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87-683: Several sites in the Margaritifer Sinus quadrangle have been proposed as areas to send NASA's next major Mars rover, the Mars Science Lab . Among the top 33 landing sites was Iani Chaos. A picture below shows a potential landing zone in Iani Chaos. Deposits of hematite and gypsum have been found there. Those minerals are usually formed in connection with water. The aim of the Mars Science Laboratory

174-519: A human mission to Mars . The rover carries a variety of scientific instruments designed by an international team. MSL successfully carried out the most accurate Martian landing of any known spacecraft at the time, hitting a small target landing ellipse of only 7 by 20 km (4.3 by 12.4 mi), in the Aeolis Palus region of Gale Crater. In the event, MSL achieved a landing 2.4 km (1.5 mi) east and 400 m (1,300 ft) north of

261-416: A nozzle , thereby producing thrust. In rockets, the burning of rocket fuel produces an exhaust, and the exhausted material is usually expelled as a propellant under pressure through a nozzle . The exhaust material may be a gas , liquid , plasma , or a solid . In powered aircraft without propellers such as jets , the propellant is usually the product of the burning of fuel with atmospheric oxygen so that

348-465: A plasma which is used as the propellant. They use a nozzle to direct the energized propellant. The nozzle itself may be composed simply of a magnetic field. Low molecular weight gases (e.g. hydrogen, helium, ammonia) are preferred propellants for this kind of system. Electromagnetic thrusters use ions as the propellant, which are accelerated by the Lorentz force or by magnetic fields, either of which

435-550: A 20 by 7 km (12.4 by 4.3 mi) landing ellipse, in contrast to the 150 by 20 km (93 by 12 mi) landing ellipse of the landing systems used by the Mars Exploration Rovers. 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. The EDL system

522-641: A 563,270,400 km (350,000,000 mi) journey. In addition to streaming and traditional video viewing, JPL made Eyes on the Solar System , a three-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 from reality. 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

609-434: A 899 kg (1,982 lb) mobile rover with an integrated instrument package. The MSL spacecraft includes spaceflight-specific instruments, in addition to utilizing one of the rover instruments — Radiation assessment detector (RAD) — during the spaceflight transit to Mars. 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,

696-483: A broad variety of payloads. Aerosol sprays , in which a liquid is ejected as a spray, include paints, lubricants, degreasers, and protective coatings; deodorants and other personal care products; cooking oils. Some liquid payloads are not sprayed due to lower propellant pressure and/or viscous payload, as with whipped cream and shaving cream or shaving gel. Low-power guns, such as BB guns , paintball guns, and airsoft guns, have solid projectile payloads. Uniquely, in

783-400: A compressor, rather than by a chemical reaction. The pressures and energy densities that can be achieved, while insufficient for high-performance rocketry and firearms, are adequate for most applications, in which case compressed fluids offer a simpler, safer, and more practical source of propellant pressure. A compressed fluid propellant may simply be a pressurized gas, or a substance which is

870-399: A fluid which is used to expel the products of that chemical reaction (and sometimes other substances) as propellants. For example, in a simple hydrogen/oxygen engine, hydrogen is burned (oxidized) to create H 2 O and the energy from the chemical reaction is used to expel the water (steam) to provide thrust. Often in chemical rocket engines, a higher molecular mass substance is included in

957-431: A gas at atmospheric pressure, but stored under pressure as a liquid. In applications in which a large quantity of propellant is used, such as pressure washing and airbrushing , air may be pressurized by a compressor and used immediately. Additionally, a hand pump to compress air can be used for its simplicity in low-tech applications such as atomizers , plant misters and water rockets . The simplest examples of such

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1044-402: A modest pressure. This pressure is high enough to provide useful propulsion of the payload (e.g. aerosol paint, deodorant, lubricant), but is low enough to be stored in an inexpensive metal can, and to not pose a safety hazard in case the can is ruptured. The mixture of liquid and gaseous propellant inside the can maintains a constant pressure, called the liquid's vapor pressure . As the payload

1131-411: A plasma and expel the plasma as propellant. In the case of a resistojet rocket engine, the compressed propellant is simply heated using resistive heating as it is expelled to create more thrust. In chemical rockets and aircraft, fuels are used to produce an energetic gas that can be directed through a nozzle , thereby producing thrust. In rockets, the burning of rocket fuel produces an exhaust, and

