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.

January 16, 2019

On January 1, the United States National Aeronautics and Space Administration (NASA) probe New Horizons flew by a 21-mile- (34-kilometer-) long rock at the outer reaches of our solar system. The probe took the rock’s first “close-up” photos, revealing details of the snowman-shaped space object, called 2014 MU69 or “Ultima Thule.” The term Thule was used by ancient European cartographers to describe the farthest northern lands of Earth. Ultima Thule (farthermost Thule) once described areas beyond the known world. Ultima Thule, then, is a fitting name for the distant object: it is 4 billion miles (6.5 billion kilometers) from Earth.

The New Horizons spacecraft took this photo of Ultima Thule on Jan. 1, 2019, from a distance of some 18,000 miles (28,000 kilometers). Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

New Horizons is the first spacecraft to study Pluto and the Kuiper belt, a band of icy bodies largely beyond the orbit of the planet Neptune. New Horizons flew past Pluto in July 2015, revealing a surprisingly varied and geologically active world. Despite its distance from the sun, Pluto has been molded and shaped by many of the same forces that created the eight planets of our solar system.

With the flyby of Ultima Thule, New Horizons became the first spacecraft to visit an object discovered after the spacecraft was launched. The craft blasted off from Cape Canaveral Air Force Station in Florida in 2006. Astronomers discovered Ultima Thule in 2014.

This NASA illustration shows New Horizons encountering 2014 MU69–“Ultima Thule.” Credit: NASA/JHUAPL/SwRI

What’s so special about Ultima Thule? It may look like just another space rock, but it is far different from the asteroids and comets found closer to the sun. The solar system’s planets and other inner objects have been transformed by the sun’s extreme heat, by catastrophic collisions, and by immense gravitational pressures. Ultima Thule and other Kuiper belt objects (KBO’s) are like frozen time capsules that show how things looked as the solar system was forming. The first grainy photographs of Ultima Thule show an object made up of two lobes that likely came together in a walking-speed “collision”—a rather serene birth in an otherwise violent universe.

New Horizons has completed its study of Ultima Thule, but NASA expects to learn more about the distant object over the next 20 months or so as information continues to trickle in. It takes a while for data to be transmitted across the immense distance to Earth. And this may not be the last distant flyby for New Horizons. NASA is searching for other space objects to visit before New Horizons runs out of power in the mid-2030’s.

November 9, 2018

On Oct. 20, 2018, an Ariane 5 rocket blasted off from French Guiana, an overseas possession of France on the northern coast of South America. The rocket carried a pair of probes bound for Mercury, the planet in our solar system closest to the sun, as part of a mission called BepiColombo. The mission’s name honors Giuseppe “Bepi” Colombo, an Italian scientist who contributed greatly to the study of Mercury. ESA missions frequently launch from French Guiana at a site called Europe’s Spaceport. The site’s remote geographic location offers advantages in launch trajectory as well as a “slingshot effect” created by the speed of Earth’s rotation near the equator.

The Mercury Planetary Orbiter is one of two probes included in the BepiColombo mission that will study the planet Mercury. Credit: ESA/ATG medialab

The European Space Agency (ESA) developed and organized the BepiColombo mission. ESA led the construction of the Mercury Planetary Orbiter (MPO), the main probe. But two other space agencies contributed to BepiColombo. The United States National Aeronautics and Space Administration (NASA) built an instrument called a mass spectrometer for the MPO. And the Japan Aerospace Exploration Agency (JAXA) built the mission’s second orbiter, the Mercury Magnetospheric Orbiter (MMO). Magnetosphere is the zone of strong magnetic forces that surrounds a heavenly body.

