April 8, 2019

After nearly 15 years on the surface of Mars, the Opportunity rover died as it lived: studying its adopted home planet. The United States National Aeronautics and Space Administration (NASA) officially ended the rover’s mission in February 2019, months after the craft was silenced by a dust storm.

The NASA Mars rover Opportunity studied the red planet from January 2004 until the summer of 2018. Credit: NASA/JPL/Cornell University, Maas Digital LLC

Opportunity and its twin vehicle, Spirit, together made up the Mars Exploration Rover Mission. They were launched in 2003 to study the history of water on the red planet. The golf-cart-sized rovers carried scientific instruments created by teams of scientists and engineers from the United States and Europe.

Spirit and Opportunity were each designed for just 90-day missions. But both continued to gather information on the surface of Mars without any major setbacks for more than five years. In early 2009, Spirit became permanently trapped in a bed of loose Martian soil, ending that rover’s exploring career. Finally accepting its loss, NASA officially ended Spirit’s mission in 2011.

Opportunity landed in January 2004 in Meridiani Planum, a broad plain on the surface of Mars. Planners chose the site because it was known to contain hematite. Hematite is an iron-bearing mineral. On Earth, hematite generally forms in the presence of water. In 2013, Opportunity detected certain clay minerals that form only in the presence of water. This discovery was proof that liquid water once existed on the surface of Mars. This finding was confirmed by other Mars missions, such as NASA’s larger Curiosity rover, sent to Mars in 2011. Opportunity went on to learn that the water was similar to bodies of water on Earth, allowing for the possibility of life on Mars.

Huge dust storms occasionally blanket the surface of Mars. A particularly intense storm occurred in mid-2018, causing NASA to lose contact with Opportunity. The dust blocked out the sun and covered the rover’s solar panels, making it impossible for Opportunity to keep its core systems warm. Even after the skies cleared, there was no response from the rover. The bitterly cold temperatures on Mars—about -80 °F (-60 °C) on average—can damage and destroy electronics.

The end of Opportunity is not the end of humankind’s robotic presence on Mars. Curiosity continues to roll along. InSight, a non-mobile lander also launched by NASA, is currently studying the interior structure of Mars. And in 2021, two new rovers will launch: NASA’s Mars 2020 rover and Rosalind Franklin, a rover developed by the European Space Agency (ESA) and Russia’s state space agency, Roscosmos. (Rosalind Franklin was a British chemist famous for her studies of molecules and crystals.) The new rovers will try to find out if Mars held life at some point in its distant past. Thanks to the hard work of Opportunity and the mission’s engineers and scientists, we know it is a possibility.

December 16, 2013

With the touchdown of the Chang’e-3 spacecraft, China has become the third country to “soft land” an unpiloted spacecraft on the moon. In a soft landing, the craft and its equipment are not damaged during the landing and so can be used for observation and scientific experiments. The last unpiloted soft landing on the lunar surface was made in 1976 by a craft launched by the former Soviet Union (now Russia). The Soviet Union also became the first country to soft-land a probe on the moon, in 1966. Surveyor 1, the first soft-lander from the United States, touched down later in 1966. The success of the Change’e mission not only advances Chinese efforts to explore the moon but also efforts to eventually land taikonauts (astronauts) on the lunar surface.

The Chinese rover Jade Rabbit appears on the surface of the moon in a photograph taken by the Chang'e lander. (CCTV.com English)

Several hours after landing, Chang’e-3 released a rover named Jade Rabbit (Yutin in the Mandarin Chinese language). In Chinese mythology, Chang’e is a moon goddess who is accompanied by a jade rabbit. The six-wheeled rover, which weighs about 300 pounds (135 kilograms), is powered by solar energy during the day and batteries at night. It is scheduled to study the geology of the lunar surface and search for minerals and other natural resources for three months. The landing craft is expected to conduct experiments and observations from its touchdown site in Sinus Iridum (the Bay of Rainbows) for a year.

