Mars Rover

Over the years, NASA has sent four robotic vehicles, called rovers, to Mars--and NASA plans to send another soon. In total, the four rovers that have already gone to Mars are: Sojourner, Spirit and Opportunity, and Curiosity. The Perseverance rover will be heading to the Red Planet soon.

NASA/JPL/California Institute of Technology

Two U.S. robotic vehicles—named Spirit and Opportunity—explored the surface of Mars beginning in January 2004. Each was known as a Mars Exploration Rover. The mission of each rover was to study the chemical and physical composition of the planet’s surface at various locations. They collected data in order to help determine whether water had ever existed on Mars. The rovers also searched for other signs that the planet might have supported some form of life.

NASA sent the twin rovers to Mars in 2003. Spirit was launched on June 10, and Opportunity followed on July 7. Spirit touched down in Gusev crater on January 3, 2004. Three weeks later, on January 24, Opportunity landed in a crater on the equatorial plain called Meridiani Planum on the opposite side of the planet.

Each rover had six wheels and weighed 384 pounds (174 kilograms). Each was equipped with cameras and a suite of instruments. These included a microscopic imager, a rock-grinding tool, and spectrometers that analyzed the rocks, soil, and dust around their landing sites.

   The first Rover ever sent to Mars was the sojouner Mars Pathfinder Rover which weigh 23 ibls (11.5 kg) and landed on Mars July 1997  It has front and rear cameras and hardware to conduct several scientific experiments. Designed for a mission lasting 7 sols, with possible extension to 30 sols. it was active for 83 sols (85 earth days). The base station had its last communication session with Earth at 3:23 a.m. Pacific Daylight Time on September 27, 1997. The rover needed the base station to communicate with Earth, despite still functioning at the time communications ended.Sojourner traveled a distance of just over 100 meters (330 ft) by the time communication was lost.It was instructed to stay stationary until October 5, 1997 (sol 91) and then drive around the lander.Sojourner is the first wheeled vehicle to rove another planet.The name of the rover was selected in an essay contest won by Valerie Ambroise, a 12-year-old from U.S. state of Connecticut. It is named for abolitionist and women's rights activist Sojourner Truth.The second-place prize went to Deepti Rohatgi, 18, of Rockville, who proposed Marie Curie, a Nobel Prize-winning Polish chemist. Third place went to Adam Sheedy, 16, of Round Rock, TX, who chose Judith Resnik, a United States astronaut and shuttle crew-member. The rover was also known as Microrover Flight Experiment abbreviated MFEX.

Sojourner has solar panels and a non-rechargeable battery, which allowed limited nocturnal operations. Once the batteries were depleted, it could only operate during the day.The batteries are lithium-thionyl chloride (LiSOCl2) and could provide 150 watt-hours.The batteries also allowed the health of the rover to be checked while enclosed in the cruise stage while en route to Mars.

0.22 square meters of solar cells could produce a maximum of about 15 watts on Mars, depending on conditions.The cells were GaAs/Ge (Gallium Arsenide/Germanium) and capable of about 18 percent efficiency. They could survive down to about −140° Celsius (−220 °F).

Its central processing unit (CPU) is an 80C85 with a 2 MHz clock, addressing 64 Kbytes of memory. It has four memory stores; the previously mentioned 64 Kbytes of RAM (made by IBM) for the main processor, 16 Kbytes of radiation-hardened PROM (made by Harris), 176 Kbytes of non-volatile storage (made by Seeq Technology), and 512 Kbytes of temporary data storage (made by Micron). The electronics were housed inside the Warm Electronics Box inside the rover.

Sojourner communicated with its base station using a 9,600 baud radio modem, although error-checking protocols limited communications to a functional data rate of 2,400 baud with a theoretical range of about half a kilometer. Under normal operation, it would periodically send a "heartbeat" message to the lander. If no response was given, the rover could autonomously travel back to the location at which the last heartbeat was received. If desired, this same strategy could be used to deliberately extend the rover's operational range beyond that of its radio transceiver, although the rover rarely traveled further than 10 meters from Pathfinder during its mission.

