An image of Venus, made with data recorded by Japan’s Akatsuki spacecraft in 2016, shows swirling clouds in the planet’s atmosphere.
Credit: PLANET-C Project Team/JAXA

Venus is heating up—figuratively, that is. It has always been the hottest planet in the solar system, with surface temperatures of about 870 °F (465 °C). But new findings from the mysterious planet have been pouring in. Soon, a new generation of space probes will transform Venus from a sleepy solar system backwater to a bustling hub of scientific discovery.

Venus is the second planet from the sun. It is known as Earth’s “twin” because the two planets are so similar in size. The diameter of Venus is about 7,520 miles (12,100 kilometers). This diameter is about 400 miles (640 kilometers) smaller than that of Earth. No other planet comes nearer to Earth than does Venus. At its closest approach, it is about 23.7 million miles (38.2 million kilometers) away.

But Venus is better described as Earth’s evil twin, in respect to its withering conditions. In addition to the high temperatures, the atmospheric pressure is 90 times greater than that on Earth. Carbon dioxide makes up most of the atmosphere. The skies are strewn with clouds of sulfuric acid.

Scientists sent several probes to learn more about the planet in the 1960’s and 1970’s. But as space agencies learned of its inhospitable conditions, they concentrated their efforts elsewhere, particularly Mars. The last United States National Aeronautics and Space Administration (NASA) mission to study Venus, called Magellan, launched in 1990. Thus, scientists know relatively little about Venus, despite its close proximity to Earth and its similar size.

Despite the dearth of missions in recent years, planetary scientists continue to scan the planet with Earth-based instruments and reanalyze older data. They have returned surprising results.

Last year, a team of scientists announced that they had discovered a gas called phosphine in Venus’s atmosphere. Many living things on Earth produce phosphine; and scientists have not been able to identify any non-biological processes on Venus that might produce it. This raised the possibility that microbial life could exist in Venus’s atmosphere, where the conditions are much milder. But the discovery has been controversial. Other teams have failed to find any phosphine signature.

Last month, a team led by researchers at Queen’s University Belfast left the floating-Venusian-microbes idea high and dry. They found that Venus’s atmosphere does not contain enough water vapor to support life, irrespective of the presence of phosphine. The team determined that even the most extreme microbes on Earth require an environment with dozens of times more water than is available in Venus’s atmosphere.

Another recent study has shed light onto possible changing of Venus’s surface. Previously, Earth was the only rocky planet known to have a moving surface. A team lead by Paul Byrne, a professor at North Carolina State University, found evidence that parts of Venus’s surface might be slowly moving today. Earth’s crust slowly reshapes itself by a process called plate tectonics. Large pieces of the surface, called plates, subduct (sink) under one another, forming mountain ranges and other features. New crust forms along the ridges where the plates pull away from each other. In contrast, Byrne’s team found that pieces of Venus’s crust move like pack ice in polar oceans. Learning more about crust movement on Venus will help scientists understand how such processes develop on other planets, including Earth and exoplanets that might harbor life.

Last month, space agencies announced that not one, but three missions will be exploring Venus in the next 15 years. On June 2, NASA announced it is sending two mission to Venus. The missions were selected as part of part of NASA’s lower-cost Discovery Program. NASA expects to launch both missions between 2028 and 2030.

VERITAS (Venus Emissivity, Radio Science, InSAR, Topography, and Spectroscopy) will orbit the planet and map its surface with greater detail than ever before. It will allow scientists to better understand the planet’s features.

DAVINCI+ (Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging) consists of a sphere that will plunge through Venus’s thick atmosphere, studying the atmosphere’s composition. The DAVINCI+ mission planners are seeking evidence of an ocean of water that might have covered Venus’s surface eons ago.

There are other players in the new Venus boom. Last year, American company Rocket Lab announced plans to launch a small probe to Venus as early as 2023. And on June 10, just over a week after NASA’s selection DAVINCI+ and VERITAS, the European Space Agency (ESA) announced that it would also be sending a probe Venus. The EnVision orbiter will search for signs of current and former tectonic activity and the presence of a past ocean. EnVision is scheduled to arrive at Venus in 2034 or 2035.