1218-455: A precise order, with the entry, descent and landing sequence occurring in four distinct event phases: 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 kilometers (12 mi). This capability helped remove some of the uncertainties of landing hazards that might be present in larger landing ellipses. Steering

1305-440: A propellant because they move at relativistic speed, i.e., the speed of light. In this case Newton's third Law of Motion is inadequate to model the physics involved and relativistic physics must be used. In chemical rockets, chemical reactions are used to produce energy which creates movement of a fluid which is used to expel the products of that chemical reaction (and sometimes other substances) as propellants. For example, in

1392-461: A reaction mass to create the thrust, such as with a chemical rocket engine, propellant and fuel are two distinct concepts. Vehicles can use propellants to move by ejecting a propellant backwards which creates an opposite force that moves the vehicle forward. Projectiles can use propellants that are expanding gases which provide the motive force to set the projectile in motion. Aerosol cans use propellants which are fluids that are compressed so that when

1479-489: A simple hydrogen/oxygen engine, hydrogen is burned (oxidized) to create H 2 O and the energy from the chemical reaction is used to expel the water (steam) to provide thrust. Often in chemical rocket engines, a higher molecular mass substance is included in the fuel to provide more reaction mass. Rocket propellant may be expelled through an expansion nozzle as a cold gas, that is, without energetic mixing and combustion, to provide small changes in velocity to spacecraft by

1566-502: A stable attitude. Along the way, the cruise stage performed four trajectory correction maneuvers to adjust the spacecraft's path toward its landing site. Information was sent to mission controllers via two X-band antennas . 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

1653-456: A substance which contains both the reaction mass and the fuel that holds the energy used to accelerate the reaction mass. For example, the term "propellant" is often used in chemical rocket design to describe a combined fuel/propellant, although the propellants should not be confused with the fuel that is used by an engine to produce the energy that expels the propellant. Even though the byproducts of substances used as fuel are also often used as

1740-451: A system are squeeze bottles for such liquids as ketchup and shampoo. However, compressed gases are impractical as stored propellants if they do not liquify inside the storage container, because very high pressures are required in order to store any significant quantity of gas, and high-pressure gas cylinders and pressure regulators are expensive and heavy. Liquefied gas propellants are gases at atmospheric pressure, but become liquid at

1827-456: A third workshop reduced the list to these four landing sites: A fourth landing site workshop was held in late September 2010, and the fifth and final workshop May 16–18, 2011. On July 22, 2011, it was announced that Gale Crater had been selected as the landing site of the Mars Science Laboratory mission. The Atlas V launch vehicle is capable of launching up to 8,290 kg (18,280 lb) to geostationary transfer orbit . The Atlas V

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1914-497: A variety of usually ionized propellants, including atomic ions, plasma, electrons, or small droplets or solid particles as propellant. If the acceleration is caused mainly by the Coulomb force (i.e. application of a static electric field in the direction of the acceleration) the device is considered electrostatic. The types of electrostatic drives and their propellants: These are engines that use electromagnetic fields to generate

2001-407: Is a mass that is expelled from a vehicle, such as a rocket, in such a way as to create a thrust in accordance with Newton's third law of motion , and "propel" the vehicle forward. The engine that expels the propellant is called a reaction engine . Although the term "propellant" is often used in chemical rocket design to describe a combined fuel/propellant, propellants should not be confused with

2088-421: Is a mass that is expelled or expanded in such a way as to create a thrust or another motive force in accordance with Newton's third law of motion , and "propel" a vehicle, projectile , or fluid payload. In vehicles, the engine that expels the propellant is called a reaction engine . Although technically a propellant is the reaction mass used to create thrust, the term "propellant" is often used to describe

2175-493: Is a stub . You can help Misplaced Pages by expanding it . Mars Science Lab Mars Science Laboratory ( MSL ) is a robotic space probe mission to Mars launched by NASA on November 26, 2011, which successfully landed Curiosity , a Mars rover , in Gale Crater on August 6, 2012. The overall objectives include investigating Mars' habitability , studying its climate and geology , and collecting data for

2262-440: Is depleted, the propellant vaporizes to fill the internal volume of the can. Liquids are typically 500-1000x denser than their corresponding gases at atmospheric pressure; even at the higher pressure inside the can, only a small fraction of its volume needs to be propellant in order to eject the payload and replace it with vapor. Vaporizing the liquid propellant to gas requires some energy, the enthalpy of vaporization , which cools

