Curiosity was launched from Cape Canaveral on November 26, 2011 at 10:02 EST aboard the MSL spacecraft and successfully landed on Aeolis Palus in Gale Crater on Mars on August 6, 2012, 05:17:57.3 UTC.[1] The final landing place for the rover was less than 2.4 km (1.5 mi) from its target after a 563,000,000 km (350,000,000 mi) journey.[2]
According to the Mars Exploration Program, the main scientific goals of the MSL mission are to help determine whether Mars could ever have supported life, as well as determining the role of water, and to study the climate and geology of Mars.[4][3][4] The mission will also help prepare for human exploration.[4]
Attempting these goals, the Curiosity rover has six main scientific objectives:[3][5]
Determine the mineralogical composition of the crater surface and near-surface geological materials.
Attempt to detect chemical building blocks of life (biosignatures).
Interpret the processes that have formed and modified rocks and soils.
Assess the long-timescale (i.e., 4-billion-year) Martian atmospheric evolution processes.
Determine present state, distribution, and cycling of water and carbon dioxide.
The Curiosity rover comprised 23% of the mass of the 3,893 kg (8,583 lb) Mars Science Laboratory (MSL) spacecraft, which had the sole mission of delivering the rover safely across space from Earth to a soft landing on the surface of Mars. The remaining mass of the MSL craft was discarded in the process of carrying out this task.
Dimensions:Curiosity rover has a mass of 899 kg (1,982 lb) including 80 kg (180 lb) of scientific instruments.[6] The rover is 2.9 m (9.5 ft) long by 2.7 m (8.9 ft) wide by 2.2 m (7.2 ft) in height.[7]
Radioisotope power systems (RPSs) are generators that produce electricity from the natural decay of plutonium-238, which is a non-fissile isotope of plutonium. Heat given off by the natural decay of this isotope is converted into electricity by thermocouples, providing constant power during all seasons and through the day and night. Waste heat can be used via pipes to warm systems, freeing electrical power for the operation of the vehicle and instruments.[8][9]Curiosity's RTG is fueled by 4.8 kg (11 lb) of plutonium-238 dioxide supplied by the U.S. Department of Energy,[10] packed in 32 cubes, each about the size of a marshmallow (≈20 cm3).[6]
Curiosity's power generator is the latest RTG generation built by Boeing and Idaho National Laboratory, called the "Multi-Mission Radioisotope Thermoelectric Generator" or MMRTG.[11][12] Based on classical RTG technology, it represents a more flexible and compact development step,[11] and is designed to produce 125 watts of electrical power from about 2000 watts of thermal power at the start of the mission.[8][9] The MMRTG produces less power over time as its plutonium fuel decays: at its minimum lifetime of 14 years, electrical power output is down to 100 watts.[13][14] The power source will generate 9 MJ (2.5 kilowatt hours) per day, much more than the solar panels of the Mars Exploration Rovers, which can generate about 2.1 MJ (0.6 kilowatt hours) per day. The electrical output from the MMRTG charges two rechargeable lithium-ion batteries. This enables the power subsystem to meet peak power demands of rover activities when the demand temporarily exceeds the generator’s steady output level. Each battery has a capacity of about 42 amp-hours.