The desire to learn more about Venus is fed by more than just curiosity about our nearest neighbor. Astronomers are looking for signs of life on exoplanets. But Venus and Earth would look quite similar from light-years away. Learning more about Venus and how it evolved to become so different from Earth will help astronomers better weed out Venus-like exoplanets in their search for ones that are more like Earth.

British businessman Richard Branson poses in front of the spaceplane VSS Unity with the other missions specialists of Virgin Galactic’s Unity-22 mission. The glass-paneled terminal of Spaceport America is visible in the background. From left to right: Beth Moses, Chief Astronaut Instructor; Branson; Sirisha Bandla, Vice President of Government Affairs and Research Operations; Colin Bennett, Lead Operations Engineer.
Credit: © Virgin Galactic

After years of delay, the age of space tourism may finally be upon us. On Sunday morning, the British businessman Richard Branson flew aboard his company Virgin Galactic’s spaceplane in a suborbital flight. Soon, paying customers will get their turn to go to space.

Branson rode with five other members of his company on VSS Unity.VSS Unity is a SpaceShipTwo model spaceplane. A special aircraft called a WhiteKnightTwo takes off from a runway carrying a SpaceShipTwo. A WhiteKnightTwo named VMS Eve took off from Spaceport America in New Mexico and carried VSS Unity up above 45,0000 feet (14,000 meters). After Eve released Unity, pilots ignited a rocket engine and the craft soared up to 300,000 feet (90,000 meters). After a few minutes of weightless freefall, Unity glided back down to Earth. The whole flight lasted about 90 minutes.

Branson and the other mission specialists float around the cabin of VSS Unity during the spaceplane’s July 10 flight.
Credit: © Virgin Galactic

Branson has always relished spectacle, and Sunday’s flight was no different. Virgin Galactic’s live stream of the event was hosted by the American comedian Stephen Colbert. The landing featured the debut performance of “New Normal”, a new song by American singer Khalid. South-African-born entrepreneur and fellow space baron Elon Musk (founder of SpaceX) was among the well-wishers at Spaceport America.

Branson’s flight is a hopeful milestone on Virgin Galactic’s long, fraught road toward commercial operations. Branson founded the company in 2004. He licensed the technology of the American aerospace company Scaled Composites, which won the Ansari X Prize that year for developing a rapidly reusable launch vehicle. Virgin Galactic unveiled SpaceShipTwo in 2006. But the next year, an explosion during a ground test killed three Scaled Composites employees and injured three others. In 2014, a SpaceShipTwo named VSS Enterprise broke apart during a test flight. The pilot was killed and the copilot seriously injured. Despite these setbacks, Virgin Galactic forged ahead. Unity was completed in 2016 and underwent several test flights prior to its mission Sunday.

Space tourism existed long before Unity’s flight on Sunday. In 2001, the American investment consultant Dennis Tito became the first space tourist, visiting the International Space Station (ISS) aboard a Russian Soyuz craft. Over the next several years, a handful of space tourists made similar trips. But they all paid tens of millions of dollars to buy extra seats aboard government-funded spacecraft.

Until about a week ago, it appeared that American businessman Jeff Bezos, not Branson, was going to be the first mogul to fly to space aboard his own spacecraft. Bezos, who made billions from his online shopping company Amazon, founded an aerospace company called Blue Origin in 2000. Bezos is scheduled to launch aboard his company’s reusable New Glenn rocket on July 20. Although Branson denied the existence of a race between the two, he added himself to Sunday’s flight, which was originally scheduled as a test flight, after Blue Origin’s announcement.

Virgin Galactic plans to hold two more test flights before starting paying trips, probably sometime in 2022. Then, it will begin scheduling rides for the 600 people who purchased tickets.

