Buzz Aldrin stands on the moon in his puffy, white spacesuit next to an American flag waving in the wind. The command module casts a long, dark shadow nearby.

In the News

This year marks the 50th anniversary of humans landing on the Moon. Now NASA is headed to the Moon once again, using it as a proving ground for a future human mission to Mars. Use this opportunity to get students excited about Earth's natural satellite, the amazing feats accomplished 50 years ago and plans for future exploration.

How They Did It

When NASA was founded in 1958, scientists were unsure whether the human body could even survive orbiting Earth. Space is a demanding environment. Depending on where in space you are, it can lack adequate air for breathing, be very cold or hot, and have dangerous levels of radiation. Additionally, the physics of space travel make everything inside a space capsule feel weightless even while it's hurtling through space. Floating around inside a protective spacecraft may sound fun, and it is, but it also can have detrimental effects on the human body. Plus, it can be dangerous with the hostile environment of space lurking on the other side of a thin metal shell.

In 1959, NASA's Jet Propulsion Laboratory began the Ranger project, a mission designed to impact the Moon – in other words, make a planned crash landing. During its descent, the spacecraft would take pictures that could be sent back to Earth and studied in detail. These days, aiming to merely impact a large solar system body sounds rudimentary. But back then, engineering capabilities and course-of-travel, or trajectory, mathematics were being developed for the first time. A successful impact would be a major scientific and mathematical accomplishment. In fact, it took until July 1964 to achieve the monumental task, with Ranger 7 becoming the first U.S. spacecraft to impact the near side of the Moon, capturing and returning images during its descent.

Side-by-side images of a model of the Ranger 7 spacecraft in color and a black and white image of the Moon taken by Ranger 7.

These side-by-side images show a model of the Ranger 7 spacecraft (left) and an image the spacecraft took of the Moon (right) before it impacted the surface. Image credit: NASA/JPL-Caltech | › + Expand image

After the successful Ranger 7 mission, two more Ranger missions were sent to the Moon. Then, it was time to land softly. For this task, JPL partnered with Hughes Aircraft Corporation to design and operate the Surveyor missions between 1966 and 1968. Each of the seven Surveyor landers were equipped with a television camera – with later landers carried scientific instruments, too – aimed at obtaining up-close lunar surface data to assess the Moon's suitability for a human landing. The Surveyors also demonstrated in-flight maneuvers and in-flight and surface-communications capabilities.

Side-by-side image of an astronaut next to the Surveyor 7 lander and a mosaic of images from Surveyor 3

These side-by-side images show Apollo 12 Commander Charles Conrad Jr. posing with the Surveyor 7 spacecraft on the Moon (left) and a mosaic of images taken by Surveyor 3 on the lunar surface (right). Image credits: NASA/JPL-Caltech | › + Expand image

In 1958, at the same time JPL was developing the technological capabilities to get to the Moon, NASA began the Mercury program to see if it was possible for humans to function in space. The success of the single-passenger Mercury missions, with six successful flights that placed two astronauts into suborbital flight and four astronauts into Earth orbit, kicked off the era of U.S. human spaceflight.

Cutaway illustration of the Mercury capsule with a single astronaut inside.

The success of the single-passenger Mercury capsule, shown in this illustrated diagram, proved that humans could live and work in space, paving the way for future human exploration. Image credit: NASA | › Full image and caption

In 1963, NASA's Gemini program proved that a larger capsule containing two humans could orbit Earth, allowing astronauts to work together to accomplish science in orbit for long-duration missions (up to two weeks in space) and laying the groundwork for a human mission to the Moon. With the Gemini program, scientists and engineers learned how spacecraft could rendezvous and dock while in orbit around Earth. They were also able to perfect re-entry and landing methods and began to better understand the effects of longer space flights on astronauts. After the successful Gemini missions, it was time to send humans to the Moon.

Cutaway illustration of the Gemini spacecraft with two astronauts inside.

The Gemini spacecraft, shown in this illustrated cutaway, paved the way for the Apollo missions. Image credit: NASA | › Full image and caption

The Apollo program officially began in 1963 after President John F. Kennedy directed NASA in September of 1962 to place humans on the Moon by the end of the decade. This was a formidable task as no hardware existed at the time that would accomplish the feat. NASA needed to build a giant rocket, a crew capsule and a lunar lander. And each component needed to function flawlessly.

Rapid progress was made, involving numerous NASA and contractor facilities and hundreds of thousands of workers. A crew capsule was designed, built and tested for spaceflight and landing in water by the NASA contractor North American Aviation, which eventually became part of Boeing. A lunar lander was developed by the Grumman Corporation. Though much of the astronaut training took place at or near the Manned Spacecraft Center, now known as NASA’s Johnson Space Center, in Texas, astronauts practiced lunar landings here on Earth using simulators at NASA's Dryden (now Armstrong) Flight Research Center in California and at NASA's Langley Research Center in Virginia. The enormous Saturn V rocket was a marvel of complexity. Its first stage was developed by NASA's Marshall Space Flight Center in Alabama. The upper-stage development was managed by the Lewis Flight Propulsion Center, now known as NASA's Glenn Research Center, in Ohio in partnership with North American Aviation and Douglas Aircraft Corporation, while Boeing integrated the whole vehicle. The engines were tested at what is now NASA's Stennis Space Center in Mississippi, and the rocket was transported in pieces by water for assembly at Cape Kennedy, now NASA's Kennedy Space Center, in Florida. As the Saturn V was being developed and tested, NASA also developed a smaller, interim vehicle known as the Saturn I and started using it to test Apollo hardware. A Saturn I first flew the Apollo command module design in 1964.