2349-436: Is generated by electricity: Nuclear reactions may be used to produce the energy for the expulsion of the propellants. Many types of nuclear reactors have been used/proposed to produce electricity for electrical propulsion as outlined above. Nuclear pulse propulsion uses a series of nuclear explosions to create large amounts of energy to expel the products of the nuclear reaction as the propellant. Nuclear thermal rockets use

2436-399: Is powered by a multi-mission radioisotope thermoelectric generator (MMRTG), and communicates in both X band and UHF bands. The rover's computers run VxWorks , a real-time operating system from Wind River Systems . During the trip to Mars, VxWorks ran applications dedicated to the navigation and guidance phase of the mission, and also had a pre-programmed software sequence for handling

2523-402: Is to search for signs of ancient life. It is hoped that a later mission could then return samples from sites identified as probably containing remains of life. To safely bring the craft down, a 12-mile-wide, smooth, flat circle is needed. Geologists hope to examine places where water once ponded. They would like to examine sediment layers. This article about the planet Mars or its moons

2610-481: Is used to compress the air is stored until it is released by allowing the propellant to escape. Compressed fluid may also be used only as energy storage along with some other substance as the propellant, such as with a water rocket , where the energy stored in the compressed air is the fuel and the water is the propellant. Proposed photon rockets would use the relativistic momentum of photons to create thrust. Even though photons do not have mass, they can still act as

2697-558: The Atlas V 541 provided by United Launch Alliance . This two stage rocket includes a 3.8 m (12 ft) Common Core Booster (CCB) powered by one RD-180 engine, four solid rocket boosters (SRB), and one Centaur second stage with a 5 m (16 ft) diameter payload fairing . The NASA Launch Services Program coordinated the launch via the NASA Launch Services (NLS) I Contract. The cruise stage carried

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2784-639: The Jet Propulsion Laboratory of California Institute of Technology . The total cost of the MSL project is about US$ 2.5 billion. Previous successful U.S. Mars rovers include Sojourner from the Mars Pathfinder mission and the Mars Exploration Rovers Spirit and Opportunity . Curiosity is about twice as long and five times as heavy as Spirit and Opportunity , and carries over ten times

2871-525: The Lorentz force may be used to expel negative ions and electrons as the propellant. Electrothermal engines use the electromagnetic force to heat low molecular weight gases (e.g. hydrogen, helium, ammonia) into a plasma and expel the plasma as propellant. In the case of a resistojet rocket engine, the compressed propellant is simply heated using resistive heating as it is expelled to create more thrust. In chemical rockets and aircraft, fuels are used to produce an energetic gas that can be directed through

2958-441: The fuel that is used by an engine to produce the energy that expels the propellant. Even though the byproducts of substances used as fuel are also often used as a reaction mass to create the thrust, such as with a chemical rocket engine, propellant and fuel are two distinct concepts. In electrically powered spacecraft , electricity is used to accelerate the propellant. An electrostatic force may be used to expel positive ions, or

3045-423: The relativistic momentum of photons to create thrust. Even though photons do not have mass, they can still act as a propellant because they move at relativistic speed, i.e., the speed of light. In this case Newton's third Law of Motion is inadequate to model the physics involved and relativistic physics must be used. In chemical rockets, chemical reactions are used to produce energy which creates movement of

3132-487: The MSL mission objectives evolved to developing predictive models for the preservation process of organic compounds and biomolecules ; a branch of paleontology called taphonomy . 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) including 390 kg (860 lb) of landing propellant ), and

3219-428: The MSL spacecraft through the void of space and delivered it to Mars. The interplanetary trip covered the distance of 352 million miles in 253 days. The cruise stage has its own miniature propulsion system, consisting of eight thrusters using hydrazine fuel in two titanium tanks. It also has its own electric power system , consisting of a solar array and battery for providing continuous power. Upon reaching Mars,

3306-792: The Mars surface and atmospheric properties. The MSL spacecraft departed Earth orbit and was inserted into a heliocentric Mars transfer orbit on November 26, 2011, shortly after launch, by the Centaur upper stage of the Atlas V launch vehicle. Prior to Centaur separation, the spacecraft was spin-stabilized at 2 rpm for attitude control during the 36,210 km/h (22,500 mph) cruise to Mars. During cruise, eight thrusters arranged in two clusters were used as actuators to control spin rate and perform axial or lateral trajectory correction maneuvers. By spinning about its central axis, it maintained