Space tourism will still be for the very wealthy. Virgin Galactic was selling tickets for $250,000 apiece before it paused ticket sales after the 2014 accident. Blue Origin has not yet begun selling tickets, but they are expected to be within the same range. So, if you’d like to go to space, save your pennies!

NASA’s Mars 2020 rover Perseverance
Credit: NASA/JPL-Caltech

Mars is one of the most difficult destinations to arrive safely at in the solar system, but you might not know it if you have been paying attention to the news lately. Earthlings are a perfect three-for-three on Mars missions this February. Two countries saw their first missions ever arrive at the Red Planet last week. Then yesterday, the United States National Aeronautics and Space Administration (NASA) landed the Mars 2020 rover Perseverance on the surface of Mars. This flotilla of missions to the Red Planet was facilitated by a favorable alignment in the middle of 2020 that brought the planet close to Earth.

On February 9, a spacecraft from the United Arab Emirates (UAE) arrived in orbit around Mars. The orbiter, called Hope or Amal, will map Martian weather on a planet-wide scale. Such mapping has never been attempted before. UAE became just the fifth country to reach the planet. All systems look good at the moment, but Hope is due to enter the orbit from which it will conduct its mapping in May. At that point, engineers will know for sure if the probe will be able to accomplish its mission.

Hot on Hope’s heels was an ambitious mission sent by the China National Space Administration (CNSA). The mission, called Tianwen-1, went into orbit around Mars the next day. The mission consists of an orbiter, a lander, and a rover. The lander and rover will attempt a landing in a few months. If CNSA successfully deploys Tianwen-1, China will become the third country to land a spacecraft on Mars and just the second to land a rover on Mars.

The last—but certainly not least—to arrive was Perseverance. The rocket carrying the beefy rover blasted off from Cape Canaveral in Florida on July, 30, 2020. Perseverance is the largest rover ever sent to Mars. It’s the size of a small automobile and weighs over 2,200 pounds (1,000 kilograms) on Earth.

Unlike China and the UAE, the United States is a Mars veteran. NASA has landed several successful missions there, including the still-operational sibling craft of Perseverance, the Mars Science Laboratory (MSL) rover Curiosity.

The design of Perseverance is based on that of Curiosity, which has been exploring Mars since 2012. Engineers used many extra components that were originally created as backups for Curiosity in case of manufacturing defects in the originals. But Perseverance is more than just a pile of spare parts. Jet Propulsion Laboratory (JPL) scientists and engineers modified—and beefed up—the design to fit Perseverance’s mission. Perseverance is about 5 inches (13 centimeters) longer and 278 pounds (126 kilograms) heavier than Curiosity.

No matter how many successful missions are under a space agency’s belt, getting a spacecraft to Mars is a heart-pounding ordeal. Landing on the Red Planet is especially challenging. Mars is a large planet, so its gravity pulls spacecraft towards it at high speed. It lacks a thick atmosphere like that of Earth, however, that spacecraft could use to slow down. Furthermore, retrorockets placed on the rover would scour the ground near the landing site and contaminate it with rocket exhaust.

JPL has developed a complex of system to land a large rover on the Martian surface, which was first used with MSL. A parachute slowed the craft after it entered the Martian atmosphere. A set of rockets then fired to hover the craft above the surface. Then, Perseverance was lowered to the ground on a tether. Mission planners call this complicated ride through the atmosphere, filled with opportunities for mission-ending disaster, “the seven minutes of terror.”

Perseverance touched down in Jezero Crater. Billions of years ago, the crater held a lake that was fed by a river system. Perseverance will explore this ancient river delta and search for signs of past life there.

Perseverance carries many sophisticated scientific instruments that will enable it study the geology and climate of the region. The rover is equipped with a special drill and sample vials. After studying the rock samples it has drilled, it will place them in sealed vials and cache (stow) them on the surface. Scientists hope to recover the cached vials and send them to Earth in an ambitious sample return mission in a decade or so.

Other special features included an upgraded autonomous driving package, which will enable Perseverance to pick its way through obstacles on its own to reach a target, and a small helicopter drone called Ingenuity that will look to demonstrate the first powered flight on a solar system body other than Earth. Expect to hear about more exciting discoveries—and see more stunning pictures of Mars—in the months and years ahead.