Unfortunately, one crewed test of the Apollo command module turned tragic in February 1967, when a fire erupted in the capsule and killed all three astronauts who had been designated as the prime crew for what became known as Apollo 1. The command module design was altered in response, delaying the first crewed Apollo launch by 21 months. In the meantime, NASA flew several uncrewed Apollo missions to test the Saturn V. The first crewed Apollo launch became Apollo 7, flown on a Saturn IB, and proved that the redesigned command module would support its crew while remaining in Earth orbit. Next, Earth-Moon trajectories were calculated for this large capsule, and the Saturn V powered Apollo 8 set off for the Moon, proving that the calculations were accurate, orbiting the Moon was feasible and a safe return to Earth was possible. Apollo 8 also provided the first TV broadcast from lunar orbit. The next few Apollo missions further proved the technology and allowed humans to practice procedures that would be needed for an eventual Moon landing.

On July 16, 1969, a Saturn V rocket launched three astronauts to the Moon on Apollo 11 from Cape Kennedy. The Apollo 11 spacecraft had three parts: a command module, called "Columbia," with a cabin for the three astronauts; a service module that provided propulsion, electricity, oxygen and water; and a lunar module, "Eagle," that provided descent to the lunar surface and ascent back to the command and service modules.

Collage of three images showing the lunar module during its descent to the Moon, on the lunar surface and during its ascent.

In this image collage, the Apollo 11 lunar module is shown on its descent to the Moon (left), on the lunar surface as Buzz Aldrin descends the stairs (middle), and on its ascent back to the command module (right). Image credit: NASA | › View full image collection

On July 20, while astronaut and command module pilot Michael Collins orbited the Moon, Neil Armstrong and Buzz Aldrin landed Eagle on the Moon and set foot on the surface, accomplishing a first for humankind. They collected regolith (surface "dirt") and rock samples, set up experiments, planted an American flag and left behind medallions honoring the Apollo 1 crew and a plaque that read, "We came in peace for all mankind."

Collage of images showing Buzz Aldrin doing various activities on the Moon.

This collage of images from the Apollo 11 Moon landing shows Buzz Aldrin posing for a photo on the Moon (left), and setting up the solar wind and seismic experiments (middle). The image on the right shows the plaque the team placed on Moon to commemorate the historic event. Image credit: NASA | › View full image collection

After 21.5 hours on the lunar surface, Armstrong and Aldrin rejoined Collins in the Columbia command module and, on July 21, headed back to Earth. On July 24, after jettisoning the service module, Columbia entered Earth's atmosphere. With its heat shield facing forward to protect the astronauts from the extreme friction heating outside the capsule, the craft slowed and a series of parachutes deployed. The module splashed down in the South Pacific Ocean, 380 kilometers (210 nautical miles) south of Johnston Atoll. Because scientists were uncertain about contamination from the Moon, the astronauts donned biological-isolation garments delivered by divers from the recovery ship, the aircraft carrier the USS Hornet. The astronauts boarded a life raft and then the USS Hornet, where the outside of their biological-isolation suits were washed down with disinfectant. To be sure no contamination was brought back to Earth from the Moon, the astronauts were quarantined until Aug. 10, at which point scientists determined the risk was low that biological contaminants or microbes had returned with the astronauts. Columbia was also disinfected and is now part of the National Air and Space Museum in Washington, D.C.

On the left, a capsule floats in the ocean while astronauts sit in a raft in a gray suits. On the right, the three astronauts smile while looking out of a small window and while Nixon faces them with a microphone in front of him.

These side-by-side images show the Apollo 11 astronauts leaving the capsule in their biological isolation garments after successfully splashing down in the South Pacific Ocean (left). At right, President Richard M. Nixon welcomes the Apollo 11 astronauts, (left to right) Neil A. Armstrong, Michael Collins and Buzz Aldrin, while they peer through the window of the Mobile Quarantine Facility aboard the USS Hornet. Image credit: NASA | › View full image collection

The Apollo program continued with six more missions to the Moon over the next three years. Astronauts placed seismometers to measure "moonquakes" and other science instruments on the lunar surface, performed science experiments, drove a carlike moon buggy on the surface, planted additional flags and returned more lunar samples to Earth for study.

Why It's Important

Apollo started out as a demonstration of America's technological, economic and political prowess, which it accomplished with the first Moon landing. But the Apollo missions accomplished even more in the realm of science and engineering.

Some of the earliest beneficiaries of Apollo research were Earth scientists. The Apollo 7 and 9 missions, which stayed in Earth orbit, took photographs of Earth in different wavelengths of light, highlighting things that might not be seen on the ground, like diseased trees and crops. This research led directly to the joint NASA-U.S. Geological Survey Landsat program, which has been studying Earth's resources from space for more than 45 years.

Samples returned from the Moon continue to be studied by scientists around the world. As new tools and techniques are developed, scientists can learn even more about our Moon, discovering clues to our planet's origins and the formation of the solar system. Additionally, educators can be certified to borrow lunar samples for use in their classrooms.

The Apollo 11 astronauts crowd around a lunar sample contained in a protective case.

The Apollo 11 astronauts take a closer look at a sample they brought back from the Moon. Image credit: NASA | › View full image collection

Perhaps the most important scientific finding came from comparing similarities in the composition of lunar and terrestrial rocks and then noting differences in the amount of specific substances. This suggested a new theory of the Moon's formation: that it accreted from debris ejected from Earth by a collision with a Mars-size object early in our planet's 4.5-billion-year history.

The 12 astronauts who walked on the Moon are the best-known faces of the Apollo program, but in numbers, they were also the smallest part of the program. About 400,000 men and women worked on Apollo, building the vehicles, calculating trajectories, even making and packing food for the crews. Many of them worked on solving a deceptively simple question: "How do we guide astronauts to the Moon and back safely?" Some built the spacecraft to carry humans to the Moon, enable surface operations and safely return astronauts to Earth. Others built the rockets that would launch these advanced spacecraft. In doing all this, NASA engineers and scientists helped lead the computing revolution from transistors to integrated circuits, the forebears to the microchip. An integrated circuit – a miniaturized electronic circuit that is used in nearly all electronic equipment today – is lighter weight, smaller and able to function on less power than the older transistors and capacitors. To suit the needs of the space capsule, NASA developed integrated circuits for use in the capsule's onboard computers. Additionally, computing advancements provided NASA with software that worked exactly as it was supposed to every time. That software lead to the development of the systems used today in retail credit-card swipe devices.

