Curiosity is a Mars rover that is exploring Gale crater and Mount Sharp on Mars as part of NASA's Mars Science Laboratory (MSL) mission. Launched in 2011 and landed the following year, the car-sized rover continues to operate more than a decade after its original two-year mission.
Curiosity was launched from Cape Canaveral, Florida, on November 26, 2011, at 15:02:00 UTC and landed on Aeolis Palus inside Gale crater on Mars on August 6, 2012, 05:17:57 UTC. The Bradbury Landing site was less than from the center of the rover's touchdown target after a journey.
Mission goals include an investigation of the Martian climate and geology, an 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.
In December 2012, Curiosity two-year mission was extended indefinitely. On August 6, 2022, a detailed overview of accomplishments by the Curiosity rover for the last ten years was reported. The rover is still operational, and as of , , Curiosity has been active on Mars for sols ( total days; ) since its landing (see current status).
The NASA/JPL Mars Science Laboratory/Curiosity Project Team was awarded the 2012 Robert J. Collier Trophy by the National Aeronautic Association "In recognition of the extraordinary achievements of successfully landing Curiosity on Mars, advancing the nation's technological and engineering capabilities, and significantly improving humanity's understanding of ancient Martian habitable environments." Curiosity rover design served as the basis for NASA's 2021 Perseverance mission, which carries different scientific instruments.
Mission
Goals and objectives
As established by the Mars Exploration Program, the main scientific goals of the MSL mission are to help determine whether Mars could ever have supported life, as well as determining the role of water, and to study the climate and geology of Mars. The mission results will also help prepare for human exploration. To contribute to these goals, MSL has eight main scientific objectives:
Biological
Geological and geochemical
Planetary process
Surface radiation
About one year into the surface mission, and having assessed that ancient Mars could have been hospitable to microbial life, 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 region it is set to explore has been compared to the Four Corners region of the North American west.
Name A NASA panel selected the name Curiosity following a nationwide student contest that attracted more than 9,000 proposals via the Internet and mail. Twelve-year-old Clara Ma from Sunflower Elementary School in Lenexa, Kansas submitted the winning entry. As her prize, Ma won a trip to NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California, where she signed her name directly onto the rover as it was being assembled.
Ma wrote in her winning essay:
Cost Adjusted for inflation, Curiosity has a life-cycle cost of US$3.2 billion in 2020. By comparison, the 2021 Perseverance rover has a life-cycle cost of US$2.9 billion.
Rover and lander specifications
Curiosity is long by wide by high, larger than Mars Exploration Rovers, which are long and have a mass of including 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 (2004–2018) rovers from the Mars Exploration Rover mission.
Curiosity comprised 23% of the mass of the spacecraft at launch. The remaining mass was discarded in the process of transport and landing.
Dimensions: Curiosity has a mass of including of scientific instruments. The rover is long by wide by in height.
The main box-like chassis forms the Warm Electronics Box (WEB).
Power source: Curiosity is powered by a radioisotope thermoelectric generator (RTG), like the successful Viking 1 and Viking 2 Mars landers in 1976.
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 generates electrical power using thermocouples, providing consistent 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. Curiosity RTG is fueled by of plutonium-238 dioxide supplied by the U.S. Department of Energy.
Curiositys 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, and fueled and tested by the Idaho National Laboratory. Based on legacy RTG technology, it represents a more flexible and compact development step, and is designed to produce 110 watts of electrical power and about 2,000 watts of thermal power at the start of the mission. 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. The power source generates of electrical energy each day, much more than the solar panels of the now retired Mars Exploration Rovers, which generated about 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 vary seasonally and the thermal system warms the rover as needed. 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 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 kilobytes (kB) of EEPROM, 256 megabytes (MB) of dynamic random-access memory (DRAM), and 2 gigabytes (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 RAD750 Central processing unit (CPU), which is a successor to the RAD6000 CPU of the Mars Exploration Rovers. The IBM RAD750 CPU, a radiation-hardened version of the PowerPC 750, can execute up to 400 Million instructions per second (MIPS), while the RAD6000 CPU is capable of up to only 35 MIPS. Of 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, 2013. 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. The rover's computers are constantly self-monitoring to keep the rover operational, such as by regulating the rover's temperature. 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.
Communications Communications: Curiosity is equipped with significant telecommunication redundancy by several means: an X band transmitter and receiver that can communicate directly with Earth, and an Ultra high frequency (UHF) Electra-Lite software-defined radio for communicating with Mars orbiters. Communication 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 Curiosity relies on internationally agreed space data communications protocols as defined by the Consultative Committee for Space Data Systems.
Jet Propulsion Laboratory (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 Express satellite. As of February 2019, the MAVEN orbiter is being positioned to serve as a relay orbiter while continuing its science mission.
Mobility systems