BepiColombo will study Mercury, the innermost planet of the solar system. Credit: NASA Goddard

Mercury, about 48 million miles (77 million kilometers) from Earth, is not a well-studied planet. Only two NASA spacecraft—Mariner 10 and MESSENGER—have reached it so far. In 1974 and 1975, Mariner 10 discovered that Mercury has a strong magnetic field. Scientists had previously thought the planet too small to host a magnetic field. Japan’s MMO is specially designed to study this feature. MESSENGER, which orbited Mercury from 2011 to 2015, learned many things about the scorched planet’s surface and confirmed that water ice existed in permanently shadowed craters at its poles.

Mercury’s magnetic field hints at our solar system’s turbulent early history and unusual composition. Most planetary systems have planets all about the same size and spaced evenly apart. In our solar system, Jupiter, the largest planet, is almost 25,000 times larger than Mercury, the smallest. Mercury might once have been larger, but layers of the planet’s surface could have worn away over billions of years. Alternatively, the planet may simply be the remnant of a collision of earlier inner planets. The BepiColombo mission hopes to learn more about Mercury as well as the formation of our solar system.

BepiColombo is powered by ion propulsion, a method of propelling space vehicles by ejecting charged particles called ions. Ion propulsion increases travel time compared to traditional chemical propulsion, but it costs much less. Ion propulsion also allows a probe to avoid the sun’s powerful gravitational field by taking a long, winding path to Mercury’s orbit. BepiColombo will fly by Earth once, Venus twice, and Mercury six times before it finally enters into orbit around the planet in late 2025.

October 3, 2018

With reusable rockets, frequent launches, and a grand vision, SpaceX is changing the nature of spaceflight.

Space Exploration Technologies Corporation (commonly called SpaceX), a United States commercial rocket company, is on a roll. The company, founded and led by South Africa-born entrepreneur Elon Musk, has had a perfect launch record since the 2016 explosion of one of its rockets during a launch pad test. So far in 2018, SpaceX has executed stunning launches, made splashy announcements, and conducted important engineering upgrades to further its mission to make space more accessible.

Space X’s Falcon Heavy launches from Florida’s Kennedy Space Center on Feb. 6, 2018. Credit: SpaceX

Driving past Mars thanks to the Falcon Heavy

When most people want to get rid of an old car, they might trade it in for credit toward a new one, tow it to a junkyard, or donate it to charity. On February 6, Elon Musk took a different route with his old Tesla Roadster: launching it into space. Musk sent the car into an elliptical orbit around the sun, traveling as far out as the main asteroid belt. The whimsical cargo was, in fact, part of an important mission. It was the test payload for the first launch of SpaceX’s new rocket, called the Falcon Heavy. It was the most powerful rocket launch since those of the U.S. space shuttle program.

The Falcon Heavy launched into space a Tesla Roadster, seen here with Earth in the background, piloted by a dummy driver named “Starman.” Credit: SpaceX

The rocket used three modified boosters from SpaceX’s workhorse rocket, the Falcon 9. The two side boosters were “flight-proven” Falcon 9 boosters from previous missions, having landed back on Earth near the launch pad or on one of the company’s drone ships (uncrewed barges) at sea. After sending the central booster into the upper atmosphere, the side boosters returned to Earth in a spectacular tandem landing. The center booster attempted to land on a drone ship in the Atlantic Ocean, but not enough of the rocket engines fired during its descent. It slammed into the water a short distance away from the barge and was destroyed.

A Falcon 9 rocket prepares to land on a drone ship in the Atlantic Ocean on April 8, 2016. Credit: SpaceX

Reusable rocket

The failure of SpaceX to land the center booster of the Falcon Heavy was the first such failed attempt since June of 2016. Since the company’s first successful booster landing in 2015, it has become a common—albeit still spectacular—occurrence. The first stage boosters represent 60 percent of the cost of the rocket, so reusing a booster saves millions of dollars. The company plans to reuse more parts of spacecraft in the future. Several times, SpaceX has narrowly missed catching payload fairings (the clamshell-like halves of the rocket’s nose that fall back to Earth) using a boat equipped with a huge net.