3393-843: 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. 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 news conference a few hours after landing, they were: John Grunsfeld , NASA associate administrator; Charles Elachi , director, JPL; Peter 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. Between March 23 and 29, 2009,

3480-555: The algorithm used for guidance of the Apollo Command Modules returning to Earth in the Apollo program . 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

3567-431: 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. When the entry phase was complete and the capsule slowed to about 470 m/s (1,500 ft/s) at about 10 km (6.2 mi) altitude, the supersonic parachute deployed, as

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3654-463: The bridle and umbilical cords to free itself from the descent stage. The descent stage then flew away to a crash landing 650 m (2,100 ft) away. The sky crane concept had never been used in missions before. Gale Crater is the MSL landing site. Within Gale Crater is a mountain, named Aeolis Mons ("Mount Sharp"), of layered rocks, rising about 5.5 km (18,000 ft) above

3741-564: The burning of the fuel and, as a consequence, thrust vs time profile. There are three types of burns that can be achieved with different grains. There are four different types of solid fuel/propellant compositions: In rockets, three main liquid bipropellant combinations are used: cryogenic oxygen and hydrogen, cryogenic oxygen and a hydrocarbon, and storable propellants. Propellant combinations used for liquid propellant rockets include: Common monopropellant used for liquid rocket engines include: Electrically powered reactive engines use

3828-421: The center of the planned landing ellipse, after a 563,000,000 km (350,000,000 mi) journey. NASA named the rover landing site Bradbury Landing on sol 16, August 22, 2012. According to NASA, an estimated 20,000 to 40,000 heat-resistant bacterial spores were on Curiosity at launch, and as much as 1,000 times that number may not have been counted. Propellant A propellant (or propellent )

3915-458: The center of the target. This location is near the mountain Aeolis Mons (a.k.a. "Mount Sharp"). 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). The Mars Science Laboratory mission is part of NASA's Mars Exploration Program , a long-term effort for the robotic exploration of Mars that is managed by

4002-435: The complexity of the entry-descent-landing. Once landed, the applications were replaced with software for driving on the surface and performing scientific activities. 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

4089-435: The compressed air is the fuel and the water is the propellant. In electrically powered spacecraft , electricity is used to accelerate the propellant. An electrostatic force may be used to expel positive ions, or the Lorentz force may be used to expel negative ions and electrons as the propellant. Electrothermal engines use the electromagnetic force to heat low molecular weight gases (e.g. hydrogen, helium, ammonia) into

4176-427: The costs for developing the rover reached $ 2.47 billion, that for a rover that initially had been classified as a medium-cost mission with a maximum budget of $ 650 million, yet NASA still had to ask for an additional $ 82 million to meet the planned November launch. As of 2012, the project suffered an 84 percent overrun. MSL launched on an Atlas V rocket from Cape Canaveral on November 26, 2011. On January 11, 2012,

4263-411: The crater floor, that Curiosity will investigate. The landing site is a smooth region in "Yellowknife" Quad 51 of Aeolis Palus inside the crater in front of the mountain. The target landing site location was an elliptical area 20 by 7 km (12.4 by 4.3 mi). Gale Crater's diameter is 154 km (96 mi). The landing location for the rover was less than 2.4 km (1.5 mi) from

4350-459: 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 two 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

4437-652: The disadvantage of being flammable . Nitrous oxide and carbon dioxide are also used as propellants to deliver foodstuffs (for example, whipped cream and cooking spray ). Medicinal aerosols such as asthma inhalers use hydrofluoroalkanes (HFA): either HFA 134a (1,1,1,2,-tetrafluoroethane) or HFA 227 (1,1,1,2,3,3,3-heptafluoropropane) or combinations of the two. More recently, liquid hydrofluoroolefin (HFO) propellants have become more widely adopted in aerosol systems due to their relatively low vapor pressure, low global warming potential (GWP), and nonflammability. The practicality of liquified gas propellants allows for

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4524-435: The exhausted material is usually expelled as a propellant under pressure through a nozzle . The exhaust material may be a gas , liquid , plasma , or a solid . In powered aircraft without propellers such as jets , the propellant is usually the product of the burning of fuel with atmospheric oxygen so that the resulting propellant product has more mass than the fuel carried on the vehicle. Proposed photon rockets would use