Heat rejection system: The temperatures at the landing site can vary from +30 to −127 °C (+86 °F to −197 °F) so for the majority of the Martian year, the thermal system will be warming the rover. The thermal system will achieve this in several ways: passively, through the dissipation of internal components; by electrical heaters strategically placed on key components; and by using the rover heat rejection system (HRS).[15] It uses fluid pumped through 60 m (200 ft) of tubing in the rover body so that sensitive components are kept at optimal temperatures.[16] The fluid loop actually serves the additional purpose of rejecting heat when the rover has become too warm, but it also can gather waste heat from the power source, by pumping fluid through two heat exchangers mounted alongside the RTG. The HRS also has the ability to cool components if necessary.[16]
Computers: The two identical on-board rover computers, called "Rover Compute Element" (RCE), contain radiation hardened memory to tolerate the extreme radiation from space and to safeguard against power-off cycles. Each computer's memory includes 256 kBofEEPROM, 256 MBofDRAM, and 2 GBofflash memory.[17] This compares to 3 MB of EEPROM, 128 MB of DRAM, and 256 MB of flash memory used in the Mars Exploration Rovers.[18]
The RCE computers use the RAD750CPU, which is a successor to the RAD6000 CPU used in the Mars Exploration Rovers.[19][20] The RAD750 CPU is capable of up to 400 MIPS, while the RAD6000 CPU is capable of up to 35 MIPS.[21][22] Of the two on-board computers, one is configured as backup, and will take over in the event of problems with the main computer.[17]
The rover has an Inertial Measurement Unit (IMU) that provides 3-axis information on its position, which is used in rover navigation.[17] The rover's computers are constantly self-monitoring to keep the rover operational, such as by regulating the rover's temperature.[17] Activities such as taking pictures, driving, and operating the instruments are performed in a command sequence that is sent from the flight team to the rover.[17] The rover installed its full surface operations software after the landing because its computers didn't have room for it during flight. The new software essentially replaced the flight software.[2]
Communications:Curiosity is equipped with significant telecommunication redundancy by several means – an X bandtransmitter and receiver that can communicate directly with Earth, and a UHF Electra-Lite software-defined radio for communicating with Mars orbiters.[15] Communication with orbiters is expected to be the main path for data return to Earth, since the orbiters have both more power and larger antennas than the lander allowing for faster transmission speeds.[15] Telecommunication includes a small deep space transponder on the descent stage and a solid-state power amplifier on the rover for X-Band. The rover also has two UHF radios,[15] the signals of which the Mars Odyssey satellite is capable of relaying back to Earth. An average of 14 minutes, 6 seconds will be required for signals to travel between Earth and Mars.[23]Curiosity can communicate with Earth directly at speeds up to 32 kbit/s, but the bulk of the data transfer should be relayed through the Mars Reconnaissance Orbiter and Odyssey orbiter. Data transfer speeds between Curiosity and each orbiter may reach 2 Mbit/s and 256 kbit/s, respectively, but each orbiter is only able to communicate with Curiosity for about eight minutes per day.[24]
JPL is the central data distribution hub where selected data products are provided to remote science operations sites as needed. JPL is also the central hub for the uplink process, though participants are distributed at their respective home institutions.[15] At landing, telemetry was monitored by three orbiters, depending on their dynamic location: the Mars Odyssey, Mars Reconnaissance Orbiter and ESA's Mars Express satellite.[25]
Mobility systems: Like rovers from the previous Mars Exploration Rover and Mars Pathfinder missions, Curiosity is equipped with six 50 centimetres (20 in) diameter wheels in a rocker-bogie suspension. The suspension system also served as landing gear for the vehicle, unlike its smaller predecessors.[26][27] Each wheel has cleats and is independently actuated and geared, providing for climbing in soft sand and scrambling over rocks. Each front and rear wheel can be independently steered, allowing the vehicle to turn in place as well as execute arcing turns.[15] Each wheel has a pattern that helps it maintain traction but also leaves patterned tracks in the sandy surface of Mars. That pattern is used by on-board cameras to judge the distance traveled. The pattern itself is Morse code for "JPL" (·--- ·--· ·-··).[28] Based on the center of mass, the vehicle can withstand a tilt of at least 50 degrees in any direction without overturning, but automatic sensors will limit the rover from exceeding 30-degree tilts.[15]
Curiosity will be able to roll over obstacles approaching 65 cm (26 in) in height,[29] and it has a ground clearance of 60 centimetres (24 in).[30] Based on variables including power levels, terrain difficulty, slippage and visibility, the maximum terrain-traverse speed is estimated to be 200 m (660 ft) per day by automatic navigation.[29] The rover landed about 10 kilometres (6.2 mi) from the foot of Mount Sharp,[31] and it is expected to traverse a minimum of 19 km (12 mi) during its primary two-year mission.[32] It can travel up to 90 meters (295 feet) per hour (0.09 kph 0.0559 mile per hour), but average speed is about 1/3 that.[32]
Instruments
The general sample analysis strategy begins with high resolution cameras to look for features of interest. If a particular surface is of interest, Curiosity can vaporize a small portion of it with an infrared laser and examine the resulting spectra signature to query the rock's elemental composition. If that signature is intriguing, the rover will use its long arm to swing over a microscope and an X-ray spectrometer to take a closer look. If the specimen warrants further analysis, Curiosity can drill into the boulder and deliver a powdered sample to the analytical laboratory (SAM) inside the rover,[33] that has a limit of 74 sample cups.[34][35] The MastCam, Mars Hand Lens Imager (MAHLI), and Mars Descent Imager (MARDI) cameras were developed by Malin Space Science Systems and they all share common design components, such as on-board electronic imaging processing boxes, 1600×1200 CCDs, and a RGB Bayer pattern filter.[36][37][38][39][40][41]
It has 17 cameras: HazCams (8), Navcams (4), MastCams (2), MAHLI (1), MARDI(1), and ChemCam (1).