Additional World Book articles:

• National Aeronautics and Space Administration (NASA)
• Space exploration
• Space exploration (2012) (a Back in Time article)
• Space exploration (2008) (a Back in Time article)
• Space exploration (2003) (a Back in Time article)

March 14, 2013

Mars once had an environment that could have been hospitable to microbial life, according to new findings by Curiosity, the most advanced rover to ever reach the red planet. The discovery by the rover, formally known as the Mars Science Laboratory (MSL), was announced by the National Aeronautics and Space Administration (NASA) this week. Since landing on Mars in 2012, Curiosity has added to the evidence from other rovers and space probes that Mars was a very different planet in the distant past than the wasteland we see today.

For its latest activity, Curiosity examined rock samples drilled from an area thought to have been part of a Martian river system at one time. The samples proved to be partially made of a type of clay that suggests conditions similar to those needed for life on Earth. Furthermore, many chemicals identified in the sample are also essential for life, including nitrates and nitrites, two chemicals used for energy by microbes on Earth.

The new findings are significant in that they show Martian water that was nearly neutral, not too acidic and not too alkaline. Earlier samples collected from other regions of the planet had found evidence of water that was less friendly to life. The discovery of nitrates and nitrites also revealed a possible source of energy for developing microbes.

A hole in a rock called "John Klein" is the site of Curiosity's first sample drilling on Mars. The drilling took place on Feb. 8, 2013. The hole is 0.63 inch (1.6 centimeters) in diameter and 2.5 inches (6.4 centimeters) deep. (NASA/JPL-Caltech/MSSS)

Many scientists think that even though the surface of Mars may not have been ideal for life, there is a possibility that life may have developed early in the planet’s history and adapted to living underground.

Additional World Book articles:

• Microbiology
• Probing the Planets (a special report)
• The Search for Water on Mars (a special report)
• Space exploration (2003) (a Back in Time article)

September 28, 2012

Rounded pebbles photographed by Curiosity, NASA’s newest Mars rover, are direct evidence that a deep, fast-moving stream of water once flowed across Gale Crater, the rover’s landing site, scientists announced on September 27. Curiosity scientists said the pebbles had been eroded and smoothed out while being carried down a stream or river that ran for perhaps 25 miles (40 kilometers) across the Martian surface. “This is the first time we’re actually seeing water-transported gravel on Mars. This is a transition from speculation about the size of streambed material to direct observation of it,” said science co-investigator William Dietrich of the University of California, Berkeley. The pebbles are too big to have been blown to the site by the wind. By comparing the size and shape of the Martian pebbles to pebbles found in streambeds on Earth, Curiosity scientists determined that the water on Mars was moving about 3 feet (0.9 meter) per second with a depth somewhere between ankle and hip deep. The largest and most advanced robotic laboratory ever sent to another planet, Curiosity is designed to answer one of the most important questions in planetary science–whether Mars is, or ever has been, capable of supporting microbial life.

The rounded pebbles found on Mars (left) are similar to rocks transported and cemented together by water on Earth (right). Some of the rocks are several inches (centimeters) wide. (NASA/JPL-Caltech/MSSS and PSI)

The pebbles were found in two tilted conglomerates named Hottah and Link. Conglomerates are rounded pebbles embedded in a fine-grained material. Scientists described Hottah as looking like a “jack-hammered … slab of city sidewalk.” The conglomerates lie about halfway between the north rim of Gale Crater and Mount Sharp, the rover’s ultimate destination. From the many channels found at the base of the rim, the scientists determined that the water flows may have lasted for thousands, even millions of years. “A long-flowing stream can be a habitable environment,” said Mars Science Laboratory Project Scientist John Grotzinger of the California Institute of Technology in Pasadena.

Scientists have long believed that water apparently has existed near the surface of Mars over part of the planet’s history. Evidence collected by spacecraft has suggested that liquid water apparently carved Mars’s large channels, smaller valleys, and young gullies. Scientists also concluded that vast quantities of ice exist within about 3 feet (1 meter) of the surface near the south pole and perhaps near the north pole. They also theorized that water is probably present beneath the surface today, kept liquid by Mars’s internal heat.

