal insulation design not only meets the requirements of the "Mars Science Laboratory"Thermal insulation materialIt also lays a technical foundation for the development of larger thermal shields for manned or unmanned deep space landers.The Orion manned spacecraft is planning to use this design model.Second, it can withstand more harsh entry environment.The huge size of the heat shield of the "Mars Science Laboratory" makes the airflow it encounters in the process of entering flow from layer to turbulence, the heat to be isolated more than twice as much as before, and the stress environment it faces also becomes more complex (most of the heat shields in the past used SLA 561V material, but the stress test shows that this material cannot meet the requirements of the "Mars Science Laboratory"Shear stress environment that may be encountered.In fact, the computer simulation research before launch shows that the limit temperature of the "Mars Science Laboratory" heat shield at the launch window in 2011 was 2090 degrees Celsius, the limit heat flux was 226 watts square centimeters, the limit shear stress was 490 pascals, the limit pressure was 0.332 atmospheres, the limit heat load was 6402 joules square centimeters, and the "Mars Science Laboratory"The successful landing on Mars shows that the spliced PICA heat shield can withstand this extreme environment[1]。
Safe and accurate landing mode
The landing mass of the "Mars Science Laboratory" reached 899 kg, which was the largest Mars lander ever. The material technology could not make it land with an airbag like the smaller landers before, and it could only seek a soft landing mode.The "Mars Science Laboratory" has designed a new type of entry, descent and landing system on the basis of the previous Mars lander parachute and braking rocket deceleration technology.The biggest highlight of the system is that it can improve the landing accuracy of the lander from 150km to 20km, which greatly reduces the probability of the "Mars Science Laboratory" landing on steep ground such as Martian rocks, and greatly improves the landing safety.In order to achieve the above goals, NASA has mainly made the following technological innovations. First, at the entry stage, the navigation computer equipped on the "Mars Science Laboratory" can calculate the position and attitude information of the heat shield, and automatically send commands according to the calculation results to control four groups of eight sets on the heat shieldVector engineTo correct the landing point.Secondly, in the descent phase, NASA first used a kind of descent aid called "overhead crane".The system is equipped with eight recoil propulsion rockets, which can eliminate the influence of the wind on Mars on the accuracy of landing, and enable the Curiosity rover to land at zero speed at the designated position.In addition, in the landing phase, in order to avoid the dust fog caused by the downward downgrade and upward recoil propulsion rocket damaging the detection instrument, when the speed of the "overhead crane" and the Curiosity rover combination drops to about 0.75 m/s, three nylon ropes and a cable will lift the Curiosity rover from the "overhead crane" and suspend it below.After the Curiosity rover touches the surface of Mars, the cable will be automatically cut off, and the "overhead crane" will then land at a safe distance from the Curiosity rover.
Flexible and stable power supply capability
The Curiosity rover uses the "Multi Mission Radioisotope Thermoelectric Generator" (MMRTG) manufactured by Boeing Company to supply power, which can avoid solar power supply problems such as poor Martian surface weather conditions affecting the quality of mission completion. Phoenix lander and Spirit rover both terminate their missions due to limited solar power supply.In fact, NASA usesradio isotopeThermoelectric generator (RTG) has a long history of solar system exploration, such as Apollo moon landing spacecraft, Viking Mars lander and those flying to the edge of the solar systemPioneer probe。However, MMRTG is more advanced than RTG in the past, mainly reflected in the following three aspects: first, the power supply range is more flexible.The thermocouple of is filled with nitrogen, which makes its thermoelectric conversion capability not limited by vacuum or planetary atmosphere conditions, can perform multiple tasks such as interstellar navigation and planetary surface roaming, and can share the power supply pressure of other power sources.During the Mars exploration mission, during the rocket launch phase, MMRTG and the rocket battery were powered together during the interstellar cruise phaseSolar panelAfter the Curiosity rover landed on the Martian surface, MMRTG became the only power supply for Viking, which only supplied power on the Martian surface.Second, the power supply capacity is more stable.With the modular design method, there are no moving parts inside the heat source module and the thermocouple module, and a spring load fixing mechanism is added inside the thermocouple module.The engineering test before launch shows that the strength of random vibration that can be withstood is more than 2.5 times of the best test results in the past.Third, the power supply is more adequate.With 4.8kg plutonium 238, the heat source is integrated with a multi-purpose heat source module, and the thermocouple is integrated with a thermoelectric conversion module, which can maintain the output power between 106~117 watts during the whole mission, and can provide energy for the simultaneous operation of multiple complex instruments. The power of Pirate 1 and Pirate 2 is 70 watts.