SpaceX’s Crew Dragon capsule sits atop a Falcon 9 rocket, in preparation for launch on May 27, 2020.
Credit: © SpaceX

A new era of human spaceflight began Saturday, May 30, as Space Exploration Technologies (commonly called SpaceX) launched its Crew Dragon capsule into space. (The launch was originally scheduled for Wednesday, May 27, when it was delayed due to bad weather.) The Dragon became the first private spacecraft ever to take astronauts into orbit. The mission, called the Demo-2 mission, transported National Aeronautics and Space Administration (NASA) astronauts Robert Behnken and Douglas Hurley to the International Space Station (ISS).

Astronauts Bob Behnken (left) and Doug Hurley (right) prepare for the first crewed launch of SpaceX’s Dragon capsule.
Credit: © SpaceX

Millions of people watched from home as SpaceX’s Falcon 9 rocket launched the Dragon from the Cape Canaveral Air Force Station into space. In orbit, the crew tested the spacecraft’s control systems to make sure the capsule was performing as intended before its arrival at the ISS. The Dragon features various modern technologies in its engineering and construction. Unlike previous spacecraft, it has a touchscreen control interface that looks similar to those used in the popular science fiction television series Star Trek.

The International Space Station (ISS)
Credit: NASA

An important part of the mission was docking the Dragon to the ISS. The capsule reached the ISS on Sunday, May 31, about 24 hours after launch. Aboard the space station, Behnken and Hurley will perform research and other tasks with the rest of the ISS crew. They will remain on the ISS for one to four months before undocking the Dragon and re-entering Earth’s atmosphere. The capsule will land in the Atlantic Ocean, where the crew will be retrieved and returned to Cape Canaveral, completing the mission.

If the Demo-2 mission is successful, NASA will certify the Crew Dragon to regularly transport astronauts to the ISS. Since NASA’s space shuttle program ended in 2011, the administration has relied on Russia’s Soyuz spacecraft to transport astronauts to and from the ISS. The Soyuz can transport up to three astronauts at a time, and NASA pays about US $86 million per seat. The Dragon is able to transport up to seven astronauts at once, and the cost per crew member is expected to be around $55 million.

November 25, 2019

This month, scientists at the United States National Aeronautics and Space Administration (NASA) released their latest findings from decoded transmissions sent from the space probe Voyager 2 in interstellar space (the space between the stars). About a year ago, Voyager 2 became the second spacecraft (following its twin, Voyager 1) to enter interstellar space, exiting the heliosphere, a vast, teardrop-shaped region of space containing electrically charged particles given off by the sun.

Voyager 2, seen here passing Neptune in 1989, entered interstellar space in late 2018. Credit: © Mark Garlick, Science Source

The sun and all the planets are inside the heliosphere. Scientists estimate that the nose (blunt end) of the heliosphere is about 9 billion to 15 billion miles (15 billion to 24 billion kilometers) from the sun. Voyager 1, launched in September 1977, crossed the boundary from heliosphere to interstellar space in 2012. The crossing was marked by a steady drop in temperature and an increase in the density of charged particles known as plasma. Voyager 1 also detected an abundance of cosmic rays (particles accelerated by exploding stars) in interstellar space and provided evidence that the heliosphere protects Earth and the other planets from much interstellar space radiation.

