Hubble view of Mars: Gale crater can be seen. Slightly left and south of center, it's a small dark spot with dust trailing southward from it.
Curiosity is about twice as long and five times as heavy as the Spirit and Opportunity Mars exploration rover payloads of earlier U.S. Mars missions,[7] and carries over ten times the mass of scientific instruments.[8]
MSL successfully carried out a more accurate landing than previous spacecraft to Mars, aiming for a small target landing ellipse of only 7 by 20 km (4.3 by 12.4 mi),[9] in the Aeolis Palus region of Gale Crater. In the event, MSL achieved a landing only 2.4 kilometres (1.5 mi) from the center of the target.[10] This location is near the mountain Aeolis Mons (a.k.a. "Mount Sharp").[11][12] The rover mission is set to explore for at least 687 Earth days (1 Martian year) over a range of 5 by 20 km (3.1 by 12.4 mi).[13] NASA anticipates that the rover will function for at least the limit the parts were tested for, which is four years.
As part of its exploration, it also measured the radiation exposure in the interior of the spacecraft as it traveled to Mars, and it is continuing radiation measurements as it explores the surface of Mars. This data would be important for a future manned mission.[17]
Specifications
Spacecraft
Mars Science Laboratory in final assemblyDiagram of the MSL spacecraft: 1- Cruise stage; 2- Backshell; 3- Descent stage; 4-Curiosity rover; 5-Heat shield; 6- Parachute
The spacecraft flight system had a mass at launch of 3,893 kg (8,583 lb), consisting of an Earth-Mars fueled cruise stage (539 kg (1,188 lb)), the entry-descent-landing (EDL) system (2,401 kg (5,293 lb) + 390 kg (860 lb) of propellant), and a 899 kg (1,982 lb) mobile rover with an integrated instrument package.[18][19]
Curiosity rover has a mass of 899 kg (1,982 lb), can travel up to 90 m (300 ft) per hour on its six-wheeled rocker-bogie system, is powered by a radioisotope thermoelectric generator (RTG), and communicates in both X band and UHF bands.
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.[20] This compares to 3 MB of EEPROM, 128 MB of DRAM, and 256 MB of flash memory used in the Mars Exploration Rovers.[21]
The RCE computers use the RAD750CPU (a successor to the RAD6000 CPU used in the Mars Exploration Rovers) operating at 200MHz.[22][23][24] The RAD750 CPU is capable of up to 400 MIPS, while the RAD6000 CPU is capable of up to 35 MIPS.[25][26] Of the two on-board computers, one is configured as backup, and will take over in the event of problems with the main computer.[20]
The rover has an Inertial Measurement Unit (IMU) that provides 3-axis information on its position, which is used in rover navigation.[20] The rover's computers are constantly self-monitoring to keep the rover operational, such as by regulating the rover's temperature.[20] 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.[20]
Like the Mars Exploration Rovers and Mars Pathfinder, Curiosity is running VxWorks from Wind River Systems.[27] During the trip to Mars, VxWorks runs applications that are dedicated to the navigation and guidance phase of the mission, and also had a pre-programmed software sequence for handling the complexity of the entry-descent-landing. Once landed, the applications were replaced with software for driving on the surface and performing scientific activities.[28][29][30]
Communications:Curiosity is equipped with several means of communication, for redundancy. An X bandsmall deep space transponder for communication directly to Earth, and and a UHF Electra-Lite software-defined radio for communicating with Mars orbiters.[19]: 46 The X-band system has one radio, with a 15 W power amplifier, and two antennas: a low-gain omnidirectional antenna that can comminicate with Earth at very low data rates (15 bit/s at maximum range), regardless of rover orientation, and a high-gain antenna that can communicate at speeds up to 32 kbit/s, but must be aimed. The UHF system has two radios (approximately 9 W transmit power[19]: 81 ), sharing one omnidirectional antenna. This can communicate with the Mars Reconnaissance Orbiter and Odyssey orbiter at speeds up to 2 Mbit/s and 256 kbit/s, respectively, but each orbiter is only able to communicate with Curiosity for about 8 minutes per day.[31] The orbiters have larger antennas and more powerful radios, and can relay data to earth faster than the rover could do directly.