4611-407: The fluid was added to the system when the fluid was compressed, such as compressed air . The energy applied to the pump or thermal system that is used to compress the air is stored until it is released by allowing the propellant to escape. Compressed fluid may also be used only as energy storage along with some other substance as the propellant, such as with a water rocket , where the energy stored in

4698-414: The fuel to provide more reaction mass. Rocket propellant may be expelled through an expansion nozzle as a cold gas, that is, without energetic mixing and combustion, to provide small changes in velocity to spacecraft by the use of cold gas thrusters , usually as maneuvering thrusters. To attain a useful density for storage, most propellants are stored as either a solid or a liquid. A rocket propellant

4785-620: The general public ranked nine finalist rover names (Adventure, Amelia, Journey, Perception, Pursuit, Sunrise, Vision, Wonder, and Curiosity) through a public poll on the NASA website. 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. Curiosity is the passion that drives us through our everyday lives. We have become explorers and scientists with our need to ask questions and to wonder. Over 60 landing sites were evaluated, and by July 2011 Gale crater

4872-439: 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

4959-461: The heat of a nuclear reaction to heat a propellant. Usually the propellant is hydrogen because the force is a function of the energy irrespective of the mass of the propellant, so the lightest propellant (hydrogen) produces the greatest specific impulse . A photonic reactive engine uses photons as the propellant and their discrete relativistic energy to produce thrust. Compressed fluid or compressed gas propellants are pressurized physically, by

5046-554: The heat shield facing Mars in preparation for Atmospheric entry . 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, 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

5133-510: 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. The Mars Reconnaissance Orbiter team were able to acquire an image of the MSL descending under the parachute. Following the parachute braking, at about 1.8 km (1.1 mi) altitude, still travelling at about 100 m/s (220 mph),

5220-403: The lander successfully. Faced with these challenges, the MSL engineers came up with a novel alternative solution: the sky crane. The sky crane system lowered the rover with a 7.6 m (25 ft) tether to a soft landing—wheels down—on the surface of Mars. This system consists of a bridle lowering the rover on three nylon tethers and an electrical cable carrying information and power between

5307-480: The mass of scientific instruments. The MSL mission has four scientific goals: Determine the landing site's habitability including the role of water , the study of the climate and the geology of Mars . It is also useful preparation for a future human mission to Mars . To contribute to these goals, MSL has eight main scientific objectives: About one year into the surface mission, and having assessed that ancient Mars could have been hospitable to microbial life,

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5394-471: The near- absolute zero temperature of space. Thermostats monitored temperatures and switched heating and cooling systems on or off as needed. Landing a large mass on Mars is particularly challenging as the atmosphere is too thin for parachutes and aerobraking alone to be effective, while remaining thick enough to create stability and impingement problems when decelerating with retrorockets . Although some previous missions have used airbags to cushion

5481-402: The newly synthesized bishomocubane based compounds are under consideration in the research stage as both solid and liquid propellants of the future. Solid fuel/propellants are used in forms called grains . A grain is any individual particle of fuel/propellant regardless of the size or shape. The shape and size of a grain determines the burn time, amount of gas, and rate of produced energy from

5568-403: The propellant is allowed to escape by releasing a valve, the energy stored by the compression moves the propellant out of the can and that propellant forces the aerosol payload out along with the propellant. Compressed fluid may also be used as a simple vehicle propellant, with the potential energy that is stored in the compressed fluid used to expel the fluid as the propellant. The energy stored in

5655-530: The propellant). Chlorofluorocarbons (CFCs) were once often used as propellants, but since the Montreal Protocol came into force in 1989, they have been replaced in nearly every country due to the negative effects CFCs have on Earth's ozone layer . The most common replacements of CFCs are mixtures of volatile hydrocarbons , typically propane , n- butane and isobutane . Dimethyl ether (DME) and methyl ethyl ether are also used. All these have

5742-422: The resulting propellant product has more mass than the fuel carried on the vehicle. The propellant or fuel may also simply be a compressed fluid, with the potential energy that is stored in the compressed fluid used to expel the fluid as the propellant. The energy stored in the fluid was added to the system when the fluid was compressed, such as compressed air . The energy applied to the pump or thermal system that

5829-584: 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 either the SAM or the CheMin analytical laboratories inside the rover. The Mars Science Laboratory was recommended by United States National Research Council Decadal Survey committee as