Some lesser-known benefits of the Apollo program include the technologies that commercial industries would then further advance to benefit humans right here on Earth. These "spinoffs" include technology that improved kidney dialysis, modernized athletic shoes, improved home insulation, advanced commercial and residential water filtration, and developed the freeze-drying technique for preserving foods.

Apollo was succeeded by missions that have continued to build a human presence in space and advance technologies on Earth. Hardware developed for Apollo was used to build America's first Earth-orbiting space station, Skylab. After Skylab, during the Apollo-Soyuz test project, American and Soviet spacecraft docked together, laying the groundwork for international cooperation in human spaceflight. American astronauts and Soviet cosmonauts worked together aboard the Soviet space station Mir, performing science experiments and learning about long-term space travel's effects on the human body. Eventually, the U.S. and Russia, along with 13 other nations, partnered to build and operate the International Space Station, a world-class science laboratory orbiting 400 kilometers (250 miles) above Earth, making a complete orbit every 90 minutes.

Graphic showing a possible configuration for the future lunar gateway

Although the configuration is not final, this infographic shows the current lineup of parts comprising the lunar Gateway. Image credit: NASA | › Full image and caption

And the innovations continue today. NASA is planning the Artemis mission to put humans on the Moon again in 2024 with innovative new technologies and the intent of establishing a permanent human presence. Working in tandem with commercial and international partners, NASA will develop the Space Launch System launch vehicle, Orion crew capsule, a new lunar lander and other operations hardware. The lunar Gateway – a small spaceship that will orbit the Moon and include living quarters for astronauts, a lab for science, and research and ports for visiting spacecraft – will provide access to more of the lunar surface than ever before. While at the Moon, astronauts will research ways to use lunar resources for survival and further technological development. The lessons and discoveries from Artemis will eventually pave a path for a future human mission to Mars.

Teach It

Use these standards-aligned lessons to help students learn more about Earth's only natural satellite:

As students head out for the summer, get them excited to learn more about the Moon and human exploration using these student projects:

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TAGS: K-12 Education, Teachers, Educators, Classroom, Engineering, Science, Students, Projects, Moon, Apollo, Summer

  • Ota Lutz

A glowing, orange ring outlines a black hole.

In the News

Accomplishing what was previously thought to be impossible, a team of international astronomers has captured an image of a black hole’s silhouette. Evidence of the existence of black holes – mysterious places in space where nothing, not even light, can escape – has existed for quite some time, and astronomers have long observed the effects on the surroundings of these phenomena. In the popular imagination, it was thought that capturing an image of a black hole was impossible because an image of something from which no light can escape would appear completely black. For scientists, the challenge was how, from thousands or even millions of light-years away, to capture an image of the hot, glowing gas falling into a black hole. An ambitious team of international astronomers and computer scientists has managed to accomplish both. Working for well over a decade to achieve the feat, the team improved upon an existing radio astronomy technique for high-resolution imaging and used it to detect the silhouette of a black hole – outlined by the glowing gas that surrounds its event horizon, the precipice beyond which light cannot escape. Learning about these mysterious structures can help students understand gravity and the dynamic nature of our universe, all while sharpening their math skills.

How They Did It

Though scientists had theorized they could image black holes by capturing their silhouettes against their glowing surroundings, the ability to image an object so distant still eluded them. A team formed to take on the challenge, creating a network of telescopes known as the Event Horizon Telescope, or the EHT. They set out to capture an image of a black hole by improving upon a technique that allows for the imaging of far-away objects, known as Very Long Baseline Interferometry, or VLBI.

Telescopes of all types are used to see distant objects. The larger the diameter, or aperture, of the telescope, the greater its ability to gather more light and the higher its resolution (or ability to image fine details). To see details in objects that are far away and appear small and dim from Earth, we need to gather as much light as possible with very high resolution, so we need to use a telescope with a large aperture.

That’s why the VLBI technique was essential to capturing the black hole image. VLBI works by creating an array of smaller telescopes that can be synchronized to focus on the same object at the same time and act as a giant virtual telescope. In some cases, the smaller telescopes are also an array of multiple telescopes. This technique has been used to track spacecraft and to image distant cosmic radio sources, such as quasars.

More than a dozen antennas pointing forward sit on barren land surrounded by red and blue-purple mountains in the distance.

Making up one piece of the EHT array of telescopes, the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile has 66 high-precision antennas. Image credit: NRAO/AUI/NSF | + Expand image

The aperture of a giant virtual telescope such as the Event Horizon Telescope is as large as the distance between the two farthest-apart telescope stations – for the EHT, those two stations are at the South Pole and in Spain, creating an aperture that’s nearly the same as the diameter of Earth. Each telescope in the array focuses on the target, in this case the black hole, and collects data from its location on Earth, providing a portion of the EHT’s full view. The more telescopes in the array that are widely spaced, the better the image resolution.

This video shows the global network of radio telescopes in the EHT array that performed observations of the black hole in the galaxy M87. Credit: C. Fromm and L. Rezzolla (Goethe University Frankfurt)/Black Hole Cam/EHT Collaboration | Watch on YouTube

To test VLBI for imaging a black hole and a number of computer algorithms for sorting and synchronizing data, the Event Horizon Telescope team decided on two targets, each offering unique challenges.

The closest supermassive black hole to Earth, Sagittarius A*, interested the team because it is in our galactic backyard – at the center of our Milky Way galaxy, 26,000 light-years (156 quadrillion miles) away. (An asterisk is the astronomical standard for denoting a black hole.) Though not the only black hole in our galaxy, it is the black hole that appears largest from Earth. But its location in the same galaxy as Earth meant the team would have to look through “pollution” caused by stars and dust to image it, meaning there would be more data to filter out when processing the image. Nevertheless, because of the black hole’s local interest and relatively large size, the EHT team chose Sagittarius A* as one of its two targets.