Typically 225 kbit/day of commands are transmitted to the rover directly from Earth, at a data rate of 1–2 kbit/s, during a 15 minute (900 second) trasnmit window, while the larger volumes of data collected by the rover are returned via satellite relay.[19]: 46 The one-way communication delay with Earth varies from 4 to 22 minutes, depending on the planets' relative positions, with 12.5 minutes being the average.[32]
At landing, telemetry was monitored by the Mars Odyssey satellite, Mars Reconnaissance Orbiter and ESA's Mars Express. Odyssey is capable of relaying UHF telemetry back to Earth in real time. The relay time varies with the distance between the two planets and took 13:46 minutes at the time of landing.[33][34]
Mobility systems: Like rovers from the previous Mars Exploration Rover and Mars Pathfinder missions, Curiosity is equipped with six wheels in a rocker-bogie suspension. The suspension system also served as landing gear for the vehicle, unlike its smaller predecessors.[35][36]Curiosity has wheels that are significantly larger (50 centimetres (20 in) diameter) than those used on previous rovers. Each wheel has cleats and is independently actuated and geared, providing for climbing in soft sand and scrambling over rocks. The four corner wheels can be independently steered, allowing the vehicle to turn in place as well as execute arcing turns.[19] 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" (•−−− •−−• •−••).[37] 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.[19]
The general 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 intrigues, 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.[38] The highly sensitive SAM analyser has a limit of 74 sample cups.[39][40]
MSL entry descent and landing instrumentation (MEDLI): The MEDLI project's main objective is to measure aerothermal environments, sub-surface heat shield material response, vehicle orientation, and atmospheric density for the atmospheric entry through the sensible atmosphere down to heat shield separation of the Mars Science Laboratory entry vehicle.[41] The MEDLI instrumentation suite was installed in the heatshield of the MSL entry vehicle. The acquired data will support future Mars missions by providing measured atmospheric data to validate Mars atmosphere models and clarify the lander design margins on future Mars missions. MEDLI instrumentation consists of three main subsystems: MEDLI Integrated Sensor Plugs (MISP), Mars Entry Atmospheric Data System (MEADS) and the Sensor Support Electronics (SSE).
MastCam: This system provides multiple spectra and true-color imaging with two cameras.
Mars Hand Lens Imager (MAHLI): This system consists of a camera mounted to a robotic arm on the rover, used to acquire microscopic images of rock and soil. It has white and ultraviolet LEDs for illumination.
MSL Mars Descent Imager (MARDI): During the descent to the Martian surface, MARDI acquired 4 color images per second, at 1600×1200 pixels, with a 0.9-millisecond exposure time. Images were taken 4 times per second, starting shortly before heatshield separation at 3.7 km altitude, until a few seconds after touchdown. This provided engineering information about both the motion of the rover during the descent process, and science information about the terrain immediately surrounding the rover.
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 Curiosity's fifth science camera, the remote micro-imager (RMI). The RMI provides black-and-white images at 1024×1024 resolution in a 0.02 radian (1.1 degree) field of view.[49] This is approximately equivalent to a 1500 mm lens on a 35 mm camera.
Alpha-particle X-ray spectrometer (APXS): This device can irradiate samples with alpha particles and map the spectra of X-rays that are re-emitted for determining the elemental composition of samples.
Radiation assessment detector (RAD): This instrument was the first of ten MSL instruments to be turned on. Both en route and on the planet's surface, it will characterize the broad spectrum of radiation encountered in the Martian environment. Turned on after launch, it recorded several radiation spikes caused by the Sun.[51]
Dynamic Albedo of Neutrons (DAN): A pulsed neutron source and detector for measuring hydrogen or ice and water at or near the Martian surface.
[52][53] On August 18, 2012 the Russian science instrument, DAN, was turned on,[54] marking the success of a Russian-American collaboration on the surface of Mars and the first working Russian science instrument on the Martian surface since Mars 3 stopped transmitting over forty years ago.[55] The instrument is designed to detect subsurface water.[54]
Engineering cameras: There are 12 engineering cameras, used to support mobility. They are identical to those on the Mars Exploration Rovers, and in the same places, but are duplicated in each position to provide a backup in case one fails.