A recycled SpaceX Falcon 9 rocket launches from Florida’s Kennedy Space Center on March 30, 2017. Credit: SpaceX

SpaceX has succeeded in bringing launch costs down by repeatedly landing and reusing its boosters, something that no other company or space agency has been able to do (the U.S. space shuttle program featured partly reusable components, but they required extensive repair and refurbishment after each flight). In 2013, when SpaceX executed its first commercial space flights, the company’s launches represented less than 10 percent of space traffic that year. In the first three quarters of 2018, SpaceX has already flown 16 times—more than 60 percent of the current traffic market. Much of the company’s increase has come at the expense of Russia, whose state-operated space company, Roscosmos, has been marred by scandals and rocket malfunctions.

At Cape Canaveral Air Force Station in Florida, the SpaceX Falcon 9 rocket carrying NASA’s Transiting Exoplanet Survey Satellite (TESS) lifts off on April 18, 2018. Credit: SpaceX

SpaceX runs itself more like a technology startup than a traditional rocket manufacturer. In addition to saving money in the short term, landing the boosters has allowed SpaceX engineers to examine them and determine which pieces functioned well and which needed redesign, so the Falcon 9 is continuously retooled and upgraded. On May 11, SpaceX launched the first Block 5 version of the Falcon 9 in a mission to put a commercial satellite in orbit. The Block 5, which the company considers the final major upgrade of the rocket, is designed for multiple reuses. So far, Falcon 9 boosters have only flown twice before being discarded. The Block 5 should be able to fly up to 10 times without significant refurbishment and as many as 100 times in total. The Falcon 9 Block 5 flew a second time on August 7. The company hopes to eventually launch 60 Block 5′s per year after reuse is perfected.

Internet from space

In February, SpaceX put two satellites of their own into orbit. The two satellites, called Tintin A and Tintin B, were prototypes for a constellation meant to provide internet access from space. SpaceX calls this ambitious project Starlink. The company plans to launch some 4,500 Starlink satellites, almost equal to the total number of satellites (both working and defunct) orbiting Earth today. Starlink’s price tag will be at least $10 billion.

SpaceX’s Falcon 9 rocket lands at Cape Canaveral Air Force Station in Florida on Dec. 21, 2015. Credit: SpaceX

Satellite internet exists today, but it offers spotty, poor service. It is provided by a few large satellites in geostationary orbit (GSO), meaning they stay fixed in one place relative to the ground. Objects in GSO have to be far from Earth’s surface, making it hard to get a good connection. SpaceX plans to place Starlink satellites in low Earth orbit (LEO). So many satellites are needed because they will only be able to communicate with a small piece of Earth’s surface. On top of that, satellites in LEO are constantly moving relative to Earth’s surface. SpaceX will have to develop ways to transfer internet traffic from one satellite to another as they travel over locations on Earth.

If SpaceX can surmount these challenges, the payoff will be enormous. The connection quality from such a constellation would meet or exceed that from a traditional cable source. The connection would be just as strong on a desert island as it would be in the middle of a bustling city.

Elon Musk founded Space Exploration Technologies (SpaceX) in May 2002. Credit: NASA

Too Heavy

SpaceX has two Falcon Heavy launches scheduled in 2019, including an important test for the U.S. Air Force. If successful, this test launch would pave the way for the Heavy to launch lucrative military satellites. But the Falcon Heavy will have a much smaller role in SpaceX’s fleet than was initially planned. Strapping three Falcon 9 boosters together has proven much more complicated than SpaceX engineers anticipated, causing a five-year delay in the Falcon Heavy’s first launch.

The Falcon Heavy is also losing out to single Falcon 9′s, as SpaceX’s process of continuous upgrades has made the rocket stronger and more durable. The Falcon 9 Block 5 is twice as powerful as the first Falcon 9, capable of lifting over 55,000 pounds (22,000 kilograms) to low Earth orbit. This capability satisfies most companies’ needs for about $30 million less than the price of a Falcon Heavy launch.