An image showing a smattering of orange stars against the black backdrop of space with a small black circle in the middle and a rectangle identifying the location of the M87 black hole.

A close-up image of the core of the M87 galaxy, imaged by the Chandra X-ray Observatory. Image credit: NASA/CXC/Villanova University/J. Neilsen | + Expand image

A blue jet extends from a bright yellow point surrounded by smaller yellow stars.

This image from NASA's Hubble Space Telescope shows a jet of subatomic particles streaming from the center of M87*. Image credits: NASA and the Hubble Heritage Team (STScI/AURA) | + Expand image

The second target was the supermassive black hole M87*. One of the largest known supermassive black holes, M87* is located at the center of the gargantuan elliptical galaxy Messier 87, or M87, 53 million light-years (318 quintillion miles) away. Substantially more massive than Sagittarius A*, which contains 4 million solar masses, M87* contains 6.5 billion solar masses. One solar mass is equivalent to the mass of our Sun, approximately 2x10^30 kilograms. In addition to its size, M87* interested scientists because, unlike Sagittarius A*, it is an active black hole, with matter falling into it and spewing out in the form of jets of particles that are accelerated to velocities near the speed of light. But its distance made it even more of a challenge to capture than the relatively local Sagittarius A*. As described by Katie Bouman, a computer scientist with the EHT who led development of one of the algorithms used to sort telescope data during the processing of the historic image, it’s akin to capturing an image of an orange on the surface of the Moon.

By 2017, the EHT was a collaboration of eight sites around the world – and more have been added since then. Before the team could begin collecting data, they had to find a time when the weather was likely to be conducive to telescope viewing at every location. For M87*, the team tried for good weather in April 2017 and, of the 10 days chosen for observation, a whopping four days were clear at all eight sites!

Each telescope used for the EHT had to be highly synchronized with the others to within a fraction of a millimeter using an atomic clock locked onto a GPS time standard. This degree of precision makes the EHT capable of resolving objects about 4,000 times better than the Hubble Space Telescope. As each telescope acquired data from the target black hole, the digitized data and time stamp were recorded on computer disk media. Gathering data for four days around the world gave the team a substantial amount of data to process. The recorded media were then physically transported to a central location because the amount of data, around 5 petabytes, exceeds what the current internet speeds can handle. At this central location, data from all eight sites were synchronized using the time stamps and combined to create a composite set of images, revealing the never-before-seen silhouette of M87*’s event horizon. The team is also working on generating an image of Sagittarius A* from additional observations made by the EHT.

This zoom video starts with a view of the ALMA telescope array in Chile and zooms in on the heart of M87, showing successively more detailed observations and culminating in the first direct visual evidence of a supermassive black hole’s silhouette. Credit: ESO/L. Calçada, Digitized Sky Survey 2, ESA/Hubble, RadioAstron, De Gasperin et al., Kim et al., EHT Collaboration. Music: Niklas Falcke | Watch on YouTube

As more telescopes are added and the rotation of Earth is factored in, more of the image can be resolved, and we can expect future images to be higher resolution. But we might never have a complete picture, as Katie Bouman explains here (under “Imaging a Black Hole”).

To complement the EHT findings, several NASA spacecraft were part of a large effort to observe the black hole using different wavelengths of light. As part of this effort, NASA’s Chandra X-ray Observatory, Nuclear Spectroscopic Telescope Array (NuSTAR) and Neil Gehrels Swift Observatory space telescope missions – all designed to detect different varieties of X-ray light – turned their gaze to the M87 black hole around the same time as the EHT in April 2017. NASA’s Fermi Gamma-ray Space Telescope was also watching for changes in gamma-ray light from M87* during the EHT observations. If the EHT observed changes in the structure of the black hole’s environment, data from these missions and other telescopes could be used to help figure out what was going on.

Though NASA observations did not directly trace out the historic image, astronomers used data from Chandra and NuSTAR satellites to measure the X-ray brightness of M87*’s jet. Scientists used this information to compare their models of the jet and disk around the black hole with the EHT observations. Other insights may come as researchers continue to pore over these data.

Why It's Important

Learning about mysterious structures in the universe provides insight into physics and allows us to test observation methods and theories, such as Einstein’s theory of general relativity. Massive objects deform spacetime in their vicinity, and although the theory of general relativity has directly been proven accurate for smaller-mass objects, such as Earth and the Sun, the theory has not yet been directly proven for black holes and other regions containing dense matter.

One of the main results of the EHT black hole imaging project is a more direct calculation of a black hole’s mass than ever before. Using the EHT, scientists were able to directly observe and measure the radius of M87*’s event horizon, or its Schwarzschild radius, and compute the black hole’s mass. That estimate was close to the one derived from a method that uses the motion of orbiting stars – thus validating it as a method of mass estimation.

The size and shape of a black hole, which depend on its mass and spin, can be predicted from general relativity equations. General relativity predicts that this silhouette would be roughly circular, but other theories of gravity predict slightly different shapes. The image of M87* shows a circular silhouette, thus lending credibility to Einstein’s theory of general relativity near black holes.

An illustration of a black hole surrounded by a bright, colorful swirl of material. Text describes each part of the black hole and its surroundings.

This artist’s impression depicts a rapidly spinning supermassive black hole surrounded by an accretion disc. Image credit: ESO | + Expand image

The data also offer some insight into the formation and behavior of black hole structures, such as the accretion disk that feeds matter into the black hole and plasma jets that emanate from its center. Scientists have hypothesized about how an accretion disk forms, but they’ve never been able to test their theories with direct observation until now. Scientists are also curious about the mechanism by which some supermassive black holes emit enormous jets of particles traveling at near light-speed.

These questions and others will be answered as more data is acquired by the EHT and synthesized in computer algorithms. Be sure to stay tuned for that and the next expected image of a black hole – our Milky Way’s own Sagittarius A*.