Hazard avoidance cameras (Hazcams): The rover has a pair of black and white navigation cameras (Hazcams) located on each of its four corners.[56] These provide closed-up views of potential obstacles about to go under the wheels.
Navigation cameras (Navcams): The rover uses a two pairs of black and white navigation cameras mounted on the mast to support ground navigation.[56] These provide a longer-distance view of the terrain ahead.
History
MSL's cruise stage on Earth
NASA called for proposals for the rover's scientific instruments in April 2004,[57] and eight proposals were selected on December 14 of that year.[57] Testing and design of components also began in late 2004, including Aerojet's designing of a monopropellant engine with the ability to throttle from 15–100 percent thrust with a fixed propellant inlet pressure.[57]
By November 2008 most hardware and software development was complete, and testing continued.[58] At this point, cost overruns were approximately $400 million.[59] The next month, NASA delayed the launch to late 2011 because of inadequate testing time.[60][61][62]
Between March 23–29, 2009, the general public ranked nine finalist rover names through a public poll on the NASA website.[63] On May 27, 2009, the winning name was announced to be Curiosity. The name had been submitted in an essay contest by Clara Ma, a sixth-grader from Kansas.[63][64][65]
MSL launched on an Atlas V rocket from Cape Canaveral on November 26, 2011.[66] On January 11, 2012, the spacecraft successfully refined its trajectory with a three-hour series of thruster-engine firings, advancing the rover's landing time by about 14 hours. When MSL was launched, the program's director was Doug McCuistion of NASA's Planetary Science Division.[67]
Curiosity successfully landed in the Gale Crater at 05:17:57.3 UTC on August 6, 2012,[2][3][4] and transmitted Hazcam images confirming orientation.[4] Due to the Mars-Earth distance at the time of landing and the limited speed of radio signals, the landing was not registered on Earth for another 14 minutes.[4] The Mars Reconnaissance Orbiter sent a photograph of Curiosity descending under its parachute, taken by its HiRISE camera, during the landing procedure.
Six senior members of the Curiosity team presented a new conference a few hours after landing, they were: John Grunsfeld, NASA associate administrator; Charles Elachi, director, JPL; Pete Theisinger, MSL project manager; Richard Cook, MSL deputy project manager; Adam Steltzner, MSL entry, descent and landing (EDL) lead; and John Grotzinger, MSL project scientist.[68]
Over 60 landing sites were analyzed, and by July 2011 Gale crater was chosen. A primary goal when selecting the landing site was to identify a particular geologic environment, or set of environments, that would support microbial life. Planners looked for a site that could contribute to a wide variety of possible science objectives. They preferred a landing site with both morphologic and mineralogic evidence for past water. Furthermore, a site with spectra indicating multiple hydrated minerals was preferred; clay minerals and sulfate salts would constitute a rich site. Hematite, other iron oxides, sulfate minerals, silicate minerals, silica, and possibly chloride minerals were suggested as possible substrates for fossil preservation. Indeed, all are known to facilitate the preservation of fossil morphologies and molecules on Earth.[71] Difficult terrain was favored for finding evidence of livable conditions, but the rover must be able to safely reach the site and drive within it.[72]
Engineering constraints called for a landing site less than 45° from the Martian equator, and less than 1 km above the reference datum.[73] At the first MSL Landing Site workshop, 33 potential landing sites were identified.[74] By the second workshop in late 2007, the list had grown to include almost 50 sites,[75] and by the end of the workshop, the list was reduced to six;[76][77][78] in November 2008, project leaders at a third workshop reduced the list to these four landing sites:[79][80][81][82]
A fourth landing site workshop was held in late September 2010,[87] and the fifth and final workshop May 16–18, 2011.[88] On July 22, 2011, it was announced that Gale Crater had been selected as the landing site of the Mars Science Laboratory mission.