Mast Camera (MastCam)
The MastCam system provides multiple spectra and true-color imaging with two cameras.[37] The cameras can take true-color images at 1600×1200 pixels and up to 10 frames per second hardware-compressed, video at 720p (1280×720).
MastCam camera is the Medium Angle Camera (MAC), which has a 34 mmfocal length, a 15-degree field of view, and can yield 22 cm/pixel scale at 1 km. The other camera, MastCam, is the Narrow Angle Camera (NAC), which has a 100 mm focal length, a 5.1-degree field of view, and can yield 7.4 cm/pixel scale at 1 km.[37] (Malin also developed a pair of Mastcams with zoom lenses,[42] but these were not included in the rover because of the time required to test the new hardware and the looming November 2011 launch date.[43])
Each camera has eight GB of flash memory, which is capable of storing over 5,500 raw images, and can apply real time lossless data compression.[37] The cameras have an autofocus capability that allows them to focus on objects from 2.1 m (6 ft 11 in) to infinity.[40] In addition to the fixed RGGB Bayer pattern filter, each camera has an eight-position filter wheel. While the Bayer filter reduces visible light throughput, all three colors are mostly transparent at wavelengths longer than 700 nm, and have minimal effect on such infrared observations.[37]
Chemistry and Camera complex (ChemCam)
ChemCam is a suite of remote sensing instruments, including the first laser-induced breakdown spectroscopy (LIBS) system to be used for planetary science and a remote micro-imager (RMI).[44][45] The LIBS instrument can target a rock or soil sample from up to 7 metres (23 ft) away, vaporizing a small amount of it with about 50 to 75 5-nanosecond pulses from a 1067 nminfrared laser and then collecting a spectrum of the light emitted by the vaporized rock. Detection of the ball of luminous plasma will be done in the visible, near-UV and near-infrared ranges, between 240 nm and 800 nm.[44]
Using the same collection optics, the RMI provides context images of the LIBS analysis spots. The RMI resolves 1 mm objects at 10 m distance, and has a field of view covering 20 cm at that distance.[44] The ChemCam instrument suite was developed by the Los Alamos National Laboratory and the French CESR laboratory.[44][46][47][48] The flight model of the Mast Unit was delivered from the French CNEStoLos Alamos National Laboratory.[49]
Navigation cameras (Navcams)
The rover has two pairs of black and white navigation cameras mounted on the mast to support ground navigation.[50][51] The cameras have a 45 degree angle of view and use visible light to capture stereoscopic 3-D imagery.[51][52] These cameras, like those on the Mars Pathfinder missions support use of the ICER image compression format.