This artist’s depiction shows the approximate locations of the two Voyager spacecraft relative to the sun, the bright spot in the center, in the mid-2010′s. In 2012, Voyager 1, shown as the upper probe in the image, sailed beyond the heliopause and into interstellar space. Voyager 2, the lower probe in the image, crossed the heliopause in 2018. Credit: NASA/JPL-Caltech

Voyager 2 was launched a month before Voyager 1 in August 1977. Slightly slower than its twin craft and following a different course, Voyager 2 reached the heliopause (the edge of the heliosphere) in November 2018. Voyager 2 also detected changes in temperature and plasma and cosmic ray density, but the heliosphere at Voyager 2′s crossing point appeared to be sharper and thinner. This could be explained by Voyager 2 crossing the heliopause at a different location or at a less angled trajectory or by crossing during a period of lower solar activity than that experienced by Voyager 1 in 2012. The sun goes through a roughly 11-year cycle of high and low activity, theoretically causing the heliosphere to expand and contract or thicken and thin. Both spacecraft found that particles from the sun are trickling through the somewhat porous heliopause into interstellar space. Voyager 2 also confirmed Voyager 1′s detection of similar magnetic fields on both sides of the distant boundary.

This artist’s impression shows Voyager 1 passing through the heliopause in 2012. Credit: NASA/JPL-Caltech

Both Voyager space craft are powered by slowly decaying plutonium. In 1977, scientists did not know exactly how long the space probes would continue to operate, nor did they know if, when, or where they would reach interstellar space. Now that the probes are there, scientists hope to learn more about the distant realm before the Voyagers power down sometime in the next few years. Voyager 1 is currently more than 13.6 billion miles (22 billion kilometers) from the sun, and Voyager 2 is about 11.3 billion miles (18.2 billion kilometers) away. After they lose power, scientists expect both to continue sailing through space for billions of years.

Click to view larger image
The path of  Voyager 2 is shown in red. Voyager 2 flew past Jupiter in 1979, Saturn in 1981, Uranus in 1986, and Neptune in 1989. Credit: WORLD BOOK illustration by Ken Tiessen, Koralik Associates

October 23, 2019

Last week, on Friday, October 18, the United States astronauts Christina Koch and Jessica Meir made history by performing the first spacewalk in which all the participants were women. Before then, all spacewalks had involved at least one man. That includes the first spacewalk by a woman, which was performed in July 1984 by the Soviet cosmonaut Svetlana Savitskaya, who was accompanied by Vladimir Dzhanibekov. In October 1984, Kathryn D. Sullivan became the first U.S. woman astronaut to conduct a spacewalk (with the mission specialist David Leestma).

NASA astronaut Christina Koch. Credit: NASA

The National Space and Aeronautics Administration (NASA) did not intentionally plan the first all-woman spacewalk. Rather, it was the natural result of an increasing number of women astronauts in the space program. Last Friday, Koch and Meir worked outside the International Space Station (ISS) for more than seven hours, replacing a crucial battery charger. The batteries power the ISS during the night portions of its orbits, which occur about every 45 minutes.

NASA Astronaut Jessica Meir. Credit: NASA

NASA had planned for Koch and another U.S. woman astronaut, Anne McClain, to conduct a spacewalk in March. But NASA did not have two appropriately sized spacesuits, and McClain was replaced by a male astronaut who “fit the suit.” In the following months, NASA delivered more varied spacesuit pieces to the ISS to reduce the likelihood of future sizing conflicts.

Koch and Meir’s spacewalk represents an important move toward gender parity in the U.S. space program. In privately-funded tests conducted in the early 1960’s, several women passed the same rigorous physical examinations that the male Mercury astronauts had passed. But NASA had no interest in selecting female astronauts at the time. No women were selected for the Mercury, Gemini, or Apollo missions. It was not until 1983 that the first woman U.S. astronaut, Sally Ride, reached space.

NASA has made strides to correct the gender imbalance in recent years. The 2013 astronaut class that produced Koch and Meir was the first class to have as many women as men (four each). The space agency is working towards returning astronauts to the moon in 2024 through the new Artemis program. NASA stated that at least one woman will walk on the moon.

Koch and Meir have stellar resumes that compelled NASA to select them for the astronaut training program. Both had done scientific work in Antarctica. Koch is an electrical engineer and helped develop a scientific instrument on the Juno mission to Jupiter. Meir has a Ph.D. in marine biology and has studied how penguins and other animals conserve oxygen in extreme environments. She raised a group of bar-headed geese from hatchlings so they would be comfortable with her during experiments. Even the two women’s hobbies prepared them for the spacewalk. Koch is an avid rock climber, having developed the climbing and tether safety skills similar to those needed for working outside a spacecraft. Meir enjoys underwater diving, where conditions are somewhat similar to those experienced during a spacewalk.