Autonomous and fast communication capability
Like the previous Mars landers, the Curiosity rover uses the direct to ground X-band and the Mars orbiter to relay UHF band, and is responsible for data communication with the Earth by combining most of the data transmission.The difference is that the Curiosity rover is equipped with a software transceiver called "Ileka Lite Version" 1“Mars Reconnaissance Orbiter”With the cooperation of the "Ileka" software transceiver, the software wireless communication between the Mars orbiter and the lander was realized for the first time."Eleka" is a kind ofJet Propulsion LaboratoryThe developed software wireless communication mode is specially used for the relay communication between the planetary lander, the planetary orbiter and the earth. Its baseband processing completely uses a reconfigurableField programmable gate arrayIt can adapt to any channel coding, modulation and data rate by proper reprogramming.The advantages of the software wireless communication mode between Curiosity and the Mars Reconnaissance Orbiter are mainly reflected in the following three aspects. First, the data rate can be adjusted independently.The "Ileka" on the "Mars Reconnaissance Orbiter" can instruct the Curiosity rover to select the optimal data rate according to the change of angle and distance between the "Ileka - Compact" and the latter, so as to maximize the amount of data transmission.Second, it supports frequency agility.The frequency range of the forward link is one MHz, and the frequency range of the return link is one MHz. The forward link frequency of traditional communication is fixed at MHz, and the return link frequency is fixed at 401.585265 MHz.Third, the data rate is high, up to 2048 kilobits per second, while the traditional communication is up to 256 kilobits per second.
international co-operation
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Mars Science Laboratory
This rover is twice the size of Mars Exploration Rover Spirit and Opportunity, and three times the weight of Mars Science Laboratory to collect Martian soil samples and rock cores, and then analyze the organic compounds and environmental conditions that may support the existence of microorganisms.This task is also supported by many international countries,Russian Federal Space AgencyA neutron based hydrogen detector for finding water is provided, a meteorological component is provided by the Spanish Ministry of Education, and a spectrometer is provided by the Chemical Research Institute of the Max Planck Society of Germany in cooperation with the Canadian Space Agency.
technical parameter
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Mass: about 3000 kg (including propellant)
Date of launch: 15:02, November 26, 2011
Date of arrival: 05:31, August 6, 2012
instrument
The Mars Science Laboratory carries 10 scientific instruments.
Main camera
Marin Space Science Systems provides the main camera for the Mars Science Laboratory.The camera has the function of taking color photos, and can take high-definition video at the same time.
The main camera is a 10x optical zoom multispectral stereo camera, which can send back high-resolution multispectral stereo photos and RGB color video clips from the surface of Mars.
Mars Science Laboratory
10x optical zoom, 60 degree field of view, can observe objects of 10cm size from a distance of 1km
Use Bell RGB filter to provide true color imaging function
Use multi filter set to provide scientific multi spectral imaging function
Use two independent lenses to provide stereo imaging function
Compression: hardware MPEG-2 video compression (I frame: 2 bits/pixel, P frame: 0.67 bits/pixel)
Camera memory: 256 MB SDRAM, 8 GB flash buffer
Mass: 1.86 kg (best estimate)
Dimensions: 8x9.5x12cm (each lens)
Power: 13 watts (working, each lens), 5 watts (idle, each lens)
The main camera can capture and compress MPEG-2 video streams at 10 frames per second without the assistance of the detector's main computer. The video size is determined by the size of the camera's internal buffer.