BFR: moon tourists and a Mars colony

SpaceX engineers are also designing and building a new booster called the Big Falcon Rocket, or BFR. The BFR would be far and away the largest rocket ever created. Musk plans for it to replace both the Falcon 9 and Falcon Heavy. It will be much larger, but Musk claims it will cost less than a Falcon 9 launch, which is already relatively cheap. One BFR could launch multiple large satellites at once. Companies could create new, super-sized satellites that were impossible to launch before.

Even more flashy than the BFR, however, is the giant spaceship Musk wants to launch with it. The Big Falcon Spaceship (BFS) would be the largest spacecraft ever launched. Its interior space would be roughly equal to that of the International Space Station (ISS), but the ISS was constructed over many years through dozens of launches. Huge windows would give BFS explorers panoramic views of space. Musk plans to use the BFS for his ultimate goal of colonizing Mars.

The National Aeronautics and Space Administration (NASA) is working on similar large boosters and space capsules, and with little commercial demand yet, SpaceX is exploring new options for financing BFR and BFS development. On September 17, the company announced that it had reached an agreement with Japanese billionaire Yusaku Maezawa to “rent” the first crewed flight around the moon in a BFS. Maezawa, an avid art collector, will be inviting artists of all kinds to share the experience. Although the terms of the deal were not made public, Musk stated that Maezawa’s payment was “a nontrivial amount that will have a material impact on the BFR program.” The flight around the moon could happen as early as 2023, though Musk, who is infamous for his aggressive timelines, admitted even this date was “aspirational.” But development is well under way. The company hopes to begin testing the BFS with suborbital flights in late 2019.

Whether or not the BFR flies, no one can accuse SpaceX or Elon Musk of thinking small. Indeed, many experts doubted the company would be able to build a reusable rocket, yet within a decade it created the cheapest and one of the most reliable rides to space available. Plans will continue to change, and time frames will continue to stretch, but all the while SpaceX will continue to reach for the stars.

September 24, 2018

Earlier this year, in April, the European Space Agency (ESA) released the second trove of data gathered by the space probe Gaia (named after the ancient Greek goddess Gaia). Gaia’s precise measurements of the position, brightness, motion, and color of over 1.3 billion stars will transform astronomers’ understanding of our galaxy, the Milky Way.

In this artist’s impression, Gaia maps the stars of the Milky Way. Credit: ESA/ATG medialab/ESO/S. Brunier

The Milky Way contains the sun, Earth, and other objects in our solar system. It also includes hundreds of billions of stars besides the sun. Huge clouds of gas and dust lie throughout the galaxy, and they constantly form new stars. The Milky Way is so massive that about 10 smaller galaxies orbit it like satellites revolving around a planet.

Because our solar system is located within the Milky Way, vast clouds of dust and dense swaths of stars prevent astronomers from determining the galaxy’s exact structure. It is a bit like trying to see the outside of one’s home from the inside. Until now, astronomers had to guess what the Milky Way looks like by observing other galaxies with similar traits—the equivalent of looking at other houses from a window. Astronomers know the Milky Way is a spiral galaxy, with long arms extending out from a central core. But no one knows how many arms it has, what kinds of stars the arms contain, or whether the galaxy is a traditional spiral or a subtype called a barred spiral galaxy where the central core is elongated.

The space probe Gaia will tell us if the Milky Way is a traditional spiral galaxy, as in this illustration, or a barred spiral galaxy with an elongated central core. Credit: Artwork © Jon Lomberg and the National Air and Space Museum

Gaia is like a flying drone taking photos around the neighborhood. Launched in 2013 by the ESA, Gaia traveled to a point behind Earth and began measuring the positions of over a billion stars. Gaia measures stellar distances using a technique called parallax. It first images a star against a background of other stars. Halfway around the sun, it takes another picture of the same star. Because the two pictures are taken from far distant positions, the star moves slightly in relation to its background. This is the same optical effect that makes an object at arm’s length to appear to change positions when viewed from just one eye or the other. Because scientists know how far away the two star pictures were taken, and how much the star appeared to move, they can precisely calculate its distance from Earth.