REMS comprises instruments to measure the Mars environment: humidity, pressure, temperatures, wind speeds, and ultraviolet radiation.[53] It is a meteorological package that includes an ultraviolet sensor provided by the Spanish Ministry of Education and Science. The investigative team is led by Javier Gómez-Elvira of the Center for Astrobiology (Madrid) and includes the Finnish Meteorological Institute as a partner.[54][55] It is mounted on the camera mast and can measure atmospheric pressure, relative humidity, wind currents and direction, air and ground temperature and ultraviolet radiation levels. All sensors are located around three elements: two booms attached to the rover Remote Sensing Mast (RSM), the Ultraviolet Sensor (UVS) assembly located on the rover top deck, and the Instrument Control Unit (ICU) inside the rover body. REMS will provide new clues about signature of the Martian general circulation, microscale weather systems, local hydrological cycle, destructive potential of UV radiation, and subsurface habitability based on ground-atmosphere interaction.[54]
Hazard avoidance cameras (Hazcams)
The rover has four pairs of black and white navigation cameras called Hazcams—two pairs in the front and two pairs in the back.[56][50] They are used for autonomous hazard avoidance during rover drives and for safe positioning of the robotic arm on rocks and soils.[56] The cameras use visible light to capture stereoscopic three-dimensional (3-D) imagery.[56] The cameras have a 120 degree field of view and map the terrain at up to 3 m (9.8 ft) in front of the rover.[56] This imagery safeguards against the rover crashing into unexpected obstacles, and works in tandem with software that allows the rover to make its own safety choices.[56]
MAHLI is a camera on the rover's robotic arm, and acquires microscopic images of rock and soil. MAHLI can take true-color images at 1600×1200 pixels with a resolution as high as 14.5 micrometers per pixel. MAHLI has a 18.3 mm to 21.3 mm focal length and a 33.8- to 38.5-degree field of view.[38] MAHLI has both white and ultraviolet LED illumination for imaging in darkness or fluorescence imaging. MAHLI also has mechanical focusing in a range from infinite to millimetre distances.[38] This system can make some images with focus stacking processing.[57] MAHLI can store either the raw images or do real time lossless predictive or JPEG compression.
CheMin is the Chemistry and Mineralogy (CheMin) X-raypowder diffraction and fluorescence instrument.[61] CheMin is one of four spectrometers. It will identify and quantify the abundance of the minerals on Mars. It was developed by David Blake at NASA Ames Research Center and the Jet Propulsion Laboratory.[62] The rover will drill samples into rocks and the resulting fine powder will poured into an instrument via a sample inlet tube on the top of the vehicle. The powder is introduced into an inlet (like for SAM). Piezo-driven actuators at the base of the funnel shake and sift soil samples into the spectrometers for analysis. The inlet design of CheMin and SAM was validated using laser vibrometers. A beam of X-rays is then directed at the powder while additional piezo actuators vibrate it, and the crystal structure of the minerals deflects the X-rays at characteristic angles, allowing scientists to identify the minerals being analyzed.
The instrument contains 32 sample cells which may be rotated into position under the inlet funnel, plus a "bypass funnel". Five of the cells are filled with calibration standards, while 27 are available for samples. The cells may be rotated to an inverted position and vibrated to empty them for re-use.[citation needed]
The SAM instrument suite will analyze organics and gases from both atmospheric and solid samples. The Space Physics Research Laboratory at the University of Michigan built the main power supply, command and data handling unit, valve and heater controller, filament/bias controller, and high voltage module. Its inside the chassis. Uncooled MCT infrared detectors used in a tunable laser spectrometer instrument have been developed and provided by the Polishhigh-tech company VIGO System.[63]
Radiation assessment detector (RAD)
This instrument was the first of ten MSL instruments to be turned on. Its first role was to characterize the broad spectrum of radiation environment found inside the spacecraft during the cruise phase. These measurements have never been done before from the inside of a spacecraft and their main purpose is to determine the viability and shielding needs for potential human explorers. Its second role is to characterize the radiation environment on the surface of Mars, which it started doing immediately after MSL landed in August 2012.[64] Funded by the Exploration Systems Mission Directorate at NASA Headquarters and Germany's Space Agency (DLR), RAD was developed by Southwest Research Institute (SwRI) and the extraterrestrial physics group at Christian-Albrechts-Universität zu Kiel, Germany.[64][65]