September 13, 2019

Last week, on September 6, an up-and-coming space agency fell just short of its goal. About 1 mile (1.5 kilometers) above the moon’s surface, the India Space Research Organization (ISRO) lander Vikram deviated from its landing course and disappeared from radio contact. Vikram was to be the crowning stage of Chandrayaan-2 (Mooncraft-2), ISRO’s second lunar mission.

This artist’s depiction shows Chandrayaan-2′s lunar lander, Vikram, approaching the moon. Credit: © Raymond Cassel, Shutterstock

India was endeavoring to become the fourth country to make a soft landing (a landing that does not destroy the craft) on the surface of the moon, after the United States, the former Soviet Union, and China. Vikram would have been the first lander near the moon’s south pole, a region full of water ice and other minerals that could one day be the site of a permanent base. Vikram would have deployed a rover to explore the landing site. The Chandrayaan-2 orbiter, which had launched Vikram, located the lander on the surface of the moon a few days after its disappearance. ISRO reported that Vikram had apparently made a “hard landing,” and the lander did not respond to contact attempts.

Before the recent failure, ISRO had been riding a wave of success. In 2008, the agency deployed its first lunar satellite, Chandrayaan-1. Chandrayaan-1 mapped the moon’s surface for about a year. The satellite also released a hard lander that impacted the lunar surface. In 2013, ISRO launched the Mars Orbiter Mission, called Mangalyaan (Marscraft). The satellite overcame a minor engine failure to reach Martian orbit in September 2014.

ISRO’s failed soft landing on the moon comes on the heels of another prominent lunar failure. In April 2019, the lander Beresheet (In the Beginning), developed by the Israeli company SpaceIL, slammed into the moon when its main engine cut out unexpectedly. SpaceIL had hoped to become the first private company to place a lander on the moon’s surface. It had been one of the competitors for the Google Lunar X Prize. The contest would have awarded $20 million to the first company to achieve a soft landing on the moon. But none of the competitors attempted a landing, even after several deadline extensions, so the prize was withdrawn. The Israeli project cost about $100 million, a fraction of what a similar mission by the United States National Aeronautics and Space Administration (NASA) would have cost, but it took greater risks and ultimately failed.

The process of landing is the most dangerous phase of a lander’s mission. Many different systems must work perfectly for the lander to bring itself to a halt on the surface. Any malfunction is usually catastrophic. At other points in a mission, such as in transit to or in orbit around another body, engineers have plenty of time to identify and work around problems with a spacecraft. But this cannot be done in the time-sensitive environment of landing.

May 20, 2019

What do you call an earthquake on Mars? A marsquake! For the first time, scientists working with the United States National Aeronautics and Space Administration (NASA) think they have detected an actual temblor on the red planet.

Scientists think they have detected marsquakes on Mars, the fourth planet from the sun. Credit: NASA/JPL/Malin Space Science Systems

At the end of 2018, NASA’s InSight probe deployed a specially-built seismometer called Seismic Experiment for Interior Structure (SEIS) to the surface of Mars. (InSight is short for Interior Exploration using Seismic Investigations, Geodesy, and Heat Transport. InSight launched from Earth in May 2018 and landed on Mars in late November.) On April 6, 2019, SEIS picked up faint vibrations that were not caused by wind or the movement of InSight’s robotic arm. The signal was faint, with a low-level magnitude between 1 and 2 on the Richter scale. On Earth, such a weak quake would go unnoticed. On Mars, however, InSight was there to feel it.

Mars is the third body on which humans have recorded seismic activity, after Earth and the moon. On Earth, quakes are caused by the bending and grinding of huge tectonic plates, which float on layers of soft rock and magma and hold the planet’s oceans and continents. Mars does not have tectonic plates. Marsquakes are likely caused by the shrinking of the planet’s interior, which itself is caused by the slow cooling of its core.