The UHF radio modems worked similar to walkie-talkies, but sent data, not voice. It could send or receive, but not both at same time, which is known as half-duplex. The data was communicated in bursts of 2 kilobytes.

The Alpha Proton X-ray Spectrometer (APXS) is nearly identical to the one on Mars 96, and was a collaboration between the Max Planck Institute for Solar System Research in Lindau, Germany (formally known as the Max Planck Institute For Aeronomy) and the University of Chicago in the United States. APXS could determine elemental composition of Mars rocks and dust, except for hydrogen. It works by exposing a sample to alpha particles, then measuring the energies of emitted protons, X-rays, and backscattered alpha particles.

The rover had three cameras: two monochrome cameras in front, and a color camera in the rear. Each front camera had an array 484 pixels high by 768 wide. The optics consisted of a window, lens, and field flattener. The window was made of sapphire, while the lens objective and flattener were made of zinc selenide.The rover was imaged on Mars by the base station's IMP camera system, which also helped determine where the rover should go.

Sojourner operation was supported by "Rover Control Software", which ran on a Silicon Graphics Onyx2 computer back on Earth, and allowed command sequences to be generated using a graphical interface. The rover driver would wear 3D goggles supplied with imagery from the base station and move a virtual model with the spaceball controller, a specialized joystick. The control software allowed the rover and surrounding terrain to be viewed from any angle or position, supporting the study of terrain features, placing waypoints, or doing virtual flyovers.

The rover had a mass of 11.5 kg (weighing about 25 pounds on Earth), which equates to a weight of 4.5 kg (10 pounds) on Mars.

   Spirit

Spirit, also known as MER-A (Mars Exploration Rover – A) or MER-2, is a robotic rover on Mars, active from 2004 to 2010.It was one of two rovers of NASA's Mars Exploration Rover Mission. It landed successfully within the impact crater Gusev on Mars at 04:35 Ground UTC on January 4, 2004, three weeks before its twin, Opportunity (MER-B), which landed on the other side of the planet. Its name was chosen through a NASA-sponsored student essay competition. The rover became stuck in a "sand trap" in late 2009 at an angle that hampered recharging of its batteries; its last communication with Earth was sent on March 22, 2010.