During the descent to the Martian surface MARDI took color images at 1600×1200 pixels with a 1.3-millisecond exposure time starting at distances of about 3.7 km to near five meters from the ground, at a rate of five frames per second for about two minutes.[39][69] MARDI has a pixel scale of 1.5 meters at two km to 1.5 millimeters at two meters and has a 90-degree circular field of view. MARDI has eight GB of internal buffer memory that is capable of storing over 4,000 raw images. MARDI imaging will allow the mapping of surrounding terrain and the location of landing.[39]JunoCam, built for the Juno spacecraft, is based on MARDI.[70]
Comparisons
Curiosity has an advanced payload of scientific equipment on Mars.[29] It is the fourth NASA unmanned surface rover sent to Mars since 1996. Previous successful Mars rovers include the Spirit and Opportunity, and the Sojourner rover from the Mars Pathfinder mission. The Soviets sent Prop-M rovers and the Prop-F Phobos hopper; the British sent the PLUTO subsurface mole.[71][72][73]
Curiosity is 2.9 m (9.5 ft) long by 2.7 m (8.9 ft) wide by 2.2 m (7.2 ft) in height,[7] larger than Mars Exploration Rovers, which are 1.5 m (4.9 ft) long and have a mass of 174 kg (384 lb) including 6.8 kg (15 lb) of scientific instruments.[6][74][75] In comparison to Pancam on the Mars Exploration Rover (MER)s, the MastCam-34 has 1.25× higher spatial resolution and the MastCam-100 has 3.67× higher spatial resolution.[40]
The leaderofBeagle 2 reacted emotionally to how many technicians monitored Curiosity's descent because he had four.[76] The Curiosity mission cost over 25 times Beagle 2, which was praised for its low cost[77] but has been missing since released by Mars Express.[76]
The region the rover is set to explore has been compared to the Four Corners region of the North American west.[78] Gale crater has similar area as Connecticut and Rhode Island combined.[79] (Rhode Island the United States State not an actual island)
The Curiosity rover landed in "Yellowknife" Quad 51ofAeolis PalusinGale Crater.[80][81][82][83] Gale crater, an estimated 2 billion-year-old impact crater, is hypothesized to have first been gradually filled in by water-deposited, and then by wind-deposited, sediments, possibly until it was completely covered. Wind erosion then scoured out the sediments, leaving an isolated 5.5 km (3.4 mi) high mountain, Aeolis Mons ("Mount Sharp"), at the center of the 154 km (96 mi) wide crater. Thus, it is believed that the rover may have the opportunity to study two billion years of Martian history in the sediments exposed in the mountain. Additionally, its landing site should be on or near an alluvial fan, which is hypothesized to be the result of a flow of ground water, either before the deposition of the eroded sediments or else in relatively recent geologic history.[84][85]
Curiosity rover and surrounding area as viewed by HiRISE (MRO). North is left. (August 14, 2012). (Enhanced colors)
Previous NASA Mars rovers became active only after the successful entry, descent and landing on the Martian surface. Curiosity, on the other hand, was active when it touched down on the surface of Mars, employing the rover suspension system for the final set-down.[86]
Curiosity transformed from its stowed flight configuration to a landing configuration while the MSL spacecraft simultaneously lowered it beneath the spacecraft descent stage with a 20 m (66 ft) tether from the "sky crane" system to a soft landing—wheels down—on the surface of Mars.[87][88][89][90] After the rover touched down it waited 2 seconds to confirm that it was on solid ground and fired several pyros (small explosive devices) activating cable cutters on the bridle to free itself from the spacecraft descent stage. The descent stage then flew away to a crash landing, and the rover prepared itself to begin the science portion of the mission.[91]
Coverage and cultural impact
On August 13, 2012, U. S. President Barack Obama, calling from aboard Air Force One to congratulate the Curiosity rover team, said, “You guys are examples of American know-how and ingenuity. It’s really an amazing accomplishment.”[92] (Video (07:20))
NASA gave the general public the opportunity from 2009 until 2011 to submit their names to be sent to Mars. More than 1.2 million people from the international community participated, and their names were etched into silicon using an electron-beam machine used for fabricating micro devices at JPL, and this microchip is now installed on the deck of Curiosity.[93] In keeping with a 40-year tradition, a Presidential Plaque was also installed, with the signatures of President Barack Obama and Vice President Joe Biden. Elsewhere on the rover is the autograph of Clara Ma, the 12-year-old girl from Kansas who gave Curiosity its name in an essay contest, writing in part that "curiosity is the passion that drives us through our everyday lives."[94]