NASA’s InSight probe has been studying the surface of Mars since late November 2018. Credit: NASA/JPL-Caltech

While detecting marsquakes is exciting, readings from SEIS might also shed light on the structure of the red planet. Scientists have reason to think that Mars, like Earth, has an interior composed of a rocky outer crust, a soft mantle, a liquid outer core, and a solid inner core. But they do not know how thick each of the layers are. Seismic waves change direction slightly when passing through core layers. If scientists know the source of the seismic waves, they can get an idea of the kinds and sizes of layers the waves had to pass through to reach the seismometer. Scientists can then create a more accurate map of the Martian interior and gain insight into the structure of all rocky planets—including those in our solar system and those orbiting stars millions of light-years away.

InSight has many instruments in addition to SEIS. The probe also serves as the only weather station on another planet. Sensors track the brisk wind gusts, low pressures, and frigid temperatures of Elysium Planitia, a vast plain near the Martian equator. On May 11, the temperature climbed to -4 °F (-20 °C) during the day, but plummeted to -148 °F (-100 °C) during the Martian night. Wind speeds topped out at 32 miles (51 kilometers) per hour.

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.

March 20, 2019

In honor of Women’s History Month in the United States, World Book looks at the American mathematician Katherine Goble Johnson. For many years, Johnson worked for the National Aeronautics and Space Administration (NASA), where she performed notable spaceflight calculations. She calculated the trajectory (path) for Apollo 11, which made the first landing on the moon. As a black woman in a racially segregated United States, Johnson broke many racial and gender barriers to excel as a mathematician.

Katherine Johnson at her desk at NASA’s Langley Research Center in Virginia. Credit: NASA/LRC

Johnson was born on Aug. 26, 1918, in White Sulphur Springs, West Virginia. She was fascinated by numbers from a young age, and she excelled in her studies. In 1937, she received a bachelor’s degree in mathematics and French from West Virginia State College. She then took a job teaching mathematics at a grade school in Marion, West Virginia. In 1939, Johnson was selected to join West Virginia University’s graduate mathematics program. She enrolled, becoming the first black woman to attend the university.

In 1953, Johnson learned that the National Advisory Committee for Aeronautics (NACA) Langley Research Laboratory in Hampton, Virginia, was hiring women mathematicians. That summer, she was assigned to Langley’s West Area Computing unit, a group of black women mathematicians headed by Dorothy Vaughan. Johnson was soon reassigned to the Flight Research Division, where she analyzed data from flight tests. In 1958, NACA transitioned into NASA.

At NASA, Johnson and other Flight Research Division members were directly involved in the budding spaceflight program. In 1961, Johnson performed trajectory analysis for the Freedom 7 mission, investigating the route that was planned for the first U.S. human spaceflight. She also calculated the trajectory for astronaut John Glenn in his pioneering orbital flight around Earth in 1962. NASA’s new electronic computers had performed these calculations, but Glenn requested that Johnson personally check and approve them before the launch.

Johnson also calculated the exit and entry trajectories for the Apollo 11 mission, which landed the first two people on the moon in 1969. She authored or coauthored many research reports throughout her career. Johnson continued to make important contributions to NASA’s spaceflight program until her retirement in 1986. She has received multiple honors and awards. In 2015, President Barack Obama awarded her the Presidential Medal of Freedom. NASA’s Katherine G. Johnson Computational Research Facility—a data center at the Langley campus—was named in her honor in 2016. In 2019, NASA renamed its Independent Verification and Validation (IV&V) Facility the Katherine Johnson IV&V Facility.

American author Margot Lee Shetterly’s book Hidden Figures: The American Dream and the Untold Story of the Black Women Mathematicians Who Helped Win the Space Race (2016) chronicles Johnson’s life and career, along with those of other members of the West Area Computing unit. American actress Taraji P. Henson depicted Johnson in the 2016 film Hidden Figures, based on Shetterly’s book.