The first and second stage along with the solid rocket motors were stacked on October 9, 2011, near the launch pad.[91] The fairing containing MSL was transported to the launch pad on November 3, 2011.[92]
The cruise stage carried the MSL spacecraft through the void of space and delivered it to Mars. The cruise stage has its own miniature propulsion system, consisting of eight thrusters using hydrazine fuel in two titanium tanks.[94] It also has its own electric power system, consisting of a solar array and battery for providing continuous power. Upon reaching Mars, the spacecraft stopped spinning and a cable cutter separated the cruise stage from the aeroshell that shielded the remaining spacecraft from frictional heat during its atmospheric entry and descent through the Martian atmosphere.[94]
During cruise, the spacecraft was spin-stabilized at 2 rpm; eight thrusters arranged in two clusters were used as actuators to control spin rate and perform axial or lateral trajectory correction maneuvers.[19] By spinning about its central axis, it maintained a stable attitude.[19][95][96] Along the way, the cruise stage performed four trajectory correction maneuvers to adjust the spacecraft's path toward its landing site.[97] Information was sent to mission controllers via two X-band antennas.[94] A key task of the cruise stage was to control the temperature of all spacecraft systems and dissipate the heat generated by power sources, such as solar cells and motors, into space. In some systems, insulating blankets kept sensitive science instruments warmer than the near-absolute zero temperature of space. Thermostats monitored temperatures and switched heating and cooling systems on or off as needed.[94]
Entry, descent and landing (EDL)
EDL spacecraft system
Landing a large mass on Mars is particularly challenging as the atmosphere is too thin for parachutes and aerobraking alone to be effective,[98] while remaining thick enough to create stability and impingement problems when decelerating with rockets.[98] Although some previous missions have used airbags to cushion the shock of landing, Curiosity rover is too heavy for this to be an option. Instead, Curiosity was set down on the Martian surface using a new high-accuracy entry, descent, and landing (EDL) system that was part of the MSL spacecraft descent stage. The novel EDL system placed Curiosity within a 20 by 7 km (12.4 by 4.3 mi) landing ellipse,[70] in contrast to the 150 by 20 km (93 by 12 mi) landing ellipse of the landing systems used by the Mars Exploration Rovers.[99]
The entry-descent-landing (EDL) system differs from those used for other missions in that it does not require an interactive, ground-generated mission plan. During the entire landing phase, the vehicle acts autonomously, based on pre-loaded software and parameters.[19] The EDL system was based on a Viking-derived aeroshell structure and propulsion system for a precision guided entry and soft landing, in contrasts with the airbag landings that were used by the mid-1990s by the Mars Pathfinder and MER missions. The spacecraft employed several systems in a precise order, with the entry, descent and landing sequence broken down into four parts[100][101]—described below as the spaceflight events unfolded on 6 August 2012.
EDL spaceflight event–6 August 2012
Martian atmosphere entry events from cruise stage separation to parachute deployment
Despite its late hour, particularly on the east coast of the United States, the landing generated significant public interest. 3.2 million watched the landing live with most watching online instead of on television via NASA TV or cable news networks covering the event live.[102] The final landing place for the rover was less than 2.4 km (1.5 mi) from its target after a 563,270,400 km (350,000,000 mi) journey.[103] In addition to streaming and traditional video viewing, JPL made Eyes on the Solar System, a 3 dimensional real time simulation of entry, descent and landing based on real data. Curiosity's touchdown time as represented in the software, based on JPL predictions, was less than 1 second different than reality.[104]
The EDL phase of the MSL spaceflight mission to Mars took only seven minutes and unfolded automatically, as programmed by JPL engineers in advance, in a precise order, with the entry, descent and landing sequence occuring in four distinct event phases:[100][101]
Guided entry
The guided entry is the phase that allowed the spacecraft to steer with accuracy to its planned landing site
Precision guided entry made use of onboard computing ability to steer itself toward the pre-determined landing site, improving landing accuracy from a range of hundreds of kilometers to 20 kilometres (12 mi). This capability helped remove some of the uncertainties of landing hazards that might be present in larger landing ellipses.[105] Steering was achieved by the combined use of thrusters and ejectable balance masses.[106] The ejectable balance masses shift the capsule center of mass enabling generation of a lift vector during the atmospheric phase. A navigation computer integrated the measurements to estimate the position and attitude of the capsule that generated automated torque commands. This was the first planetary mission to use precision landing techniques.