Teach It

Capture your students’ enthusiasm about black holes by challenging them to solve these standards-aligned math problems.

Model black-hole interaction with this NGSS-aligned lesson:

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Check out these related resources for students from NASA’s Space Place

TAGS: Black Hole, Teachable Moments, Science, K-12 Education, Teachers, Educators

  • Ota Lutz

In the News

This summer, a global dust storm encircled Mars, blocking much of the vital solar energy that NASA’s Opportunity rover needs to survive. After months of listening for a signal, the agency has declared that the longest-lived rover to explore Mars has come to the end of its mission. Originally slated for a three-month mission, the Opportunity rover lived a whopping 14.5 years on Mars. Opportunity beat the odds many times while exploring the Red Planet, returning an abundance of scientific data that paved the way for future exploration.

Scientists and engineers are celebrating this unprecedented mission success, still analyzing data collected during the past decade and a half and applying lessons learned to the design of future spacecraft. For teachers, this historic mission provides lessons in engineering design, troubleshooting and scientific discovery.

How They Did It

Launched in 2003 and landed in early 2004, the twin Mars Exploration Rovers, Spirit and Opportunity, were the second spacecraft of their kind to land on our neighboring planet.

Preceded by the small Sojourner rover in 1997, Spirit and Opportunity were substantially larger, weighing about 400 pounds, or 185 kilograms, on Earth (150 pounds, or 70 kilograms, on Mars) and standing about 5 feet tall. The solar-powered rovers were designed for a mission lasting 90 sols, or Mars days, during which they would look for evidence of water on the seemingly barren planet.

Dust in the Wind

Scientists and engineers always hope a spacecraft will outlive its designed lifetime, and the Mars Exploration Rovers did not disappoint. Engineers at NASA’s Jet Propulsion Laboratory in Pasadena, California, expected the lifetime of these sun-powered robots to be limited by dust accumulating on the rovers’ solar panels. As expected, power input to the rovers slowly decreased as dust settled on the panels and blocked some of the incoming sunlight. However, the panels were “cleaned” accidentally when seasonal winds blew off the dust. Several times during the mission, power levels were restored to pre-dusty conditions. Because of these events, the rovers were able to continue their exploration much longer than expected with enough power to continue running all of their instruments.

Side-by-side images of Opportunity on Mars, showing dust on its solar panels and then relatively clean solar panels

A self-portrait of NASA's Mars Exploration Rover Opportunity taken in late March 2014 (right) shows that much of the dust on the rover's solar arrays was removed since a similar portrait from January 2014 (left). Image Credit: NASA/JPL-Caltech/Cornell Univ./Arizona State Univ. | › Full image and caption

Terrestrial Twin

To troubleshoot and overcome challenges during the rovers’ long mission, engineers would perform tests on a duplicate model of the spacecraft, which remained on Earth for just this purpose. One such instance was in 2005, when Opportunity got stuck in the sand. Its right front wheel dug into loose sand, reaching to just below its axle. Engineers and scientists worked for five weeks to free Opportunity, first using images and spectroscopy obtained by the rover’s instruments to recreate the sand trap on Earth and then placing the test rover in the exact same position as Opportunity. The team eventually found a way to get the test rover out of the sand trap. Engineers tested their commands repeatedly with consistent results, giving them confidence in their solution. The same commands were relayed to Opportunity through NASA’s Deep Space Network, and the patient rover turned its stuck wheel just the right amount and backed out of the trap that had ensnared it for over a month, enabling the mission to continue.

Engineers test moves on a model of the Opportunity rover in the In-Situ Instrument Laboratory at JPL

Inside the In-Situ Instrument Laboratory at JPL, rover engineers check how a test rover moves in material chosen to simulate some difficult Mars driving conditions. | › Full image and caption

A few years later, in 2009, Spirit wasn’t as lucky. Having already sustained some wheel problems, Spirit got stuck on a slope in a position that would not be favorable for the Martian winter. Engineers were not able to free Spirit before winter took hold, denying the rover adequate sunlight for power. Its mission officially ended in 2011. Meanwhile, despite a troubled shoulder joint on its robotic arm that first started showing wear in 2006, Opportunity continued exploring the Red Planet. It wasn’t until a dust storm completely enveloped Mars in the summer of 2018 that Opportunity finally succumbed to the elements.

The Final Act

animation showing a dust storm moving across Mars

This set of images from NASA’s Mars Reconnaissance Orbiter (MRO) shows a giant dust storm building up on Mars in 2018, with rovers on the surface indicated as icons. Image credit: NASA/JPL-Caltech/MSSS | › Full image and caption

simulated views of the sun as the 2018 dust storm darkened from Opportunity's perspective on Mars

This series of images shows simulated views of a darkening Martian sky blotting out the Sun from NASA’s Opportunity rover’s point of view in the 2018 global dust storm. Each frame corresponds to a tau value, or measure of opacity: 1, 3, 5, 7, 9, 11. Image credit: NASA/JPL-Caltech/TAMU | › Full image and caption

Dust storm season on Mars can be treacherous for solar-powered rovers because if they are in the path of the dust storm, their access to sunlight can be obstructed for months on end, longer than their batteries can sustain them. Though several dust storms occurred on Mars during the reign of the Mars Exploration Rovers, 2018 brought a large, thick dust storm that covered the entire globe and shrouded Opportunity’s access to sunlight for four months. Only the caldera of Olympus Mons, the largest known volcano in the solar system, peeked out above the dust.

The transparency or “thickness” of the dust in Mars’ atmosphere is denoted by the Greek letter tau. The higher the tau, the less sunlight is available to charge a surface spacecraft’s batteries. An average tau for Opportunity’s location is 0.5. The tau at the peak of the 2018 dust storm was 10.8. This thick dust was imaged and measured by the Curiosity Mars rover on the opposite side of the planet. (Curiosity is powered by a radioisotope thermoelectric generator.)

