Curiosity

FIELDS OF STUDY: Space Technology; Remote Sensing; Observational Astronomy

ABSTRACT: Curiosity is an unmanned mobile unit about the size of a large car that can move independently on the surface of Mars. It was launched on November 26, 2011. Its mission includes taking photographs, gathering scientific data and samples, and transmitting information to Earth-based scientists. The information provided by the Curiosity rover about Mars in the present and the past helps scientists understand more about that planet and the solar system as a whole.

Principal Terms

  • Aeolis Palus: a plain that stretches between the northern rim of Gale Crater and the mountain Aeolis Mons on the planet Mars.
  • Deep Space Network: a collection of large radio antennae positioned in three locations around the world that provide a communications system that can reach into space.
  • National Aeronautics and Space Administration: the government agency established in 1958 by an act of Congress to run and oversee the United States’ space program and research.
  • Opportunity: a rover that, as of 2017, has spent the longest amount of time and traveled the greatest distance on the surface of Mars to date. It landed in 2004 and has provided crucial data about the planet.
  • rover: an unmanned, self-propelled mobile research unit that can travel independently to gather information about a location, especially a planet, moon, or other celestial body.
  • Sojourner: the first robotic rover to land on Mars. It landed in 1997 and began sending information from Mars’s surface back to Earth.
  • Spirit: a rover that landed on Mars in 2004. It sent information about the planet back to Earth until it ceased transmission in 2011.

History of Mars Exploration

Aside from Earth, Mars has been discovered to have the most hospitable climate of all of the planets in the solar system. Therefore, scientists have made efforts to explore and learn more about this planet and its potential for life since early in the world’s various space programs. In 1964, less than a decade after the establishment of the National Aeronautics and Space Administration (NASA), the United States launched its first exploratory missions toward Mars. The first attempt, the spacecraft Mariner 3, experienced technical difficulties and never reached Mars. However, its identical twin spacecraft, Mariner 4, reached Mars in July 1965. It took the first photographs of a planet other than Earth.

In 1976, Viking 1 and Viking 2 became the first spacecraft to touch down on the surface of Mars. They were equipped with a number of instruments for measuring the soil and atmosphere of the red planet. The Viking craft allowed scientists to conduct the first tests seeking life on another planet.

In 1992, the Mars Observer orbiting spacecraft failed just before deployment. However, the 1996–7 Mars Global Surveyor spacecraft was more successful. Among the information it recorded was data showing that Mars has repeating weather patterns.

The Mars Pathfinder mission launched in 1996 with Sojourner, the first robotic rover to land on Mars. Several other exploratory missions, including others with rovers, were launched during the first decade of the twenty-first century. The Opportunity and Spirit rovers both landed on Mars’s surface in January 2004. After Spirit helped scientists learn more about the presence of water on the planet in the past, it became lodged in soft soil. NASA lost contact and ended its mission in 2011. Opportunity was still transmitting information more than ten years later. It has investigated the makeup of craters such as Endurance and Victoria. By late 2011, NASA was ready to launch the Mars Science Laboratory mission with Curiosity, its most ambitious and advanced rover to date. Curiosity would look for any habitable places and signs of microbial life.

About the Rover

The spacecraft that included the Curiosity rover was launched with an Atlas rocket from the Cape Canaveral Air Force Station in Florida on November 26, 2011. The payload, including the rover, landed on Mars on August 6, 2012.

Curiosity measures 3 meters (about 10 feet) long, 2.7 meters (about 9 feet) wide, and 2.2 meters (7 feet) tall, with an arm that can reach an additional 2.2 meters (7 feet). It is roughly the size of a small sport utility vehicle and weighs about 899 kilograms (1,982 pounds). The rover is equipped with a geology lab, a rock-vaporizing laser, and a variety of cameras to help it gather data.

The rover has six tires equipped with cleats along with a special suspension to enable it to move across the rocky surface of Mars. Unlike its predecessors, Curiosity is powered by a radioisotope thermoelectric generator (RTG). The generator’s thermocouples use heat produced by the decay of plutonium-238 to create an electric current that powers the rover. Residual heat from the process is also used to heat other parts of the rover’s operating equipment without losing any of its electrical power. This makes the RTG very efficient. The RTG has a lifespan of at least a full Martian year, or 687 Earth days. This allows Curiosity to move farther and faster than previous rovers.