Spirit

The Mars Exploration Rover-2 (MER-2) during testing for mobility and maneuverability.The rover completed its planned 90-sol mission. Aided by cleaning events that resulted in more energy from its solar panels, Spirit went on to function effectively over twenty times longer than NASA planners expected. Spirit also logged 7.73 km (4.8 mi) of driving instead of the planned 600 m (0.4 mi),allowing more extensive geological analysis of Martian rocks and planetary surface features. Initial scientific results from the first phase of the mission (the 90-sol prime mission) were published in a special issue of the journal Science. On May 1, 2009 (5 years, 3 months, 27 Earth days after landing; 21.6 times the planned mission duration), Spiritbecame stuck in soft sand.This was not the first of the mission's "embedding events" and for the following eight months NASA carefully analyzed the situation, running Earth-based theoretical and practical simulations, and finally programming the rover to make extrication drives in an attempt to free itself. These efforts continued until January 26, 2010 when NASA officials announced that the rover was likely irrecoverably obstructed by its location in soft sand,though it continued to perform scientific research from its current location. The rover continued in a stationary science platform role until communication with Spirit stopped on March 22, 2010 (sol 2208) JPL continued to attempt to regain contact until May 24, 2011, when NASA announced that efforts to communicate with the unresponsive rover had ended, calling the mission complete.Spirit is powered by solar arrays. Until Opportunity overtook it on May 19, 2010, the Mars probe with longest operational period was Viking 1that lasted for 2245 Sols on the surface of Mars. On March 22, 2010, Spirit sent its last communication, thus falling just over a month short of surpassing Viking 1's operational record. An archive of weekly updates on the rover's status can be found at the Spirit Update Archive. Spirit's total odometry as of March 22, 2010 (sol 2210) is 7,730.50 meters (4.80 mi). Design and construction Annotated rover diagram Spirit (and its twin, Opportunity) are six-wheeled, solar-powered robots standing 1.5 meters (4.9 ft) high, 2.3 meters (7.5 ft) wide and 1.6 meters (5.2 ft) long and weighing 180 kilograms (400 lb). Six wheels on a rocker-bogie system enable mobility over rough terrain. Each wheel has its own motor. The vehicle is steered at front and rear and is designed to operate safely at tilts of up to 30 degrees. Maximum speed is 5 centimeters per second (2.0 in/s);0.18 kilometers per hour (0.11 mph), although average speed is about 1 centimeter per second (0.39 in/s). Both Spirit and Opportunity have pieces of the fallen World Trade Center's metal on them that were "turned into shields to protect cables on the drilling mechanisms". Solar arrays generate about 140 watts for up to four hours per Martian day (sol) while rechargeable lithium ion batteries store energy for use at night. Spirit's onboard computer uses a 20 MHz RAD6000 CPU with 128 MB of DRAM, 3 MB of EEPROM, and 256 MB of flash memory. The rover's operating temperature ranges from −40 to +40 °C (−40 to 104 °F) and radioisotope heater units provide a base level of heating, assisted by electrical heaters when necessary. A gold film and a layer of silica aerogel provide insulation. Communications depends on an omnidirectional low-gain antenna communicating at a low data rate and a steerable high-gain antenna, both in direct contact with Earth. A low gain antenna is also used to relay data to spacecraft orbiting Mars. Science payload The science instruments include: Panoramic Camera (Pancam) – examines the texture, color, mineralogy, and structure of the local terrain. Navigation Camera (Navcam) – monochrome with a higher field of view but lower resolution, for navigation and driving. Miniature Thermal Emission Spectrometer (Mini-TES) – identifies promising rocks and soils for closer examination, and determines the processes that formed them. Hazcams, two B&W cameras with 120 degree field of view, that provide additional data about the rover's surroundings. The rover arm holds the following instruments: Mössbauer spectrometer (MB) MIMOS II – used for close-up investigations of the mineralogy of iron-bearing rocks and soils. Alpha particle X-rays spectrometer(APXS) – close-up analysis of the abundances of elements that make up rocks and soils. Magnets – for collecting magnetic dust particles. Microscopic Imager (MI) – obtains close-up, high-resolution images of rocks and soils. Rock Abrasion Tool (RAT) – exposes fresh material for examination by instruments on board.         