Since the last communication with Opportunity on June 10, 2018, NASA has sent more than 1,000 commands to the rover that have gone unanswered. Each of these commands was an attempt to get Opportunity to send back a signal saying it was alive. A last-ditch effort to reset the rover’s mission clock was met with silence.

Why It’s Important

The Mars Exploration Rovers were designed to give a human-height perspective of Mars, using panoramic cameras approximately 5 feet off the surface, while their science instruments investigated Mars’ surface geology for signs of water. Spirit and Opportunity returned more than 340,000 raw images conveying the beauty of Mars and leading to scientific discoveries. The rovers brought Mars into classrooms and living rooms around the world. From curious geologic formations to dune fields, dust devils and even their own tracks on the surface of the Red Planet, the rovers showed us Mars in a way we had never seen it before.

tracks on Mars with a patch of white soil showing

This mosaic shows an area of disturbed soil made by the Spirit rover's stuck right front wheel. The trench exposed a patch of nearly pure silica, with the composition of opal. Image credit: NASA/JPL-Caltech/Cornell | › Full image and caption

Mineral vein on the surface of Mars

This color view of a mineral vein was taken by the Mars rover Opportunity on Nov. 7, 2011. Image credit: NASA/JPL-Caltech/Cornell/ASU | › Full image and caption

The rovers discovered that Mars was once a warmer, wetter world than it is today and was potentially able to support microbial life. Opportunity landed in a crater and almost immediately discovered deposits of hematite, which is a mineral known to typically form in the presence of water. During its travels across the Mars surface, Spirit found rocks rich in magnesium and iron carbonates that likely formed when Mars was warm and wet, and sustained a near-neutral pH environment hospitable to life. At one point, while dragging its malfunctioning wheel, Spirit excavated 90 percent pure silica lurking just below the sandy surface. On Earth, this sort of silica usually exists in hot springs or hot steam vents, where life as we know it often finds a happy home. Later in its mission, near the rim of Endeavor crater, Opportunity found bright-colored veins of gypsum in the rocks. These veins likely formed when water flowed through underground fractures in the rocks, leaving calcium behind. All of these discoveries lead scientists to believe that Mars was once more hospitable to life than it is today, and they laid the groundwork for future exploration.

Imagery from the Mars Reconnaissance Orbiter and Mars Odyssey, both orbiting the Red Planet, has been combined with surface views and data from the Mars Exploration Rovers for an unprecedented understanding of the planet’s geology and environment.

Not only did Spirit and Opportunity add to our understanding of Mars, but also the rovers set the stage for future exploration. Following in their tracks, the Curiosity rover landed in 2012 and is still active, investigating the planet’s surface chemistry and geology, and confirming the presence of past water. Launching in 2020 is the next Mars rover, currently named Mars 2020. Mars 2020 will be able to analyze soil samples for signs of past microbial life. It will carry a drill that can collect samples of interesting rocks and soils, and set them aside in a cache on the surface of Mars. In the future, those samples could be retrieved and returned to Earth by another mission. Mars 2020 will also do preliminary research for future human missions to the Red Planet, including testing a method of producing oxygen from Mars’ atmosphere.

It’s thanks to three generations of surface-exploring rovers coupled with the knowledge obtained by orbiters and stationary landers that we have a deeper understanding of the Red Planet’s geologic history and can continue to explore Mars in new and exciting ways.

Teach It

Use these standards-aligned lessons and related activities to get students doing engineering, troubleshooting and scientific discovery just like NASA scientists and engineers!

Explore More

Try these related resources for students from NASA’s Space Place

TAGS: K-12 Education, Teachers, Educators, Students, Opportunity, Mars rover, Rovers, Mars, Lessons, Activities, Missions

  • Ota Lutz

The supermoon lunar eclipse captured as it moved over NASA’s Glenn Research Center on September 27, 2015.

In the News

Looking up at the Moon can create a sense of awe at any time, but those who do so on the evening of January 20 will be treated to the only total lunar eclipse of 2019. Visible for its entirety in North and South America, this eclipse is being referred to by some as a super blood moon – “super” because the Moon will be closest to Earth in its orbit during the full moon (more on supermoons here) and “blood" because the total lunar eclipse will turn the Moon a reddish hue (more on that below). This is a great opportunity for students to observe the Moon – and for teachers to make connections to in-class science content.

How It Works

Eclipses can occur when the Sun, the Moon and Earth align. Lunar eclipses can happen only during a full moon, when the Moon and the Sun are on opposite sides of Earth. At that point, the Moon can move into the shadow cast by Earth, resulting in a lunar eclipse. However, most of the time, the Moon’s slightly tilted orbit brings it above or below Earth’s shadow.

Watch on YouTube

The time period when the Moon, Earth and the Sun are lined up and on the same plane – allowing for the Moon to pass through Earth’s shadow – is called an eclipse season. Eclipse seasons last about 34 days and occur just shy of every six months. When a full moon occurs during an eclipse season, the Moon travels through Earth’s shadow, creating a lunar eclipse.

Graphic showing the alignment of the Sun, Earth and Moon when a full moon occurs during an eclipse season versus a non-eclipse season

When a full moon occurs during an eclipse season, the Moon travels through Earth's shadow, creating a lunar eclipse. Credit: NASA/JPL-Caltech | + Enlarge image

Unlike solar eclipses, which require special glasses to view and can be seen only for a few short minutes in a very limited area, a total lunar eclipse can be seen for about an hour by anyone on the nighttime side of Earth – as long as skies are clear.

What to Expect

The Moon passes through two distinct parts of Earth’s shadow during a lunar eclipse. The outer part of the cone-shaped shadow is called the penumbra. The penumbra is less dark than the inner part of the shadow because it’s penetrated by some sunlight. (You have probably noticed that some shadows on the ground are darker than others, depending on how much outside light enters the shadow; the same is true for the outer part of Earth’s shadow.) The inner part of the shadow, known as the umbra, is much darker because Earth blocks additional sunlight from entering the umbra.