The water in the ancient streambed found by Curiosity likely flowed into Gale Crater from a channel called Peace Vallis. As the water flowed over the rim of the crater, it created an alluvial fan, a fan-shaped deposit of layered gravels, sands, silts, and other materials. Curiosity's landing site is marked by a cross in the black oval. (NASA/JPL-Caltech/UofA)

Additional World Book articles:

• Mars Exploration Rover Mission
• Mars Pathfinder
• Phoenix (spacecraft)
• Space exploration (Probes to Mars)
• The Search for Water on Mars (a Special Report)

September 14, 2012

After “flawlessly” completing a series of instrument tests this week, Curiosity, NASA’s newest Mars rover, was scheduled to resume its journey across the surface of the red planet Friday evening. So far, Curiosity has traveled 269 feet (82 meters) across Gale Crater, its landing site. After this short drive, Curiosity’s controllers began testing its operating systems and 10 scientific instruments. Curiosity’s next target is Glenelg, a rocky spot in the crater. The rover will study the area with a high-resolution camera and a spectrometer, which determines the level of chemical elements in rock and soil. The largest and most advanced robotic laboratory ever sent to another planet, Curiosity is designed to answer one of the most important questions in planetary science–whether Mars is, or ever has been, capable of supporting microbial life.

A pebble about 3 inches (8 centimeters) in diameter dominates an image of the Martian surface taken by Curiosity's high-resolution Mars Hand Lens Imager (MAHLI). The patch of ground shown is about 34 inches (86 centimeters) across. (NASA/JPL-Caltech/Malin Space Science Systems)

Curiosity's Alpha Particle X-Ray Spectrometer (APXS) (center) can determine the abundance of chemical elements in rocks and soil. (NASA/JPL-Caltech/Malin Space Science Systems)

The rover’s prime target is Mount Sharp (also known as Aeolis Mons), a mysterious 3-mile- (5-kilometer-) high mountain in Gale Crater. Mount Sharp consists of layers of rock that may have been laid down over billions of years. Although the mountain looks similar to layered mountains on Earth, scientists do not know how it formed. As the rover scales the mountain, it will analyze the layers in an attempt to discover how Mars, which was once warmer and wetter, became so cold and dry.

Three of Curiosity's left wheels appear in a composite image made by the MAHLI. The lower slopes of Mount Sharp, the rover's ultimate destination, appear in the distance. (NASA/JPL-Caltech/Malin Space Science Systems)

Additional World Book articles:

• Mars Pathfinder
• Phoenix [spacecraft]
• Space exploration (Probes to Mars)
• The Search for Water on Mars (a Special Report)

A new Mars rover named Curiosity lifted off for the red planet atop an Atlas 5 rocket from Cape Canaveral in Florida on November 26. The rover’s mission is to answer one of the most exciting questions in planetary science–whether Mars is, or ever has been, capable of supporting microbial life. The rover is scheduled to land on Mars in August 2012, after spending 8 ½ months traveling some 354 million miles (570 million kilometers) through space.

A channel on Mars that may have been carved by flowing water appears in this photograph from the European Space Agency's Mars Express orbiter. Images taken by the orbiter showed evidence of water on Mars both now and in the planet's past. Photo courtesy European Space Agency.

Officially named the Mars Science Laboratory, the car-sized rover carries a scientific payload about 10 times as massive as those carried by NASA’s three previous Mars rovers. Curiosity, which has been described as a self-contained geology laboratory, holds eight sophisticated instruments powered by a nuclear generator. Two of the instruments were provided by Spain and Russia. Unlike earlier rovers, Curiosity will be able to gather samples of rock and soil, process them, and then distribute them to on-board instruments. The rover is set to land in Gale Crater, near the foot of a 3-mile- (5-kilometer-) high mountain whose lower layers contain minerals that formed in water.

Scientists are anticipating the complex process of getting Curiosity onto the Martian surface as “six minutes of terror.” When Curiosity is about 1 mile (1.7 kilometers) above the surface, a rocket-powered platform called the “sky crane” will drop from the protective shell holding the rover. After flying Curiosity to Gale Crater, the sky crane will lower the rover by tether.

Additional World Book articles:

• Mars Pathfinder
• Phoenix [spacecraft]
• Space exploration (Probes to Mars)
• The Search for Water on Mars (a Special Report)