Opportunity (Rover) Opportunity, also known as MER-B(Mars Exploration Rover – B) or MER-1, and nicknamed "Oppy",is a roboticrover that was active on Mars from 2004 until the middle of 2018. Launched on July 7, 2003, as part of NASA's Mars Exploration Rover program, it landed in Meridiani Planum on January 25, 2004, three weeks after its twin Spirit (MER-A) touched down on the other side of the planet. With a planned 90-sol duration of activity (slightly less than 92.5 Earth days), Spirit functioned until it got stuck in 2009 and ceased communications in 2010, while Opportunity was able to stay operational for 5111 sols after landing, maintaining its power and key systems through continual recharging of its batteries using solar power, and hibernating during events such as dust storms to save power. This careful operation allowed Opportunity to exceed its operating plan by 14 years, 46 days (in Earth time), 55 times its designed lifespan. By June 10, 2018, when it last contacted NASA, the rover had traveled a distance of 45.16 kilometers (28.06 miles). Opportunity An artist's portrayal of Opportunity on the surface of Mars          Design and construction Spirit and Opportunity are twin rovers, each a six-wheeled, solar-powered robot standing 1.5 meters (4.9 ft) high, 2.3 meters (7.5 ft) wide, and 1.6 meters (5.2 ft) long and weighing 180 kilograms (400 lb). Six wheels on a rocker-bogiesystem enable mobility. Each wheel has its own motor, the vehicle is steered at front and rear and was designed to operate safely at tilts of up to 30 degrees. Maximum speed is 5 centimeters per second (2.0 in/s) although average speed was about a fifth of this (0.89 centimeters per second (0.35 in/s)). Both Spirit and Opportunity have pieces of the fallen World Trade Center's metal on them that were "turned into shields to protect cables on the drilling mechanisms". Solar arrays generate about 140 watts for up to fourteen hours per sol, while rechargeable lithium ion batteries stored energy for use at night. Opportunity's onboard computer uses a 20 MHz RAD6000 CPU with 128 MB of DRAM, 3 MB of EEPROM, and 256 MB of flash memory. The rover's operating temperature ranges from −40 to +40 °C (−40 to 104 °F) and radioisotope heatersprovide a base level of heating, assisted by electrical heaters when necessary.A gold film and a layer of silica aerogel provides insulation. Communications depend on an omnidirectional low-gain antenna communicating at a low data rate and a steerable high-gain antenna, both in direct contact with Earth. A low gain antenna is also used to relay data to spacecraft orbiting Mars. Fixed science/engineering instruments included: Panoramic Camera (Pancam) – examines the texture, color, mineralogy, and structure of the local terrain. Navigation Camera (Navcam) – monochrome with a higher field of view but lower resolution, for navigation and driving. Miniature Thermal Emission Spectrometer (Mini-TES) – identifies promising rocks and regolith for closer examination, and determines the processes that formed them. Hazcams, two B&W cameras with 120 degree field of view, that provide additional data about the rover's surroundings. The rover arm holds the following instruments: Mössbauer spectrometer (MB) MIMOS II – used for close-up investigations of the mineralogy of iron-bearing rocks and regolith. Alpha particle X-ray spectrometer(APXS) – close-up analysis of the abundances of elements that make up rocks and regolith. Magnets – for collecting magnetic dust particles Microscopic Imager (MI) – obtains close-up, high-resolution images of rocks and regolith. Rock Abrasion Tool (RAT) – exposes fresh material for examination by instruments on board. The cameras produce 1024-pixel by 1024-pixel images, the data is compressed with ICER, stored, and transmitted later. The rover's name was chosen through a NASA sponsored student essay competitions. Opportunity was 'driven' by several operators throughout its mission, including JPL roboticist Vandi Vermawho also cowrote the PLEXIL command language used in its software.          Curiousity (ROVER) Curiosity is a car-sized Rover designed to explore the crater Gale on Mars as part of NASA's Mars Science Laboratorymission (MSL).Curiosity was launched from Cape Canaveral on November 26th, 2011, at 15:02 UTC and landed on Aeolis Palus inside Gale on Mars on August 6th, 2012, 05:17 UTC. The Bradbury Landing site was less than 2.4 km (1.5 mi) from the center of the rover's touchdown target after a 56 million km (35 million mi) journey.The rover's goals include an investigation of the Martian climate and geology; assessment of whether the selected field site inside Gale has ever offered environmental conditions favorable for microbial life, including investigation of the role of water; and planetary habitability studies in preparation for human exploration. Curiosity Self-portrait of Curiosity located at the foothill of Mount Sharp (October 6, 2015) 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, 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.In comparison to Pancam on the Mars Exploration Rovers, the MastCam-34 has 1.25× higher spatial resolution and the MastCam-100 has 3.67× higher spatial resolution. Curiosity has an advanced payload of scientific equipment on Mars. It is the fourth NASA robotic rover sent to Mars since 1996. Previous successful Mars rovers are Sojourner from the Mars Pathfinder mission (1997), and Spirit(2004–2010) and Opportunity (2004–2019) rovers from the Mars Exploration Rover mission. Curiosity comprised 23% of the mass of the 3,893 kg (8,583 lb) spacecraft at launch. The remaining mass was discarded in the process of transport and landing. Dimensions: Curiosity has a mass of 899 kg (1,982 lb) including 80 kg (180 lb) of scientific instruments.