At 6:36 p.m. PST (9:36 p.m. EST) on January 20, the edge of the Moon will begin entering the penumbra. The Moon will dim very slightly for the next 57 minutes as it moves deeper into the penumbra. Because this part of Earth’s shadow is not fully dark, you may notice only some dim shading (if anything at all) on the Moon near the end of this part of the eclipse.

Graphic showing the positions of the Moon, Earth and Sun during a partial lunar eclipse

During a total lunar eclipse, the Moon first enters into the penumbra, or the outer part of Earth's shadow, where the shadow is still penetrated by some sunlight. Credit: NASA | + Enlarge image

At 7:33 p.m. PST (10:33 p.m. EST), the edge of the Moon will begin entering the umbra. As the Moon moves into the darker shadow, significant darkening of the Moon will be noticeable. Some say that during this part of the eclipse, the Moon looks as if it has had a bite taken out of it. That “bite” gets bigger and bigger as the Moon moves deeper into the shadow.

The Moon as seen during a partial lunar eclipse

As the Moon starts to enter into the umbra, the inner and darker part of Earth's shadow, it appears as if a bite has been taken out of the Moon. This "bite" will grow until the Moon has entered fully into the umbra. Credit: NASA | + Enlarge image

At 8:41 p.m. PST (11:41 p.m. EST), the Moon will be completely inside the umbra, marking the beginning of the total lunar eclipse. The moment of greatest eclipse, when the Moon is halfway through the umbra, occurs at 9:12 p.m. PST (12:12 a.m. EST).

Graphic showing the Moon inside the umbra

The total lunar eclipse starts once the moon is completely inside the umbra. And the moment of greatest eclipse happens with the Moon is halfway through the umbra as shown in this graphic. Credit: NASA | + Enlarge image

As the Moon moves completely into the umbra, something interesting happens: The Moon begins to turn reddish-orange. The reason for this phenomenon? Earth’s atmosphere. As sunlight passes through it, the small molecules that make up our atmosphere scatter blue light, which is why the sky appears blue. This leaves behind mostly red light that bends, or refracts, into Earth’s shadow. We can see the red light during an eclipse as it falls onto the Moon in Earth’s shadow. This same effect is what gives sunrises and sunsets a reddish-orange color.

The Moon as seen during a total lunar eclipse at the point of greatest eclipse

As the Moon moves completely into the umbra, it turns a reddish-orange color. Credit: NASA | + Enlarge image

A variety of factors affect the appearance of the Moon during a total lunar eclipse. Clouds, dust, ash, photochemical droplets and organic material in the atmosphere can change how much light is refracted into the umbra. Additionally, the January 2019 lunar eclipse takes place when the full moon is at or near the closest point in its orbit to Earth – a time popularly known as a supermoon. This means the Moon is deeper inside the umbra shadow and therefore may appear darker. The potential for variation provides a great opportunity for students to observe and classify the lunar eclipse based on its brightness. Details can be found in the “Teach It” section below.

At 9:43 p.m. PST (12:43 a.m. EST), the edge of the Moon will begin exiting the umbra and moving into the opposite side of the penumbra. This marks the end of the total lunar eclipse.

At 10:50 p.m. PST (1:50 a.m. EST), the Moon will be completely outside the umbra. It will continue moving out of the penumbra until the eclipse ends at 11:48 p.m (2:48 a.m. EST).

What if it’s cloudy where you live? Winter eclipses always bring with them the risk of poor viewing conditions. If your view of the Moon is obscured by the weather, explore options for watching the eclipse online, such as the Time and Date live stream.

Why It’s Important

Lunar eclipses have long played an important role in understanding Earth and its motions in space.

In ancient Greece, Aristotle noted that the shadows on the Moon during lunar eclipses were round, regardless of where an observer saw them. He realized that only if Earth were a spheroid would its shadows be round – a revelation that he and others had many centuries before the first ships sailed around the world.

Earth wobbles on its axis like a spinning top that’s about to fall over, a phenomenon called precession. Earth completes one wobble, or precession cycle, over the course of 26,000 years. Greek astronomer Hipparchus made this discovery by comparing the position of stars relative to the Sun during a lunar eclipse to those recorded hundreds of years earlier. A lunar eclipse allowed him to see the stars and know exactly where the Sun was for comparison – directly opposite the Moon. If Earth didn’t wobble, the stars would appear to be in the same place they were hundreds of years earlier. When Hipparchus saw that the stars’ positions had indeed moved, he knew that Earth must wobble on its axis!

Lunar eclipses are also used for modern-day science investigations. Astronomers have used ancient eclipse records and compared them with computer simulations. These comparisons helped scientists determine the rate at which Earth’s rotation is slowing.

Teach It

Ask students to observe the lunar eclipse and evaluate the Moon’s brightness using the Danjon Scale of Lunar Eclipse Brightness. The Danjon scale illustrates the range of colors and brightness the Moon can take on during a total lunar eclipse, and it’s a tool observers can use to characterize the appearance of an eclipse. View the lesson guide below. After the eclipse, have students compare and justify their evaluations of the eclipse.

Use these standards-aligned lessons and related activities to get your students excited about the eclipse, Moon phases and Moon observations:

TAGS: Lunar Eclipse, Moon, Teachers, Educators, K-12 Education, Astronomy

  • Lyle Tavernier

This year, Montana took a leap toward bringing the Next Generation Science Standards to the state’s K-12 teachers by kicking off its first state science teachers conference. This pilot meeting brought together more than 100 of the state’s top educators, who shared best practices with the teaching community. One of these experts was Natalia Kolnik, a native of Bozeman, Montana, who leads education programs at the Children’s Museum of Bozeman. Her program stood out among attendees (including us) not just because her programs involved designing missions to Mars, but also because of her commitment to making connections with scientists in the area. We caught up with Kolnik to learn more about how, with the help of local companies – including some that have produced components for JPL missions – she turned a JPL lesson into an exploration of careers in STEM.

