Curiosity (rover)


Curiosity is a Mars rover that is exploring Gale crater and Mount Sharp on Mars as part of NASA's Mars Science Laboratory 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, 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 since its landing.
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 serves 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:

  1. Determine the nature and inventory of organic carbon compounds
  2. Investigate the chemical building blocks of life
  3. Identify features that may represent the effects of biological processes
;Geological and geochemical:

  1. Investigate the chemical, isotopic, and mineralogical composition of the Martian surface and near-surface geological materials
  2. Interpret the processes that have formed and modified rocks and soils
;Planetary process:

  1. Assess long-timescale Martian atmospheric evolution processes
  2. Determine present state, distribution, and cycling of water and carbon dioxide
;Surface radiation:

  1. Characterize the broad spectrum of surface radiation, including galactic and cosmic radiation, solar proton events and secondary neutrons. 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 crewed mission.
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 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 dollars 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, and Spirit and Opportunity 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.
  • Power source: Curiosity is powered by a radioisotope thermoelectric generator, like the successful Viking 1 and Viking 2 Mars landers in 1976.
  • 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. 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 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. Each computer's memory includes 256 kilobytes of EEPROM, 256 megabytes of dynamic random-access memory, and 2 gigabytes of flash memory. For comparison, the Mars Exploration Rovers used 3 MB of EEPROM, 128 MB of DRAM, and 256 MB of flash memory.

    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 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. Communication from and to Curiosity relies on internationally agreed space data communications protocols as defined by the Consultative Committee for Space Data Systems.

    Mobility systems

  • Mobility systems: Curiosity is equipped with six diameter wheels in a rocker-bogie suspension. These are scaled versions of those used on Mars Exploration Rovers. 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.

    Landing

Curiosity landed in Quad 51 of Aeolis Palus in the crater Gale. The landing site coordinates are:. The location was named Bradbury Landing on August 22, 2012, in honor of science fiction author Ray Bradbury. Gale, an estimated 3.5 to 3.8 billion-year-old impact crater, is hypothesized to have first been gradually filled in by sediments; first water-deposited, and then wind-deposited, possibly until it was completely covered. Wind erosion then scoured out the sediments, leaving an isolated mountain, Aeolis Mons, at the center of the wide crater. Thus, it is believed that the rover may have the opportunity to study two billion years of Martian history in the sediments exposed in the mountain. Additionally, its landing site is near an alluvial fan, which is hypothesized to be the result of a flow of ground water, either before the deposition of the eroded sediments or else in relatively recent geologic history.
According to NASA, an estimated 20,000 to 40,000 heat-resistant bacterial spores were on Curiosity at launch, and as many as 1,000 times that number may not have been counted.