Gaia’s portrait of the Milky Way also extends into the fourth dimension—time. Over the course of its five-year mission, Gaia will map the sky 29 times. From those time-lapsed maps, astronomers can determine the speed and direction in which the galaxy’s stars and gas clouds are moving through space. This information tells us the origins of Milky Way objects and can even warn of galactic collisions or violent stellar explosions. This time-based study of the galaxy is called galactic archaeology.

Gaia is gathering more than just information about stars. The second data release also had the locations of 14,000 known asteroids within our solar system, allowing astronomers to precisely map their orbits. Future data releases will map even more solar system objects.

ESA released the first Gaia dataset in 2016. For each release, scientists have raced to mine the data for new discoveries. Usually, data from such spacecraft are temporarily reserved for scientists directly associated with the mission. But mission managers have released Gaia’s data to everyone at the same time. This has led to another impressive statistic: over 1,000 peer-reviewed scientific papers that use Gaia’s data have already been written since the first data release. Many thousands more will be written before all Gaia’s insights are revealed.

September 19, 2018

The sun is the center of our solar system and vital to life on Earth, but there is a lot we do not know about it. On August 12, the United States National Aeronautics and Space Administration (NASA) launched the Parker Solar Probe that will help unravel some of the the sun’s secrets. Over the next few years, the probe will orbit the sun at least 24 times and come blisteringly close to its surface. The probe will reach its first perihelion (the point of an orbit that is closest to the sun) on November 5.

In this NASA illustration, the Parker Solar Probe approaches the sun. The probe launched from Earth on Aug. 12, 2018, and will make its first close pass of the sun on November 5. Credit: NASA/Johns Hopkins APL/Steve Gribben

The Parker Solar Probe is record setting in many ways. It will come within 3.8 million miles (6.1 million kilometers) of the sun, closer than any spacecraft in history. The current record-holder, NASA’s Helios 2, came within 27 million miles (43 million kilometers) of the sun in 1976. (Helios was the god of the sun in Greek mythology.) In comparison, Earth orbits about 93 million miles (150 million kilometers) from the sun, and Mercury, the planet nearest the sun, orbits about 36 million miles (58 million kilometers) away.

The Parker Solar Probe will also be the fastest object ever created by humans—another record it will take from Helios 2—traveling at some 430,000 miles (700,000 kilometers) per hour. Its high speed comes from the huge gravitational pull of the sun. As an object nears the sun, the sun’s gravity accelerates it, much in the way a drain accelerates a circling toy boat.

The probe is also the first to be named after a living person. In 1958, American scientist Eugene Parker hypothesized that ionized atoms were streaming from the sun. He coined the term solar wind for this phenomenon. This explained why a comet’s tail points away from the sun, no matter which direction it is traveling—something that had been observed for centuries but never fully understood. NASA named the groundbreaking probe after Parker to honor his contributions to heliophysics, the study of the sun and its effects on space.

Not far from the sun’s surface, the solar wind speeds up to more than 155 miles (250 kilometers) per second. Scientists are hoping to use the Parker Solar Probe to understand how and why this happens. The probe will dip into the sun’s corona (outer atmosphere) during its closest approaches. Temperatures there reach an unimaginable 4 million °F (2.2 million °C), far hotter than the temperature at the sun’s surface (10,000 °F, or 5,500 °C). Measurements made by the probe will help make sense of this temperature difference.

Getting close to the sun is not easy. The Parker Solar Probe launched from a Delta IV Heavy rocket, one of the most powerful rockets ever built. But it launched in the opposite direction of Earth’s orbit, causing it to slow down in relation to the sun and fall towards it. It will also use the gravity of Venus to slow it down further. At seven different times throughout its mission, it will pass close to Venus, which will act as a brake and hurtle the probe closer to the sun.