Mars lesson graphics

Mission to Mars Unit

In this 19-lesson, standards-aligned unit, students learn about Mars, design a mission to explore the planet, build and test model spacecraft and components, and engage in scientific exploration.

Tell me a bit about yourself and your teaching background.

I am the director of education at the Children’s Museum of Bozeman and its STEAMlab in Bozeman, Montana. I’ve been the director there for six months, so I teach various lessons in a couple different programs for students ages 6 through 12.

I was born and raised in Bozeman and earned bachelor’s degrees in journalism and fine arts from the University of Montana, Missoula. I also have a master’s in education from the University of Oxford.

I’ve been teaching formal education classes to different grade levels for the last 13 years in various places around the world, including South Korea and Kosovo.

What unique challenges do you face engaging or addressing the needs of your students?

Teaching at the Children’s Museum is wonderful and challenging for the same reason: the diversity of the students. It’s like an educational casserole. Our STEAMlab programs are primarily filled with 6- to 12-year-old students who come to us from different school districts and different towns in Montana – or even from different states and countries. During the school year, they learn in public, private and home-school settings. Since the students come with such a variety of educational backgrounds and are a variety of ages, having them all together in a program, like a summer camp, can be challenging.

However, bringing various age groups together allows students of the same age to not feel left out if one of their age peers already knows the material, since it is likely that several others in the room have not encountered it either. Also, since our activities are hands-on, interactive and incorporate a high-tech element, even if students know the concepts and have done the project or activity before, they are still excited to do it again and help others.

Two kids explore the STEAMlab at the Children's Museum of Bozeman

Two kids explore the STEAMlab at the Children's Museum of Bozeman. | Image courtesy: Children's Museum of Bozeman + Expand image

It can also be tough to work with so many new students, rather than to teach in a classroom setting, in which you’ve had months to develop relationships with the students and establish a classroom rhythm, so students know what is expected. On the other hand, because we run short programs – one day to one week – we have the luxury of flexibility and of letting the content breath. We allow students to take that extra time for exploration, reflection and redesign that might not be possible in a regular classroom setting or time frame.

What NASA/JPL Education lessons have you been using with your students?

JPL has such a wealth of resources. It is so easy to incorporate them into all kinds of STEAMlab programs. For instance, we were able to design and offer a summer camp about Mars in large part because of all of the amazing, up-to-date information available on JPL’s website about Mars missions, the planet and all the new discoveries occurring on a daily basis. Activities such as Imagine Mars allowed students to plan a trip to Mars that would allow them to arrive safely and potentially build a habitat. As part of that lesson, we had the students extend their mission by creating a board game capturing the difficulties that could arise, despite even the best planning.

How did you modify the NASA/JPL Education lessons you used to best serve your specific students?

Being so far from a NASA site means we need to be creative to find connections between our community and careers in science. The support of our local business community is an incredible resource for us to build that bridge. We have one such partnership with the Montana Photonics Industry Alliance, or MPIA. Since the Curiosity Mars rover has laser diodes made by Quantel, a company right here in Bozeman that’s part of MPIA, we were able to help students connect the local with the supra-global.

Students listen to a presentation about Photonics

Student listen to a presentation about Photonics. | Image courtesy: Children's Museum of Bozeman + Expand image

This past semester, volunteers from these photonic companies have been meeting at the museum, brainstorming, planning, designing, redesigning and creating a spectroscope activity to use as one of the museum’s field-trip programs. We used the museum’s Full STEM Ahead summer camp as a pilot test of the activity. The MPIA volunteers found light sources they work with in their jobs (that could be safely viewed by students) to demonstrate the variety of light spectra all around us. Meanwhile, I used the STEAMlab’s 3D printers to print all the end caps for the students’ spectroscopes, which are small devices capable of separating wavelengths of light into individual colors.

We divided students into two age groups to observe how they might interact differently with the activity. For example, while one of the MPIA volunteers talked with half of the students about the photonics industry, ways in which photonic technology is used, and related career pathways in Bozeman, other volunteers led the rest of the students in using and understanding their spectroscopes, observing different lights and colors with their new tools.

How did the activity help you meet your objectives? How did students react to the lesson?

The goal for the STEAMlab is to foster an engaging, fun high-tech space in the museum where students ages 7 and older can be a part of a community of other young tech explorers, inventors and tinkerers. It’s a place to try out all kinds of ideas to fix a problem or build something new, all while reflecting and talking out the design and its challenges with friends and adult mentors nearby. And if something doesn’t work the way they intended, which happens a lot, then they’re encouraged to go ahead and try it again.

I gathered feedback about the spectroscopy activities by asking students a few questions and letting them write and/or draw their answers on sticky notes, with each color representing a different question. Their responses varied depending on age but were overwhelmingly positive. All of the students were able to respond with something they remembered learning that was new to them. And their suggestions were primarily about wanting more time to decorate and experiment with their spectroscopes and wanting to talk to more people who work with lasers.

I heard back from the parents of our student mentors about how their children – who had been a part of the activity as helpers – had come home talking all about lasers, how they now want to pursue a career in photonics and now they point out photonics companies that they drive past every day.

Have a great idea for implementing NASA research in your class or looking to bring NASA science into your classroom? The Educator Professional Development Collaborative, or EPDC, can help. The EPDC at JPL serves educators in the greater Los Angeles area. Contact JPL education specialist Brandon Rodriguez at Note: Due to the popularity of EPDC programs, JPL may not be able to fulfill all requests.

Outside the Southern California area? The EPDC operates in all 50 states. Find an EPDC specialist near you.

The EPDC is managed by Texas State University as part of the NASA Office of Education. A free service for K-12 educators nationwide, the EPDC connects educators with the classroom tools and resources they need to foster students’ passion for careers in STEM and produce the next generation of scientists and engineers.

TAGS: K-12 Education, Informal Education

  • Brandon Rodriguez