The rover was folded up within an aeroshell that protected it during the travel through space and during the atmospheric entry at Mars. Ten minutes before atmospheric entry the aeroshell separated from the cruise stage that provided power, communications and propulsion during the long flight to Mars. One minute after separation from the cruise stage thrusters on the aeroshell fired to cancel out the spacecraft's 2-rpm rotation and achieved an orientation with the heat shield facing Mars in preparation for Atmospheric entry.[107] The heat shield is made of phenolic impregnated carbon ablator (PICA). The 4.5 m (15 ft) diameter heat shield, which is the largest heat shield ever flown in space,[108] reduced the velocity of the spacecraft by ablation against the Martian atmosphere, from the atmospheric interface velocity of approximately 5.8 km/s (3.6 mi/s) down to approximately 470 m/s (1,500 ft/s), where parachute deployment was possible about four minutes later. One minute and 15 seconds after entry the heat shield experienced peak temperatures of up to 2,090 °C (3,790 °F) as atmospheric pressure converted kinetic energy into heat. Ten seconds after peak heating, that deceleration peaked out at 15 g.[107] Much of the reduction of the landing precision error was accomplished by an entry guidance algorithm, derived from the algorithm used for guidance of the Apollo Command Modules returning to Earth in the Apollo space program.[107] This guidance uses the lifting force experienced by the aeroshell to "fly out" any detected error in range and thereby arrive at the targeted landing site. In order for the aeroshell to have lift, its center of mass is offset from the axial centerline that results in an off-center trim angle in atmospheric flight. This is accomplished by a series of ejectable ballast masses consisting of two 75 kg (165 lb) tungsten weights that were jettisoned minutes before atmospheric entry.[107] The lift vector was controlled by four sets of two Reaction Control System (RCS) thrusters that produced approximately 500 N (110 lbf) of thrust per pair. This ability to change the pointing of the direction of lift allowed the spacecraft to react to the ambient environment, and steer toward the landing zone. Prior to parachute deployment the entry vehicle ejected more ballast mass consisting of six 25 kg (55 lb) tungsten weights such that the center of gravity offset was removed.[107]
Parachute descent
MSL's parachute is 16 m (52 ft) in diameter.NASA's Curiosity rover and its parachute were spotted by NASA's Mars Reconnaissance Orbiter as Curiosity descended to the surface. August 6, 2012.
When the entry phase was complete and the capsule slowed to Mach 1.7 or 578 m/s (1,900 ft/s) and at about 10 km (6.2 mi), the supersonic parachute deployed,[99][109] as was done by previous landers such as Viking, Mars Pathfinder and the Mars Exploration Rovers. The parachute has 80 suspension lines, is over 50 m (160 ft) long, and is about 16 m (52 ft) in diameter.[109] Capable of being deployed at Mach 2.2, the parachute can generate up to 289 kN (65,000 lbf) of drag force in the Martian atmosphere.[109] After the parachute was deployed, the heat shield separated and fell away. A camera beneath the rover acquired about 5 frames per second (with resolution of 1600×1200 pixels) below 3.7 km (2.3 mi) during a period of about 2 minutes until the rover sensors confirmed successful landing.[110] The Mars Reconnaissance Orbiter team were able to acquire an image of the MSL descending under the parachute.[111]
Powered descent
Following the parachute braking, at about 1.8 km (1.1 mi) altitude, still travelling at about 100 m/s (220 mph), the rover and descent stage dropped out of the aeroshell.[99] The descent stage is a platform above the rover with eight variable thrust monopropellanthydrazine rocket thrusters on arms extending around this platform to slow the descent. Each rocket thruster, called a Mars Lander Engine (MLE),[112] produces 400 N (90 lbf) to 3,100 N (700 lbf) of thrust and were derived from those used on the Viking landers.[113] A radar altimeter measured altitude and velocity, feeding data to the rover's flight computer. Meanwhile, the rover transformed from its stowed flight configuration to a landing configuration while being lowered beneath the descent stage by the "sky crane" system.
Sky crane landing
Entry events from parachute deployment through powered descent ending at sky crane flyawayArtist's concept of Curiosity being lowered by the sky crane from the rocket-powered descent stage.