Operating close to the sun is also difficult. The Parker Solar Probe is protected by a thick, carbon-composite heat shield that faces the sun at all times. The sun interferes with radio signals at such close range, so the probe must operate without human contact for much of the time. Even getting power is difficult so close to the sun. Of course, solar energy is plentiful, but the scorching temperatures can fry solar cells. Parker’s panels will peek out from behind its heat shield only when the craft is at a safe distance, and they retract as the probe nears the sun.

Improving our knowledge of solar science may help prevent disasters on Earth. Solar events called coronal mass ejections (CME’s) come from the corona and can damage satellites and electrical systems on Earth. Findings from the Parker Solar Probe may help scientists better predict CME’s, allowing officials to temporarily shut down power grids to prevent major damage.

September 10, 2018

One planet in our solar system might be a little wetter than we previously thought. A team of Italian scientists recently found evidence that a lake of liquid water most likely exists on Mars, buried deep beneath the planet’s southern polar ice cap. The team published its findings on July 25, 2018, in the journal Science.

Italian scientists recently found evidence of what they believe to be a liquid water lake beneath the southern polar ice cap of Mars, the fourth planet from the sun. Credit: NASA/JPL/Malin Space Science Systems

Mars is a very cold place. On average, the surface of the planet is about -80 °F (-60 °C). As on Earth, however, the poles are even colder. Both poles of Mars feature permanent caps of water ice that are more than 1 mile (1.6 kilometers) thick. In addition, the southern cap has a roughly 25-foot (8-meter) thick permanent covering of frozen carbon dioxide. The northern cap has a diameter of about 625 miles (1,000 kilometers), and the southern cap has a diameter of about 220 miles (350 kilometers). In the Martian winter, the caps expand as layers of carbon dioxide frost condense from the atmosphere.

Images such as this one, showing curved depressions in Mars’s Utopia Planitia region, prompted the search for subterranean water with ground-penetrating radar. Credit: NASA/JPL-Caltech/Univ. of Arizona

The team of scientists analyzed data from the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS), an instrument aboard the European Space Agency (ESA) probe Mars Express. Mars Express has been studying the surface of Mars since 2004. MARSIS is a ground-penetrating radar device. Ground-penetrating radar can detect underground features and objects beneath rock and ice. The radar waves reflect off liquid water, however, and for years MARSIS has returned many images with this tell-tale reflection beneath the planet’s south pole. At last, after ruling out other possibilities, the scientists concluded that the radar had found a triangular lake basin about 12 miles (19 kilometers) wide and 1 mile (1.6 kilometers) deep.

The Martian lake might be similar to Lake Vostok and other subglacial lakes on Earth. Lake Vostok, the largest lake in Antarctica, lies beneath 2.5 miles (4 kilometers) of ice, has been isolated for 35 million years, and has temperatures below the normal freezing point of water. But life still likely exists there. If life exists on Mars, it could likely be found in such subglacial lakes. The odds of finding life there are still long, however. The Martian lake would be dozens of degrees below the normal freezing point of water and filled with salts toxic to life on Earth.

As scientists pinch and probe Mars for life, they are also eager to search for life beneath other planetary ice in our solar system. Europa and Enceladus, moons of Jupiter and Saturn, have warm oceans beneath their icy exteriors, and present the best possible chances for extraterrestrial life. The search for life will involve drilling through ice, however, an incredibly complex task even here on Earth. Engineers will have to design a remotely operated drilling system that can withstand the stresses of launch, spaceflight, and landing; drill through massive layers of ice using only batteries or nuclear power; and capture, analyze, and return data to Earth—quite a list! The testing for such a drilling system will begin on our own planet’s subglacial lakes.