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. Power source: Curiosity is powered by a radioisotope thermoelectric generator (RTG), like the successful Viking 1 and Viking 2 Mars landers in 1976.[32][33] Radioisotope power systems (RPSs) are generators that produce electricity from the decay of radioactive isotopes, such as plutonium-238, which is a non-fissile isotope of plutonium. Heat given off by the decay of this isotope is converted into electric voltage by thermocouples, providing constant power during all seasons and through the day and night. Waste heat is also used via pipes to warm systems, freeing electrical power for the operation of the vehicle and instruments.​[32]​[33]​Curiosity​'s RTG is fueled by 4.8 kg (11 lb) of plutonium-238 dioxide supplied by the U.S. Department of Energy.[34] Curiosity's RTG is the Multi-Mission Radioisotope Thermoelectric Generator (MMRTG), designed and built by Rocketdyne and Teledyne Energy Systems under contract to the U.S. Department of Energy,[35] and assembled and tested by the Idaho National Laboratory.[36] Based on legacy RTG technology, it represents a more flexible and compact development step,[37] and is designed to produce 110 watts of electrical power and about 2,000 watts of thermal power at the start of the mission.[32][33] 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.[38][39] The power source generates 9 MJ (2.5 kWh) of electrical energy each day, much more than the solar panels of the now retired Mars Exploration Rovers, which generated about 2.1 MJ (0.58 kWh) each 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 ampere-hours. Heat rejection system: The temperatures at the landing site can vary from −127 to 40 °C (−197 to 104 °F); therefore, the thermal system warms the rover for most of the Martian year. The thermal system does so in several ways: passively, through the dissipation to internal components; by electrical heaters strategically placed on key components; and by using the rover heat rejection system (HRS).It uses fluid pumped through 60 m (200 ft) of tubing in the rover body so that sensitive components are kept at optimal temperatures. The fluid loop serves the additional purpose of rejecting heat when the rover has become too warm, and it can also gather waste heat from the power source by pumping fluid through two heat exchangers that are mounted alongside the RTG. The HRS also has the ability to cool components if necessary 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. The computers run the VxWorks real-time operating system (RTOS). Each computer's memory includes 256 kBof EEPROM, 256 MB of DRAM, and 2 GB of flash memory.For comparison, the Mars Exploration Rovers used 3 MB of EEPROM, 128 MB of DRAM, and 256 MB of flash memory. The RCE computers use the RAD750CPU, which is a successor to the RAD6000 CPU of the Mars Exploration Rovers.The RAD750 CPU, a radiation-hardened version of the PowerPC 750, can execute up to 400 MIPS, while the RAD6000 CPU is capable of up to only 35 MIPSOf the two on-board computers, one is configured as backup and will take over in the event of problems with the main computer. On February 28, 2013, NASA was forced to switch to the backup computer due to a problem with the active computer's flash memory, which resulted in the computer continuously rebooting in a loop. The backup computer was turned on in safe mode and subsequently returned to active status on March 4.The same problem happened in late March, resuming full operations on March 25, 2013. The rover has an inertial measurement unit (IMU) that provides 3-axis information on its position, which is used in rover navigation.[42] The rover's computers are constantly self-monitoring to keep the rover operational, such as by regulating the rover's temperature.[42] 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. The rover installed its full surface operations software after the landing because its computers did not have sufficient main memory available during flight. The new software essentially replaced the flight software. The rover has four processors. One of them is a SPARC processor that runs the rover's thrusters and descent-stage motors as it descended through the Martian atmosphere. Two others are PowerPC processors: the main processor, which handles nearly all of the rover's ground functions, and that processor's backup. The fourth one, another SPARC processor, commands the rover's movement and is part of its motor controller box. All four processors are single core.