For several reasons, a different landing system was chosen for MSL compared to previous Mars landers and rovers. Curiosity was considered too heavy to use the airbag landing system as used on the Mars Pathfinder and Mars Exploration. A legged lander approach would have caused several design problems.[107] It would have needed to have engines high enough above the ground when landing not to form a dust cloud that could damage the rover's instruments. This would have required long landing legs that would need to have significant width to keep the center of gravity low. A legged lander would have also required ramps so the rover could drive down to the surface, which would have incurred extra risk to the mission on the chance rocks or tilt would prevent Curiosity from being able to drive off the lander successfully. Faced with these challenges, the MSL engineers came up with a novel alternative solution: the sky crane.[107] The sky crane system lowered the rover with a 7.6 m (25 ft)[107] tether to a soft landing—wheels down—on the surface of Mars.[99][114][115] This system consists of a bridle lowering the rover on three nylon tethers and an electrical cable carrying information and power between the descent stage and rover. As the support and data cables unreeled, the rover's six motorized wheels snapped into position. At roughly 7.5 m (25 ft) below the descent stage the sky crane system slowed to a halt and the rover touched down. After the rover touched down, it waited 2 seconds to confirm that it was on solid ground by detecting the weight on the wheels and fired several pyros (small explosive devices) activating cable cutters on the bridle and umbilical cords to free itself from the descent stage. The descent stage flew away to a crash landing 650 m (2,100 ft) away.[116] The sky crane powered descent landing system had never been used in missions before.[117]
Gale Crater is the MSL landing site.[119][120][69] Within Gale Crater is a mountain, named Aeolis Mons ("Mount Sharp"),[11][12][121] of layered rocks, rising about 5.5 km (18,000 ft) above the crater floor, that Curiosity will investigate. The landing site is a smooth region in "Yellowknife" Quad 51[122][123][124][125]ofAeolis Palus inside the crater in front of the mountain. The landing site is elliptical, 20 by 7 km (12.4 by 4.3 mi).[70] Gale Crater's diameter is 154 km (96 mi).
The landing site contains material washed down from the wall of the crater, which will provide scientists with the opportunity to investigate the rocks that form the bedrock in this area. The landing ellipse also contains a rock type that is very dense, very brightly colored, and unlike any rock type previously investigated on Mars. It may be an ancient playa lake deposit, and it will likely be the mission's first target in checking for the presence of organic molecules.[126]
An area of top scientific interest for Curiosity lies at the edge of the landing ellipse and beyond a dark dune field. Here, orbiting instruments have detected signatures of both clay minerals and sulfate salts.[127] Scientists studying Mars have several hypotheses about how these minerals reflect changes in the Martian environment, particularly changes in the amount of water on the surface of Mars. The rover will use its full instrument suite to study these minerals and how they formed. Certain minerals, including the clay and sulfate-rich layers near the bottom of Gale's mountain, are good at latching onto organic compounds—potential biosignatures—and protecting them from oxidation.[128]
Two canyons were cut in the mound through the layers containing clay minerals and sulfate salts after deposition of the layers. These canyons expose layers of rock representing tens or hundreds of millions of years of environmental change. Curiosity may be able to investigate these layers in the canyon closest to the landing ellipse, gaining access to a long history of environmental change on the planet. The canyons also contain sediment that was transported by the water that cut the canyons;[129] this sediment interacted with the water, and the environment at that time may have been habitable. Thus, the rocks deposited at the mouth of the canyon closest to the landing ellipse form the third target in the search for organic molecules.[citation needed]
Videos
The MSL launches from Cape Canaveral
Curiosity's Seven Minutes of Terror, the EDL phase NASA animation.
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^Brown, Adrian. "Mars Science Laboratory: the budgetary reasons behind its delay: MSL: the budget story". The Space review. Archived from the original on March 2, 2009. Retrieved August 4, 2012. NASA first put a reliable figure of the cost of the MSL mission at the "Phase A/Phase B transition", after a preliminary design review (PDR) that approved instruments, design and engineering of the whole mission. That was in August 2006—and the Congress-approved figure was $1.63 billion. … With this request, the MSL budget had reached $1.9 billion. … NASA HQ requested JPL prepare an assessment of costs to complete the construction of MSL by the next launch opportunity (in October 2011). This figure came in around $300 million, and NASA HQ has estimated this will translate to at least $400 million (assuming reserves will be required), to launch MSL and operate it on the surface of Mars from 2012 through 2014.{{cite web}}: More than one of |author= and |last= specified (help)
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