July 3, 2018

On July 1, Australia’s space industry blasted off into uncharted territory with the establishment of the Australian Space Agency. The agency aims to coordinate and develop Australia’s space industry to make it competitive on the global stage. In the near future, the Australian Space Agency will work with the National Aeronautics and Space Administration (NASA) in the United States, the European Space Agency (ESA), and other world space programs.

The Australian Space Agency will soon be funding its own continental “selfies.” Credit: © Harvepino/Shutterstock

In a May press release, Malcolm Davis of the Australian Strategic Policy Institute clarified that the Australian Space Agency will not be a “NASA Down Under.” Rather than building and launching space hardware and running space missions, the agency will aim to boost private investment in the space sector by helping drive funding, research, and policy initiatives.

Initially, the agency will be headquartered in Canberra, the capital, and will share space with the Department of Industry, Innovation and Science. Australia’s states and territories are bidding to build a permanent headquarters for the agency. Geologist Megan Clark, who formerly served as chief executive of Australia’s Commonwealth Scientific and Industrial Research Organization, will serve as the agency’s first leader.

April 24, 2018

Last week, on April 18, a next-generation planet-hunting satellite was carried into orbit. The Transiting Exoplanet Survey Satellite (TESS) was launched from Cape Canaveral in Florida. Designed by the United States National Aeronautics and Space Administration (NASA), TESS will search for exoplanets (planets orbiting stars beyond our solar system).

At Cape Canaveral Air Force Station in Florida, the SpaceX Falcon 9 rocket carrying NASA’s Transiting Exoplanet Survey Satellite (TESS) lifts off on April 18, 2018. Credit: SpaceX

TESS was carried into space by a SpaceX Falcon 9 rocket. After boosting the satellite into orbit, the first stage of the rocket landed on a crewless barge in the Atlantic Ocean and will be used again. When TESS reaches its desired orbit, it will undergo testing and calibration before it begins the search for exoplanets.

TESS will replace NASA’s planet-hunting satellite Kepler, which is almost out of fuel. Launched in 2009, Kepler has discovered thousands of exoplanets. Like Kepler, TESS will use the transit method to search for exoplanets. As an exoplanet passes in front of its parent star, it blocks out a tiny portion of the star’s light (an event called a transit). TESS can detect these telltale dips in the intensity of the light.

NASA’s Transiting Exoplanet Survey Satellite (TESS), shown here in a conceptual illustration, will identify exoplanets orbiting stars beyond our solar system. Credit: NASA Goddard Space Flight Center

Although TESS will use the transit method, it is far from a Kepler clone. TESS will study brighter stars than Kepler did. This means that all of TESS’s targets will be at most 200 light-years from Earth. Because TESS is limited to closer, brighter stars, it will be easier for astronomers to confirm the finds and perform follow-up studies. TESS will also be able to observe the whole sky, as opposed to Kepler’s ability to only study small sections of sky at a time. TESS will also focus its search on finding Earth-sized exoplanets, especially those that orbit their star in the habitable zone, the range of an orbit where liquid water may be present on a planet’s surface. Liquid water is necessary for all life on Earth.

One of the tools astronomers will use to follow up on TESS’s discoveries will be NASA’s James Webb Space Telescope (JWST). The JWST is the most powerful space telescope ever built. Due to launch in 2020, it will be able to search for possible signs of life on the planets that TESS finds. Another observatory will be the Characterizing Exoplanets Satellite (CHEOPS). Designed by the European Space Agency, CHEOPS will launch at the end of 2018. Rather than being strictly a planet hunter, CHEOPS will focus on studying the makeup of smaller exoplanets that have already been discovered. It will likely be able to better define some of the exoplanets TESS discovers.

Astronomers have long hoped to learn whether—and, if so, where—other life exists in the universe. With TESS, JWST, and CHEOPS, they will be able to pinpoint nearby exoplanets with potential for life. But it will likely take even more advanced telescopes to determine if the planets actually teem with living things, like Earth.