[50] Curiosity transmits to Earth directly or via three relay satellites in Mars orbit. Communications: Curiosity is equipped with significant telecommunication redundancy by several means: an X band transmitter and receiver that can communicate directly with Earth, and a UHF Electra-Lite software-defined radio for communicating with Mars orbitersCommunication with orbiters is 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.telecommunication included 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,the signals of which orbiting relay satellites are capable of relaying back to Earth. Signals between Earth and Mars take an average of 14 minutes, 6 seconds.Curiosity can communicate with Earth directly at speeds up to 32 kbit/s, but the bulk of the data transfer is being relayed through the Mars Reconnaissance Orbiter and Odyssey orbiter. Data transfer speeds between Curiosity and each orbiter may reach 2000 kbit/s and 256 kbit/s, respectively, but each orbiter is able to communicate with Curiosity for only about eight minutes per day (0.56% of the time).Communication from and to Curiosityrelies on internationally agreed space data communications protocols as defined by the Consultative Committee for Space Data Systems. 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.At landing, telemetry was monitored by three orbiters, depending on their dynamic location: the 2001 Mars Odyssey, Mars Reconnaissance Orbiter and ESA's Mars Expresssatellite.As of February 2019, the MAVEN orbiter is being positioned to serve as a relay orbiter while continuing its science mission. Mobility systems: Curiosity is equipped with six 50 cm (20 in) diameter wheels in a rocker-bogie suspension. The suspension system also served as landing gear for the vehicle, unlike its smaller predecessors.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.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 estimate the distance traveled. The pattern itself is Morse code for "JPL" (·--- ·--· ·-··). The rover is capable of climbing sand dunes with slopes up to 12.5°. Based on the center of mass, the vehicle can withstand a tilt of at least 50° in any direction without overturning, but automatic sensors limit the rover from exceeding 30° tilts After six years of use, the wheels are visibly worn with punctures and tears. Curiosity can roll over obstacles approaching 65 cm (26 in) in height,and it has a ground clearance of 60 cm (24 in).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.The rover landed about 10 km (6.2 mi) from the base of Mount Sharp,(officially named Aeolis Mons) and it is expected to traverse a minimum of 19 km (12 mi) during its primary two-year mission. It can travel up to 90 m (300 ft) per hour but average speed is about 30 m (98 ft) per hour. The vehicle is 'driven' by several operators led by Vandi Verma, group leader of Autonomous Systems, Mobility and Robotic Systems at JPL,who also cowrote the PLEXIL language used to operate the rover. Scientific instruments Instrument location diagram           Preserverance (ROVER) The Perseverance rover's design is derived from the Curiosity rover, and will use many components already fabricated and tested, new scientific instruments and a core drill.It will also carry the Ingenuity helicopter drone. Mars 2020 Artist's impression of Perseverance The mission will seek signs of habitable conditions on Mars in the ancient past, and will also search for evidence — or biosignatures — of past microbial life. The Perseverance rover is planned for launch in 2020 on an Atlas V-541and the Jet Propulsion Laboratory will manage the mission. The mission is part of NASA's Mars Exploration Program. The Science Definition Team proposed that the rover collect and package as many as 31 samples of rock cores and surface soil for a later mission to bring back for definitive analysis on Earth. In 2015, they expanded the concept, planning to collect even more samples and distribute the tubes in small piles or caches across the surface of Mars  In September 2013, NASA launched an Announcement of Opportunity for researchers to propose and develop the instruments needed, including the Sample Caching System. The science instruments for the mission were selected in July 2014 after an open competition based on the scientific objectives set one year earlier. The science conducted by the rover's instruments will provide the context needed for detailed analyses of the returned samples. The chairman of the Science Definition Team stated that NASA does not