The RTG provides power for four individual steering motors on Curiosity’s two front and two rear wheels. This four-wheel steering allows the rover to turn in a complete circle in place. A special suspension system called a rocker-bogie keeps Curiosity stable and balanced on Mars’s rocky, hilly terrain. While its programming is set to prevent the rover from attempting any inclines greater than 30 degrees, the rocker-bogie system is designed to keep it from tipping over at any angle up to 45 degrees. Curiosity averages a speed of 30 meters (98 feet) per hour, depending on the terrain it is covering.

The rover’s robotic arm has three main joints, just like a human arm. It can hold instruments, pick up objects, and maneuver a camera to take photos. Other instruments onboard the rover include a spectrometer, special chemistry equipment such as an x-ray diffraction and fluorescence instrument, and a radiation assessment detector. An array of environmental monitoring sensors, sample-collecting instruments such as a drill, and specialized cameras for taking pictures in different conditions are also included.

Since the mission is unmanned, the rover needs a communications system to send information back to scientists on Earth. Curiosity has three antennae that have different functions. One is an ultrahigh-frequency antenna that sends messages to Earth by way of the Odyssey and Reconnaissance orbiters put in place in previous missions. Also included are high-gain antennae that receive signals from the Mars Science Laboratory mission team on Earth. Communication is helped by NASA’s Deep Space Network, an array of antennae in three locations on Earth that provides continuous communication with planetary missions.

Curiosity’s Accomplishments

The Curiosity rover took its first drive on August 22, 2012, after NASA scientists completed tests on its systems and determined that the ground around it was safe. It had landed on Aeolis Palus, a plain in Gale Crater that scientists hoped would be rich with geological deposits to study. During its first trip, Curiosity traveled about 4.5 meters (15 feet) forward and then 2.5 meters (8 feet) back. It had logged more than 10 kilometers (about 6 miles) through the early part of 2015. During its two-year planned mission and the time it has remained functional beyond that, Curiosity has benefited the space program and future exploration in many ways.

Scientists pioneered a new landing method to bring Curiosity safely to Mars’s surface. Instead of airbags, a soft-landing technique known as a sky crane was designed and used to lower the rover from the vehicle. NASA engineers believe this technique could be useful for future large-payload missions, including manned missions to Mars and other celestial bodies.

Once Curiosity began roving, it determined that radiation levels on Mars are not high enough to prevent manned missions to the red planet. Data collected during the trip to Mars indicated that the levels of radiation in space are greater than those Curiosity detected on the planet’s surface. In addition, the rover drilled beneath the surface of the planet to collect samples, marking the first time this has been done on any planet other than Earth. Continued investigation revealed the location of an ancient streambed that once held water several feet deep. This suggests that there could once have been life on Mars. The rover has identified sulfur, nitrogen, hydrogen, oxygen, phosphorus, and carbon as well as clay minerals in collected samples. These are all indicators that the planet once had an environment with enough water to sustain microbial life. In the fall of 2015, a NASA team confirmed using data from Curiosity that water had been at least partially responsible for depositing sediment that had built up in Gale Crater, forming the foundation of Mount Sharp. By March 2017, Curiosity had traveled approximately 16 kilometers (10 miles).

Significance and Future Mars Study

Curiosity has explored many regions on Mars, gathering large amounts of data that will help NASA teams plan future missions to Mars and to other planets. The mission’s success has encouraged NASA to plan additional missions with rovers similar in design to Curiosity.

Curiosity’s exploration of Mars is important for many reasons. While still risky, Mars is the best bet for a manned landing on another planet. The ability to land and live for a time on another planet would provide the opportunity to develop new techniques and technologies that could be applicable on Earth. The lunar missions of the 1960s and 1970s provided innovations that have since become part of everyday life. Mars could also become a base for colonies to launch exploration further into the universe. Having the tools, technology, and know-how to successfully live on a temporary or permanent basis on Mars could also provide the opportunity for humans to live somewhere other than Earth for the first time.

As of the fall of 2017, NASA was developing a new rover modeled generally off of Curiosity to send to Mars to continue studies after Curiosity eventually dies; this rover was expected to begin its flight to Mars in 2020. Based off of what scientists have learned from observing Curiosity's accomplishments and struggles, the new rover is expected to include changes in wheel design and will possibly be used to record sounds from the surface.

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