Scientists at the Getty Conservation InstituteinLos Angeles, California viewed the CheMin instrument aboard the Curiosity as a potentially valuable means to examine ancient works of art without damaging them. Until recently, only a few instruments were available to determine the composition without cutting out physical samples large enough to potentially damage the artifacts. The CheMin on Curiosity directs a beam of X-rays at particles as small as 400 µm[95] and reads the radiationscattered back to determine the composition of the artifact in minutes. Engineers created a smaller, portable version named the X-Duetto. Fitting into a few briefcase-sized boxes, it can examine objects on site, while preserving their physical integrity. It is now being used by Getty scientists to analyze a large collection of museumantiques and the Roman ruins of Herculaneum, Italy.[96]
Live video showing the first footage from the surface of Mars was available at NASA TV, during the late hours of August 5, 2012 PDT, including interviews with the mission team. The NASA website momentarily became unavailable from the overwhelming number of people visiting it,[97] and a 13-minute NASA excerpt of the landings on its YouTube channel was halted an hour after the landing by a robotic DMCA takedown notice from Scripps Local News, which prevented access for several hours.[98] Around 1,000 people gathered in New York City's Times Square, to watch NASA's live broadcast of Curiosity's landing, as footage was being shown on the giant Toshiba Vision LED television screen.[99]
Bobak Ferdowsi, a JPL systems engineer, became an Internet meme and attained Twitter celebrity status, with 45,000 new followers subscribing to his Twitter account, due to his Mohawk hairstyle with yellow stars which he wore for the televised broadcast.[100][101]
Prior to the landing, NASA and Microsoft released "Mars Rover Landing", a free downloadable game on Xbox Live that uses Kinect to capture body motions, which allows users to simulate the landing sequence.[102]
Successful landing confirmed simultaneously by monitoring Mars orbiters. Curiosity landed on target and only 2.4 kilometres (1.5 mi) from its center.[109] Some low resolution images were beamed to Earth by relay orbiters.[110]
Surface science
Date
Event
Notes
August 6, 2012
Status report.
Hours after landing, the rover begins to beam detailed data on its systems' status as well as on its entry, descent and landing experience. [110]
August 8, 2012
Scheduled software upgrade.
Mission Control spent parts of the next days upgrading the rover's dual computers by switching the entry-descent-landing software to the surface operation software;[111] the switchover was completed by August 15.[112]
The rover will spend several days performing instrument checks and mobility tests.[113][30] The science and operations teams have identified at least six possible routes to the base of the mountain, and estimate about a year studying the rocks and soil of the crater floor while Curiosity slowly makes its way to the base of Mount Sharp.[113][114] Its first drive is planned to start in September to a rock formation called Glenelg about 400 metres (1,300 ft) to the East.[115]
Images
Videos
Rover's descent to the surface of Gale Crater (August 6, 2012).
Rover's landing site - first 360 color panorama (August 8/10vid, 2012).
Rover's landing site and projected mission traverse track (narrated animation).
Rover
Mast head with ChemCam, MastCam-34, MastCam-100, and NavCam
Rover wheels are 50 centimetres (20 in) in diameter
Images taken by Curiosity
The 4.5 m (15 ft) diameter heat shield falls away from the rover, imaged by the Mars Descent Imager camera (MARDI) installed on bottom of Curiosity. Sol 0 (2012-08-06 05:15:30 UTC).
Curiosity's first image after landing (August 6, 2012). The rover's wheel can be seen.
Rear Hazcam image after landing with no clear-dust-cover.
Curiosity landed on August 6, 2012 near the base of Aeolis Mons (or "Mount Sharp")[116]
Curiosity's first color image of the Martian landscape (August 6, 2012). MAHLI
^ abMSL Technical and Replan Status. Richard Cook. (January 9, 2009) Cite error: The named reference "usra" was defined multiple times with different content (see the help page).
^R. Rieder, R. Gellert, J. Brückner, G. Klingelhöfer, G. Dreibus, A. Yen, S. W. Squyres (2003). "The new Athena alpha particle X-ray spectrometer for the Mars Exploration Rovers". J. Geophysical Research. 108: 8066. Bibcode:2003JGRE..108.8066R. doi:10.1029/2003JE002150.{{cite journal}}: CS1 maint: multiple names: authors list (link)
^Sarrazin P., Blake D., Feldman S., Chipera S., Vaniman D., Bish D. (2005). "Field deployment of a portable X-ray diffraction/X-ray fluorescence instrument on Mars analog terrain". Powder Diffraction. 20 (2): 128–133. Bibcode:2005PDiff..20..128S. doi:10.1154/1.1913719.{{cite journal}}: CS1 maint: multiple names: authors list (link)
^ ab"Status Report - Curiosity's Daily Update". NASA. August 6, 2012. Retrieved August 13, 2012. This morning, flight controllers decided to forgo the sixth and final opportunity on the mission calendar for a course-correction maneuver.