5916-533: The rover and descent stage dropped out of the aeroshell. The descent stage is a platform above the rover with eight variable thrust monopropellant hydrazine rocket thrusters on arms extending around this platform to slow the descent. Each rocket thruster, called a Mars Lander Engine (MLE), produces 400 to 3,100 N (90 to 697 lbf) of thrust and were derived from those used on the Viking landers. A radar altimeter measured altitude and velocity, feeding data to

6003-473: The rover must be able to safely reach the site and drive within it. Engineering constraints called for a landing site less than 45° from the Martian equator, and less than 1 km above the reference datum . At the first MSL Landing Site workshop, 33 potential landing sites were identified. By the end of the second workshop in late 2007, the list was reduced to six; in November 2008, project leaders at

6090-571: 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. 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 Rovers . A legged lander approach would have caused several design problems. It would have needed to have engines high enough above

6177-422: The shock of landing, the 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 mass of this EDL system, including parachute, sky crane, fuel and aeroshell , is 2,401 kg (5,293 lb). The novel EDL system placed Curiosity within

6264-507: The spacecraft stopped spinning and a cable cutter separated the cruise stage from the aeroshell. Then the cruise stage was diverted into a separate trajectory into the atmosphere. In December 2012, the debris field from the cruise stage was located by the Mars Reconnaissance Orbiter . Since the initial size, velocity, density and impact angle of the hardware are known, it will provide information on impact processes on

6351-426: 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 . Curiosity successfully landed in the Gale Crater at 05:17:57.3 UTC on August 6, 2012, and transmitted Hazcam images confirming orientation. Due to

6438-523: The spaceflight events unfolded on August 6, 2012. Despite its late hour, particularly on the east coast of the United States where it was 1:31 a.m., 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. The final landing place for the rover was less than 2.4 km (1.5 mi) from its target after

6525-413: The system. This is usually insignificant, although it can sometimes be an unwanted effect of heavy usage (as the system cools, the vapor pressure of the propellant drops). However, in the case of a freeze spray , this cooling contributes to the desired effect (although freeze sprays may also contain other components, such as chloroethane , with a lower vapor pressure but higher enthalpy of vaporization than

6612-526: The top priority middle-class Mars mission in 2003. NASA called for proposals for the rover's scientific instruments in April 2004, and eight proposals were selected on December 14 of that year. 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 to 100 percent thrust with a fixed propellant inlet pressure. By November 2008 most hardware and software development

6699-551: The use of cold gas thrusters , usually as maneuvering thrusters. To attain a useful density for storage, most propellants are stored as either a solid or a liquid. Propellants may be energized by chemical reactions to expel solid, liquid or gas. Electrical energy may be used to expel gases, plasmas, ions, solids or liquids. Photons may be used to provide thrust via relativistic momentum. Propellants that explode in operation are of little practical use currently, although there have been experiments with Pulse Detonation Engines . Also

6786-403: Was accomplished by ejecting ballast masses consisting of two 75 kg (165 lb) tungsten weights minutes before atmospheric entry. 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

6873-440: Was achieved by the combined use of thrusters and ejectable balance masses. 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

6960-563: Was also used to launch the Mars Reconnaissance Orbiter and the New Horizons probe. The first and second stages, along with the solid rocket motors, were stacked on October 9, 2011, near the launch pad. The fairing containing MSL was transported to the launch pad on November 3, 2011. MSL was launched from Cape Canaveral Air Force Station Space Launch Complex 41 on November 26, 2011, at 15:02 UTC via

7047-408: 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 in the mid-1990s by the Mars Pathfinder and Mars Exploration Rover missions. The spacecraft employed several systems in a precise order, with the entry, descent and landing sequence broken down into four parts —described below as

7134-434: 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 mineralogical evidence for past water. Furthermore, a site with spectra indicating multiple hydrated minerals

7221-402: Was complete, and testing continued. At this point, cost overruns were approximately $ 400 million. In the attempts to meet the launch date, several instruments and a cache for samples were removed and other instruments and cameras were simplified to simplify testing and integration of the rover. The next month, NASA delayed the launch to late 2011 because of inadequate testing time. Eventually

7308-402: 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. 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. After the parachute was deployed,

7395-457: 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

7482-411: 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 . Much of the reduction of the landing precision error was accomplished by an entry guidance algorithm, derived from

7569-439: 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. Difficult terrain was favored for finding evidence of livable conditions, but

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