presume that life ever existed on Mars, but given the recent Curiosity rover findings, past Martian life seems possible. The Perseverance rover will explore a site likely to have been habitable. It will seek signs of past life, set aside a returnable cache with the most compelling rock core and soil samples, and demonstrate technology needed for the future human and robotic exploration of Mars. A key mission requirement is that it must help prepare NASA for its long-term Mars sample-return mission and crewed mission efforts.The rover will make measurements and technology demonstrations to help designers of a future human expedition understand any hazards posed by Martian dust, and will test technology to produce a small amount of pure oxygen (O 2) from Martian atmospheric carbon dioxide (CO Spacecraft of Mars 2020 Perseverance will carry seven scientific instruments across the Martian surface. Ingenuity will scout for points of interest for Perseverance to study. The cruise stage and EDLS will carry both spacecraft to Mars.engineering team were involved in the rover's design.Engineers redesigned the Perseverance rover wheels to be more robust than Curiosity's wheels, which have sustained some damage. The rover will have thicker, more durable aluminium wheels, with reduced width and a greater diameter (52.5 centimetres (20.7 in)) than Curiosity's 50 centimetres (20 in) wheels The aluminium wheels are covered with cleats for traction and curved titanium spokes for springy support.The combination of the larger instrument suite, new Sampling and Caching System, and modified wheels makes Mars 2020 heavier than its predecessor, Curiosity,by 17% (899 kg to 1050 kg). The rover will include a five-jointed robotic arm measuring 2.1 metres (6 ft 11 in) long. The arm will be used in combination with a turret to analyze geologic samples from the Martian surface.A Multi-Mission Radioisotope Thermoelectric Generator (MMRTG), left over as a backup part for Curiosityduring its construction, will power the rover. The generator has a mass of 45 kilograms (99 lb) and uses 4.8 kilograms (11 lb) of plutonium dioxideas the source of steady supply of heat that is converted to electricity.The electrical power generated is approximately 110 watts at launch with little decrease over the mission time.Two lithium-ion rechargeable batteriesare included to meet peak demands of rover activities when the demand temporarily exceeds the MMRTG's steady electrical output levels. The MMRTG offers a 14-year operational lifetime, and it was provided to NASA by the US Department of Energy.[36] Unlike solar panels, the MMRTG provides engineers with significant flexibility in operating the rover's instruments even at night and during dust storms, and through the winter season Ingenuity Main article: Mars Helicopter Ingenuity Ingenuity is a robotic helicopter that will test the technology to scout interesting targets for study on Mars, and help plan the best driving route for Perseverance.The aircraft will be deployed from the rover's deck, and is expected to fly up to five times during its 30-day test campaign early in the mission.[39] Each flight will take no more than 3 minutes, at altitudes ranging from 3 m to 10 m above the ground, but it could potentially cover a maximum distance of about 600 metres (2,000 ft) per flight.It will use autonomous control and communicate with Perseverance directly after each landing. If it works as expected, NASA will be able to build on the design for future Mars missions.[40] Cruise stage and EDLS The three major components of the Mars 2020 spacecraft are the cruise stage for travel between Earth and Mars; the Entry, Descent, and Landing System(EDLS) that includes the aeroshell, parachute, descent vehicle, and sky Crane; and the Perseverance rover. The rover is based on the design of Curiousity.[8] While there are differences in scientific instruments and the engineering required to support them, the entire landing system (including the sky crane and heat shield) and rover chassis can essentially be recreated without any additional engineering or research. This reduces overall technical risk for the mission, while saving funds and time on development. One of the upgrades is a guidance and control technique called "Terrain Relative Navigation" (TRN) to fine-tune steering in the final moments of landing.[[44]This system will allow for a landing accuracy within 40 m (130 ft) and avoid obstacles. This is a marked improvement from the Mars Science Laboratory mission that had an elliptical area of 7 by 20 kilometres (4.3 by 12.4 mi). In October 2016, NASA reported using the Xombie rocket to test the Lander Vision System (LVS), as part of the Autonomous Descent and Ascent Powered-flight Testbed (ADAPT) experimental technologies, for the Mars 2020 mission landing, meant to increase the landing accuracy and avoid obstacle hazards.